Aquion Battery Review: Safe… But Limited Power & Efficiency

DIY Salt Water Battery

You can now buy an Aquion salt water battery to power your home. Nemo not included.

UPDATE MARCH 2017: As of March 8, 2017, Aquion has filed a voluntary petition under Chapter 11 of the United States Bankruptcy Code

UPDATE JULY 2017 : Aquion Energy is resuming operations

Keen on storing your excess solar in a big battery? Worried about having a big box of toxic and/or flammable chemicals in your home? Then you’ll want to know about the Aquion battery and its salt water technology.

Salt water batteries are making a splash in Australia right now. Or rather, since they are completely sealed, they haven’t splashed at all. But the good news is if they did splash you it would not be a problem, as the liquid inside is simply salt water. They are almost certainly the safest battery around. Although their low toxicity does not make them the most environmentally friendly battery, for reasons I’ll go into a little later.

Australia is a world leader in salt water battery technology with Western Australia’s Dr Manickam Minakshi doing ground breaking work in the area. Unfortunately, as is far too often the case, lack of support for locally developed clean technology means that the only salt water batteries you can buy here come from the United States.

Salt water batteries are not a new invention, but the first ones practical for home energy storage were produced by the American company Aquion in 2011. By the middle of 2015 they had sold around 2 megawatt-hours worth of them in Australia. They are one of the few new battery types that are readily available without the need to go on a waiting list.

aquion install

A very nice NZ Aquion install using 5 batteries for ~10kWh of storage. I’ve drawn around a single battery so you can see their shape. They are 94cm high. The red box is the solar inverter. The yellow box is the battery inverter. Pic courtesy of SkySolar NZ.

The Aquion salt water battery has the disadvantage of being very heavy per kilowatt-hour stored. You won’t want to lug one around with you to charge your phone when hunting Pokemon.

It also has a low power output. Although the spec sheet claims 1 kilowatt peak power, this is only for 5 minutes. Their usable steady-state power is closer to 400 watts per battery.  The power of multiple batteries is additive, so for a typical Aussie home, which can easily draw 5kW for sustained periods, you’d be looking at 12 or more batteries.

It is also important to know that the rate at which you charge and discharge the batteries affects both their:

  • storage capacity, and
  • roundtrip efficiency.

The details of their current model, the Aspen 48S-2.2 battery, are shown in the table below:

[wpdtable id=”7314″]

And the official Aquion battery specs are here:

Download (PDF)

Saltwater Battery Design Philosophy

The Aquion salt water battery was designed by Professor Jay Whitacre. I don’t know if he is as smart as Australia’s Manickam Minakshi, but he has worked for NASA and he did help develop batteries that are currently in a rover on Mars, so he should know a thing or two about designing reliable batteries.

Jay Whitacre, or J. Whit, as no one calls him, set out to design a battery that was not only low cost, but could also be rapidly put into production to assist the integration of renewable energy into electricity grids. He created a list of materials that were both common and cheap and set to work creating a battery from them.

He succeeded in making a salt water battery quite literally using the shirt off his back.  He cut it up to make cotton separators for his first effective cells. While a salt water battery was not a new invention, his design was innovative and, very importantly in the world of business, beat the competition into manufacturing.

aquion exploded view

The great thing about the Aquion salt water battery is its simple construction and its use of abundant, non-toxic materials. The downside is the sheer amount of material needed due to its enormous size. The image shows a cell that will store 0.275 kWh. So 8 of these make up a single 2.2kWh battery. Image: Aquion

Australia Received The Very First Aquion Batteries

Aquion sent their very first commercial batteries to Australia for testing.  So many battery companies have selected Australia for their first installations it makes me feel very special.  I haven’t felt a warm glow like this since the time Britain shipped some of the very first atomic bombs they made to South Australia.

Aquion Battery Technology

The Aquion salt water battery consists of a plastic case with layers of stainless steel charge collectors, manganese oxide cathodes, anodes that are mostly carbon, and separators made of what Aquion call synthetic cotton but normal people call rayon.

The entire cell assembly soaks in a salt water electrolyte solution that makes use of sodium, lithium, and hydrogen ions to transport charge between the cathodes and anodes. This is about as non-toxic as a battery can get. If you are low on electrolytes I don’t recommend drinking it because I don’t know the lithium concentration, but if for some reason it leaks you can just mop it up and pour it down the drain. It is likely to cause less environmental harm than one mediocre cow fart.

Salt Water Batteries Are Fire Resistant

Similar to the ocean, salt water batteries are very unlikely to catch fire. However, because they contain water, if something goes wrong and they are overcharged, then electricity can split water into hydrogen and oxygen which does burn.

If salt water batteries are located outside, which they often will be due to their large size, even if a significant amount of hydrogen is released it is extremely unlikely it could become concentrated enough to result in an explosion.

The Aquion website suggests fire resistance gives them a major advantage over lithium-ion batteries, but given the number of Australians who are happy to have lithium-ion batteries in their laptops and even shove them in their pants when they’re not using their mobile phones to chase Pokemon, I’m not sure how big a selling point that will be here.

Usable Energy Storage May Only Be 1.6 kilowatt-hours

Aquion batteries are low power and slow to charge and discharge. The faster they are charged or discharged the more energy is lost as waste heat and the lower their efficiency and capacity.  To provide the maximum amount of stored electricity they need to be discharged very slowly.  If one is slowly discharged over 20 hours, providing an average power of only 110 watts, it would be possible to get 2.2 kilowatt-hours of electricity from it.

But slowly discharged over 20 hours is not how household battery storage is normally used. As Churchill always said, “Ain’t nobody got time fo’ dat.”  Note it is possible we are thinking of different Churchills.

A more realistic discharge time would be 8 hours or less.  When discharged over 8 hours it will only provide 1.78 kilowatt-hours.   The shortest discharge period Aquion provides data for  is 4 hours.  When discharged this rapidly their salt water battery can only provide 1.6 kilowatt-hours.

Their Power Is Low And Inconsistent

The highest power output the Aquion battery can maintain over 5 minutes is 1 kilowatt. The 5 minute peak power drops to 900 watts by the time the battery is only one-third charged and then falls rapidly to 200 watts when the battery is almost fully discharged.

When discharged over 4 hours with a depth of discharge of 90% it should be able to manage a continuous output of around 400 watts.

Round Trip Efficiency Is 80-90%

The rate at which the Aquion battery is discharged has a large effect on its efficiency. If it is charged over 20 hours and discharged over 20 hours its efficiency can be 90%, but as already mentioned, ain’t nobody got time fo’ dat. If it is instead charged over 4 hours and discharged over 4 hours its efficiency will fall to around 80% or less.

They Can Be Discharged 100% Without Harm

One clear advantage of salt water over lithium-ion and lead-acid batteries is they can be fully discharged without suffering harm. This makes them very safe to transport and store. Unlike lithium-ion batteries they do not gradually decay over time when not in use and so a retailer could store them for months without affecting their warranty. Their ability to be completely discharged and left flat without suffering harm makes them particularly useful for any off-grid use where they may be left inactive for extended periods of time.

Operating Temperature Is -5 To 40°C

Aquion salt water batteries operate from -5 to 40°C.  In Australia the lower limit is not likely to be a problem.  Even if the temperature does fall below -5°C overnight the batteries are large and have a lot of thermal mass and so they are not likely to have time to freeze before the cold snap is over.

If you do somehow manage to freeze your batteries, you can thaw them out and they will still work.  They will be damaged and their capacity will be reduced, but it’s a lot better than turning one into a 118 kilogram conversation piece.

In this country higher temperatures are more likely to be a problem.  The good news is, provided they are installed out of the sun, they should very rarely if ever exceed their maximum operating temperature in most of Australia.  Their massive size is an advantage because it will take them time to heat up.  Also, because they are so massive, the waste heat they generate will only slightly increase their temperature, despite their low efficiency.

On the product specification sheet, Aquion states the tests with which they determined their battery’s performance were performed at 30°C.  This strikes me as an odd temperature to use because, even in a warm location such as Brisbane, a salt water battery installed out of direct sunlight is unlikely to ever reach 30 degrees.  As no reason is given I am wondering if the battery functions optimally at around 30°C and its real world performance will be slightly less at typical operating temperatures.

They Will Gradually Degrade

As most batteries do, salt water batteries will degrade with use. Aquion claims they can be cycled 3,000 times while falling to 70% of their original capacity. So after 8 years one should still be able to provide 1.1 kilowatt-hours when discharged over a 4 hour period.  While some battery systems do considerably better than this, the rate of degradation is comparable to many lithium-ion systems.

Aquion Batteries Are Big. Really Big.

Per kilowatt-hour of storage, salt water batteries are the heaviest batteries on the market.  They are more than twice as heavy as lead-acid batteries. Put 12 of them on a pallet and it will be 1.2m high, 1.3m wide, 1m deep, and weigh 1.5 tonnes. Here are Aquion’s specs for such a beast:

Download (PDF)

Aquion Salt Water Battery Warranty

The Aquion battery has a 5 year warranty. In addition, after the five years are up, it has a three year pro rata warranty.  And I can only assume “pro rata” is Latin for “half-arsed”.  In those three years they will repair or replace your battery, but only if you pay 63% to 100% of the cost of a new one, depending on how much of the three year period is left. Any new batteries you purchase under this half-arsed warranty will not have a new warranty, despite the fact you that you may have paid almost full price for them.

Pro rata warranties are normal for lead-acid batteries because they are so easy to destroy through misuse.  But with the much more durable Aquion battery, I’d much rather have just a 6 year full warranty and nothing else, than 5 years of full warranty followed by 3 half-arsed years.

Not The Most Environmentally Friendly Battery

The salt water battery is the least toxic battery that doesn’t involve sticking pieces of metal into fruit.  However, this doesn’t necessarily mean it is the most environmentally friendly battery available.

Batteries used for home energy storage contribute to carbon emissions in two main ways:

  • Embodied energy: Carbon emissions from producing the materials used in its manufacture and a smaller amount from manufacturing and transport.
  • Lost solar generation: Carbon emissions that result from clean solar energy being lost when batteries are charged and discharged.

Not many people consider the second point. Each kilowatt-hour of solar electricity lost from charging and discharging grid connected batteries usually results in one extra kilowatt-hour of electricity being generated from fossil fuels.  This applies even in Tasmania and South Australia, the two states with high levels of renewable generation, because they can normally export electricity to Victoria.

Lower Embodied Energy Than Lithium-ion

Both salt water and lithium-ion batteries result in CO2 emissions from their manufacture.  But because a large portion of the weight of Aquion batteries are just salty water, their carbon footprint will be considerably less per kilogram.

A rough estimate of the amount of CO2 released from producing complex manufactured goods is 2kg per 1kg of a product’s weight.  If the Aquion battery’s footprint is assumed to be half this and its usable energy storage is 1.78 kilowatt-hours, then its carbon footprint would be 66kg of CO2 per kilowatt-hour of usable capacity.

The lithium-ion LG Chem RESU weighs 60kg and has 5.12 kilowatt-hours of usable storage.  At 2kg of CO2 per kg of weight its carbon footprint would be 23kg per kilowatt-hour of usable capacity.  But others who have thought about the embodied energy of lithium-ion batteries a lot more than I have come up with a much higher number than this. This review of the literature, from two and a half years ago, estimates about 170kg of CO2 is used to manufacture 1kWh of Li-ion storage1.  But because the technology is developing rapidly I suspect the figure has improved since then.

I can’t find similar estimates of saltwater battery embodied energy – so we’ll have to go with my guesstimate of 66kg. Let me know in the comments if you think this is way-out.

Lifecycle Emissions Worse Than Lithium-ion

When used for home storage, Aquion batteries are likely to have a round trip efficiency of 83% or less.  A lithium-ion energy storage system such as the LG Chem RESU has a round trip efficiency of 95%.

Aquion lifecycle emissions

If the Aquion battery is cycled once a day for 8 years until the end of its pro rata warranty it would have stored a total of around 4,441 kilowatt-hours2.  At 83% efficiency, 755 kilowatt-hours would have been lost in total corresponding to about 717kg of CO2 emissions3. With an average of 1.52 kilowatt-hours of usable storage, that’s 472kg of CO2 emissions per kilowatt-hour of capacity lost to inefficiencies.

Add that to the guesstimated 66kg embodied energy per kilowatt-hour of capacity, and the total environmental impact of the Aquion is 538kg of CO2 per usable kilowatt-hour of capacity.

Lithium-ion lifecycle emissions 

Cycled once per day the LG would store 17,386 kilowatt-hours over its 10 year warranted life. With its 95% roundtrip efficiency it would lose 869 kilowatt-hours of solar electricity. That’s 173kg Co2 emitted per kilowatt-hour of storage due to inefficiencies.

Add that to the 170kg embodied energy per kilowatt-hour for lithium-ion, and the total environmental impact of the LG Chem Resu is 343kg CO2 per kilowatt-hour of usable capacity.

That is just over half the emissions of the Aquion battery per kWh capacity.  As optimistic assumptions were made about the rate at which it would be charged and recharged, the Aquion battery’s actual performance is likely to be worse.

graph showing emissions of saltwater vs li-ion

Saltwater batteries may have a lower carbon footprint from manufacture – due to their simple design, but their low roundtrip efficiency means that their total lifecycle emissions are likely to be higher than li-ion.

Salt Water Batteries And The Future

Aquion’s salt water battery is touted as being made out of low cost materials.  But looking at its uninstalled price of around $2,200 it is not cheap compared to other new battery chemistries on the market, per kilowatt-hour of usable storage.

But at the moment, new generation home battery storage is not sold for cost plus a reasonable margin, they are sold for as much as their manufacturers can get for them.  This is not unreasonable, as they can cost a fortune to develop.  So just because the Aquion battery isn’t cheap at the moment doesn’t mean they can’t afford to lower its price in the future.

The battery is made of low cost components, but because it uses so much of them that is not as large an advantage as it may seem.  It can still fall a very long way in cost per kilowatt-hour of storage before its price approaches the cost of the materials used.  But in the long run, because the competition requires much less material per kilowatt-hour of storage, salt-water may not be able to beat lithium-ion or other battery chemistries on material costs per kilowatt-hour.

Cost Comparison With Lithium-Ion Batteries

On-grid battery storage does not yet pay for itself in Australia.  But which type of battery storage will result in you losing the least amount of money is a question I can try to answer. Let’s look at how much they cost per kilowatt-hour of usable stored electricity over their lifetime.

Aquion states their battery’s life is 3,000 cycles and it will have declined to around 70% of its original capacity by then.  When cycled once a day it will take over eight years to reach that point, which is well beyond its 5 year full warranty period.  If the battery is allowed to fully discharge over 8 hours at a constant rate each cycle, which is optimistic for one that is used for home energy storage, then the average amount of usable energy it can store is approximately 1.5 kilowatt-hours which would come to a total of 4,500 kilowatt-hours over its cycle life.  Dividing its cost of approximately $2,200 by that figure gives 49 cents per kilowatt-hour stored.

The lithium-ion LG Chem RESU costs approximately $7,500 and can store 5.12 usable kilowatts of usable electricity when new.  It is warranted for 4,125 cycles and taking into account loss of capacity can store a total of 17,386 kilowatt-hours when cycled once a day over its 10 year warranty period.  Dividing its price by total stored kilowatt-hours gives 43 cents a kilowatt-hour which is around 11% cheaper than the Aquion battery.

Should You Buy Saltwater Batteries?

While the Aquion is a little more expensive than lithium-ion per kWh stored, there’s not much in it. And factors other than price can determine which type of battery people will consider best.  For example, some may place a high value on the Aquion battery’s non-toxicity, extremely low fire risk, and ability to be fully discharged and left unused for long periods without deteriorating.

However, given the power limitations of the Aquion battery, their low efficiency, large footprint and high lifecycle CO2 emissions, I doubt they will remain competitive in the on-grid energy storage market without a big fall in price.


  1. “caused mainly by the production chains of battery cell manufacture, positive electrode paste, and negative current collector.”
  2. 1.78 kilowatt-hours per cycle at first with a decline in battery capacity of 29.2% over 8 years. This decline is assumed to occur at a steady rate.
  3. Australia emits 0.95 kg CO2 to generate 1 kilowatt-hour of electricity from fossil fuels, including emissions from extraction and processing.
About Ronald Brakels

Joining SolarQuotes in 2015, Ronald has a knack for reading those tediously long documents put out by solar manufacturers and translating their contents into something consumers might find interesting. Master of heavily researched deep-dive blog posts, his relentless consumer advocacy has ruffled more than a few manufacturer's feathers over the years. Read Ronald's full bio.


  1. Erik Christiansen says

    A delight to read, as always, Ron.

    When considering Aquion, I decided against them first on price/performance ratio (I.e. _not_ cheap, in fact overpriced), but irrevocably because of slow charge rate. (In addition to the slow discharge rate that you’ve considered.)

    The greatest problem with Aquion is their reduced efficiency and capacity when charged over the limited period that a solar array is at high output, i.e. the 4 hrs around noon. OK, with an overdimensioned array, we might have 6 hrs around noon, but we’ll never have the 12 hrs charge period that an Aquion needs in order to overcome its dismal charge rate.

    And it is just not possible to repeatably charge for 10 hrs, then discharge over 20 hrs, to achieve the 2.2 kWh capacity daydream, as that doesn’t even fit into 24 hrs! In my notes, taken from reading the specs some time ago, I have noted:

    Energy: 2.2 kWh if charged for 10 hrs, then 20 hr discharge = only 110W !!!
    1.4 kWh if charged for 4 hrs, then 12 hr discharge = only 117W !!!

    I.e. to get 1.4 kWh out, don’t load the colossus with more than two old 60w lightglobes, after a solar array charge.

    If they were sold for just a bit less than lead-acid batteries, I’d still not put up with their limitations. OK, I need twice the capacity in lead-acid, due to their low discharge tolerance, but I can arc up the microwave or milling machine outside the 4 hr array window.

    I was about to say that for an off-grid situation, all the yellow disappears from your bar-graph, but then realised that if a “do without” approach is overridden
    by “them indoors”, then arcing up the generator is even worse.

  2. Ronald, once again a well researched and thought out article from you. Unlike some in this arena you come across articulate and erudite. A credit to you.

    This is an area I’ve paid a trivial interest to, and I wonder how these cells will progress in their development. They appear a good technology for those who cannot devote time to maintain wet cells.

    On that topic, do you have any information comparing them to wet cells. Ours are 8 years old and we have 24x2v in series with a total storage capacity of 84kWh. They’re balanced monthly for two hours with the generator and we’ve only had a couple die that were easily and cheaply replaced. Monthly electrolyte checks and they’re great. Wondering if these would be a good replacement in a hybrid format.

    • Ronald Brakels says

      Jon, last time I looked at lead-acid batteries I saw I could buy around 10 kilowatt-hours of ones that appeared to be decent quality for the cost of one Aquion battery. Since you already know how to handle and maintain lead-acids and haven’t had major problems, at current prices I’d say stick with them.

  3. Hi Ronald, very informative and witty article. Have you purchased or tested an Aquion battery yourself or are you working off the spec sheet? I know many Li ion battery suppliers exaggerate their battery capabilities and I wonder if Aquion’s claims are more or less true to actual performance. Cheers

    • Ronald Brakels says

      Hi Noah. I’m afraid I didn’t have an actual Aquion battery to work with. And maybe that’s for the best, given that I would have been very tempted to open it up and taste the electrolyte inside to check just how non-toxic it really is.

  4. Ben Standford says

    This is a great read and a spot on, but fair assessment. The buzz about this battery is derived from the use saltwater, dirt, and cotton to describe it. These are more of a novelty, feel good battery for those with deep pockets and low expectations. Outputting 400 W at beginning of life…imagine what they will be like after two years of NOT 30 degree, optimal performance weather.

  5. Adam Champion says

    Hi Ronald, thanks for featuring our battery in your article, there’s a few areas I would like to add to and clarify.

    In talking about fire safety, the key advantage for the Aqueous Hybrid Ion technology is that it doesn’t go into thermal runaway which some lithiums can do, case in point Samsung phones, hoverboards and there has already been at least one lithium fire caused by home storage products in Australia.

    Having many kilowatt hours of energy stored for your home comes with risks as all the lithium installation and operation guides tell customers. Whether it’s the risk of fire and explosion, the toxicity of the cooling system gas, the potential exposure to toxic gases should a fire occur or the requirement for specialist firefighting equipment, there are good reasons to choose the inherent safety of Aquion’s water based chemistry.

    Most lithium ion battery companies put layers of protection into their systems, however, if there is another ignition source for a fire, what happens when the battery is exposed to those temperatures? In that case, the battery is going to go off like a grenade… so even if the battery doesn’t cause the fire, it is going to contribute significantly to increasing danger and damage if a fire were to start from another source.

    Power delivery:
    Aquion is very much an energy battery as opposed to a power battery but there is a mix of both in most residential requirements and the good all- rounder aspect of the salties, as some installers call them, is still very usable in on-grid applications.

    Worth also noting that the power delivery characteristic where more power is available in the top part of a battery SOC range is not unique to Aquion and also happens in lead acid and lithium technologies. The power delivery of a typical 4 stack system can be higher than the power rating of some of the battery inverters available to the market and used by lithium solutions (circa 2.5kW AC), so the battery power is not the limiting factor for the majority of the operating range.

    Flat tariff scenarios:
    If your on-grid installation happens to be a flat tariff electricity bill region, running the batteries at a low level through the night gets higher capacity out of the batteries. Many of the battery inverters on the market have the ability to limit the battery power being delivered so it can be spread over a longer period and this can be a great way to optimise the storage performance. This also brings a big smile to many owners when they see they have used battery all through the night.

    Aquion installations for residential energy storage typically have more than one battery installed, so there is an immediate benefit in being able to size the solution to fit the specific needs of the site. There are some Lithium battery solutions that are small and modular (not naming names), but at the four hour rating quoted in the article, Aquion delivers more capacity, continuous power, peak power per building block.

    Off-grid applications:
    For off-grid installations the safe, simple, all-rounder performance aspects of the battery have found good application. The battery chemistry also has the advantage of being more tolerant of high temperature and partial state of charge situations than lead acid batteries.
    Speaking of temperature our battery temperature does not rise appreciably with use and due to the battery size and weight, takes a long time to be affected by changes in ambient temperature. Our installation guidance is 40°C average 24 hour temperature, making it great for hot locations.
    Additionally, partial state of charge tolerance and the ability to go to 100% depth of discharge mean that if an off-grid site has a problem with the generator (not really if but when) the battery bank is not damaged by existing at low states of charge for extended periods whilst the generator issue is worked through.

    Embodied energy and emissions
    Good to pick up on the low embodied energy that the Aquion materials and production processes have. To date we don’t have a figure for it but it is on the list to get compiled.

    Might be worth reiterating that the emissions calculation is not actually emissions from the battery itself, but rather from the grid generated electricity foregone under different efficiencies. The Aquion round trip efficiency is comparable to lead acid and better than flow battery technology.

    Also worth noting that for those that want to go 100% renewable, the emissions calculation is significantly different for off grid applications where extra capacity is built in to the battery and PV array to cover winter loads and multiple days of autonomy.

    Into the future
    Aquion’s AHI technology is a relative newcomer compared to the decades of manufacturing in lead acid, lithium and flow batteries… and we are competitive now. We have more capacity and power that can be achieved with improvements in the design and material options within the battery. Additionally we are still scaling our production and optimizing the supply chain. All this means Aquion is well positioned to bring costs down to meet the market over the coming years.

    Adam Champion
    Aquion Sales Director – Oceania

    • prexpressions-readiescards says


      “We have more capacity and power that can be achieved with improvements in the design and material options within the battery. Additionally we are still scaling our production and optimizing the supply chain. All this means Aquion is well positioned to bring costs down to meet the market over the coming years.”

      For my UK off-grid new residential property I like the Aquion but I need it to drop in price (or improve its performance). I can hold out for 6 months max before I need to commit to a battery storage device. Are you able to say if these improvements will hit the market in the next 6 months?

      Also as I don’t have any energy data consumption on my new (unfinished) property is it possible to start with a small number of units and purchase further Aquions without the newer batteries being dragged down by the older units? (I’ve asked a couple of your UK resellers and have had mixed answers)

      Paul Read, Lincolnshire, UK

      • Adam Champion says

        Hi Paul, great to hear you’re considering Aquion for your storage system.
        Aquion is very well suited for off-grid when you are building a new residence as you can build up the capacity once you know your load profile. If you design with lead acid and find that your energy requirements are higher than you expected then the batteries can be damaged. I have seen a few sites that have killed the batteries quickly due to this situation.
        Ideally you implement any additional batteries within the first year so you can get similar performance across the enlarged battery bank. Also be mindful that new batteries should be matched to your system voltage at the time you add them in and reconfigure the capacity of the system.

        Regarding price movements, these will be subject to the stock management of your Aquion distributor but yes there are performance and price improvements scheduled from the factory within the next 6 months. Here’s hoping that an improving exchange rate also helps you!

      • Interesting Article…

        Paul, we are a U.K based Aquion integrator/installer if you want straight talk regards system design and performance, along with sizing and modularity options we would be happy to help you out and our pricing is likely competitive to what you may have encountered previously. The company is , drop us a line.



    • Adam, I have 2, 48 volt stacks and I need a charger for them I have contacted Aquion for help and they told me to contact MeanWell chargers I was not geven a charger model or part number. So I called MeanWell and they had never heard of Aquion or it’s battires and had no idea of what I was talking about, so I called Aquion back a couple of times for help AND now no one at Aquion will call me back.

      • Adam Champion says

        Hi Dave, I believe you spoke with our support team earlier this week and they confirmed you can use a MeanWell 48v charger. the part number is PB300-48

        Aquion batteries can be charged up with any standard 48v charger which is designed for lead acid battery charging. Typically they provide a 3 stage charge but the key factor is to ensure the charger is not oversized. The peak current for a stack (I assume you have S30 or Aspen 2.2) will be about 17A DC per stack.

        In practice you can have much less than this. I have used a 9A charger from Jaycar (US website catalog number MB3628), the MeanWell one is also good I believe. The other parameter to note will be the peak voltage. As you don’t need to use this charger to completely fill the battery when commissioning this may not be reached but ideally the peak voltage is 57.6v for S30 or 59.5v for Aspen 48S 2.2.

        If you are just doing a commissioning charge you will only need less than 30 minutes to bring the voltage up to a level where your charge controller or inverter charger can be used in normal operation. This is typically anything over 45V. You should try to get each battery to the same voltage , ready for parallel connection.

        Which ever charger you get, you will need to create a pair of charging cables with Amphenol A4 connectors on the ends (ensure the polarity is correct).

        Finally, check out our Installation and operation manuals and our knowledge base at

        Hope this was helpful.

    • Gary Looney says

      Hello Adam,

      I am currently designing off-grid solar system for an insulated panel building.

      The Load is fixed at 48v 5A for 12hrs per day and can be set to operate only during the day, or night. There is no inverter, regulation is only required if the Bank reaches or exceeds 69v.

      Plan for each bank is 9x 320w panels in 3×3 configuration for 150 VOC.

      This project is modular, and could be repeated with a successful design.
      I am posting here because your Battery might work into my requirements with your companies help! There is also question about a competitive price?

      FTA are the current choice, let me know if we can come to arrangement.

      I will include email if you wish to talk: [email protected]

      Gary Looney.
      Menindee. NSW.

      • Gary Looney says

        Additional Information/correction:

        My sizing requirements match the S30-0080 Battery Stack specification.
        The maximum voltage of 57.6v is also better for Load.

        Note: I have made an error above with 69v maximum for load.
        The load voltage upper limit should be around 60v.


      • Adam Champion says

        Thanks for the post Gary I will private email you to discuss your storage application further.

        • Gary Looney says

          Cheers Mate

        • Gabe Campisi says

          does any one havwe access to any more aquion battery systems? since this time they have filed bankruptcy and i cant find them anywhere. I am intrested in this type of battery and belive this to be amazing technology

          • Hello Gabe, we don’t have access to the Aquion battery systems but we do have access to the FIAMM Sodium nickel chloride battery technology. Rather than salt water these batteries operate with molten salt. They have all the safety and recyclability positives of the Aquion battery technology but they also have the ability to draw down large amounts of power quickly which the Aquion didn’t.
            You can get more information on the SoNick battery at

          • Hi Linda,
            Are you offering 10 year warranty, a discount for new adopters and stand behind the specifications listed for Sonick batteries.
            If so, I am happy to consider,

  6. After reading all the info on lithium ion batteries, led acid batteries and now aquin batteries I am more confused and disappointed than ever. We are serious about being of the grid and need a large system but so far have not been wowed with whats available in the off the grid technology. If anyone knows anything that might help us please let me know because with the technology that is available now surely there is something that works efficiently, reliably and is reasonably cost effective. Ken and Fotina

    • Ronald Brakels says

      Ken, I’m afraid that if you are already on-grid, there are no batteries available at the moment that are cheap enough to make it close to being cost effective to go off-grid, even under fairly ideal circumstances. This may change over the next couple of years, so you may not have to wait too long before something is available that suits your needs at a reasonable price.

      Provided it performs as well as promised, the Powerwall 2 will come closest, but it is still far from cost effective to go off-grid with it. I wrote about it here:

      Perhaps in the future the Powerwall 3 or 4 will be cheap enough to give people the option of going off-grid at little extra cost.

    • Hello Ken

      I am not sure if you are still looking at a good battery alternative for an off grid solution but you may want to consider the SoNick or heated salt battery.

      The SoNick battery has all the good points of the Aquion battery in regards to safety and 100% recyclability but also has the power the Aquion battery is lacking. The SoNick battery has the highest energy density of any of the energy storage batteries, is non-flammable so no possibility of thermal runaway.

      The SoNick battery has been in use in Europe and the USA for a number of years so is not a new technology. Although not the cheapest battery upfront, over the life of the battery the SoNick is actually one of the best value batteries, particularly as it doesn’t degrade like most lithium ion and lead acid batteries do.

      You can get more information at

  7. Hi Ronald, At the moment the property has not got grid power and it will cost approximately $35,000.00 to get it so with this cost what do you think, regards Ken

    • Ronald Brakels says

      Hello again Ken. You mentioned you need a large system, so it is possible you would be better off spending the $35,000 to get connected to the grid if your family is a big user of electricity and you’d prefer not to make the lifestyle changes that living off-grid would require.

      But at $35,000 to get connected, it is definitely worth considering an off-grid solution.

      Our battery comparison table lists 26 different batteries and battery systems and can give you an idea of what your options are:

      If you look at the graph showing the cost per warranted kilowatt-hour of storage when cycled daily, you’ll see lowest cost ones are the Ampetus “Super” Lithium battery and the Tesla Powerwall 2.

      If you are in a hurry I’m afraid not a single Powerwall 2 has been installed anywhere so far and I’m not sure how available the Ampetus “Super” Lithium batteries are, but they are the current leaders on price for off-grid home use.

      • Gary Looney says

        Reply I received 16 December 2016
        Energy Specialist | Tesla Energy
        Sydney, NSW Australia

        Quote: Thank you for your feedback, the exciting news Powerwall 2 is able to be installed in an Offgrid application unlike the Powerwall 1. The Tesla Powerwall 2 is arriving in Australia February 2017 and ready for install from March onwards.:End Quote.

        The story behind this is not for here, best left unsaid.
        Not sure if this target is still on track but it might give some incite.

        2x Aquion S30-0080 could work very well for a specific project, but the cost is too high. I really like what they are doing, the %100 discharge and cycle life has many applications.

        I am looking for around 200A Battery storage with relatively high charge rate to capitalize on affordable panels. Nothing in mind, just a starting position.

        I know this doesn’t match the other Specs I have given, have a few ideas running at the same time.

        Been informed, but not personally confirmed that AGM are shorter lived but accept higher current then FLA? Life span probably trumps!

        Another option said to compare with or exceed FLA is LiFePO4.

        Pylontech Extra2000 LFP
        Lithium-ion (Lithium Iron Phosphate)
        $1,999 per 2.4kWh battery
        currently only compatible with SolaX Power Hybrid inverters and Redbacks?

        Less panels and more batteries seems counter intuitive with less input in low light, unless it can be done with similar cost divided by years!

        Researching this is going to take time.
        What option do you see for DIY around 200A

        Your opinion would be appreciated.


        • Ronald Brakels says

          Hello Gary. My opinion on do-it-yourself is – don’t do it!

          Unless of course you are properly qualified and so know what you are doing. In that case, you may want to consider the Ampetus “Super” Lithium battery. I don’t know a lot about it, but you can see some of its details on our battery comparison table:

          If you look at the graph below the battery descriptions you’ll see that when cycled once daily it has the lowest cost per warranted stored kilowatt-hour of them all. So if it suits your needs and you can get your hands on one it may be the most cost effective way to go.

          • Gary Looney says

            Hi Ronald. I do everything myself, very successfully for over 50 years 🙂

            Will be interested to find out when the Ampetus “Super” Lithium is released.


          • Gary Looney says

            I have been in discussion with Avrohom Jacks to purchase the new 3kWh Sinlion Power Super Lithium Battery. There was confusement about the price in only being available for 5+ Quantity orders and no Freight arrangements.

            I hope that we can find an acceptable middle ground for this purchase.
            Awaiting reply,

            Gary Looney
            Menindee. NSW.

          • Gary Looney says

            Hi Ronald, Ampetus has informed me there is a 5+ Minimum Quantity order for 3kwh Batteries as part of product installation. Can you please clarify this for the users of website.


          • Ronald Brakels says

            Thanks for the heads up, Gary. I have looked into this and it appears that now Ampetus will sell single batteries for $2,300. I have been told they will come with a 15 year or 16,930 kilowatt-hour warranty – which ever comes first.

          • Gary Looney says

            Quote: Thanks for the heads up, Gary. I have looked into this and it appears that now Ampetus will sell single batteries for $2,300. I have been told they will come with a 15 year or 16,930 kilowatt-hour warranty – which ever comes first. :EndQuote.

            I tried to make an honest purchase through Avrohom Jacks.
            At the time he was not selling the batteries in Australia and offered me one of his first available shipments. Said I was a trail blazer?

            He said there was no warranty and I agreed to make a purchase on the goodwill between individuals.

            Avrohom then sent me an email stating that these types of batteries are very reliable, and if one fails it would be in 20minutes, otherwise 20years!

            This was a “very stupid” or smart ass thing to say during sale process!

            The PayPal invoice arrived without even been given a product data sheet!

            I cancelled deal and payment because:
            If the Battery did fail in 20minutes, Avrohom’s statement would make my argument or any challenge to battery quality irrelevant. Legally or Morally.

            I have researched Large format Lifepo4 prismatics as suitable and available in the right price range.

            The packed cell type batteries around 100AH 48 to 60v are also suitable with the right offer, but I am not chasing after this option.


  8. Christopher says

    nice write up

    I am making my own inside PVC pipes using Magnesium / Graphite Foam sheets rolled up,
    I’ll look into using rayon as a separator I was using fibreglass

    so far I have 60x 3m long storm water pipes used
    for post hole digger depth so they can be stored in the ground, they hold about 15~20L each

    and are quite cheap to make
    I run a mixer to help stir them up inside
    To do this it is as simple as pumping circulated air through them for turbulence
    closed loop system to prevent contamination as the air is shared between all cells and being air it is an insulator, I was going to pump water through and exchange it etc …

    • Where are you buying your magnesium and the graphite foam sheets? Do you have more info on the construction of your cells?

  9. Christopher says

    I was looking at how they made their cells I don’t understand how they are not shorting out

    the – + are stainless steel collectors are placed in-between the manganese oxide and carbon anode’s while sitting inside saltwater bath

    wouldn’t the stainless steel need some form of coating to stop electrons flowing just in-between the stainless steel tabs , or is the distance far enough apart to have no effect?

    I always thought you needed a fair amount of liquid sloshing around I guess I was wrong 😛

    got some viscose rayon fiber on order will be interesting to see what I can do with it 😛

  10. With all due respect, the environmental analysis makes no sense. The batteries have a density lower than that of water, and are primarily not made of plastic (in the diagrams you can see it is only the shell). This means they do not contain a lot of metal and as such are mostly water. An estimate based on manufacture of solid goods will be quite inaccurate as a result.

    Secondly it doesn’t make much sense to use energy produced by fossil fuels as the comparison, a better metric would be carbon embodied in additional solar panels — this is around 1/3rd to 1/10th the emissions that would be emitted by fossil fuels for the same energy output if you consider their whole lifetime (which would include the life of several batteries).

    This brings me to the real downside of the aquion: Price

    When you account for the cost of extra panels and the cost of buying a bigger battery to get the same capacity, then the cost of replacing them sooner: they cost a fair bit more than lithium. Thus they don’t really make sense as a low cost solution.

    For the extra cost you are getting a lower fire risk, and much lower pollution and questionably ethical labour involved in the system’s production, along with a much lower embodied carbon, so it’s not all negative, but they really aren’t going to be appealing at that price point.

    • Gary Looney says

      I looked into Tesla Powerwall, then Aquion 48S, followed by Ampetus “Super” Lithium and now prepare to import the Batteries instead, so just to talk of why!

      Tesla: I filled my details to purchase and distribute DC Powerwall when intention of manufacture was made. Folks can Google if interested what transpired in the years since.

      Ampetus: I am being diplomatic and perhaps generous to say, the sales practice is questionable. There was a PayPal invoice for more then quoted price before I seen a Data Sheet.
      Due to assumption this was a genuine error, the invoice was paid.
      Putting it nicely, $2000 of money got transferred out of my bank account, through to PayPal, even now the order was cancelled, there is another $300 invoice from Ampetus on my PayPal Account.

      Aquion 48S: Would cost me 30Ah at $1600 for my application.

      Where is the market?

      Manufactures are producing 3.2v Prismatic Lifepo4 50Ah and 100Ah for less then US $1 per Ah. This is not for those wanting set and forget product.
      If you want a DIY storage bank with moderate charge and discharge rate DIY. You also need to understand specialised cell charging with Lifepo4 cells.

      There are big risks for me to import cells, but it is the lesser risk based on my experience with local suppliers.


  11. Interesting review Ron. I had looked at the Aquion as part of a potential house PV hybrid grid interactive solution and was greatly concerned with the power limitations of the battery. And then I found out about a project in the US by Duke Energy where an Aquion battery was integrated with a super-capacitor from Maxwell Technologies to provide substation local energy storage..

    So I ask you, does an Aquion with a super-capacitor outperform a Lithium Ion battery in terms of overall performance and cost in a household scale? Can a super-capacitor capture most of the otherwise lost solar energy from a 4 hour burst from PV and “trickle charge” the Aquion at 100W per stack? Would the battery+supercapacitor have a longer overall cycle life than the battery alone? From my calculations, even a small ~US$400 super-capacitor would vastly increase the peak power, but alas long sustained high power consumption would still be an issue…

    • Ronald Brakels says

      Hello Johnny. An Aquion battery plus supercapacitor would be somewhat similar to the CSIRO ultrabattery:

      For an application where there are frequent but very brief high loads, a super or ultra capacitor could be very useful for dramatically increasing the peak power available. But unless they are uneconomically large, capacitors are better at absorbing seconds or minutes of excess electricity production rather than hours. They are still quite expensive and with the cost of batteries falling the question becomes does it make more sense to pay for capacitors or to increase battery capacity instead? For typical household storage, the answer at the moment appears to be more batteries. But for something with high brief power demands, such an electric vehicle, a combination of batteries and capacitors can make sense. For example, the Nissan leaf has a big black supercapacitor the length of my forearm that helps provide power for acceleration and store energy from regenerative braking.

    • Ronald Brakels says

      Johnny, I’m afraid Aquion has just filed a voluntary petition under Chapter 11 of the United States Bankruptcy Code. That means they have gone bust and are flogging off their assets.

    • Gary Looney says

      Hi Johnny,

      After looking at Aquion Specification I mentioned in Email to Adam Champion, that the Battery needed a capacitor.

      I had no idea this was being done, can assume Adam thought I had.

      As Ronald has described, a capacitor can only resolve short fluctuations above your target charge level averaging with times below.

      I have not really thought about this concept seriously, the comment to Adam was a bit of frustration that the long sought battery from seawater was not going to cut it.

      You might also, store energy in a capacitor just before sunset to be discharged to bank after dark, but we are adding complexity for questionable benefit.

      Found this to read:
      Quantitative Evaluation of LiFePO4 Battery Cycle Life Improvement Using Ultracapacitors


  12. I guess Aquion went broke because most of the original owners that had a two year warranty period started on their warranty claims, as I did.
    Just for your information, the internal impedance of the units were a killer. The battery DC Volts fell for every addition of load. I did some calcs a one stage and worked the internal impedance to be around 1.6 ohms. This is also part of the problem with charging. Within an hour in the morning the battery gets to its float voltage and reduces the charge to around 1kW/h.
    If you increase the charge voltages as per the technical service update, you will boil some of the cells. Did it twice. Also noticed that the battery kwh has dropped by 20% within 2 years.
    I cannot see (if another company buys them out) can ever compete with any of the current technology.
    I bought for environmental reasons. Two years and looking at replacing.

    • Hi Trevor

      If you are looking at battery storage for environmental and safety reasons you may like to look at the SoNick or sodium nickel chloride technology battery. The molten salt battery has all the pluses of the Aquion battery but also has the power drawdown capability that the Aquion didn’t have. You can get more information on the SoNick battery at

  13. I have 19.2 kw of declared net capacity PV installed on my roofs. Under the UK FIT system I can use all of the power generated, but 50% of it is deemed to go into the Grid, for which I am paid, roughly, between between 3 and 5p per kWh. More than half of our electricity use is to power a 30amp AGA cooker which has a 5.5 kW loading on our 240v single phase. This is set up to charge on economy 7 for which we pay (august 2017) about 7.5ppu against the 12.5ppu day rate. Clearly it is impossible to, consistently reliably,run the AGA on our solar panels without some very nifty switching system that uses the solar when available and will, almost certainly, be ineffective costwise.

    My thought is that installing a bank of c.20kw Aquion batteries (which I have been offered), would allow them to be charged in the daylight and then release the charge to the AGA when it cuts in at night. If there is any shortfall, as may happen in the winter months, the Economy 7 will, as at present, pick up the demand. Is my thinking sensible and are there other considerations that may make this impractical?

  14. If you set the charger to only let them cycle down to 70% then there is not much difference in performance.
    So it’s only temperature above 25 deg. C that can affects the performance and make a difference then.
    VRLA Gel Batteries cost around $250/kWh, the price of these Aquiot ones is around $1000/kWh!
    That might actually break the budget!

    Whose big idea was that … ?
    Just put the Gels in the fridge below the milk and move on.


  15. The slow charge would be somewhat less of an issue for an owner with an east and west facing array which would deliver a longer charging period.

  16. Carl Querfurth says

    We installed 10, 2.2kWh Aquion 48S Aspen batteries in our off grid home in Jaffrey NH USA in 2017. We have 38 PV panels divided into two separate systems. 22 panels are 350w and they go through two Schneider MPPT80 charge controllers and an XW+ 6848 inverter to the original 10 Aquion 48S Aspen batteries. The other 16 panels are 250w and they go through a Midnite Classic 200 charge controller and XW+ inverter. Originally they went to a 48v bank of lead acid batteries. After Aquion went bankrupt we wanted to replace our lead acid battery bank and so we searched for more Aquion batteries. In 2018 we found some at a company in Canada. We purchased and installed 14 more of the 48S Aspen batteries and created two banks of 12 batteries each. Since then we have been experiencing a slow but steady decline in power. Recently we’ve been experiencing Low Battery Cut Out episodes triggered by spikes in amperage. When the battery monitors are reporting 60-70% SOC the voltage will drop precipitously and cause a LBC and shut the system down. We’re not sure why this is happening but are looking for ideas. We are thinking we should re-calibrate the battery monitors to see if we can get a more accurate SOC, but that won’t help with the voltage drop. We are concerned that our batteries are worn out and don’t have the power density to maintain during spikes of amperage. Any thoughts? Thanks, Carl Querfurth


  1. 6th Canberra Battery Test Centre Report — 61% Of Tested Batteries Faulty – Solar Power & Energy Tips Blog says:

    […] little interruption in operation.  For others the situation was more serious.  In the case of the Aquion Salt Water Battery, the Battery Test Centre was unable to install it and couldn’t get any assistance because the […]

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