Change panels from parallel to series

2Lazy · Member

Change panels from parallel to series

Jaahn · Guru

Hi 2Lazy smile

Yes you are correct about the wiring for series connection.

You do not have to do that however, you could just wire them up in parallel as you have done the other controller. There will be no difference in output IMHO in your case. I assume you have normal 12V panels with a VMP about 17-18V.

Cheers jaahn

2Lazy · Member

Thanks, I was told more that a series connection would be more efficient as a higher voltage lower amperage would result in less loss in the cables and more amps to the batteries

If this is marginal, I will just replace like for like

Cheers

Les

macka17 · Guru

Marginal mate.
That's why 99.99% of 12\24v Solar systems are Parallel.
up to 340w myself.
Others having much more.

Don't ask for trouble for a marginal gain.

Something like moving a single panel round after max, sun.

It realistically, makes minimal difference for the time and effort taken.

Lot's have tried over the decades. lot's no longer bother.
It's easier to just add an extra panel.

Jaahn · Guru

2Lazy wrote:
Thanks, I was told more that a series connection would be more efficient as a higher voltage lower amperage would result in less loss in the cables and more amps to the batteries
If this is marginal, I will just replace like for like
Cheers
Les

Hi Les smile

What was said can be correct if the wires are connected in series close to the panels so the current is reduced in the wiring going down to the controller. But in your case they are just connected at the controller anyway so no difference in losses.

I assume your controller will be close to the battery as it should be. To get the most benefit from a MPPT controller the wiring size from the panels should be generous too.

Jaahn

2Lazy · Member

Thanks

I have installed as a straight replacement, moving the controller and changing cable rating and run are both a pain, I will see how the new set operates on a day to day basis before ripping cabling out of the van

Cheers

Les

PeterD · Guru

Les. Jaahn has explained that there will be no advantage in the way of power loss for series connection. There is also another thing to consider and that is panel shading. If you are running a series string, if one panel gets shaded your array will nearly close down. If you have the panels in parallel and one gets shaded, the other panel will still operate at full capacity. Your charging will thus be better with the parallel panels.

Reed · Senior Member

Series has a number of advantages that are discussed in detail by others elsewhere.

Series becomes important when you get to large arrays. We have 1410 W of panels and have gotten over 1400 W into controller when camped at 3.5 km, sunny days, in June.
This is 117 amps at 12 V but only 16 amps at 90 V and 29 amps at the 48 V nominal of the LFP battery suite. We have a 45 amp MTTP controller and thus have 50% over capability

Reed and Elaine

Bagmaker · Senior Member

Hiya 2lazy,
be aware that if you "series" up the voltage past 49 you require a registered sparky for the fit........

Aus-Kiwi · Guru

Short distance as in caravan etc there's not much gain ! In a house situation ? Distances can be longer so is the load and output. parallel can be multy cables to regulator .. Or run in groups .. We are running a low wattage system compared to home solar .. 400 watt is enough for most system with 2 or 3 batteries . Or should I say 2 or 300AH ... 50% more than required so there's less drain on batteries ..

swamp · Senior Member

hi
Everybodies got it nailed

Series is beneficial for
long cable runs ,
a little loss does not matter ,
miss matched panels work better in this situation Victron mentions this .

negs in semi shade u have a great reduction in power

www.victronenergy.com/blog/2015/11/10/connecting-different-sized-victron-energy-pv-modules-series-or-parallel/

www.youtube.com/watch [ actual reality no bs] proof in a small well designed system [same panels ] system ,series vs parallel makes little difference .

2Lazy · Member

All Thanks for the advice, wired in parallel and been off grid for 7 days. Batteries (2 x 120 AGM Deep cycle) go to float around lunch off 300 Watts of panel Cheers

macka17 · Guru

Hi.
OK so far. But a little light on with the panels when weather gets moody.
I'd stick another one up there. Just to be sure.