AiO appears to discharge significant amount when on low load

As background we have a GiV AiO 13.5kw, fitted 15 months ago, we have 4kw Solar Panel array, fitted about 11 years ago and a Heat Pump, fitted 3 ½ years ago. Also we’re on the Octopus Cosy tariff. In summer the AiO is primarily to store solar and save us importing from the grid. Typically over the last quarter our average weekly import is under 8kw. (largely because we have a 10.5kw electric shower used daily).

Finally we are on Inverter Firmware Version D0.616-A0.616 & Battery Firmware Version 12.

Last night – for the second time in 3 weeks our battery discharged at quite a high rate when the load was pretty low. So, at 19:55 the battery was at 67% but by 22:55 it was down to 34%, the typical load was around 250w per hour – running fridge / freezer / odd lights etc. Typically on “normal” nights our AiO will drop ~3% overnight. (to my knowledge this has only happened twice since the end of May.

I’m not sure if we have a problem / are doing something wrong but would appreciate any thoughts / comments before I make contact with GiV.

Many Thanks

Malcolm Hassall

I’m sure others will chip in, but the first thing I would try is to discharge the battery to empty (4%) and then charged to full (all the way to 100%, even though it may hang around at 99% for a while). This will ensure that a calibration of the reported charge level takes place.

The batteries are very prone to “losing their way” if they are operated in a narrow range of charge for a period of time. Taking them to the extremes will reset. It is good practise to do this regularly.

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OK & thanks for this - makes sense - was told to do this to an electric razor years ago but assumed battery technology had improved - I know it has but maybe not in this respect!!

Also you should note inverter is most efficient at 20-80% power
If you are drawing really low power the inverters own draw will be a significant part of your battery use.

Thanks for that - I’m learning about this all the time. We try to run between 20 & 80% and let solar top it up when there is some. Didn’t realise there was another good reason for doing this. We don’t always achieve it especially in really cold weather!
Cheers
Malcolm

I’ve just updated the battery firmware to BAAA0013 and inverter firmware to 619.A0.619

Tomorrow I’ll charge to 100%. Let it naturally run down and then slow charge to see how that goes.

To limit to 80% max would setting the target SOC be enough? Or is there another option to use?

I have GivTCP into home assistant so can toggle all the bits.

Thanks

As a matter of interest how did you get the latest firmware? Was it offered via the portal software tab, or did you download it onto a stick from somewhere and do it manually. Cannot see anywhere online to get it from, and told that GE are difficult to contact these days. Please let us know if it solves the this SOC issue.

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Just google “Givenergy firmware” and you will get the results. The page that has it is “Installer resources”

https://givenergy.co.uk/wp-content/uploads/AIO-Firmware-Package-Complete-Set.zip