Mixing same voltage but different wattage panels

[DigitalMind]

OK, back to this ...

  Lets say I have a couple of 50 watt - 12 volt solar panels, and I want to add a 90 watt - 12 volt panel, don't I just connect it in parallel and I'll get 50 + 50 + 90 Watts output ?? (Obviously I'm charging a 12 volt battery bank)

I thought this was the case, but someone trying to sell me panels is telling me otherwise ... I suppose I could be wrong, but I can't help but feel the panel he's trying to sell is really a 24 volt panel which would be totally different.  

As always, thanks so much for your help.

[Flux]

Yes basically that is right, you just connect them in parallel. The actual wattage you get will be a fair bit under the nominal but that is always the case unless you use large series strings with a mppt controller.

You can't add different sized panels in a series string for use with a mppt converter but for a basic simple 12v system then carry on as you intend.

Flux

[DigitalMind]

Thank you very much Flux.  Over the last year or two that I've been here, your advise has always been excellent.  Responses from you mean I don't need to triple check everything as I usually would.  

[SteveCH]

I did it your way for 20 yr., mix-match of panels I'd come across over the yr. No problem. However, as the previous person said, you won't see the rated output at the charging end. Couple yr. ago, I decided to upgrade to a couple MX60s, add a few more panels. I ended up rewiring my entire array into 36 v. strings [formerly all just left at 12 v] and run them all into a combiner box. Then, two circuits out at 36 v. to the controllers, 12 v. out from them to the batteries. Much, much more efficient and equal to adding even more panels. Of course, the controllers cost, too. For what you are doing now, however, you should have no problem. If your system grows, and your usage needs increase, at some point it will make good sense to change things around with an MPPT and etc.

[DigitalMind]

Thanks Steve !