Charging Troubleshooting

[Chaker]

I have two felicity lithium batteries 8.7 kw connected to a Deye inverter. The problem is that the inverter is not charging fully the batteries. The reading of the two batteries gets shrinking with each day. For instance, it reads 99% for the first battery and 97% for the second. The next day it becomes 98% - 97%. the day after 98% - 96%. ... Today 97% - 93% and the charging stops at these percentages, as if the batteries are full.
Can anyone help me?
Thank you in advance

 

[robbob2112]

How are they wired?

Series? Parallel?

If series you need an active balancer to equalize the charge

For parallel with 2 you need to have them wired in a Z configuration. This means

Inverter+ b1+ b2+
Inverter- b2- b1-

If using bus bars just swap the b1 and b2 leads on one side or the other.

This will keep the batteries better balanced

Your two batteries have slightly different internal impedance which is causing to problem.

 

[BenQ]

What @robbob2112 suggests is solid. If that doesn’t help try letting us know what you are using to determine the state of charge (SOC) of your batteries. Are the felicity batteries connected to the Deye via RS485 or CAN comms? What settings have you configured on your Deye inverter?

 

[BenQ]

How are they wired?

Series? Parallel?

If series you need an active balancer to equalize the charge

For parallel with 2 you need to have them wired in a Z configuration. This means

Inverter+ b1+ b2+
Inverter- b2- b1-

If using bus bars just swap the b1 and b2 leads on one side or the other.

This will keep the batteries battery balanced

Your two batteries have slightly different internal impedance which is causing to problem.

This video from @Will Prowse might help you visualize what @robbob2112 is saying.