TheNinjaCat

Okay great, this helps a lot. Its looking like 3 problematic cells so far. Cell 4 is overcharging, and Cell 7 & 8 are over discharging. I'll try a few more days with slow charge/discharge and see what happens. Failing that, i'll have to take it for someone to have a look. Appreciate the knowledge & assistance !

Hi @I84RiS thanks for the insight, let me give this a try. Side note, today it appears that the voltage of the (faulty) battery has gone over 26.9 V and is not reporting at 100% SOC yet, in fact its only reporting ~62% SOC which according to voltage charts i have read is now reporting SOC as too low. The battery is currently 26.94V which i have not seen for a long time all cells seem to be currently balanced (cell 4 is not currently drifting ahead as it has been over the past few weeks). I have had 2 nights in a row with the battery switching off for low voltage protection (perhaps some sort of a balancing happened) I will be able to report more findings as the day goes on ====EDIT===== Just as things were looking up, cell 4 started to drift ahead, i slowed down the rate of charge when it got to 3500mV to not hit the overcharge protection and the voltage of cell 4 has started to drop with the SOC slowly creeping up. Thanks for your insight, i am going to try and charge discharge at a much slower rate as you suggested

Hi @TaliaB thanks very much for the prompt response. I do charge the batteries full on a daily basis provided there is enough sunlight (or as full as the battery will currently allow). So the (faulty) battery is reporting at 100% SOC and around 90% on the other battery, which is at a voltage of around 26.9V. I do not have comms between the inverter and batteries as i couldnt get that to work. Currently, the bulk charge is set to 26.9V, and float charge to 26.8V (the inverter [Growatt 3000] appears to take try the batteries to 27V and then switch to float, however the battery in question stops taking charge before it gets to 27V)

Hi Guys, I have 2 (no so great) 24V LifePo4 batteries on my small 24V solar system. The batteries are MUST LP16100, 25.6V, 100AH (x2). [Link to battery] One is the latest model as per the link above (which I bought a year after the first one, and used it alone to get the cycles to match the older battery, and then paralleled them with a busbar). The other is the model prior, however same brand model, specs etc. Also worthy to note, i stored the older one for one year at 100% SOC, which according to my research might not have been the best approach to that. The older battery (the one that was stored for 1 year) appears to be imbalanced or more likely appears to have a faulty BMS. - While discharging (at a bit less than ~40% SOC) cell 8 & 9 reports voltage of ~250mV lower than the other 6 cells. The other 6 cells are around 3250mV and cell 6 & 8 report at around ~2900mV (this also appears to trigger the low voltage protection cut off) - While charging, all cells are around ~3300 mV and only cell 4 reports at 3532mV and this also appears to engage the over voltage protection, not allowing the full pack to even reach 27V and reporting at 100% SOC and not taking any more charge. During the charge cycle, all cells are reporting as pretty evenly balanced with 20mV difference max. Its only when its around ~95% while charging or around ~40%(or less) while discharging do they (apparently) go out balance. Any advice on this would be much appreciated !

https://www.geyserwise.com/wp-content/uploads/2023/05/GeyserWise-Max-installers-manual-2015.07.01.pdf

If the mechanical thermostat is set to 65 then its 100% the geyser wise controller switching the element off at 55, and then you would need to follow the tutorial posted above to set that higher

Yeah so the geyser wise is controlling the geyser element and switching it off at 55 degrees. Earlier when i suggested using the sun to heat the water further, it was under the assumption that you had a solar geyser as well, the evacuated tubes for example

I imagine the thermostat at the geyser to be set to higher than 55, however if it was 55 then it would be a bit of a co-incidence, but that i guess could also cause it to stop heating at 55

It will show as still 'on' and could be confused with 'still heating' but it will switch off the element according to your settings (55) until the water drops below 55 and will start heating via the element again, much like a normal geyser works

Hi, It appears in some models that you can go to 65 degrees via the element (video on how to change the settings below) If your model only goes to 55 degrees u can use the sun to go higher than that, you would need to heat the water to 55 degrees with the electric element while there is still sun out, and let the sun heat it past that, now during winter and depending on your direct sunlight, u might want to be 55 at around 2pm already via the element, and then let the sun take it to 65 from 2 - 5 pm. You will need to play around with the times for your geyser location specifically

Hi @Echme3lat, Did you ever manage to get this issue resolved. I have the same issue, however with the Growatt 3000 and 24V Must 100Ah battery. I have been in communication with MUST and there are a few things that you need to do, the main one is that you have to change the protocol on the battery via MUST's PBMSTools battery software (see attached image), as well as get the comms cable made up as per their specifications. I have *most of the information as well as the software Would be great to hear if you have manged to get this sorted and if not, perhaps we can get it sorted here