I am currently not at home, and the AIO Battery has shown rapid drop in battery charge status, several times, with no obvious increase in power utilisation
My Battery is 13.5 KW, I Wouldn’t expect the background power utilisation in an empty house, to deplete the battery to 4% and start charging during the expensive part of the day.
My normal utilisation when I am home is in the region of 40%, so why is vacant house utilisation varying between 20% and 75%
I think you’ll have to look at the house load - the Giv inverter will no doubt have a clamp monitoring that. It’s possible for the battery SOC to adjust, but that sounds too high - more like something is drawing power. Check the house load in the portal
If I was able to leave pictures, I Would have included an image showing no appreciable difference between house load, before the questionable reduction in battery capacity and during the period of concern.
If the battery state of charge needs re calibrating frequently, there must be something wrong with the system.
this is almost definitely the cause of your problem. If you keep your battery in a narrow SoC range then the battery can loose track of how much is actually stored in it.
The power didn’t discharge, it was never there, and what you saw was the inverter correcting for how much charge it realises that it actually has
You don’t need to recalibrate the battery, but what you do need to do is ensure you are on the latest firmware for your AIO, and regularly (every week or so) ensure your battery gets discharged fully and recharged fully. This should solve your problem. It is quite common.
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Hi Geofferey,
Do I need to actively disconnect my mains supply, to cause a discharge to re ballance the batteries?
at the moment there is enough solarpv to charge the battery to 100% most days however the state of charge is getting progressively worse for the same load conditions.
that seems to be an odd way to run a whole house backup system.
regards Joan
You shouldn’t need to disconnect the grid supply.
To explain a bit further….
The inverter can’t directly measure state of charge (SoC), i.e how full/empty the battery is. What it does instead is measure the battery cell voltage. A reading is taken of the voltage when the battery is empty, this is recorded as the 4% level, and then a reading is taken when the battery is full, this is the 100% level. The inverter then calculates what the SoC is for any given battery voltage level.
The voltage range between full and empty is quite narrow though and what happens is that over time the inverter looses track of how full/empty the battery is. A sudden SoC drop then occurs when the inverter realises the battery is less full than it thought it was.
Quite a few people had this problem with the AIO and progressively GivEnergy improved the firmware so it got better at working out what the SoC was. So hence my advice to ensure you are on the latest firmware.
The other part of the advice is to semi-regularly let the battery go from full to empty which massively helps the inverter to work out what the SoC level is. If the battery is kept in a narrow usage range then this problem is exacerbated.
As solar generation is increasing your battery gets to 100% quite easily, but if you don’t have the house load to match its capacity, then you won’t get to 4% empty before it starts charging off solar again. If you can do a forced export overnight to drain the battery, ideally to finish an hour or so before the start of solar generation to give the inverter time to recalibrate the empty SoC level.
Thank you Geoffery,
Givenergy will not tell me, how frequently I need to flatten the battery in order to overcome this .
flattenning your whole house backup system would seem to undermine the ‘backup’ element of the system.
I thought the idea of a solar battery, was storing the PV, so that you could use it later.
How many times per week do you need to fully cycle the battery?
I haven’t seen any Givenergy reccommendations.
I Have asked for advice from them directly and through their suppliers, so far, silence!
Joan
I don’t think there is any hard and fast rule, but once a week, once a fortnight would be good, even once a month is better than keeping the battery at a high charge level for an extended period of time