How many volts should full battery show?
Just looking at some of the info on my battery using the web interface and it’s showing 370v. I have 7 hv2600 batteries. Is that correct? I would expect it to be near to 240volts being in the uk. I might be way wrong and probably am but just looking for clarification. Battery’s are fully charged btw
-
Dave Foster
- Posts: 1298
- Joined: Thu Oct 13, 2022 7:21 pm
I'll give you the full info on the packs which will help.
Each HV2600 has 16 LifePo4 (LFP) cells, a LFP cell has a maximum voltage of 3.6V (100% SoC when charging), a max resting voltage of 3.4V (100% SoC not charging) and a minimum of 3.0V (10% SoC) DC - so each of your packs has a voltage range of 48V to 57.6 DC.
You have 7 packs which are connected in series and so the battery voltage presented to the inverter will be in the range 336V and 403.2V DC
The pack is DC voltage (as are your solar strings) and the inverter converts this from DC current to AC (which is where the heat comes from when it is working hard), and it synchronises it to the national grid (your grid should be between 216.2V & 253V - although it is typically set at the higher end so normally around 240V)
Each HV2600 has 16 LifePo4 (LFP) cells, a LFP cell has a maximum voltage of 3.6V (100% SoC when charging), a max resting voltage of 3.4V (100% SoC not charging) and a minimum of 3.0V (10% SoC) DC - so each of your packs has a voltage range of 48V to 57.6 DC.
You have 7 packs which are connected in series and so the battery voltage presented to the inverter will be in the range 336V and 403.2V DC
The pack is DC voltage (as are your solar strings) and the inverter converts this from DC current to AC (which is where the heat comes from when it is working hard), and it synchronises it to the national grid (your grid should be between 216.2V & 253V - although it is typically set at the higher end so normally around 240V)
You'll only see the voltages at the upper end of the range when you're charging (the 3.6V Dave mentions). Fully charged and not under load, you might see a voltage as high as 3.4*16*7 = 380.8V. But most of the time, your battery will be under some load and you'll see some "sag" vs the unloaded voltage - this is completely normal and occurs for all batteries of whatever type.
For instance, we have x6 HV2600 modules, and as of right now the pack is lightly loaded, with an SoC of 68% and showing 318V, or ~3.3V per cell.
If you take your overall battery voltage and divide it by 112 (16 cells in each of your 7 modules), you should get a number in the 3-3.4 range, depending on the SoC of the overall system.
Looking back over last night when our batteries charged to 100%, the overall voltage peaked at 333V, which is 3.47V per cell. Immediately before they started charging the per-cell voltage was 3.2V, so in practice you tend not to see as much variation as you theoretically could, mainly because the inverters don't quite drive the batteries to the ragged edge, in order to protect their longevity.
For instance, we have x6 HV2600 modules, and as of right now the pack is lightly loaded, with an SoC of 68% and showing 318V, or ~3.3V per cell.
If you take your overall battery voltage and divide it by 112 (16 cells in each of your 7 modules), you should get a number in the 3-3.4 range, depending on the SoC of the overall system.
Looking back over last night when our batteries charged to 100%, the overall voltage peaked at 333V, which is 3.47V per cell. Immediately before they started charging the per-cell voltage was 3.2V, so in practice you tend not to see as much variation as you theoretically could, mainly because the inverters don't quite drive the batteries to the ragged edge, in order to protect their longevity.