Water tank heating

Hi. I searched high and low, but cannot figure out how to heat water tank with excessive current from solar/alternator when my two batteries are charged. I think to switch current to 12v heating element when state of charge is 100% and turn it back to battery charge when SOC is let's say 90%. I do not want to use voltage level, because I am not sure when charger will be at 'float' state. I think I can deduct SOC from battery monitor using microcontroller which can operate relay to switch current direction back and forth.

Please advise what charger can I use where I can control charge direction - battery or heating element. In other words I saw chargers which have 'Load' and 'Battery' outputs. I want to switch between them at will, i.e. measuring SOC and turn on 'load' or 'battery'.

Thanks!

konstantin.vyaznikov@xplo said:

I think to switch current to 12v heating element when state of charge is 100% and turn it back to battery charge when SOC is let's say 90%. I do not want to use voltage level, because I am not sure when charger will be at 'float' state. I think I can deduct SOC from battery monitor using microcontroller which can operate relay to switch current direction back and forth.

Please advise what charger can I use where I can control charge direction - battery or heating element. In other words I saw chargers which have 'Load' and 'Battery' outputs. I want to switch between them at will, i.e. measuring SOC and turn on 'load' or 'battery'.

Thanks!

Click to expand...

How would one calculate State of charge w/o considering voltage?

This is the one I use to charge my two batteries with a common source

State of Charge is normally a voltage level.