over charge is NOT an issue
batteries are self limiting .. within correct applied charge voltage
charge controller will Not over charge batteries
what is at issue is batteries ability to supply power during insufficient solar output and not fall below 50% of capacity
and then be fully recharged during the Solar Day, while at the same time Solar is also supplying the power to keep the fridge going
basic example if fridge uses 100Ahr daily
given 5hr max charge rate
solar must supply fridge for 5 hrs and in that 5 hours also recharge 19 hrs of battery use, which will require more than 100ampHrs
don't forget lights, water pump, TV, mobile device chargers etc..
total use plus 10% minimum for recharge conversion losses
if you take out 150ampHrs your charging must equal at least 165ampHrs
this is a very simplified example
solar will begin at sun up with low batteries and low solar
but will taper off before sundown because the low solar late afternoon hrs cannot produce enough to add More charge to batteries that have been charging all day
but at 7am with 3amps solar the batteries will still be discharging while the fridge is running and only charging when the fridge is Not actively cooling, if the inverter pulls 9amps running the fridge (9-3=6) the batteries will be supplying 6amps of the needed power at 7am
the amp numbers may not match your location panel wattage, but the example is correct
at solar noon max power will be applied while fridge is not cooling,
But will only receive partial charge rate while fridge is cooling ..(Max - fridge use) left over goes to batteries
so batteries get full solar rate about 50%~60% per hour the other 40~50% they get less than full rate
500w will not overcharge your batteries, but a larger battery bank that can more easily accept the full rate when available will be more efficient and work better and last longer
