Safe Voltage?

[felixdennis]

Hi,

I'm setting up a solar generator 24v system with MPPT controler that takes up to 140v.

I have four 290W panel each max 32v.

What is the safe voltage to use? Should I do 32v x 4 in series to get 128v or do 64v with parallel?

 

[Steve_S]

It all depends on your Solar Controller and the ratings / capacities it has. Some SCC Manufacturers have tools to figure out optimal panel configurations, others do not. To get a better answer, please provide links to the SCC and even the docs if possible. Same for the solar panels, the data panel on the back is very important.

 

[Pierre]

It may not be practical here but I have 2x 130w panels on the roof of my offroad vehicle coupled to a Victron MPPT SCC feeding a 105Ah aux battery. I wired a change over switch in at the panels so as to select between a serial and parallel combination. In low light conditions I find that a higher o/p voltage ( i.e. series connection ) benefits the system and at the charge controller the higher voltage translates into more current flowing into the battery. One caveat though - the SCC specs must allow for this. Any comments Steve_S ?

 

[Steve_S]

It may not be practical here but I have 2x 130w panels on the roof of my offroad vehicle coupled to a Victron MPPT SCC feeding a 105Ah aux battery. I wired a change over switch in at the panels so as to select between a serial and parallel combination. In low light conditions I find that a higher o/p voltage ( i.e. series connection ) benefits the system and at the charge controller the higher voltage translates into more current flowing into the battery. One caveat though - the SCC specs must allow for this. Any comments Steve_S ?

I can see that working fine IF either method ensures that volts, watts & amps from the solar panels fall within the SCC specifications and limits. If not and one day you forget to flip the switch, well... it likely wouldn't be pleasant.