12v solar system for outbuildings

[scbk]

Hi folks, found this forum after looking online for navitron - I never posted on there, but every so often would go on for a browse and a read.

Maybe this forum is more for household size installations, but that's not something I'm looking at yet!


Already have a couple of small solar systems using 2nd hand batteries. One is running various lights in an outbuilding, and an ex council streetlamp that I changed over to 12v. Think that is a 100w panel, from ebay/amazon.


A recent visit to the scrappies picked up 4x 220ah 12v lead acid batteries, over 200kg in total.
I have another couple of outbuildings it might be handy to have more 12v lights in, as they currently have a 'temporary' 240v extension lead running to them.

I haven't really decided what I'm doing yet, but what sort of size of panel(s) would be good to charge 2x 220ah battery parallel?

[Stinsy]

Welcome!

To answer your question about solar panel: Bigger is better!

2x 220Ah batteries would give you 1325Wh at 50% DoD. On a sunny day in August you’d easily get that from a 250W panel. In January you’d struggle to get that much from a 1500W array most days.

I’d suggest setting the batteries up as 24V. Even in a small “few hundred W” system it makes the cable sizes more sensible and makes it easier to get power to the other side of the room with sensible voltage drop.

[scbk]

Thanks, I'd not thought about doing it as 24v. Initially I would've said no as it's easier to get 12v lights etc. But when you look through aliexpress etc a lot of stuff is multivolt like 12-85v dc

[scbk]

Are there any good suppliers to look at for buying a small quantity of large panels? Most of what I've found so far would come on a pallet, so the delivery price to the Highlands is a killer for just a few panels.

[ecogeorge]

Off course you're using LED lighting to maximise efficiency ?
George

[Stinsy]

Are there any good suppliers to look at for buying a small quantity of large panels? Most of what I've found so far would come on a pallet, so the delivery price to the Highlands is a killer for just a few panels.

Small quantities are always difficult because they’re just too big and too fragile to go with a standard courier. Have a look at ITS and Bimble for good value / small quantities. Highlands is always going to be difficult, the companies cannot tie enough drops into a single run to make it work at £50 per drop.

[Mr Gus]

You can:
A. over order, get the best discount, suck the pallet delivery fit everything & luxuriate in a job well done & extra electrons in shoulder months.
B. as above but flog on the excess from some slick local advertising & make a few bob back over time having ensured you have a few spares panels set aside "just in case"

C. group buy within your area, shared costs, would still recommend a few spare panels bought & stored for failures.

We all understand the pain, its pricey any day of the week, but sometimes easier than never!

Easter ross (Hiss) or Wester ross ..incidentally?