I am completely off grid - no commercial power available.
6000XP with 2 indoor wall mount batteries.
During the winter my system goes from 100% down to 20% every couple of days and the gen kicks in and brings back to 100%
However, during the summer my SOC rarely (if ever) get below 85%.
I think my Top end SOC has drifted as my resting voltage on the batteries at 100% are showing right around 54.2. in the winter they would consistently be around 55.2.
I am trying to figure out how to perform an SOC recalibration for both Top and Bottom.
Having read the instruction at EG4 and seeing some videos I am just not certain how to accomplish this, or I am misunderstanding it.
I am assuming I will need to do the following:
1 - Disconnect solar (what is the best way to this since the manual says not to disconnect while the inverter is under load) Do I need to completely shut the system down to be able to disconnect the solar safely?
2 - Disconnect one of the batteries and turn off my generator.
3 - Allow the system to drain down until the battery alarms and the system faults out thereby setting the bottom end of the SOC for one battery. Now, if that battery has faulted out, how do I charge it again without an inverter running?
4 - Charge the battery up until it alarms out with an over voltage on a cell thereby setting the Top SOC. (I am assuming that I will need to use lead acid setting to accomplish this. Would there be an EG4 set of recommended setting to accomplish this?
5 - This battery when it hits full charge.
6 - Repeat with second battery.
7 - Check both "full" batteries to make sure that the voltage between the two are close enough to be able to connect them up again.
8 - Connect all batteries and resume normal operations.
I anticipate that the drain down time for me will be at least a couple of days so the whole process in theory should take me 4 to 5 days.
Does the above process need to run more than once to get the SOC recalibrated well or is once enough?
The recalibration documentation also indicates that this should be done once a month, is that realistic? I will be spending a good portion of my month just recalibrating batteries.
Is there an easier way to accomplish this? I know quite a few folks say to run in Lead acid mode all the time. I have been hesitant to do that since I am completely off grid, I try to avoid nuisance starts on my generator by a pump kicking on or some other load so using the BMS works well for me, but this recalibration seems overly difficult.
I appreciate any advice, direction to a how to from EG4, or a detailed whitepaper?
Thank all.
