Batteries Not getting enough charge

[montana36]

I had the batteries tested and they are fine. The only thing i can think of is the panels need to be Larger in watts, Volts and Amps. I have two panels now and they dont seem to be doing the work. Need Help.

 

[BillK-AZ]

Not enough information supplied for us to help you.

Where is the system located?

What is the energy need? If you have a DC system, provide battery voltage and needed amp-hours per day. If you have a AC system, provide battery voltage and needed watt-hours per day.

Please specify the ratings of the equipment you have: PV module ratings, battery capacity.

How was the battery tested? Full capacity test at known load for a specific/measured period? Just a simple load test?

Battery voltages, Morning, noon, and evening would help others understand your situation.

 

[dereckbc]

I agree you have not provided any useful information to help you out.

Battery Voltage
Battery Amp Hour Capacity
Panel wattage and specs
Daily watt hour useage
Location
Charge controller Type.

As a general rule of thumb the panels need to supply a C/10 charge rate to the batteries, where C = Battery Amp Hour capacity @ 20 hour discharge rate.

Now with that said is still useless because if you have say a 100 Amp Hour Battery @ 12 volts using 600 watt hours per day, you have a dead destroyed battery in a short time regardless of panel wattage. The system as a whole has to be matched to do the job at hand.

Daily discharge on a battery should be limited to 20%, and panels have to be large enough to fully recharge the batteries during the shortest days of winter, plus enough to recover from cloudy days

For example if you use 1 Kwh/day in Kansas City on a 12 volt system using a PWM Charge Controller you need:

12 Volt Solar Panel Wattage = 600 watts
PWM CC = 40 amps
12 Volt Battery AH Capacity = 400 Amp Hours .

If using a MPPT Charge Controller you would need:

Solar Panel Wattage = 450 watts
MPPT Charge Controller = 40 amps
12 Volt Battery Capacity = 400 AH