HV2600 missing capacity - help me understand

[andrewmoore]

Hi all,

I've had 5x FoxESS HV2600 v2 batteries for a while now, and it seems the actual total capacity isn't quite right.

Here are my numbers of what I think the total capacity should be:
- Advertised Capacity: 12.8 kWh
- SoH: 95%
- Total Capacity: 12.16 kWh

However, in reality, my total capacity is only around 10.25 kWh. I've calculated this by doing the following calculation in Home Assistant:

Code: Select all

sensor.bmw_kwh_remaining / sensor.battery_soc * 100

Given you can only discharge to 10% SoC, usable capacity is actually only 9.23 kWh. Just 72% of the 12.8 kWh quoted. Reality seems to match up to this, I hit 10% SoC yesterday and charging last night only added 9.1 kWh.

Is this just how it is, or am I missing something? I feel like my usable capacity should be much closer to 11 kWh. If it helps, here are my firmware versions:

Inverter:
- Manager: 1.63
- Master: 1.60
- Slave: 1.02

Battery:
- Master: 1.008
- All slaves: 1.07

tl;dr: usable capacity is only ~9.2 kWh but expecting it to be closer to 11 kWh.

Thanks in advance!