Calling on Solar Techies
I have been thinking of going solar for some time and decided to pull the plug. My wants are a 400 to 500 watt system. I have four 12 volt batteries with 340ah. I am not planning on changing b...
Forum Discussion
The weak battery can be left in for whatever AH it can add to the bank, but it should NOT be left connected to the others when there is no shore power or solar to keep the bank on a Float voltage, or it will drag the other batts down too.
A Float voltage will "float all boats". On solar you will likely make up in the daytime what the good batts lost at night from the weak battery.
When charging, the good batts might never get to full as the weak batt steals some of the amps, but you might not notice this for the next year.
You need 16v on the weak battery, so disconnect from rig where fridge limit is 15.4v. One way to equalize the weak battery is to isolate it from the others, and use your 12v (don't do this with 24v panels) solar panel(s) disconnected from the controller, but connected directly to the weak battery. Spot check the battery for voltage and SG, stop charging when SG stops rising or when voltage goes past 16.5v or when "water" pours out of top battery caps.
A Float voltage will "float all boats". On solar you will likely make up in the daytime what the good batts lost at night from the weak battery.
When charging, the good batts might never get to full as the weak batt steals some of the amps, but you might not notice this for the next year.
You need 16v on the weak battery, so disconnect from rig where fridge limit is 15.4v. One way to equalize the weak battery is to isolate it from the others, and use your 12v (don't do this with 24v panels) solar panel(s) disconnected from the controller, but connected directly to the weak battery. Spot check the battery for voltage and SG, stop charging when SG stops rising or when voltage goes past 16.5v or when "water" pours out of top battery caps.
