Solar array setup

[budgie348]

I have just purchased 4*250w 24v panels and a 40a MPPT controller(tracer 4215BN).

I am running a 24v 460amp batteries (4*12v 230amp in series and parallel).

Which would you suggest as the best way to set up the panels with the Controller?

Max voltage or maximum amps? Or split 2 and 2?

[MtB]

Are you sure they are 24v panels? Panels are usually rated at a higher voltage, eg 36v.

[budgie348]

VMP is 30.7v

[Loafer]

They should be around 30V minimum.

 

Your tracer can handle 150V and 40A. We need to know your panels' Open circuit voltage (Voc) and the short circuit current of your panels (Isc), usually on a sticker on the back. If it's say 32V and 9A, then they can all go in series. All the Voc's then add up and your current is low, which might reduce cable losses.

 

Just seen your second post - Vmp isn't as high as Voc. Can you tell us that?

Edited May 24, 2016 by Loafer

[budgie348]

VOC is 38.1

ISC 8.80amp

[nicknorman]

wire the panels like your batteries - series/parallel. All in series would give too high a voltage for the Tracer especially in cold weather.

[budgie348]

wire the panels like your batteries - series/parallel. All in series would give too high a voltage for the Tracer especially in cold weather.

Thank you for that, it's what I expected.

[Loafer]

Agreed, given your Voc!

Furthermore, watch it when you connect them up. 80V with that current backing could hurt!

[MtB]

Agreed, given your Voc!

Furthermore, watch it when you connect them up. 80V with that current backing could hurt!

 

 

Worse than that, it's DC which a million times more dangerous than the AC shock you might get from a mains electricity supply. DC makes your muscles 'spasm' so you can't let go, apparently.

(AC gives you 100 chances a second to let go as the voltage passes through zero.)

[Loafer]

 

 

Worse than that, it's DC which a million times more dangerous than the AC shock you might get from a mains electricity supply. DC makes your muscles 'spasm' so you can't let go, apparently.

(AC gives you 100 chances a second to let go as the voltage passes through zero.)

 

You should always test stuff with the back of your first knuckles on your fingers. It's thick-skinned, and any contraction takes your skin away from the source!

[MtB]

 

You should always test stuff with the back of your first knuckles on your fingers. It's thick-skinned, and any contraction takes your skin away from the source!

 

 

I've always been taught it's even safer to get the apprentice to carry out this test!

Edited May 24, 2016 by Mike the Boilerman

[Loafer]

 

 

I've always been taught it's even better to get the apprentice to carry out this test, not you.

 

Well of course, but you 'ave to start somewhere guv!

[WotEver]

As my boss once said to me after telling me to hold the shiny end of a red wire, "Oh good, that's dead then."