Mixed panel voltage 31v and 48v

DIY
, ,
1

I have 5 panels 265W 31v I want double the system to 10 panels for an off grid cabin about 2500-3000 watts
I read to make the system 48V is preferred to 12v.
I need to buy new batteries so it’s a good opportunity to buy the 48’s

If I wire the 31v panels in series that will give me enough to charge I believe.

So I was going to join the two arrays into one controller.

Any problems or suggestions

Thanks

2

Have a look at the Victron MPPT calculator.

If you have 2 strings into one controller they need to have the same Voc, otherwise use a controller with 2 trackers or 2 controllers.

When connecting in series take account of Voc at your lowest ambient temperature as Voc is higher when cold.

3

The additional 5 panels I’m adding will be 48V , I’m thing one controller with 2 trackers.

THe 5 existing 31v in series and the 5 new panels will be 48v in parallel, I assume ?

The battery bank 2 48v 220ah

Which Victron models might handle this

4

5 31V panels in series should be OK for a 250V MPPT.

As you have a 48V battery the solar panel voltage needs to be higher than this so you can not use tjen in parallel. Different MPPTs have different requirements of minimum PV voltage. Putting them in series may or may not be OK for a 250V MPPT. You could use 6 in a 3S2P arrangement.

Again, try the MPPT calculator, it will suggest suitable controllers.

5

Don’t understand that I looked at the calculator didn’t see 48v

Am I complicating this trying use 48V panels instead just more 12v panels with the 30v range and doing all of them in series?

6

I can not give specific advice with the limited details provided.

1 Like
7

thanks for your feedback, can you tell me what other info you would like please

8

Try out Solar Panel Series & Parallel Calculator - Footprint Hero

9

You can combine different panels on one controller of they have separate trackers on them like the mppt RS series.
Otherwise separate charge controllers are more optimal when the string have different mpp and imp values.
Its not that it wont work, its just that performance will be hurt.

10

that says
All panels wired in SERIES:

Max power output: 2692.2W
Max power voltage (Vmp): 320.5V
Max power current (Imp): 8.4A
Loss: 4.11%
11

So you need the RS range anyway. Its the only victron mppt that can handle VOC that high.

12

Or combination of series & parallel

13

Mixing panels is never a good idea.

Take one mppt for the 48v panels, another for the 31v panels.

Which controllers you need can be checked with the calculator