4 18v panels in series parallel with two 38v in series

[KeithSwanger]

Hey folks.
So... I have 4 18v 200watt panels in series running now on a 12v battery bank.
I have come across 6 38v 230watt panels for cheap.
If I make 3 series of 72 volt 460 watt
Can I run the all in parallel with the 800 watt 72 volt array?
Would the amps stack in parallel like with batteries or would I loose 340 watts from the 800watt array?
The nominal amps on the 18v panels is 11.
The nominal amps on the 38v panels is 8.4
Any knowledgeable help would be much appreciated.
Thanks much.

 

[Supervstech]

I would use separate charge controllers for the differing types of panels. 76 V vs. 72 of the 4 panels in series tied together could cause issues with an MPPT, likely watts would be lost.
it would work though.
Not to mention the shading issues potential of having 4 panels in series...

 

[KeithSwanger]

I would use separate charge controllers for the differing types of panels. 76 V vs. 72 of the 4 panels in series tied together could cause issues with an MPPT, likely watts would be lost.
it would work though.
Not to mention the shading issues potential of having 4 panels in series...

Thanks for the reply ?
In reality when connected both arrays show 76 volts on my multimeter.
If the voltage of the arrays were the same within +/- .2 or.3 volts would the wattage loss be minimal ?
The reason Im asking is that I'm considering going to 48v and would like to use one 60a mppt .
Thanks again

 

[KeithSwanger]

Thanks for the reply ?
In reality when connected both arrays show 76 volts on my multimeter.
If the voltage of the arrays were the same within +/- .2 or.3 volts would the wattage loss be minimal ?
The reason Im asking is that I'm considering going to 48v and would like to use one 60a mppt .
Thanks again

Thanks for the reply ?
In reality when connected both arrays show 76 volts on my multimeter.
If the voltage of the arrays were the same within +/- .2 or.3 volts would the wattage loss be minimal ?
The reason Im asking is that I'm considering going to 48v and would like to use one 60a mppt .
Thanks again

Also I live on high desert mesa and there is ZERO SHADE for 10 miles lol

 

[Rocketman]

If I remember correctly (not guaranteed):
in the same array:
In series connections the volts add, but everything drops to the lowest amps.

In parallel connections the amps add but everything drops to the lowest volts.

The most efficient path would be to have the 200watt panels in probably a 4s on one solar charge controller, and the 230w panels on a different solar charge controller probably in a 3s2p array. (That gets you to the 48v battery).

Be sure and very careful check the voltages - use the Voc voltage (the higher one), and leave room for the voltage to rise when the panels get cold.

Different panels can be combined into the same array, but you need to be careful and make sure it works, otherwise you just wasted a lot of the watts of the panels.

 

[KeithSwanger]

If I remember correctly (not guaranteed):
in the same array:
In series connections the volts add, but everything drops to the lowest amps.

In parallel connections the amps add but everything drops to the lowest volts.

The most efficient path would be to have the 200watt panels in probably a 4s on one solar charge controller, and the 230w panels on a different solar charge controller probably in a 3s2p array. (That gets you to the 48v battery).

Be sure and very careful check the voltages - use the Voc voltage (the higher one), and leave room for the voltage to rise when the panels get cold.

Different panels can be combined into the same array, but you need to be careful and make sure it works, otherwise you just wasted a lot of the watts of the panels.

Thank you very very much

 

[Horsefly]

If I remember correctly (not guaranteed):
in the same array:
In series connections the volts add, but everything drops to the lowest amps.

In parallel connections the amps add but everything drops to the lowest volts.

The most efficient path would be to have the 200watt panels in probably a 4s on one solar charge controller, and the 230w panels on a different solar charge controller probably in a 3s2p array. (That gets you to the 48v battery).

Be sure and very careful check the voltages - use the Voc voltage (the higher one), and leave room for the voltage to rise when the panels get cold.

Different panels can be combined into the same array, but you need to be careful and make sure it works, otherwise you just wasted a lot of the watts of the panels.

@Rocketman is partially correct here. You are right about the series and parallel connections.

However, the voltages to look at are NOT the Voc (open circuit) voltages. The voltages and amperages that matter are the max power numbers, Vmp and Imp. That's because the performance of the panels in parallel / series matters the most when they are producing power. The Voc condition has no current, and so has no power. So use Vmp and Imp when trying to decide what you can do with mismatched panels. @KeithSwanger didn't say if the voltages he was stating were Voc or Vmp, but it makes a really big difference.

Voc matters the most when examining the potential maximum voltage at the input of the charge controller. Voc goes up as the temperature goes down, so one needs to account for the higher than spec Voc so as not to burn out the charge controller under very cold conditions.

 

[Rocketman]

Horsefly thanks for the clarification to my post. I typed it in a way that confused the post (so easy to do).