Another Solar Controller question

tensch wrote:
I have a 100w Renogy solar panel that is used to keep the two 6 volt batteries (flooded) charged while dry camping. The controller that came with the trailer when I bought it was one of the cheap generic chinese models (blue) that sell on amazon for $15 or $20. The usb ports broke and I am looking to replace. My thought is that a PWM is fine for my needs. What amp size controller is recommended? And what are the optimum float, high voltage and low voltage disconnect settings, and load on setting for this setup? Thanks

First look up the charging voltage specs for those 6v batteries. Typically 14.8v absorption with 13.6 float at 77F, but higher with lower temps and lower with higher temps. If you get a temperature compensated controller, then just set for 77F and leave it.

100w at 6.2 amps Isc (which is what you see with PWM) is not much for keeping up a pair of 6s unless you hardly use any 12v and it is always sunny.

So in case you get more solar, go for more amps size of a controller with adjustable voltage settings ( even if you don't get more panel watts.)

The Grape 40 amper is often recommended here (Home Depot ISTR) for not much money.