Calling on Solar Techies
I have been thinking of going solar for some time and decided to pull the plug. My wants are a 400 to 500 watt system. I have four 12 volt batteries with 340ah. I am not planning on changing b...
Forum Discussion
With either MPPT or PWM controllers in Float (both being PWM in Float defining PWM that way) you see the same thing when a load comes on.
The solar controller shows how many amps are "available" and the Trimetric monitor shows how many amps are to the battery. When a load comes on that needs some of the amps the battery was getting, the amps to the battery drops. If the load needs more than that, beyond what the solar has "available", then the Trimetric shows amps now coming from the battery to make up the difference.
That is the same with any charger of course; the loads come first and the battery gets whatever is left over, if any.
On PWM "wasting" power, you have to compare with the power lost due to panel heating, wire loss, and controller loss, because MPPT controllers do their amps to the battery by power out/battery voltage not like PWM controllers that just deliver amps. I have done some "field tests" where amps to the battery stayed the same when swapping an MPPT with a PWM.
Usually, you get a few more amps to the battery with MPPT "depending" on the whole situation, but not as many as often advertised by MPPT vendors who pick the best situations for their claims.
So it is fair to tell the OP here that he should stick with his PWM and if it does the job, as seems likely, there is no point in changing to MPPT.
The solar controller shows how many amps are "available" and the Trimetric monitor shows how many amps are to the battery. When a load comes on that needs some of the amps the battery was getting, the amps to the battery drops. If the load needs more than that, beyond what the solar has "available", then the Trimetric shows amps now coming from the battery to make up the difference.
That is the same with any charger of course; the loads come first and the battery gets whatever is left over, if any.
On PWM "wasting" power, you have to compare with the power lost due to panel heating, wire loss, and controller loss, because MPPT controllers do their amps to the battery by power out/battery voltage not like PWM controllers that just deliver amps. I have done some "field tests" where amps to the battery stayed the same when swapping an MPPT with a PWM.
Usually, you get a few more amps to the battery with MPPT "depending" on the whole situation, but not as many as often advertised by MPPT vendors who pick the best situations for their claims.
So it is fair to tell the OP here that he should stick with his PWM and if it does the job, as seems likely, there is no point in changing to MPPT.
