diy solar

diy solar

Overpanel Renogy Wanderer 10a

It's just a test system, I don't have the cable to join for parallel.
Time to get a pair of Y parallel cables.
Try the 2 in series but PWM has limitations.
Your 36Vmp will be pulled down to say 14V

@snoobler said it better than I could.

PWM controllers REQUIRE all panels to be the correct nominal voltage AND they must be in parallel NOT series.

PWM controllers effectively SHORT the panels to the battery thus forcing the panel to be the battery voltage. If you put a 24V panel on a PWM controller for a 12V battery, the panel will produce less than half the rated power.

The "shorting" of the panel to the battery via the PWM controller misses out on a lot of efficiency.
As you've seen, a 100W panels with Vmp of 17.8V have an Imp of 5.62A. On a PWM controller, the panel will not be allowed to rise above the battery voltage. Thus at peak bulk voltage of say 14.4V, you're limited to 14.4V * 5.62A = 81W out of that panel in perfect conditions.
 
Can you double check my math for this hypothetical setup please? I don't own this equipment but want to see if I have the limitations correct.

Let's say you are charging a 100ah 12v LiFePO4 battery and you have 3 195w 12v panels (Voc: 21.6v, Isc: 10.83a). The Victron MPPT 75/10 (max 75v, 13a) looks like it can handle the panels but only takes 145w and charges at 10a. Is that amount of overpaneling (440w) safe for the charge controller?

The Victron MPTT 100/50 looks like a better fit, accepting 700w and charging at 50a. Could this charge controller handle 4 of these 195w panels, or would the 86.4 voltage be cutting to close to the 100v limit in cold weather?
 
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