Newbie here needing advice for my new setup

[Blackzeus]

Hi all, I'm new to this forum and new to solar in general.. I've read many posts here and they've been great for answering thoughts I've had so thanks everyone for great advice and sharing your knowledge here..

So I've had a single panel + battery for a while that's done me great for camping, and recently upgraded to a slightly bigger setup to be installed in a tiny house or housebus type thing in the future however it's greatly under-performing from what I expected so I'm guessing I've done something wrong or maybe I was just expecting too much?..
So my new set consists of..
3x 270w 24v mono panels which I've wired in parallel to a 30amp 12/24v mppt controller
2x 12v 120ah deepcycle batteries in parallel
and a 2000w 12v invertor
And so my problem is.. The specs from the panels list the (Imp) as 7.4 amps each, but even in full midday sun the charge controller reads the max I'm getting as 3.7 amps total from the 3 panels together.. It is Autumn here so I wouldn't expect the max at all but I would have thought it should be more than this.. I did think it might have been the wire sizing, and I've just upgraded from 12g to 6g wire through-out but with no change.. I wondered if it's something to do with the 24v to 12v in the charge controller but I thought that should boost the amps even more?.. And would it help if the whole system was 24v but then I would need to purchase a new invertor..

Any help and advice is greatly appreciated and thanks all for taking the time to read this

[littleharbor]

Model of MPPT controller?

It kind of sounds like you may have a panel wired backwards

What was the state of charge when you noticed this low current? If the controller was in absorb mode it could be that the batts were nearly fully charged and only accepting minimal current.

[Blackzeus]

The controller is an.. Epever tracer 3210AN it doesn't display which mode it's in and I don't think I have the option to choose it's all auto I think.. The panels are wired for correct polarity and it's this low all the time in full sun and gets about 1.1amps in full cloud

[Mike90250]

WE need the specs off the sticker on the back of the panel. If you are charging a 24V battery bank, then the panel's Vmp needs to be about :
30V to work with a PWM controller.
40V to work with a MPPT controller

Batteries have to be recharged at a higher voltage. A 24v battery needs up to 30V to be charged If your PV panels only output 25V, they can only provide a partial charge to the batteries and thusly, killing them from undercharge..

[Blackzeus]

The battery bank is only 12v.
The panels are Vmp 36.5 Voc 44.8.
the charge controller reads the input as being between 39v and 44v depending on sun or cloud

[littleharbor]

Do you have a DMM or a DC clamp meter? You should be able to disconnect the panels from the CC and individually short circuit test them for current. Better yet put a load on them and test while under load. While you're at it re verify polarity. If your panels are working correctly it would seem your controller is the culprit. At that point a repair is pretty much out of the question being that a replacement controller would be more cost effective.

[Blackzeus]

Thanks, yeah I have a multimeter and I'll look at giving that a try today if the weather holds out.. How can I put the panel under load if it's disconnected? I guess I can try to connect only 1 panel at a time to the controller and see if they all read the same? At least that would point out a faulty panel or connection? I know there is a lot of variables but any idea around about how much I should be getting from the whole lot or each? Thanks again

[littleharbor]

Not sure what to recommend for 24 volt panels. 12 volt panels are easy using 12 volt bulbs pumps etc. I have an inline load gadget made with a piece of nichrome coiled wire and a pair of MC-4 connectors on each end. The stuff they use in electric heaters. It puts a heck of a load on a panel and gets really hot really fast, if your not careful, you'll fry your fingers.