Change in Charge Power

[SolarJunkie]

More of a query for understanding than a problem, but is it the case that a V2 BMS or V2 battery, changes the charge power of HV2600 batteries?

I have added a V2 battery to an existing stack of 5 V1s and replaced the BMS with a V2 also. The system is running fine and the nominal voltage and power look correct. The batteries charge to 100% overnight and all appears well, but since the BMS firmware was updated, as it was quite old on first install, my typical charge power has gone from 4.79KWh to 1.63KWh.

Perhaps this is due to a better BMS?

[Dave Foster]

The V2 BMS has the updated temperature compensation algorithm which starts to throttle charge power below 21C, whereas the V1 did not compensate until much lower temperatures - be worth watching to see how charge power responds as temperature increases.

[SolarJunkie]

Thank you.

21C ambient or battery temp?

Edit: Ambient seems quite high, I assumed ambient to be an environmental temp, but it looks to be something else, as it's around 8C higher than the battery.

[Dave Foster]

Thank you.

21C ambient or battery temp?

Edit: Ambient seems quite high, I assumed ambient to be an environmental temp, but it looks to be something else, as it's around 8C higher than the battery.

It’s the lowest cell temperature, that is displayed as ‘Temp’ in the app when you look at Device, Battery but it’s not available through the OpenAPi so Energy Stats and the home assistant cloud app don’t report it.

Battery temp is actually the BMS junction temperature which is 6-10C warmer than lowest cell temp.

[baldmosher]

Bumping this thread, as I've been looking at an upgrade from 2x v1 to 3x v2 and can't find any v1 stock left.

it sounds like they've fixed the early issues I heard about using v2 BMS with a mix of v1 and v2 batteries.

Was this issue related to the ambient temp? I'm keen to upgrade but not if it ruins the performance. (Starting to regret putting the batteries in the loft now... it can get pretty cold up there!)

[SolarJunkie]

I think the loft would be more of an issue in summer, when it can get quite hot.

I still get a full charge, but at a reduce charge power. Still no idea why.