{"id":100063,"date":"2026-06-26T05:05:42","date_gmt":"2026-06-25T19:35:42","guid":{"rendered":"https:\/\/www.solarquotes.com.au\/blog\/?p=100063"},"modified":"2026-06-25T23:14:15","modified_gmt":"2026-06-25T13:44:15","slug":"solar-batterys-minimum-reserve-level","status":"publish","type":"post","link":"https:\/\/www.solarquotes.com.au\/blog\/solar-batterys-minimum-reserve-level\/","title":{"rendered":"A Solar Battery\u2019s Secret Lever: The Minimum Reserve Level"},"content":{"rendered":"

\"AThe minimum level of charge a battery will keep up its sleeve can be customised to best suit your priorities – whether it\u2019s maximising energy trading profits, blackout protection or reducing degradation. You can even tweak it temporarily in response to unusual conditions – as I found during a power price surge earlier this week.<\/p>\n

A Price Spike That Drained My Battery<\/h2>\n

I had a Sungrow<\/a> SBR home battery (pictured above) installed a couple of months ago and joined Amber, to see what life on the wholesale price rollercoaster was like.<\/a><\/p>\n

It had been a pretty uneventful ride until last Sunday night, when wholesale electricity prices skyrocketed in part due to a severe wind drought – an event that prompted Pauline Hanson to falsely claim that us South Australians were paying $5 just to boil a kettle (despite almost all non-Amber households being shielded from price spikes behind flat retail rates).<\/p>\n

Amber\u2019s AI-driven energy management system, which is still getting to know my home’s consumption patterns, got a bit excited about cashing in on the very attractive prices, and ramped up exports of our battery’s stored energy for profit.<\/p>\n

I was happy enough with this – until realising that it had left our battery at just over 25% capacity ahead of a cold evening. Suddenly it looked like I was going to have to buy back the energy I’d just sold, with the prices still sky-high.<\/p>\n

\"The

The June 21 price hike, as shown in the Amber app.<\/p><\/div>\n

Time For A Fireside Chat<\/h2>\n

My partner raised a skeptical eyebrow when I intercepted her as she was on the way to turn the ducted heating on, and I suggested out of nowhere that it was a great night to get our little-used fireplace going.<\/p>\n

She wasn’t buying it, and I had to begrudgingly admit that after forking out thousands on our new energy storage system, we’d better both put an extra jumper on rather than turn on the ducted reverse cycle.<\/p>\n

But then I had another thought: why not instead lower our battery’s minimum reserve level so it uses more of its stored energy than usual to get us through the evening with the heater in full swing, without supercharging our energy bill by drawing from the grid?<\/p>\n

A Battery’s Minimum Reserve Level<\/h2>\n

A home battery generally has a programmable minimum reserve level that the system doesn\u2019t drop below, ensuring homeowners will be able to keep the lights on and the fridge humming in case of a blackout.<\/p>\n

This is usually set between 10% and 30% of your battery capacity. Setting aside at least 2 kWh is advisable, but what percentage level you choose should really depend on the size of your system, what your priorities are, and what kind of backup features your system boasts.<\/a><\/p>\n

The higher you go, the longer your payback period will be, as some of your battery capacity is going to sit unused most of the time. But likewise, the lifespan of your battery is extended as there\u2019s less battery degradation.<\/p>\n

Go for a lower reserve however, and you\u2019ll put the battery to work more often and enjoy better financial returns – less drawing from the grid, more exporting for a profit.<\/p>\n

Modern battery chemistry will reliably work much harder than legacy lead acid for instance, but you will also put more strain on the battery<\/a> and risk degradation, especially if you routinely cycle below 20%.<\/p>\n

Allowing charge levels to drop very low in exceptionally cold weather is also bad for the battery, although this applies more in freezing conditions we don\u2019t see often in Australia.<\/p>\n

You will obviously be more vulnerable to running out of power during a blackout, which might be more of a going concern if you\u2019re in a fringe of grid area that experiences them more frequently.<\/p>\n

Manufacturers often specify recommended level to set your battery at, as well as maximum depth of discharge (DoD), which can in turn impact warranties, so consider that before mucking around with your minimum reserve level.<\/p>\n

Sungrow set a floor on their battery so you can never use the last 5%, whereas other makers allow 0%, but immediately force a grid charge to recover a safe level.<\/p>\n

How Do You Change A Battery’s Minimum Reserve Level?<\/h2>\n

The answer depends very much on your brand of battery, but a good installer will ask you what your preferred level is during the install and do it for you – and might even take you through how to adjust it yourself.<\/p>\n

In my case, in typical Sungrow style<\/a> I had to navigate a slightly convoluted adventure through obscurely-named options buried in menus and submenus of the brand’s iSolarCloud app (to be fair, many other brands subject users to similarly Byzantine journeys).<\/p>\n

The menu path for me in the\u00a0app was:<\/p>\n