Voltage drop from solar controller
or: Here we Go Again. Still trying to get my 420 Watts of solar to fully charge my 484 AH of battery. (Currently in southern Mexico.) Layout: 2 80 Watt panels and 2 130 Watt panels in paralle...
Forum Discussion
liborko wrote:
Problem #1: 420W:14V=30A. You need at least 30A controller, more is better. Don't forget that MPPT controller boosts the output current.
I've never seen more than 21 Amps out of the controller. Also, the BlueSky 2000E is current limited to 25 Amps, will not pass more.
Problem #2: Too much voltage drop between the controller and the batteries. You need to analyze voltage drops on ALL wiring, including wiring between the panels and the controller. Decide where to mount the controller and then adjust wire sizes. Wire size is determined by maximum expected current and the length of wire. Work from voltage drop tables or calculate.
This much I know. It's not as easy as it sounds in this rig. As I said earlier, all I am looking for now is a temporary improvement until we get home in April. More a learning thing.
Problem #3: Heat means resistance and voltage drop. Replace fuse holder and the fuse with properly rated holder and the fuse so that it will stay cool in operation. That includes wire terminals and crimps.
The holder and fuse came as a pair, supposedly rated for 30A. I wasn't not too happy with the quality though and should have replaced it when we got home last year. The previous one had melted! I sense a theme here! Hopefully the tendonitis in my right thumb and wrist will settle down soon so I can change the fuse holder.
DO NOT INCREASE OUTPUT VOLTAGE FROM THE CONTROLLER. Bad idea. Do it right and select proper size of wires(all).
As above, a temporary thing, I'll monitor the voltages closely.
