Solar Charger Question

[dj2109]

Hello!

I’ve attached pictures of my panel specs and solar charge controller.

Tech support says with those panel specs I should be getting 50amps max. I’m okay with that.

Any reason I can’t get above 30? Wire gauge is correct and everything is plugged in right.

Thanks

[dj2109]

Manual says its a PWM. Should I upgrade to MPPT?

[john61ct]

Might give you 10-15% higher output.

It is perfectly normal for actual power output to be far below the max rating.

Noon at the equator on a perfectly clear morning, near freezing temperatures, reflections off the snowy peaks

is when you get near rated output.

Also, are you sure the loads on the SC are trying to pull more current than the 50A the panels can supply?

Often a lead battery bank cannot, even 50% depleted.

LFP cells are a different story

or a bar heater hooked up to a big inverter

Since you're talking different Voltages, Amps aren't so useful, use Watts for apples to apples

[dzl_]

Originally Posted by dj2109

Manual says its a PWM. Should I upgrade to MPPT?

if you want to squeeze max power out of your panels, particularly during the winter, then yes, you may want to upgrade.


As John says 10% to maybe 20% is probably a realistic expectation for improvement, but depending on conditions the difference can be anywhere from 0% to 30%


Looks like you are using "20V" nominal panels (60 cell) what is your battery bank voltage?


I don't know a ton about PWN, but it was my vague understanding that 24v battery banks were usually paired with 72 cell panels and 12v battery banks were usually paired with 36 cell panels, and 60 cell panels were popularized once MPPT caught on. Maybe John or someone with more PWN experience can comment on this.

[john61ct]

PWM (not PWN) throws away all power produced by voltages higher than the minimum used to charge the bank

So 19-21V is the highest worth using for 12V.

With MPPT, at least the Victrons anyway, get best advantage with 40+V panels.

Absolutely must be 5+V over the bank voltage or they won't even power up.

[dzl_]

DJ what is your battery bank voltage?

[dj2109]

My battery bank voltage is 6 12v 100ah batteries wired in 24v system.

I upgraded to a SolarGrape 60amp MPPT and now I'm getting 0amps!

help

[dzl_]

Originally Posted by dj2109

I upgraded...now I'm getting 0amps!

That is less than ideal


Hard to give any meaningful help without any information. As a general point, I would say if you haven't already, look through the documentation that came with the charge controller, there is usually a section for troubleshooting and how to diagnose a problem, as well as installation instructions, if you didn't read the manual beforehand its possible you missed a step or performed a step out of order.


How are your panels wired? 60 cell panels on there own are not well suited for for 24v battery banks. 2-3 in series would be best.

[dj2109]

They are wired in parallel.

[BeNimble]

Did you press the on button? lol

Maybe the batteries are full?

[dzl_]

Originally Posted by dj2109

They are wired in parallel.

This may or may not be the cause of the problem, but its definitely something you should address.


A 72 cell panel, is a "24V" nominal panel (Vmp of 36ish volts). Your 60 cell panels are something like "20V" nominal (Vmp of 30ish volts). MPPT requires the PV array be at a higher voltage than the battery bank.

Your 60 cell panels may not be operating at a high enough voltage for the MPPT to turn on (a Victron controller for instance requires Vbatt +5V to turn on and Vbatt +1V to stay on, other controllers operate in a similar fashion and cheap controllers can require an even larger amount).


If you wire your panels in strings of 2 or 3, and then put those strings in parallel this may solve your problem.