Low amps

[Whats-n-Watts]

Hello all. I had great sun today and decided to hook up some pv and see how it did. I have 3*300w pv in series feeding a 100A/100v Mppt controller on 2 parallel lead acid 12v 66ah interstate deep cycle marine batteries (just for testing).

PV Specs:
ISC 18.1A
Voc 22.1 V
Imp 16.5 A
Vpm 18.2 V

With peak hours direct sunlight, zero clouds, aand 100 percent correct.angle for my location in January.
I am only seeing 10 Amps max on the controller. Is that the MPPT lowering amps? Second question is that at full charge I connected a 150 watt 16 amp heating element to the battery and the 900 watts of PV could not keep up so the battery voltage dropped slowly and would not recover to full charge unless I disconnected the load.

So 900 watts of PV can't handle a 150w load? Yep that's ridiculous so could anyone explain what is going one?
Many thanks in advance!

 

[green mountain boys]

What is the Mppt controller?

 

[Whats-n-Watts]

What is the Mppt controller?

It's supposed to be 100 Amps and 100 Volts.

 

[hwy17]

You're never gonna get 300w out of a 300w panel in January at your latitude, angle doesn't fix your lack of solar radiation.

A better MPPT might get a little more, but if you're saying you already got like 180w per panel then not a lot more.

 

[green mountain boys]

Can you test the amperage and voltage with a meter? What tools do you have available for testing?

 

[scrubjaysnest]

your panels in series only provide 16.5 amps, Imp. Second fla's determine how much they will take based on their SOC.

 

[Whats-n-Watts]

You're never gonna get 300w out of a 300w panel in January at your latitude, angle doesn't fix your lack of solar radiation.

A better MPPT might get a little more, but if you're saying you already got like 180w per panel then not a lot more.

Humm I tested a 100 watt panel on a cloudy day at the connectors with a meter and if that is reliable I was getting 50 watts out of it and it was heavy overcast. Amps*volt reading. That must not give accurate operating readings?

 

[Whats-n-Watts]

Can you test the amperage and voltage with a meter? What tools do you have available for testing?

Yes I can tomorrow I have a meter.

 

[Whats-n-Watts]

your panels in series only provide 16.5 amps, Imp. Second fla's determine how much they will take based on their SOC.

So with a Lifepo4 I would have seen higher amps? Winter or not my solar are heater right beside the panels was putting out 115 degrees F the solar radiation was there. I mean high noon hot your back at 52 degrees today with a 10 mph wind blowing.
I can hardly see winter dropping a 300 w panel to 180 watts tops. I wondered of battery type wqas the problem or not.

 

[Whats-n-Watts]

You're never gonna get 300w out of a 300w panel in January at your latitude, angle doesn't fix your lack of solar radiation.

A better MPPT might get a little more, but if you're saying you already got like 180w per panel then not a lot more.

On another thought even if it was only putting out 180 watts per panel that's more than enough for a 150 watt load so that's puzzling. That doesn't make any sense. How many panels does it take for a 150w load in that case? A pallet ? Gezzz solar left a bad taste in my mouth today.

 

[mikefitz]

only seeing 10 Amps max on the controller. Is that the MPPT lowering amps?

You are only seeing a low current because its a PWM controller, thus you only see the string current. Putting the panels in parallel will help, but using a true MPPT would be better.
Also consider that the small batteries will be limiting the current they will accept. Your technique of loading the battery will give a better measure of current produced from solar.


Mike

 

[Whats-n-Watts]

You are only seeing a low current because its a PWM controller, thus you only see the string current. Putting the panels in parallel will help, but using a true MPPT would be better.
Also consider that the small batteries will be limiting the current they will accept. Your technique of loading the battery will give a better measure of current produced from solar.


Mike

Correct sir as I have found the problem. It's not a MPPT as labeled but rather a PWM. I did plug in just a single 300w panel and got the same readings 10.1 amps and the same rate of charging. It was basically not using 2 of the panels at all.