PV water heating.....again, but wait!
I had a thought today, that seems a little too obvious and I'd like to see if anyone can set me right.
There's been a lot of talk these days about using PV to heat water. Seeing as the price of panels have come down, depending on your particular cirumstance it can make some sense. However the biggest technical obstacle that I can see is that any MPPT still needs a battery which leads to concerns about trashing a vital off-grid battery bank should anything go wrong, adding an addition complication of a SSR system controlled by the charger or the need for an expensive battery in a situation where none is needed elsewhere.
That being the case, my question is this.
Is it possible to modify a MPPT charger so that the controler side is electrically isolated from the output? This would enable the charger to output to a heating element directly without drawing on the same battery that is powering the controller. The advantage is that it would be impossible to draw too deeply on the main battery pack, the disadvantage would be that that MPPT controller would now be dedicated to heating, so ideally one would use a cheaper controller without all the bells and whistles.
Can anyone with a deeper understanding of the technical issues send me in the right direction?
Midnight Solar Classic 150 w/ wizbang jr
4x 6v crowm 395 ah
location - Lanaudiere, Quebec, Canada