Gel Batteries Gurgling
Long time reader, first time poster.
We put together a solar system last year for a cabin that we use as a summer house. Last week we started to have a problem where the solar controller (A cheap PWM model) would stop charging the batteries. There was no error, the LCD just didn’t show any current going from the panels to battery. To fix the problem we would reset the controller (disconnect solar and battery, let stand 20min then reconnect). That would fix it for 2-3 days. We thought maybe the PVMax was to low for our panels output (the problem would happen at peak sunshine). During this time we wouldn’t notice the problem and the batteries drained to 44.5-45V at least 5 times.
Anyway, we bought a new controller:
SRNE MPPT 60A with a 150V PVMax
2 days in and we have a new problem. The gel batteries started gurgling or maybe a squishing noise when at 100% SOC. We had a clear day today and the batteries got up to what the charge controller says SOC was 100%, The battery voltage was 56.7 and was charging at 25A in "boost" mode.
We used the default settings on the controller for Gel batteries:
Overcharge Disconnect 16.0V
Charge Limit 15.5V
Boost Charge 14.2V
Floating charge 13.8
If the batteries are bubbling my assumption is that they are overcharged or charging to quickly. Is a charge limit of 15.5V to high?
The other think I could think of is that maybe the batteries are damaged from discharging to 45V. I'm not sure how to troubleshoot this or what to do next.
Thanks in advance!
Current at Pmax: 8.83A
4 series of 2 panels each
Cheap PWM 48V
Charging Current 60A
Solar Max Voltage 88V
SRNE MPPT 4860
12V batteries (2 series of 4 batteries each)
Max Charge 37.5A
Pure sine wave