Hi,
Over the weekend I installed a couple of extra battery modules in my system, I'm now up to 5 modules from 3. We had a couple of great sunny and warm days sunday, monday and tuesday to charge and discharge it to balance the modules, but today is the first day with not a lot of sun, and I notice the battery discharging itself pretty quickly.
I have the minimum soc set to 20%, it reached that around 4.00 tonight and the inverter switched over to the grid as expected. However, without the inverter putting a load on the battery, the charge level kept dropping until it reached 16% at 6.45, and re-charged from the grid at 7.10. Now it's dropping again at the same rate.
I know that a battery will always lose some charge when it's not doing anything, but this seems excessive to me. I have the home assistant modbus integration running, and I can see it dropping from 2,22kwh at 7.35 to 1,99kwh at 8.35.
Could this still be caused by imbalanced cells, or can there be something more going on?
Battery discharging itself
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Dave Foster
- Posts: 1392
- Joined: Thu Oct 13, 2022 7:21 pm
You've not said which batteries you have HV2600 (V1/V2), ECS etc... - that would help with the diagnosis.
The SoC you see is constructed by the BMS from the state of all the batteries and so if some have a higher state of charge than others you may see SoC jump, or drop below minsoc - that's a good indicator of the pack being out of balance.
When you add new batteries they existing batteries should have beeen at 50%, if they are not it can take many weeks for the batteries to balance (the balance circuits are not designed for large changes) - doing full cycles will help, set your minsoc to 10% and let it get there, then allow charge up to 100%, but is might still take time for the balance to correct.
Also adding new batteries to the system needs the battery firmware to be updated on all battery modules, has that been done ? - if you drop an email to Fox service with your inverter serial number and ask for the battery firmware to be updated they usually update it within a day or 2.
The SoC you see is constructed by the BMS from the state of all the batteries and so if some have a higher state of charge than others you may see SoC jump, or drop below minsoc - that's a good indicator of the pack being out of balance.
When you add new batteries they existing batteries should have beeen at 50%, if they are not it can take many weeks for the batteries to balance (the balance circuits are not designed for large changes) - doing full cycles will help, set your minsoc to 10% and let it get there, then allow charge up to 100%, but is might still take time for the balance to correct.
Also adding new batteries to the system needs the battery firmware to be updated on all battery modules, has that been done ? - if you drop an email to Fox service with your inverter serial number and ask for the battery firmware to be updated they usually update it within a day or 2.
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Donkeychote
- Posts: 4
- Joined: Wed May 03, 2023 11:46 am
Thank you for the reply.
I have the HV2600 V2. When I installed the new modules I checked the voltage on them, and hooked them up when it matched with the reported voltage in the app(divided by 2 because there were 2 modules hooked up already). That may have been wrong, the existing battery was only around 13% at the time, but I figured the new ones had lost charge while in storage.
I did see the jumps in SoC you mentioned while chargin the first 2 days. One from 72% to 92% the first day, one from 86% to 97% the second day. Both in just a couple of seconds, I already suspected that was because of balancing.
I'll drop the minsoc and do a few more full cycles the next few days, see if that helps.
I can't update the firmware myself since I'm not an installer, and my installer went bankrupt, but I'll send a mail to Fox to do so. It seems like they do have different firmware, I can see 2 modules with version 1.01, and 3 with 1.00 in the cloud interface.
I have the HV2600 V2. When I installed the new modules I checked the voltage on them, and hooked them up when it matched with the reported voltage in the app(divided by 2 because there were 2 modules hooked up already). That may have been wrong, the existing battery was only around 13% at the time, but I figured the new ones had lost charge while in storage.
I did see the jumps in SoC you mentioned while chargin the first 2 days. One from 72% to 92% the first day, one from 86% to 97% the second day. Both in just a couple of seconds, I already suspected that was because of balancing.
I'll drop the minsoc and do a few more full cycles the next few days, see if that helps.
I can't update the firmware myself since I'm not an installer, and my installer went bankrupt, but I'll send a mail to Fox to do so. It seems like they do have different firmware, I can see 2 modules with version 1.01, and 3 with 1.00 in the cloud interface.
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Dave Foster
- Posts: 1392
- Joined: Thu Oct 13, 2022 7:21 pm
Ok, yes that’s quite a big difference in SoC, new batteries are supplied with approx 50% charge, it doesn’t lose that much in storage so it will take a while to balance (possibly a couple of weeks).
They are old firmware versions so drop an email to Fox service with your inverter SN, they are usually very quick to respond particularly if you tell them your installer is no longer trading.
They are old firmware versions so drop an email to Fox service with your inverter SN, they are usually very quick to respond particularly if you tell them your installer is no longer trading.
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Donkeychote
- Posts: 4
- Joined: Wed May 03, 2023 11:46 am
Foxess was indeed very quick to respond with the requested update. I made a ticket this morning, and a couple of hours later they updated the firmware, now all batteries are on 1.11.
I'll keep an eye on the discharging the next couple of weeks, but thanks for reassuring me there isn't anything wrong with the batteries.
I'll keep an eye on the discharging the next couple of weeks, but thanks for reassuring me there isn't anything wrong with the batteries.
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Donkeychote
- Posts: 4
- Joined: Wed May 03, 2023 11:46 am
It seems like the couple of extra cycles from this week, plus the battery firmware update resolved the issue. It discharged to 10% last night, and then sat there for 4 hours, not losing anything until the solar panels kicked in and started charging.
I thought that warranted one final post in here, if anyone is in the same situation in the future, Dave's advice fixed it!
I thought that warranted one final post in here, if anyone is in the same situation in the future, Dave's advice fixed it!