Solar Guidance
Ok, I have done research and read what I could find. I am pretty sure the installation I have down, but I just want to make sure I am barking up the right tree on certain aspects of the build. I re...
Forum Discussion
Calkidd wrote:smkettner wrote:
30 amp Morningstar should serve you well. Kill it with a 45 if you must.
http://www.morningstarcorp.com/products/tristar-mppt/
There is no must about it. This is why I posted the thread. I am looking for advice.
I assumed if my amperage the panels were producing is over 35 amps then a 30 amp controller would not work.
How is it you suggest a 30 amp? Also, the controller is good for 400 watts, but my system is 416. Am I am missing something here?
Yes you need the buck converter 24-12 controller unless you go 24v battery bank.
So with two 208w panels mounted flat you will get less than 416w unless you are camping around the 23N latitude at noon in June with the sun overhead (called zenith) but let's pretend you will get that for sun angle. Now you get panel heating which will kill a few watts, so let's say you are getting 400w in this scenario. (good luck with that in real life!)
The typical MPPT controller (which has a 24-12 buck converter) also "clips the amps" so you can ignore the usual 1.25 times rule set by the NEC for that.
So what is your "expected amps" from 400w in full sun? My magic (but correct) formula is 400/130 x 8.2 = 25.23 amps. So yes, a 30 amp MPPT controller will be ok for you.
Now it is all about dollars. You can get a 20a Eco-Worthy MPPT controller for each panel and put them in parallel on the one battery bank, OR get a 30 amp Brand X controller (of which there are several) and have that one on the bank. Up to you.
