Strange charging behavior with liFePO4 batteries and EAsun hybrid inverter.

[Mattb4]

Since I changed my battery from AGM 24vDC to lithium 2 days back I am noticing an odd charging behavior. At some point in the day the voltage cycles at 28.0 when the solar power wattage drops to zero. Then the battery voltage drops to 27.4 before charging starts again until voltage climbs back up to 28.0 before cutting out all wattage from panels. It does this over and over. Incidently I do not have any settings that are at 28.0 for lithium batteries so I do not know where that comes from

Yesterday after awhile the solar disconnected entirely (the bar indicator from the solar icon disappears) although PV voltage still indicated. I understand that to be battery fully charged and thus no more charging will occur.

I just not used to this wattage from solar going on and off, it did not do that with the lead acid. Can anyone provide an answer if this is something I should expect to see?

 

[Mattb4]

There is no question that operation of this inverter is quite different when going from lead acid to lithium batteries. The fact it cuts out solar after lithium batteries are fully charged and does not start recharging them until they drop to low ends up with not being able to easily match time of day to charging. At this point I am not sure if I will go back to lead acid. With lead acid they are basically always ready to take a charge.

ETA: After looking at various setups I am going to try SOL with OSO (solar only) charging. I set my transfer to utility at 25.6v to keep the battery at around 20% minimum state of charge. With solar only charging that should force it to take maximum advantage of solar and fall back to utility only when needed. I hope I have this stuff figured out. Way too many things to consider for this aging mind.

8/30/22, I increased the battery fully charged recovery point from the default 26v to 26.4v and it seems to help. I also increased the float voltage to 29.0v from 27.6v default.

8/31/22 Continuing tweaking of the settings seems to be getting to a point where solar does not cut out entirely. I dropped the float down to 28.4v and changed utility to battery set point to 27.2v