Solar wasted watts/volts

starcraft69 wrote:

BFL13 wrote:

starcraft69 wrote:
Ok forget the hot water part If i put a over size system in how does the system dissipate the extra power being generated?

It is not being generated. Like you only get water if you turn on the tap.

Aside, there is a discussion of "over-panelling" for your controller's rating (with MPPT only--don't do it with PWM) on ISTR Morningstar's website. In the shoulder hours you get more amps with the extra panelling and those amps are still less than controller rating. Your controller cuts off the amps at its limit so you lose some mid-day AH, but you gain over the whole day averaged out for your AH haul.

So some over-panelling with MPPT is good, but within reason of course.

Next you will ask what happens with the extra amps the controller cuts off at its limit and can't use? :)

Thank you for the strait forward answer? Yes i do plan on a MPPT controller and was looking at a bit oversize in panels.

Using Go power calculator we use about 126.7 Amphrs a day in winter running furnace. summer much less. I currently have 2 6v GC batteries = 220 Amphrs. I plan on putting 300-400 watts 24v+ panels of solar and add 2 mor 6v batts

I don't think you would have a problem on a sunny day harvesting 127 AH with 400 watts @ 24v and an MPPT controller in the winter.
You will get 8-9 hours of sun daily which would work out to only about 16 amps that the panels/controller would need to generate.