Solar low amp output

Hello onlinejames and welcome to Solar Panel Talk

When batteries start to "fill up" or get close to 80% SOC the charge controller will reduce the charging amps and voltage going to them. There is usually confusion for people that first set up their system so don't be worried yet. Also 1200 watts charging a 200Ah 12V battery with an MPPT CC may be too much for it. It really only needs about 20amps and what you have may cause it to charge too fast and get to full too quickly.

You should be able to get close to the Imp x 4 from those panels when the battery needs to be charged but if not it could be how they are wired and exactly how much sunlight is hitting them. Remember that in the Winter time the sun is lower in the sky and will not provide a lot of usable sunlight for solar. Also the age of the panel may cause them to put out less then the rated amount.

Oh I forgot to ask. Since you have 4 panels wired in parallel, do you have a combiner box with separate fusing for each panel. If so you might want to check to see if any fuses are bad. A bad fuse will reduce the amount of charging amps going to the CC.

Hi suneagle and thanks for the reply
all panels are just joined by splitter cables like these

https://www.autoelec.com.au/atem-pow...waAj1-EALw_wcB

that's the problem though with 1200watts, im only showing 4 to 6 amps to the controller max- in direct sun , i would expect 20 amps from 4 panels?
I even tried it on a flat battery and i get the same, so i don't think its because the battery is too full.
this is what i am getting full sun 30 degree day, no shade just sun.off 4 x 300w panels

IMG_2205.jpg

If you have a combiner box then you can "turn off" each panel and see what it is providing. My guess is that one or more panels are either wired incorrectly or they are bad which is dropping the output.

It is a little hard to troubleshoot a system this way. All I can do is suggest something for you to try but I would break down the system and check each component and then build it up to see what is happening. You might be able to determine what part is causing the issue.

From the looks of it your batteries are full and cannot take much current. Turn off the charging sources and allow the battery to drain into the low 12.xx volt range and reconnect the panels around noon. You should see full available current from your panels then. You mentioned you tried on another battery. Are you disconnecting the solar panels first and connecting the battery first to allow the controller to reboot before reconnecting your panels?

Yes, i disconnect everything, then connected a low voltage battery, then connected solar panels, did very little in the way of amps in

IMG_9394.jpgIMG_9395.jpgIMG_9396.jpgIMG_9397.jpg I connected each panel by itself which gave roughly the same output to the controller, im starting to think the panels are at the end of their lifespan, although they are only a few years old
They were just cheap ebay panels.
even if the battery is fully charged, the controller would only output the required amperage to the battery, the controller should show the input from the panels to what they are producing, or am i wrong in this?
If the panels are producing 16-18volts at 5 amps, why would the controller show 1 amp or less input amperage?

Must be an MPPT charger since battery current is higher than panel current.
With a discharged battery, I would try a DC clamp on ammeter on each panel
and see if they are quite unequal. Check the weak one. Bruce Roe

THat seems to be about a fraction of what you should see. I am at about the same latitude as you and see more than that, even on my flat panels not pointed at the sun.

At this time of year with the sun is so low to the ground, from 1200 watts of panels, I would expect to receive 72 amps if the panels were oriented at the sun in both angle and azimuth, and perhaps 30 amps if they were flat. My rule of thumb 6 amps can be sent to the batteries for each 100 watts of panels. On my portable panels that can go into the sun, I see this. If they are the ones flat on my roof, I will only get 2 or 3 amps. Especially in the shorter days of the year.

One thing that doesn't look right is the low voltage coming from the 300 watt panels. Could you have the polarity crossed in one or more of them?

I agree. The OP has some issue either with the panels, wiring or CC because that readout is crazy low.