First Solar for a beginner

[Hazema]

I am new to this but have done quite a bit of electrical work diy.
I am thinking of putting the following together:
Solar panels - 6
Model Number:
Jinko Solar JKM395M-72HL-V / JKM400M-72HL-V

Electrical Specs:
395 Watt
49.5 Voc
41.4 Vmp
10.23 Isc
9.55 Imp
Max Series Fuse 20A

Controller inverter-
Growatt SPF 3000tl LVM-48P
4500 watt input max
145 V open voltage
80 Amp maximum Solar charge current.

I work at an auto parts store, so even though I’d prefer lithium batteries I can get 8 golf cart batteries for $600.

I believe I will need to put 2 sets of 3 panels in series.

Thanks in advance.
Bruce

​

 

[Leeds]

Close. Three sets of two panels each would be better. They will top out at 99v which is well under the max of 145. And 30.7 incoming amps would be well below your 80a max.

Cheers

 

[Hazema]

Awesome, thanks.

 

[rmaddy]

And 30.7 incoming amps would be well below your 80a max.

Don't confuse the input limit with the max output. They have nothing to do with each other. The 80A is the max output current of the charge controller.

6 395W panels is 2370W. When the batteries are charging at 48V (I don't know what golf cart batteries really charge at but this is close enough) then you will get 2370W / 48V = 49.375A which is well under the 80A.

Due to the Voc of the panels and the 145V max PV input voltage limit you can't put 3 panels in series. So 2S3P would be the best option. Since you will have 3 strings in parallel you will need to fuse all three of the parallel strings. 20A fuses would be good since that is the max series fuse rating.

To avoid any confusion, 2S3P means that you take 2 panels and put them in series with each other. Take 2 more and put them in series with each other. Do that 1 more time. You now have 3 pairs of panels with each pair in series. Now combine those 3 pairs together in parallel.

The Isc of your array will be 3 x 10.23A which is 30.69A. Most MC4 connectors have a limit of 30A. You will probably need a combiner box so you can avoid having any MC4 connectors leaving the combiner box and going to the inverter. Given the voltage and amperage you will want 10AWG from the panels to the inverter is the length is less than about 30 feet one way. If it's longer you will need 8AWG which would be good up to about 60 feet one way. Longer than that and you are up to 6AWG.

 

[Hazema]

Thanks. My controller will be about 40 ft from the panels. That’s going to be a lot of cabbage for the wire.

 

[ghostwriter66]

Thanks. My controller will be about 40 ft from the panels. That’s going to be a lot of cabbage for the wire.

have the controller as close to the batteries as possible ...