MPPT Charge Controller Over-voltage

[sjkted]

Hi All,

I have a LiTime battery being charged by a PowMR MPPT solar charge controller. A 3000 Giandel inverter is powering a small residential fridge. Right now, the battery is charged to 100%. I have an intermittent alarm that is going off on the inverter for high voltage. When I check the charge controller, over a 1 minute period, theses are the voltages I see on the SCC: 15.2, 14.2, 13.7, 13.6, 14, 16.1, 17.4, 18, 16.3. It seems like the SCC is looping from a high voltage back to a normal voltage over and over and over again. I have the battery type set to L04 which should be correct on the SCC. My temporary solution is to just turn off the solar as I don't need it right now. Is this normal? Is there a way to program the SCC not to do it? Per the manual a LIPoe4 battery should have the following:

Boost charging voltage: 14.5V
Float charging voltage: 13.8V
Low DC cut-off voltage: 11.2V
Low DC cut-off recovery voltage: 12.8V

I can edit these values as a custom setting but I don't really see the point if it is not respecting what is already in there. Please advise. I already e-mailed the manufacturer.

Thanks,

sjkted

 

[sunshine_eggo]

LiTime battery is imbalanced and cutting off charge causing MPPT voltage to spike as the battery is suddenly removed from the charge circuit. The MPPT can't clamp down on the current fast enough to prevent a spike.

Very common especially with new batteries. Typicaly installed 90+ days since they were last charged and must ship at 30% SoC max due to hazmat regs.

Boost to 13.8V
Float to 13.6V
Boost duration to 4 hours.

Should reduce/eliminate spikes. Leave it this way for about a week.

Once you can charge to 14.4V w/o spikes:
Boost to 14.4V
Float to 13.5V
Boost duration to 30 minutes.

 

[sjkted]

Thanks, I remember seeing this elsewhere on the forum.

Can you explain how that works in a practical sense? Do I need to unplug the inverter and fridge?

Are you saying just to charge once and let it sit for a week?

I have the MPPT SCC, a Litime 40A charger and a generic 10A charger that will do LiPOE4 batteries?

sjkted

 

[sunshine_eggo]

Thanks, I remember seeing this elsewhere on the forum.

Can you explain how that works in a practical sense?

It lowers the absorption voltage to a point that should reduce eliminate spikes (BMS protection events) while still allowing battery to achieve a near full SoC (98%+) over a longer period of time.

Do I need to unplug the inverter and fridge?

If you can eliminate the spikes, it should be unnecessary.

Are you saying just to charge once and let it sit for a week?

No. Let it operate with those settings for a week.