New LG Chem RESU Batteries: Smaller, More Powerful And Cheaper Than A Powerwall

powerwall and LG Resu 6.5 to scale

Smaller, cheaper, more powerful. LG Chem’s new batteries look very compelling compared to a Powerwall.

If you are in the market for a home battery and are tempted to buy a Powerwall, then I urge you to also consider the new range of LG Chem batteries announced last week.

Whilst LG have been unable to compete with Elon Musk for mainstream media coverage, the LG Chem RESU, or Residential Energy Storage Unit for the long winded, has been one of the biggest successes in on-grid home energy storage in Australia. While solid figures are hard to come by, it may have been used in almost half of all on-grid home battery installations.

While it was popular, ye olde RESU6.4 is no more. LG Chem has replaced it with something better. And not just with an updated version of itself, but with a whole slew of new RESU.

There are now 5 RESU systems to choose from with nominal capacities ranging from 3.3 to 9.8 kilowatt-hours.  Three of the new RESU use 48 volt DC power:

LG 48v batteries

The new 48V batteries

And two use around 400 volts (just like a Powerwall funnily enough):

LG 400V batteries

LG’s new 400V batteries

The usable capacity of the lower voltage systems is around 90% of their nominal capacity and around 95% for the higher voltage ones.  As they are lithium-ion battery systems, their capacity will gradually decline with use and over time.

The two different voltages allows for a wide range of installation options including DC coupling and AC coupling.  No matter what type of coupling you prefer, you can do it with an LG Chem RESU.  And they are suitable for on-grid or off-grid use.

The 48 volt RESUs have higher power than most comparable battery systems and are lighter and much more compact than the competition.  They are warrantied to retain at least 60% of their nominal capacity for 10 years or until they have stored slightly under 2,500 kilowatt-hours for each kilowatt-hour of nominal capacity.  Taking an estimate of battery degradation into account this is approximately 3,200 cycles.  When cycled once per day it will take around 8 years and 9 months to reach that point.

The New RESUs’ Vital Statistics

In order to save me having to make a table, I have grabbed a screen shots off the new RESUs datasheets.  Here are the vital statistics for the 48 Volt systems:

The vital statistics of the 48 Volt LG Chem RESU battery systems.

The vital statistics of the 48 Volt LG Chem RESU battery systems.

And here is information on the two RESU that LG Chem refers to as 400 volt systems:

The vital statistics of the two 400 volt LG Chem RESU battery systems.

The vital statistics of the two 400 volt LG Chem RESU battery systems.

Indoors Or Outdoors Installation Is Okay

The Enclosure Protection Rating of the RESUs is IP55 which means they are protected against both dust and water. But if dust and water combined their powers to make mud, well, it would be protected against that also. According it its rating it can handle being sprayed with water under moderate pressure from any direction but not immersion.  So if you are going to use it on a submarine, try to remember to install it on the inside.

Maintenance Free

Like most new battery storage systems, apart from keeping them reasonably clean, RESU require no maintenance.

exploded view

If you have an LG Chem battery NEVER do this to it

Round Trip Efficiency

LG Chem gives the round trip efficiency of the 48 volt RESUs as greater than 95%, but states this is only under good conditions.  In real life I would expect its round trip efficiency to be a little under 95%, especially if it is installed outdoors and often exposed to temperatures above 30 degrees or below 15 degrees.

The efficiency of the higher voltage RESU will be lower because their built in DC converter will result in additional losses.  But since the 48 volt RESUs will need DC conversion anyway, either from a multimode inverter or a separate DC converter, overall their efficiencies should be comparable.

Operating Temperature is -10 to 45 Degrees Celsius

One important piece of information missing from the above tables is its operating temperature.  RESUs can function at ambient temperatures from -10 to 45 degrees Celsius.  Ambient simply means the air temperature in the immediate surroundings.  It is possible that some day we may know why battery manufacturers don’t just say, “local air temperature”.

The lower limit is not likely to be a problem for Australians, but it is possible for it to shut down during a severe heatwave.  To prevent it conking out from heat exhaustion, installing RESUs out of direct sunlight is a very good idea.  LG Chem gives its recommended operating temperature as 15-30 degrees, so placing it indoors is probably a good idea and will help improve its efficiency and extend its battery life.

It’s Quiet

The RESUs have no cooling fan and rely on natural convection from its metal case for cooling.  This means they are very quiet, which is useful for indoor installation.

Fire Safety!

LG Chem claim that their method of producing battery packs makes theirs the safest lithium-ion battery on the market.  I am inclined to believe them.  So far, I am not aware of any RESU installed in Australia having safety issues, but since only around 1,000 or so may be installed in Australia at the moment, only time will tell.

If you are the type of fearless daredevil who leaves a charging laptop unattended on a wooden desk covered in papers, then you are clearly a risk taker who is not going to be worried about installing a lithium-ion battery system.  Possibly because they realize how utterly reckless and immune to fear the average Australian is, LG Chem recommends installing RESUs away from flammable materials.

Nominal Battery Capacity

The nominal battery capacity is the total amount of energy the battery can hold.  Because completely draining the battery is bad for its lifespan, the usable storage capacity for the three 48 volt RESUs is limited to around 90% of their nominal capacity and for the two higher voltage RESUs it is around 95%.  This usable storage capacity will decline over time as the battery is used and will also slowly decline even if it isn’t used.  So the moral is, use it or lose it, but using it also causes it to lose it.

Battery Capacity And Names

LG Chem does a good job of matching the names of their RESUs to their nominal capacities 3 times out of 5.

They start off well, as the numbers in the names of the RESU3.3, RESU6.5, and RESU7H all match their nominal storage capacities.  Unfortunately someone must have stamped the names on the RESU10 and RESU10H before they figured out how many battery cells they could actually fit inside them, because they both only have a nominal capacity of 9.8 kilowatt-hours.

This is a surprising oversight given the care LG Chem appears to have taken with the rest of the product.  I suppose it could just be a marketing decision because they decided a RESU10 would sell better than a RESU9.8 but that’s just nuts.  How does forcing me to tell everyone you can’t trust the numbers LG Chem puts on their products help their marketing?

For More Storage Connect Two 48 Volt RESUs

An adapter is available that allows any two 48 volt RESU systems to be connected together.  So if you wanted you could slap together a RESU10 and a RESU3.3.  Although I strongly suggest using the adapter rather than just slapping them against each other.  This means the usable storage capacity available to a household from the new systems will range from 2.9 kilowatt-hours with a single RESU3.3 to 17.6 kilowatt-hours from a doubled up RESU10.

RESUs Are High Power Battery Systems

The new RESUs have a lot of power.  The “Max Power” figures on the datasheet tables above are the amount of continuous power they can supply when new.

For on-grid applications higher power improves the economics of battery storage as households will need to draw on grid power less often during the day when electricity consumption exceeds rooftop solar production.  It also allows households on time-of-use tariffs to more easily use all the available stored energy during peak periods when grid electricity prices are high.

For off-grid applications, higher power allows more appliances to be operated at once without tripping the system.

LG Chem says using RESU at only half their continuous power output level will extend their battery life.  In practice most households are likely to use them at an average well below their continuous power output.

The amount of power a RESU can supply will often be limited by the power conversion device (i.e. battery inverter/hybrid inverter/DC-DC Converter) it is used with.  Some popular battery inverters only allow 2.5 kilowatts of power, which is 83% of a RESU3.3’s continuous power output and 60% of a RESU6.5’s.

RESUs Have Plenty Of Installation Options

There are plenty of options available when it comes to installing RESU.  Currently there are 8 compatible mulitmode inverters available that can be used with the 48 volt RESUs and 2 suitable for use with the 400 volt RESUs.

The 48 volt RESUs could be installed without a compatible inverter by using a DC converter such as the Goodwe GW2500-BP.  This is suitable for a rooftop solar system with a string inverter and panels wired up so they produce under 500 volts.  The GW2500-BP can only provide 2.5 kilowatts of power, so even the smallest RESU can’t be used at full continuous power when installed this way.

The 400 volt RESUs can also be installed without a compatible inverter by using a battery-inverter.  An example of one of these is the Sunny Boy Storage.  This particular battery-inverter will also limit the RESU to 2.5 kilowatts of power.

The Most Compact Battery Systems Available

LG claims the RESUs are the most compact and energy dense battery systems available and I believe them.  The RESU6.5 takes up less space than my microwave oven while only being 12 centimeters thick which makes it very easy to find room to install it.  At 52kg it is not exactly light, but it is lighter per kilowatt-hour than all the other battery systems out there.  Much lighter in some cases.

If you are short of space, a RESU is an excellent choice.  It also makes it easy to install inside which can help extend its life by avoiding high temperatures.  Unless perhaps your house is an oven in the summer.

LG Chem Battery Technology

Lithium-ion battery cells are very thin and are manufactured in long ribbons.  Because enormously broad but extremely thin and thus fragile batteries aren’t very practical, there are three methods used to make them more manageable.

The first is to roll them into  cylinders and this type can be found in power tools, Tesla cars, and laptops1.  Their drawback is whenever you stack cylinders together there will be spaces left between them.

Cells can also be folded into a flat rectangular shape like a long scarf.  This reduces but does not eliminate the amount of dead space.

Unfortunately both rolled and folded cells can distort over time due do expansion and contraction caused by changes in temperature and this can affect their performance.

LG uses the third method, which they call lamination and stacking, where they don’t roll or fold but cut the cells into sheets and stack them flat on top of each other.  This eliminates dead space and minimizes distortion, contributing to energy density and battery life.

Here is an LG Chem video of their batteries being made by robots.  With all that automation, now is clearly not a good time to get a job in a battery factory, despite rapid expansion in capacity.

Warranty And Battery Degradation

No matter how they are made, lithium-ion batteries degrade with use and slowly decay even when not used.  The RESU warranty, while better than some others, reflects this.

The 48 volt RESUs’ warranty promises they will still have at least 60% of their nominal capacity after 10 years or until they have stored a total amount of electricity just under 2,500 kilowatt-hours for every kilowatt-hour of nominal capacity.  This comes to:

  • RESU3.3  8,200 kilowatt-hours
  • RESU6.5  16,100 kilowatt-hours
  • RESU10  24,300 kilowatt-hours.

If your RESU cannot keep its capacity up, then LG will repair or replace it.  If they no longer produce RESUS they have the option of compensating you with cash.  Unfortunately, the amount of money they offer can be pretty insignificant and depends upon the age of your system:

  • 0-2 years:  100% of purchase price
  • 2-3 years:  72% of purchase price
  • 3-4 years:  58% of purchase price
  • 4-5 years: 44% of purchase price
  • 5-6 years:  30% of purchase price
  • 6-7 years:  16% of purchase price
  • 7-8 years:  6% of purchase price
  • 8-9 years:  4% of purchase price
  • 9-10 years:  2% of purchase price
% of purchase price refunded vs. year of failure

Does LG Chem has a very low opinion of its own storage technology once it is more than a few years old?  I mean, I expect energy storage to fall in cost over time, but in nine years’ time you are not going to be able to buy a replacement with just 2% of a RESU’s current price.

Number Of Cycles Until End Of Warranty

A new RESU6.5 can provide 5.9 kilowatt-hours of stored electricity each cycle.  But this capacity will slowly decrease.  Because the 60% of capacity in its warranty is a minimum, I am going to assume that once it has provided the 16,100 kilowatt-hours of storage its warranty covers its capacity will average 65%.

I will also assume the fall in its capacity will be linear.  This means the average cycle will be 5.06 kilowatt-hours.  If the RESU6.5 is cycled once per day it will take 3,180 cycles to reach the end of its warranty.

If it is cycled once per day that comes to under 8 years and 9 months. The number of cycles required to reach the end of warranty for the RESU3.3 and RESU10 are very similar, as is the amount of time if cycled once per day.

LG Resu Price

I have a list of estimated retail prices for the 48 volt RESUs.  I will keep the identity of my source to myself in case they turn out to be wrong, but it is not a shady source.  It is actually a sunny source and so I have confidence in the estimates which, including GST, are:

  • RESU3.3 – $4,400
  • RESU6.5 – $6,600
  • RESU10 – $8,800

As the RESU6.4 was around $7,500 this makes the RESU6.5 about 13% cheaper per kilowatt-hour of nominal storage.

Note this is just the retail price of the battery and not the installed cost, which will be considerably more.  A fully installed RESU6.5 with the ability to be used for back up power during a blackout could easily cost over $14,000.

RESU Cannot Pay For Themselves

Unfortunately like all home batteries, even under ideal circumstances, RESUs cannot pay for themselves when used for on-grid storage.

While battery storage is gradually clawing its way towards breaking even, even under ideal circumstances it can’t manage it yet after the total cost of installation, the foregone solar feed-in tariff, and cost of capital are considered. I will consider each of these to make a very optimistic estimate of the total cost per stored kilowatt-hour for a RESU6.5.

Estimated RESU Lifespan

A RESU6.5 is warrantied to provide 16,100 kilowatt-hours of stored electricity while retaining at least 60% of nominal capacity. If it has 65% capacity by the time it reaches this point and it is cycled once per day, it will take a little under 8 years and nine months to reach the end of its warranty.

I am going to assume the RESU will provide a total of 50% more storage than its warranty covers over its lifetime while losing capacity at the same rate.  This means it will have 57% of its nominal capacity when it finally stops working after a total of nearly 14 years and 10 months after having stored a total of 24,150 kilowatt-hours.

Foregone Feed-in Tariff

If a household stores solar electricity for later use they forgo the solar feed-in tariff they would have received if they had sent it into the grid.  Feed-in tariffs for new solar are now low and typically range from 5-10 cents.  If a household has a feed-in tariff of 6 cents, after efficiency losses are accounted for, they will lose around 7 cents per kilowatt-hour stored.

Cost Of Capital

Because the money spent on a battery system could have instead been used to pay off debt or invested , the cost of capital has to be included and working this out can get very complex. 

To keep things simple, I will determine how much interest the cost of the installed battery system would have earned if it had been invested at a 1% real interest rate. I will then divide the total interest by the total number of stored kilowatt-hours to determine the cost per kilowatt-hour.  And that’s all I will do.  It is a very basic approach. A real interest rate is what’s left after the effects of inflation are accounted for. If you have money sitting in a term deposit in the bank at the moment, then after inflation, you are currently earning a real interest rate of about 1%.

Most people don’t have money sitting in the bank they can use to purchase a battery storage system and so should use a higher interest rate, but as far as capital costs are concerned I am going to make this a best case scenario and use 1%.

I am going to assume the total cost of an installed RESU6.5 is $10,000.  It may not be possible to get one installed that cheaply at the moment, but I am being optimistic.

If the RESU6.5 lasts for almost 14 years and 10 months then the interest that could have been earned at a rate of 1% comes to around $1,660.  Dividing that by the 24,150 kilowatt-hours it is expected to store over its lifetime, the cost of capital alone comes to 7 cents per kilowatt-hour.

Total Cost Of RESU6.5 Storage Per Kilowatt-Hour

Using the optimistic estimate of $10,000 for the cost of installation and dividing it by the number of kilowatt-hours stored over its lifetime gives 41 cents.  Adding 7 cents for the forgone feed-in tariff brings it up to 48 cents.  And adding 7 cents for the cost of capital brings the total to 55 cents.  Since this is much higher than the cost of grid electricity, a RESU6.5 installed for $10,000 cannot pay for itself even using optimistic assumptions.

An Optimistic Break Even Point

Currently some people on time-of-use tariffs pay 45 cents per kilowatt-hour during peak periods.  If they were able to use all their stored electricity during these peak periods, which is unlikely, then with the assumptions used above they would be able to save money using a RESU6.5 if the total installed cost was around $7,500 or less.

But households that could use all the stored electricity during peak periods would be extremely rare and the cost of electricity during peak periods is likely to fall as more people install battery storage.

A Quality Lithium-Ion Battery System

LG Chem RESUs won’t save people money when used on-grid at their current installed cost.  But they are also suitable for off-grid and I can see many people choosing them over lead-acid batteries for their compact size, maintenance free operation, and a warranty that can last for up to 10 years2.

As the LG Chem RESU now has a proven track record in Australia and is available from hundreds of installers, I’m sure many people will choose it over other battery systems. And if they can live without the TESLA logo on their wall, they may even choose it over a Powerwall.


  1. But not those really thin laptops which I keep loosing through the cracks in my floor
  2. Although it is exceptionally stingy after 6 years as the graph in the post shows
About Ronald Brakels

Many years ago now, Ronald Brakels was born in Toowoomba. He first rose to international prominence when his township took up a collection to send him to Japan, which was the furthest they could manage with the money they raised. He became passionately interested in environmental matters upon his return to Australia when the local Mayor met him at the airport and explained it was far too dangerous for him to return to Toowoomba on account of climate change and mutant attack goats. Ronald then moved to a property in the Adelaide Hills where he now lives with his horse, Tonto 23.


  1. I have a question which no one to my knowledge has addressed.
    Why are the manufacturers of solar batteries and panels allowed to quote figures on their systems which they cannot attain???
    it seems there is something seriously wrong when you can advertise that you can stick a 6.3 KW system on your roof yet it will never ever produce that amount.
    Should not there be truth in advertising because as i have found there is no truth passed on to the consumer regarding accuracy of the system advertised.
    Why do authorities allow all these systems to be falsely advertised ??

    • Ronald Brakels says:

      Solar panels and batteries are required to, and generally do meet their technical specifications. If you are ever sold a solar panel or battery that doesn’t meet the specifications you have been given, then whoever sold it to you is required to either repair or replace it or give you your money back.

      However, sometimes companies do engage in activity that result in them receiving infringement notices from the Australian Competition & Consumer Commission. For example, in 2011 True Value Solar advertised a system with 1.52 kilowatts of panels and a 3 kilowatt inverter as a 3 kilowatt system and received an infringement notice as a result:

      With home on-grid home battery storage being a fairly new technology most people do not have a good understanding of what their technical specifications mean or appreciate how quickly most batteries can degrade with normal use and many people don’t appreciate that a system with x kilowatt-hours of usable storage storage many only have that in its first few months of life. And manufacturers of these systems may not be in a hurry to point this out. So they are not technically doing anything wrong. They’re just keeping their mouths shut when it would be more honest to be more forthcoming about the limitations of their systems.

      Personally, I point out things I think people need to know when I write about battery systems and SolarQuotes has a battery comparison table to assist consumers:

      Just as we require new cars to come with a sicker that displays their fuel efficiency and appliances have an energy star rating, perhaps battery storage could be required to carry clear and simple metrics that help households easily compare systems. But I’m not sure what those simple metrics might be at the moment and I would have to think about it.

  2. Great article, thanks for this info… I guess installing yourself voids the warranty?

    • Ronald Brakels says:

      LG Chem is clear that that improper installation voids the warranty.
      For the safety of the household, installation should only be done by someone who is qualified.

  3. This was actually a very good article about LG Chen resu products.
    Author has obviously spent some time doing their research and wasn’t the typical copy/paste directly from corporate press release.
    Next to check if these are available in the UK…

  4. @ Ronald Brakels

    Hi Ronald – firstly, a general comment to say how much I like your articles. Very informative. Humour tends to fall into the so-bad-it’s-good category and I would encourage you on to ever greater heights (depths?) on this point.


    What I want to know is (A) when will batteries be economically worth buying (A-2) how & when will that happen? (B) when will batteries be worth it from a not-contributing-to-the-carbon-induced-climate-change problem? (B-2) How will that happen?

    Cheers, Jimmec

    • Ronald Brakels says:

      Thank you, Jimmec. And don’t worry, you can rest assured that my humour will only get worse.

      I’m afraid it is not possible to say when batteries will become worthwhile. And even if I knew exactly how much they would fall in price each year, a great deal would depend on individual circumstances. A person who has money sitting in the bank might be happy with batteries that provide a 1% real return a year since that around what a term deposit provides at the moment, but a person who invests in the stock market and expects to live for a long time might not be happy investing in batteries until they provide an 8% real return or more.

      And there is a lot of uncertainty about what electricity prices will be in the future. At the moment there are people on time of use tariffs paying 45 cents or even more during peak periods, but the more battery storage that gets installed, the lower the peak price is be as batteries start reducing peak demand. And there could be changes in how people are charged for electricity and these could be either good or bad for battery storage.

      So it’s very hard to say, but I would guess batteries will start to pay for themselves on-grid for people in exceptional circumstances in a few years. But it is also possible rapid cost declines and/or improvements in reliability will cause it to happen quicker than that. But it’s still quite possible that the large majority of people won’t benefit for 5 years or more.

      I could refine my estimate, but that would take effort, so I won’t at the moment. I’ll probably give it more thought later.

      As for when batteries will be an environmental plus, well, as soon as they prevent renewable energy from being wasted because there is too much generated at once. South Australia isn’t in this position yet and generates electricity from wind and solar equal to 40% or more of its consumption from wind and solar.

      Batteries in your car could provide an environmental benefit considerably before ones in your house do.

      • Hi Ronald,
        New to the whole solar and battery world, only installed a PV system last August.
        Has your view in regards to batteries paying for themselves changed at all with the release of Tesla PW2?
        I’m in Perth and don’t have a special feed-in tariff, 7c at the moment, with 27c buy back.
        Thanks for your articles, there is so much to the technology to understand as I now find out.

        • Ronald Brakels says:

          Hello Daniel. I’m afraid that even at the estimated installed cost Tesla has given, the Powerwall 2 won’t pay for itself for any normal household. Also, I’ve just posted an article with some bad news about the Powerwall 2. Tesla is not going ahead with the DC version and to me it looks likely the AC version will be delayed.

          But battery storage is a rapidly changing field and in a couple of years batteries are likely to be considerably cheaper.

          Update: I probably should mention that the rules and regulations for home energy storage could be changed so that even if batteries become much cheaper, they may not necessarily pay for themselves.

      • Smartiepants says:

        Check out the SA company using molten silicone a very exciting and potentially disruptive energy storage system.

      • Hi, While Lithium is still way too expensive lead still works fine as it has for 100 yrs.
        How about putting up Golfcart batteries at the prices you can bargain for, they get marked up a lot and see how they come out against lithium.
        Here in the states they cost under $100/kwh and last 5-7 yrs in offgrid service.
        And by the time they need replacing lithium will have dropped to where it is cost effective, $200/wh.
        I’ve already found mine in the form of crashed Chevy Volt packs that cost less than lead! ;^)

  5. Jack Wallace says:

    Perhaps a timely reminder that there’s no such thing as a free lunch.
    Everything has a price attached, but, fortunately, in the case of solar energy production the producer has SOME say as to what that price should be ~ and particularly how much he, personally, is prepared to pay for get what he wants: in production, usage and environmental terms.

    While I’m a great fan of innovation, discovery and R&D generally, I maintain that up to the present the stand-alone lead-acid storage system is still streets ahead of any other option on ANY basis.
    And as a general rule: the more dependent one makes oneself on ‘authorities’/agencies outside one’s personal control (ie the requirement that the ‘Powerwall’ must remain connected to the grid) the more expensive in all terms any article becomes.
    The same goes for battery-powered cars, given that a pragmatic dollar-value can also be attributed to environmental elements.

    • Yes Minister says:

      A factor rarely mentioned but which has considerable value to some is the ability to give governments and electricity providers the finger. Few inhabitants of planet earth have more contempt than moi for the organized crime trading as ‘government’ and consequently the cost of getting the upper hand on these criminals needs to be factored into any assessment of cost-effectiveness. Mind you as an advocate for victims of the guardianship racket and victims of council corruption, I have probably had more interaction with official crooks than most, which accounts for my extreme cynicism regarding officialdom..

  6. The Schneider Electric Conext series inverters (XW & CSW) will be available mid-2017 with their interface, the Conext Bridge for Li-Ion. I am testing this for them now with the RESU 10. I enjoyed this article and yes this system can run without the internet and utility grid.

    • @ Dave Angelini and Ronald,

      (The questions below are in the context of Off-grid systems. I’m not into Grid-tied systems.)

      Gents, I have been searching for info on the RESU and Powerwall2. My unanswered questions are:
      1) How do you charge these Li-Ion batteries with solar panels? Do they have a built-in DC/DC converter and MPPT tracker just like conventional Charge controllers so you don’t need the usual “charge controller”?
      Or can you use a conventional off-grid charge controller (Midnite/Schneider/MorningStar…) to charge them? (this would be odd since most conventional Charge controllers would not have the proper charging algorithms for the Li-Ion cells.

      2) From Dave’s comment about testing the Schneider inverter with a RESU-10, it seems like a special inverter is needed to run with the RESU. Is that the case?


      • Ronald Brakels says:

        Hi Seb. I’m afraid that while the AC version of the Powerwall will apparently be able to be installed on-grid without additional hardware, the DC version will need a multimode inverter (also known as a hybrid inverter). The same is true for the LG Chem RESUs.

        The DC Powerwall 2 has a DC converter and accepts 350-550 volts of DC current. It is apparently compatible with SolarEdge, Fronius, and SMA inverters.

        There are 2 RESU, the RESU7H and the RESU10H, that have DC converters and accept 350-450 volts. Other RESU without a “H” at the end don’t have a DC converter.

        Inverters that are apparently compatible with RESU are SMA, SolarEdge, and Solax.

        There may now be additional inverters that are compatible for the Powerwall 2 or the RESU that I don’t know about yet.

        None of the battery systems have built in MPPT or charge controllers that I am aware of and so the multimode inverter and/or additional hardware will need to do those jobs.

  7. Hi Ronald and Seb from a very rural offgrid home in Mariposa CA.

    The Schneider Bridge is really just a safety check of the LG (and other makes) BMS. The LG BMS does not need to have this but Schneider did not want there clients and suppliers (me) to not have a failsafe device.

    The Bridge also has self-consumption help for grid-tie.

    Really all you need for the LG Resu Offgrid is 58vdc in bulk/absorb/and float and stable temps as Ronald refers to in the excellent. I like knowing if the Bridge were to fail I could still use the system for my offgrid home. I also like the piece of mind that the Bridge offers me. There will be a web page at Schnieder Solar at the end of February, I am told.

    So really all you need is a good 48vdc inverter charger. The XW+ and the CSW’s are Schneider models. You would need their mppts also as they send out a heartbeat signal to the Bridge that would shut down the charging if you got hit with lightning or had an unlikely mppt failure. Not hard to install the bridge BTW. Good Luck! Summer is coming ! For me….

  8. The prices quoted are, to say the least, very high. In fact so high as to make battery installation non viable. Looking at the technology, it is not really that advanced. Indeed quite old, so the question that leaps forth is Why?

    It seems that it is the standard in Australia to rip off the customer as much as possible. I can see that you do say that a system installed will cost more than it is worth, so the second question comes again Why?

    Yes the supplier needs to make a profit, and I can see that it will be a long time before a company can have a sustainable business, so I suspect that is the reason and the answer for both of my Why? Questions.

    However I look to the future and pray for Governments with forethought of a span greater than their next pay increase. A govt that actually thinks about the real future of Australia, without selling it away to O/S interests.

    Again However, I also look at businesses and making money in general. As an example I use car parks as a money making example. In Canberra there were quite a number of large car parks quite some distance from the CBD but folks used them a lot because they were cheap and they got a reasonable amount of exercise walking too and from work to the car. The ACT govt. greedy as usual, put up the price by a factor of 3. Those car parks are now rarely used on work days.

    Again another example is the Tidbinbilla reserve, after the Victorian fire burned its way up and through the ACT, this was closed to the public, even though no fire had ever been caused by the public using the reserve. The Govt wisdom re-opened the reserve but again they charged a large entry fee. No one came! They then spent several million $$ building a car park and a large information centre to tell people how wonderful the Tidbinbilla reserve is… people stay away in droves.

    Bottom end is, when you make the cost high, people don’t buy or use the product, time for return or growing profits will be much longer or indeed the venture will fail. Make things cheaper and people will take up usage in a big way.

    I think it is time to really push Govt to look to the real future the Solar and in fact the whole renewables industry needs to push much harder, and use better business methods. Heavier lobbying needs to be used, something akin to those used by the Coal industry

    • Yes Minister says:

      @Kevin Guy ‘However I look to the future and pray for Governments with forethought of a span greater than their next pay increase.’

      Surely you jest !!! As Claude Jerimiah Greengrass (Heartbeat) is wont to exclaim ‘pigs might’. No sentient lifeform relies on the clowns in Canberra to do anything to the benefit of constituents, if you want something done then you need to do it for yourself. I have a 2011 vintage 10kw on-grid system that returns a tidy income, a personally installed 3kw off-grid system mit batteries that runs my home and a 6kva Honda generator that is only needed if all else fails. The government can go forth and multply. My next trick is to modify the on-grid system so it produces power when the grid is down and I’ll provide power to charge the battery-electric car I’ll be getting in the near future and any surplus can go to the neighbours (yes I do know that is officially naughty, but then my definition of ‘government’ is organized crime)

  9. adebola odu-onikosi says:

    Hello Ron

    I am planning to purchase a 10kwh battery storage with inverter to charge via mains and diesel generator when that is in use. I also plan to add some LG panels or alternative in the future.

    Are there any of the new batteries systems that you have reviwed – LG, Powerwall etc that can work with both solar and other charging sources?

    I would really appreciate your advise.

    • Ronald Brakels says:

      Generally all battery systems can be charged from multiple sources, but it can depend on just how they are set up. For example, if batteries are DC coupled with a DC converter such as the Goodwe GW2500-BP:

      They can normally only be charged with solar power. But other arrangements, such as a mulitmode (hybrid) inverter can allow charging from solar panels, off-peak electricity, peak electricity if desired, or generators.

      I presume you know what you are doing, but I will mention that in Australia it is normally very uneconomical to have an on-grid battery system without rooftop solar and it usually makes much more sense to have rooftop solar and no batteries than the other way around.

  10. Carmel and Neil Jones says:

    we are looking at a RESU10 battery and a 6.5 kw solar panel system, ( 1.5kw already installed and a new 5kw system in quote) our daily usage is approx 45kws per day , we have been quoted $15,000 to supply and install this system to be used off grid back into our house and additional power feed into the grid.
    What are your thoughts on this would this be worth while for us . was told by sales person that we should be self sufficient with the need to draw very little power from the grid . Really need help to understand the whole solar power advantage, really want to cut down our power costs. please give your honest opinion and comment .

    • Ronald Brakels says:

      Hello Carmel and Neil. I’m afraid at the moment there are no battery systems that will allow people who are on-grid to save money. I have written about how difficult it is to save money with what should be the lowest cost method of adding batteries to a home, the Powerwall 2:

      So if the cheapest system (according to Tesla) can’t pay for itself, no more expensive system can.

      But, rooftop solar without batteries definitely pays for itself, so I strongly suggest getting solar now and in the future you can get battery storage if prices drop low enough for it to save you money.

      There is no need to do anything to prepare to get battery storage at a later date except perhaps ensuring your rooftop solar system is large enough. Your 6.4 kilowatt system is likely to be fine.

      If you are worried about blackouts you are probably much better off getting a small generator rather than batteries. It’s not as convenient, but it’s a lot cheaper.

      • Yes Minister says:

        The cost of off-grid solar can be slashed if one is prepared to do the work themselves. Its not rocket science, just needs basic handyman skills and the ability to design a system that doesn’t break every rule in the book. Mind you I’ve always considered that laws are meant to be bent or broken but some may not agree. Laws in all states and territories do not require a qualified electrician to install equipment running at 120v or lower. Providing the off-grid panels produce under 120v per string, anyone who knows the basics can install the regulator, inverter and whatever. I have twelve panels off-grid, a an Australian regulator and switchgear, and chinese inverter / batteries. The whole setup cost around $5000 and I can run the whole house off it. That said, my house is arguably the most energy- efficient in the country using less than 5kwh per day.

  11. Alan Beaumont says:

    Hi I have installed a Battery on grid system and am very happy with the results. When we moved to the house we are currently in it had a very ordinary 1.5 kw chinese system allready on the house, this has now gone and has been replaced with a 5Kw system with a LG Chem 6.5 RESU. Cost of the entire system installed (18 Panels, sungrow inverter, battery and assorted parts) was $13700.00. On a good day there is no feed from the grid for upwards of 12 hrs / day, it remains to be seen how this will pan out during the winter. Our , main driver for doing this has been the terrible inconsistancy in the grid supply in our area SA power networks seems to have little interest in maintaining the supply to our area, however we allways hve the lights on at our place. Scince installing the system in Janurary 4 others have been installed in our small town ship we are just fed up with poor supply.

  12. Yes Minister says:

    I’m considering upgrade options from my existing lead-acid setup but it doesn’t appear that even the latest lithium batteries are as cost-effective as lead-acid batteries as yet, unless perhaps the smaller size, less weight and longevity tip the favour of lithium batteries. I did look at Redflow recently but I’m not convinced they are worth the trouble.but the urea – aluminium concept developed by Stanford University looks like a possible option if it gets commercialized.

  13. Yes Minister says:

    Whilst its far from a critical issue, can someone advise me regarding what is the current state of knowledge regarding use of on-grid panels when the grid is down. I have 2 x SMA5000TL inverters which probably have quite a few more years usable life in them, consequently I’m not about to replace them with hybrid inverters in the near future. Its not supposed to be possible to trick most on grid inverters to work when the grid is down (anti-islanding and all that) although I’m far from convinced that doing so is impossible. (yes Martha I am aware of the need to isolate the system from the grid so I don’t zap some linesman blah blah Presumably nothing has changed apart from the availability of hybrid inverters. That said, it is ridiculous to have all that generating capacity going to waste when the grid is borked as it is in my area right now. I get the impression from posts here that there are workarounds, including some of these newer battery systems which accept the 400 – 500v DC my 64 on-grid panels produce to charge batteries. Even if that techology was only used with relatively small batteries, it would be a relatively inexpensive way to produce meaningful amounts of 240v in very heavy overcast conditions (when the output from my 12 off-grid panels is lower than my usage). The 64 panels would certainly produce well in excess of my present needs even with stuff-all sunlight. It goes without saying that it would only be worth using on-grid panels to charge batteries when the grid is down as it would cost me $2000 per quarter if I can sell the power to the grid, consequently there is no point in me spending $10,000 to lose $8000 per year. I’m thinking of a 500v input regulator which charges my existing lead-acid battery bank or a bigger one I’m considering, and initially the same 3kva 48v DC to 240VAC inverter. Is there such a thing as a 500v solar regulator (standalone, not part of a $10,000 battery setup) as I had to do a lot of searching to find my present 180v capable one.?. .

  14. The Schneider Electric Mppt-80-600 is a 600vdc solar charger that can charge a 24 or 48 vdc nominal battery. Morningstar makes a similar one also.

    • Yes Minister says:

      At $1350 odd, these devices represent good value for money, especially for folk with non-hybrid grid connect inverters and who aren’t getting a decent FiT. I.m not considering one personally at this point as my FiT is up to 54.6c per kwh as from 1st July, but it will be a different story the moment the 2011 deal finishes. I’ll stop supplying green electrons that AGL can re-sell at a massive markup and up my battery system considerably.

  15. Can the LG Chem be charged with a normal high quality 48V regulator such as Midnite Classic, Outback, or Schneider Mppt-80-600, Victron etc?

    • Ronald Brakels says:

      I’m afraid I don’t have any experience dealing the LG Chem RESU personally, so I can’t give you any specific advice, but the standard LG Chem RESU are 48 volt batteries, so I don’t see why they couldn’t be charged with a decent quality 48 volt charge controller, provided it was suitable for use with lithium batteries. For example, I don’t think the Schneider Mppt-80-600 supports lithium batteries, so ensuring compatibility would be important.

  16. There are two things to consider with the LG RESU10.
    The Inverter/charger needs to support the CAN network into and out of LG.
    Without it the LG will shut down! No WAY AROUND THIS !!!

    If you want the Solar Mppt to be in this LG CAN network, it needs to be able to communicate with LG. The Schneider MPPT-80 and the -60 both do and I am testing them for Schneider since last year. LG will be giving final approval this month.

    The MPPT does not need to be in the network and you would be responsible for picking the set-point. The inverter/charger does have to be in the LG network or it will shut down 10 minutes later.

    You can think of this system as LG protecting and recording itself and you.
    You can think of Schneider as doing the same with guidance from LG. Two separate systems working together. Schneider will have a website where one can get all the firmware. It will be the Conext Bridge for any BMS based battery on the market.

    Dave Angelini / [email protected]

  17. Neil Jonasson says:

    I liked the article except for one thing. It places too much emphasis on looking at the domestic PV generator, the battery storage and the end user power consumption pattern as separate parts. This badly warps the picture of benefits. With the advent of batteries and inverters that can marry the domestic daytime PV energy, the H24 grid and on-site energy storage and consumption into an integrated energy system we should think differently. Anybody considering adding battery storage to a PV generator for their house most probably owns their house and a motor car. I am one of those people and I didn’t base my decision on what car to buy on whether or not it would pay for itself in 10 years, because it won’t. However I do consider the car as an asset. Likewise I didn’t go for PV power in 2007/8 to make money. I saw it as an asset in the same way as I saw adding insulation to my house ceiling.

    I have logged our 10 year domestic solar power experience and it is as follows in round numbers. Our house in S.E. Queensland of three or four occupants on a yearly average has consumed 17 Kwh per day. Our solar system has generated <4 Kw per installed Kw's of PV panel. 1.5 Kwh per day of the generated power was consumed by the house in 24 hours. The remainder was exported to the grid. We have not paid an electricity bill since installing the PV system. The yearly output of the PV system is still similar to the first year of operation. It is a BP solar system. Now I will leave it to the reader to figure out the dollars on that record. Oh, we have an all electric house and individual reverse cycle air conditioners in each room.

    Today the purchase price of our system would probably be 40% of what we paid, and the solar feed in tariff has bottomed out, but the feed out of grid tariff has also risen 20%. Our system will well and truly pay for itself and a replacement system in 10 years time at the end of its nominal 20 year life. That's a lot better financial deal than my present 5 year old motor car which cost me more than twice as much as the PV system.

    Now I am advising our daughter to install a PV system with an LG RESU 10 in her new house to be built in Perth. In simple terms the reasoning is based on our home experience. A 5 Kw hybrid inverter (has 8 Kw peak input) and 5.6 Kw of panels, plus an RESU 10H.This should generate an daily average of <20Kwh. Assuming that initially the daily power household consumption is a similar 17Kwh, the daily 20Kwh PV output matches. But if like our house only 1.5 Kwh of the PV power is consumed during the day the system is benefiting Synergy more than the home by exporting an average of 18.5 Kwh per day @7c/Kwh. The payback argument for such a PV system is bad. Even if it were down sized to half the capacity (which costs more than half the price). However now take advantage of looking at a more integrated electrical consumption regime for the house. Add an intelligent power management meter to the PV hybrid inverter, install a heat pump hot water heater on a time switch, install central reverse cycle air conditioning with zone and time control and add battery storage to the PV system. The hybrid inverter has the capability to not only direct excess PV power to the battery but it can also control the operation of the air conditioner during the day to maintain the environment of a vacant bedroom or two, thus significantly reducing the night time electrical consumption of the air conditioner. The same goes for the heat pump hot water unit. This system integration of battery storage with generation and consumption units can mean that a high proportion of the 20 Kwh PV power can be used in the home every day instead of exported. On days of high solar generation any exported power will go to off-set Synergy's fixed charges. On the subject of such fixed charges, I consider these in the same way a car registration and insurance costs. Unavoidable but also a guarantee of supply for night and zero PV days.

    Conclusion: A $9000 5 Kw PV system alone does not make much sense for a working girl. Add other $9000 for 10kwh battery storage to an integrated power management system and the 10 year picture is quite different. Maybe on a yearly average only pay fixed charges and not the 27c per Kwh for 17 Kwh per day = $1675 per year at current prices. Forego the 7c/Kwh feed in tariff, the system is our house asset and installed to benefit us not Synergy.

  18. Agree Neil and my clients who all live offgrid the asset of power is even more valuable not to mention the beautiful places they live all over the world. The LG [email protected] is the perfect choice for a home with the ability to add more later.

    I can take my asset (the truck) and load a 165 pound battery (sorry metric challenged American here) Go to a clients home and with some firmware and 2
    1 meter battery cables, a few network cables, replace a very heavy battery system with a nice small box that gives a percentage of state of charge and even tells you when you are getting near the end of life. 95% efficiency after years of lead acid is also a pretty amazing asset.

    Dave Angelini / [email protected]

    • My apologies to everyone, but I made a typo error in saying;
      ” But if like our house only 1.5 Kwh of the PV power is consumed during the day the system is benefiting Synergy more than the home by exporting an average of 18.5 Kwh per day @7c/Kwh.”
      To be clear, that should have read “the house consumed just 4.5 Kwh of the Kwh’s the PV panels generated”.
      My point is still the same, that without a battery and a total energy management system, Synergy would get the bulk of the benefit of a 5 Kw PV system = 15.5 Kwh/day @7c/Kwh. Not a good deal.

  19. Endeavour Energy in Sydney is offering a battery program that they will pay 75% of the battery system total cost including installation. I got a letter in the mailbox and as I had nothing to do one night, I went to the link provided online and registered my interest. I was advise that out of 118 applicants, only 41 were approved. In exchange, they said that they will have to use the power from the battery for 12 times in a year. The battery they offered is a RESU10H, I am to pay only $3084. I’m not sure what is the catch but it seems too good an offer to not take. An Endeavour Energy contractor already came to have a look at my solar system and confirmed that my house is capable to have the battery system installed, they also checked that I have Internet and spare network port on my router. I already got the formal quotation and it does say that Endevour is paying the 75% of the total cost. The contract also states the need for them to use the battery 12 time. Here is what it says “I understand that Endeavour Energy can control the charge and discharge of my Battery System on up to 12 occasions (known as an Endeavour Energy SolarSaver Event) per summer and winter period, and can discharge the Battery System for an approximate four-hour period during the Endeavour Energy SolarSaver Event to its permitted capability”. I now have two weeks to think about this deal before the offer expires, what do you think?

    • Ronald Brakels says:

      Hello Andrew. We are keeping a very close eye on a similar program here in Adelaide. If you are interested in getting batteries I’d say you are very unlikely to get a better deal for a long time. Even if batteries continuously fall in cost by 10% a year it will be about 14 years before they fall by a total of 75%. It sounds like they can use the battery a total of 24 times a year, but that is not a major problem. When they discharge the battery it should reduce your own consumption first, so you’ll still be getting a benefit from it. It is also possible you will get your solar feed-in tariff for battery electricity sent into the grid, depending on how the metering is done.

    • For $12,300 they must be also supplying an ac coupled inverter. Either the SMA or Solar Edge inverter and a matching model of RESU10H. Both inverters are 2.5 Kw. That makes the 4 hours they require use of the battery to suck it dry. Gee I wish others would make such an offer.

  20. Hi Ron,
    Up here in the Nthn Rivers, NSW, there’s a bulk buy campaign run by Shine Hub. They’re advertising cheap prices for the capacity to bulk buy & they have the support of ENOVA – the community owned elect comp. which you may have heard about.

    For the system they quoted me:
    Suntech STP 270W (2.16KW) solar panels;
    Sungrow Hybrid SH5k 5000 (5kW) inverter;
    LG Chem – RESU 6.5kW LV (6.5 kW) battery.

    For $11,740, installed.

    The panels are around $2000 & battery around $7,500.
    I read in your blog, is that the break even for a battery is $7,500. Is that true? Given this package, should I go for it?

    Also, is it extra for connections etc., that the battery can be used for black-outs?

    Appreciate your sage advice here.


    • Ronald Brakels says:

      Hello Hans. After having a quick look at electricity prices in your area, I can’t see any time of use tariffs that have very high peak rates, as in Sydney. Instead, you are likely to be paying under 30 cents a kilowatt-hour. A feed-in tariff of 10 cents is already available. As a result, with charge and discharge losses, you might only save around 18 cents for each kilowatt-hour of stored solar electricity you use. If we assume the LG RESU 6.5 provides 50% more stored kilowatt-hours over its lifetime than it is warranted to, that will come to 24,150 kilowatt-hours of storage. If each one of them saves you 18 cents the total savings will be $4,347 over its lifetime. If the battery costs around $7,500 then clearly it cannot pay for itself even before the cost of capital is considered.

      I am afraid the Sungrow SH5k 5000 will not provide back up power off-grid. It’s a major drawback. You may be able to purchase a separate module that will let it provide back up power, but I don’t know if that is currently available.

      You may be interested in this video by Mark Cavanagh installing a Sungrow SH5k:

  21. Hi Ronald,
    Did my SPS course 2 years ago and decided to jump in the market by setting my house Off Grid.
    I understand that the economics are not there even when applying the equipment at cost price and free labour…
    I have a 9.5 KW solar array with a Fronius 8.2 KW inverter.
    I am planning to buy a Selectronic Sp Pro 481 and 2 X 9.8KW LG Chem batteries( $17500 investment)
    My daily consumption is 9KWh ( 4 during the day and 5 at night)
    My design is bordeline with a 3 days autonomie and plan to buy a back generator if necessary ( another 3K)
    I am using my install as a case study for my permanent accreditation but can’t answer some of the questions of the case study application:
    – manufacturer’s float voltage ( Do lithium battery have this?)
    -Rated current current @ C100
    -Battery protective device rating ( unknown as they are internal)
    Thank you.

    • Ronald Brakels says:

      Hello Roger. With 9.5 kilowatts of solar panels you’ll generate a lot of electricity. Even on the very worst of days I’d expect you to be generating over 4 kilowatt-hours. I presume 9.5 kilowatts of panels is the most you can reasonably install, but I will mention that with an 8.2 kilowatt inverter you could install up to 10.93 kilowatts of panels, so if you have the space for extra ones they would not be expensive for you.

      If you were desperate to save money you could get a generator and try to get by on one RESU, but that would complicate your life and redundancy is really nice to have when off-grid. And of course a single RESU would be worked harder and die sooner.

      As for your specific questions, I’m afraid I’ve never had anything to do with installing a RESU, so I don’t know any specifics. Maybe someone else reading this can help you. That said, lithium ion batteries don’t have a float charge as they can’t stand over charging. This page goes into details:

      They may be occasionally be topped up after self discharging for a while.

      Rated current at C100? Well, looking up the LG Chem RESU 10 (RESU 9.8) installation manual:

      I see it is supposed to have 189 ampere hours, so when discharged over 100 hours that should be 1.89 amps.

      As for battery protective device rating, I’m afraid I don’t know. I searched the manual for the word “protection” and all it gave me was a list of safety certifications towards the end. But the case is rated IP55 if that’s what you need to know.

  22. Hey Ron & Roger,

    I am also running the LG resu10 with the Schneider electric solar “bridge” Offgrid.

    The LG is protected by a 175A circuit breaker, a Contactor that will disconnect 48V and as a last resort if the inverter out put were to short, a 200 A class T fuse. This info may not be what you are asking but I have tested it all and it works correctly.

    As for floating, I agree with Ron but would add that since LG outputs its Soc there is not a reason that you can lower all the setpoints to 57.1 vdc. This will bring the LG up to about 96% Soc and avoid problems including over charge,
    cycling up and down from full to a lower Soc. It should make the battery last longer from what I have read.

    Here is a link to the Schneider Bridge.

    Dave Angelini Offgrid Solar
    “we go where powerlines don’t”
    e-mail [email protected]
    text 209 813 0060

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