Solar panel output

[Borneoboy]

I have 4 280-watt panels for my 24v system... what sort of charging current should I be getting?
I only see 30 volts and around 200 to 300 watts on the MPPT, morning and midday...
This gives 8 to 10 amps charging current, which does charge my LIPO batteries in about 6 hours (to 90%), but I would have expected more with a 1kw+ array, wouldn't you ?
They are in full sun, near the equator and all about a year old...

 

[Don B. Cilly]

It could be... a few things. First that comes to mind, 30V... hmm. They're all in parallel, right?
Have you tried wiring them in series? At least two and two?
Maybe they're just not rated for 24V - at least in parallel.

[EDIT] If you don't post any specs, you make it harder for people to guess, don't you? ;·)
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[Supervstech]

I agree.
With an mppt, it’s best to double the incoming voltage from the charge voltage, so, you will want around 60V entering the controller.
I would arrange the panels in a 2S2P setup, for better results.
30V is just too close to battery voltage to generate any current in the mppt. If you had a pwm controller, it might work.

 

[Borneoboy]

Thanks... I think that may be the problem or part of it...
I did try once putting them in series, but no output at all - must have done something very wrong...
Just join the MC4 connectors at the panels positive to negative ?
My MPPT will take up to 105 volts.

 

[Borneoboy]

It could be... a few things. First that comes to mind, 30V... hmm. They're all in parallel, right?
Have you tried wiring them in series? At least two and two?
Maybe they're just not rated for 24V - at least in parallel.

[EDIT] If you don't post any specs, you make it harder for people to guess, don't you? ;·)
-

Yes all in parallel.
Cheapie panels direct from China.
Sorry about lack of specs - they are on the farm roof, 200 miles from here and from memory I will probably get the numbers wrong...
Found this on the vendor's website:
Specification:
Cell Type: Polycrystalline
Maximum Power Voltage(Vmp): 32.6V
Maximum Working Power Current(Imp/A): 8.9A
Power Tolerance: ±5%
Weight(Kg): 18
Dimension(cm): 164 x 99.2 x 4
Cable connection: MC4 connector

 

[Supervstech]

You are missing an important voltage parameter.
VOC. To determine how many panels can be put in series, you need the unloaded max output voltage.
That number gets factored into the minimum possible temperature at your location, and that number is divided into your permissible max voltage to toe controller.
All 4 in series is never going to work with a 105V max controller… no way.
But two in series shouldn’t exceed 90V so, ok to do.

 

[Borneoboy]

Thanks for your help... I will put two in series... as soon as I can get up on that roof !