I'm still using SOC and I initiated a manual charge with the 6000xp for 2 ea. wall mounts. The inverter was only showing 55.9 volts at 100% and then settled at 54.2 volts. For charging by voltage, what is the recommended EG4 wall mount battery charging voltage? Awhile back I was told 56.2 volts
My batteries are the Basengreen DIY 314aH/16.2kWh with an active 2A balancer and I originally assembled and connected 2 packs together and I ran them down to 5% by charging our EVs and then let it fully charge in order to reset the SoC coulomb counter in the BMS. This was because I was using SoC for charge control in the 18KPV. But I did noticed the 18KPV stopped charging with a 100% SoC but going into the BMS configuration software they showed 98% SoC. Balancing was happening since that was set for 3.45V(54.4V) but even after 3 days of good sun they batteries didn't get fully charged.
I've since added a 3rd DIY battery pack and ran it down to 3% SoC and as I'm running them all to a full charge I have switched the 18KPV to use voltage level for charge control and I set the top Charge Voltage Limit to 58.3V since the BMS and battery manufacturer states 58.4V as max upper charge voltage.
Yesterday I saw my batteries reporting 100% SoC while only at 54.45V and before I lost sunlight/charge power I saw 7kWh go into the batteries and still only saw 85.5V so there's a decent amount of capacity missing from my previous SoC charging. I think I will try switching back to SoC level charging and then in a few months revert to Voltage level charging and see if there's a change in capacity. I have my discharge cut-off set to 50V which equates to ~5%.
I will update this msg when I see how many kWh go into the battery today to get it to 58.3V/100% SoC.
So in the meantime we have flipped the system to "Lead-Acid" and coded in the proper voltages. He stated to keep it this way for minimally 7 days (oddly specific, but maybe someone can shed some light on that statement)
FWIW, The balancing of the BMS's are top-balancing and for the most part they bleed power off of the higher level batteries but only while the batteries are held above a high threshold voltage. And what I've seen is that it take a number of cycles to 100% and being held there for at least a couple of hours each time before the high cells are bled down so that the low cells end up getting charged to within 10mV of the high cell. So 7 cycles is probably a good number but it's also a big deal that the charge is held for a bit so the balance circuit has time to bleed off energy from those high cells.
Remember, your BMS also has a threshold for cell over voltage(OV alarm and likely OV protect) and when those high cells hit that threshold, the BMS will signal to the inverter to stop charging. The low cells can be well over 150mV lower and will sit at this lower SoC since charging has stopped. This is why the high cells get their energy bled off so that the next time the low cells get a bit more charge. If you see your batteries at 100% and they show a cell difference of under 50mV then you'll likely get a decent SoC out of it.
