Charge Controller Size? - Help Please

[alexgadd]

Hi

I currently have 18W solar panel for charging 72Ah leisure battery as part of my offgrid living. I am intending to buy either 1 or 2 130W panels giving me either 148W or 278W.

Can someone recommend the size of a charge controller for:

a) 148W, and
b) 278W

Thanks

Alex

[contadino]

I think charge controllers are sized to the batteries, rather than the panel. You have to decide based on the size and nature of the battery, and the demand you will put on it. A 3-stage charge controller is best, AFAIK, and it has to be able to charge faster than your applications draw. i.e. a 3A charge controller will keep your battery topped up, so long as you're not constantly drawing 3.5A.

[gug]

Hi

I currently have 18W solar panel for charging 72Ah leisure battery as part of my offgrid living. I am intending to buy either 1 or 2 130W panels giving me either 148W or 278W.

Can someone recommend the size of a charge controller for:

a) 148W, and
b) 278W

Thanks

Alex

As far as i knew (or thought i did) most charge controllers are sized by what amperage they can handle.
So, it depends how many amps your panels are putting out (max).

so for example...

148 Watts @ 12 volts would be just over 12 amps
278 Watts @ 12 volts would be just over 23 amps

So, as long as your charge controller can handle that many amps then thats what you require ( i think ).


(as an aside.....
The larger panels tend to be 24 volts (although maybe not @ 130 watt panels) - but if so, you'll half the amps required - but beware, you wont easily be able to mix a single 12volt panel with one or more 24 volt panels.
.....)

Apologies if i'm talking rubbish !

[alexgadd]

Thanks people, had a reply from a company that deals and sells solar stuff, this is what they say:

"The charge controller is related to the power output of the solar panel (since you can always connect loads directly to the battery if the load current would exceed the current rating of the controller's output.

With 130 + 130 + 18 you're looking at up to 25-30 Amps of current getting to your batteries - therefore you need a charge controller rated at 30+ Amps. Since such controllers are considerably more expensive than <10A rated controllers you should purchase a controller which will give you room for further expansion later - e.g. 50 Amps - if you think you'll ever add solar panels again later."

and then later:

"If you only had 150 Watts approximately, then we have a 20 Amp charge controller which you could have. It is basically the 20A version of the 10A charge controller we sell here: http://www.reuk.co.uk/buy-SUNSAVER-10A- ... ROLLER.htm.

It is an excellent unit which we could let you have for £39 plus postage as it is the last one we have and we do not sell them in our shop. Standard retail price is around £50-55 if I remember correctly. It works very efficiently ensuring as much charge gets into the batteries as possible without over charging them."

Decided on buy only one 130W panel to add to my 18W panel and am now buying a 20A charge controller.

If anyone is buying anything solar would recommend the reuk.co.uk guys, so helpful.

Alex