Solar Install - best starting place for easy expasion later

Thread Starter

Upex

Joined Nov 10, 2013
76
No door to the south, the door that I'm putting the panels on is north facing and its opposite wall is solid. No windows or doors and isn't mine, so I can't start putting holes in it or the like. Plus it meets a path on that side, so would be subject to abuse from passers by even if I could use the south wall.

Dont 100% need 2 banks of batteries. Just looking to have a small set up for some lights and a heavier set up (originally for an inverter, but that's kind of faded away due to low input as panels are arse about face) for some 12v battery charging facility. Still not sure how id do the latter mind now I'm thinking about it.

If I had one bank for my lights and the number 2 supply from the split switch went to a set of cables that didn't go to batteries (kind of like insulated jump leads) then could I plug the drill, bike lights, all other 12v batteries to that cable and it would become the other battery?

Guess I'm saying, if I have normal set up of panel, cc and batteries, can I / how would I charge these small items from those batteries? Ie if connected my bike lights to the battery bank. Yeah they would pull charge to equalise between the light pack and the battery bank) but I dont think this is the right way or even safe to charge like this no?
I had in my head that say the cig socket charger could be cut off and the cable fused and the used to supply the power from the cc?

Confusing myself now. Just want some 12v led lights and a way to charge the 12v bits and bobs in the garage without having to keep lugging them to the house and back. (The inverter would be nice if anyone knows a way that fits this funny situation. But I'm not hopefull on this part).

The over the door frame is a proper good idea. Won't work for me, but something ill remember and probably use when move etc.

Cheers all.
 

MrChips

Joined Oct 2, 2009
30,712
Use 12V 7Ah sealed lead acid batteries. They are light weight compared to car batteries and easy to carry back to the house for charging.
 

Thread Starter

Upex

Joined Nov 10, 2013
76
No where to put it. Literally, I have the real estate of the garage door, and thats it. Next nearest space I have control over is 150 meter away and across others land, so unless I can stick the panels in my house/garden and wirelessly transfer the power to the garage, this is it. The garage door that points north, or lug batteries up and down the whole while, which I don't want to do, thus this thread.

I'm in the east of England, UK.
 

Thread Starter

Upex

Joined Nov 10, 2013
76
Anyhow, from all the help, I think we're there, set up wise, in principle.

Panels on the door feeding charge controller but running through a disconnect on the + feed, charge controller to the battery selector switch thing that then has feed 1 to batteries for lights and alarm (found a 12v alarm in a box at the back of the garage today, so going to run that off the perm battery to. Feed 2 the branches off to a quick connect that I can them make my separate chargers fit, ie plug it in to my bike lights, led torch etc and can charge 1 at a time by using switch to feed 2, but making sure to kill the panel + disconnect before unplugging one for the other.

I assume this would be fine? If so, I assume that it wouldn't be good to run the switch in 'both' position, as the light/alarm battery would be much larger than say my bike lights battery?

Thanks, Upex
 

NorthGuy

Joined Jun 28, 2014
611
Your bike light probably is not lead-acid battery, so it's likely not 12V. It all depends on the battery chemistry and voltage.

If you go with solar panels and a charge controller, the battery will be around 13-14V while charging (around 12V at night), which might be ok for the bike charger, or may be not. If voltage is good, you can simply connect it in parallel with the regular battery to charge.

Otherwise, you must convert voltages. Small inverter will work, but overall it won't be very efficient. You can also build (buy on eBay) 24V battery and use buck charger to convert it to whatever voltage you need to charge.
 

Thread Starter

Upex

Joined Nov 10, 2013
76
The bike light 12v, but not a clue what type.

So I can charge in parallel, how would I wire that up? Have two + and two - from the cc one set for battery bank and the other for the other 12v bits that can just be swapped out?
 

Sensacell

Joined Jun 19, 2012
3,432
Buy a wagon, fill wagon with big lead acid batteries.
Charge batteries from AC powered charger in alternate location, drag wagon to location of use, connect inverter.
Drag wagon back for charging.

The solar idea sounds like an expensive disappointment based on the circumstances.
 

Thread Starter

Upex

Joined Nov 10, 2013
76
All done.

Used a solar type connector MC4 or whatever they called, on the + solar lead so can disconnect to swap out batteries, fitted a female quick cable connector to the CC output leads. Have installed the male connector to the battery bank and made another male lead with clips so I can attach it to whatever. Nice and quick and simple, plus can easily change what I'm charging by simply using the connector.

Maynot be the most apt or pretty way to do it, but I can't see any issues with it at this stage.

It was overcast/hazy, but I was seeing circa 70-100 mA when I checked yesterday. Saw 160 mA the other day when it wasn't particually bright, but wasn't hazy either. Will check it on a normal day to see what it's like (it's foggy today, so back at the 70 mA mark). I'm just unsure if this is enough to actually do anything though? i.e. if left Mon-Sat with no use, @3 amps will be gained, if 5hrs worth per day. Not sure what 3 amps (if thats the right calcualtion) is worth for low power lights etc. I can fit another 4 panels on the door, which (if the 3amp is right) would put it up to @15amp per day (but again, not sure if this is an hours worth of light or ten)

I agree that all in, it doesn't provide the power to make it worth while, however that is driven by my limitations on direction/location, which I have no control over. I will utilise this equiptment in the shed when it's built, so I've not lost anything other than getting a few holes in the garage door in exchange for the experience, but it's been a fun experience and I've learnt a bit that will help with the shed set up and having spent less than £60, I don't think it's been a bad excercise at all, especially as it'll be reused in the shed. I just wonder if I can forgo the need for a roof and use panels instead....... ;-)

Thanks for everyones input, much appreciated.

Upex
 

MrChips

Joined Oct 2, 2009
30,712
The proper calculation uses units of Ah.

Measure the average current in amps and multiply that by time in hours.

Now compare that with your battery usage. Use about 80% efficiency, i.e. derate your charging Ah by 80%.

For example, let's say on average you get 4 hours at 100mA for 7 days

7 x 4 x 100 mAh = 2800 mAh = 2.8Ah

80% of that is 2.2Ah

This means you can take approx. 2.2A for one hour, 1A for 2.2 hours etc, per week.

or you can draw 1A for 30 minutes on four days each week, etc.
 
Last edited:

NorthGuy

Joined Jun 28, 2014
611
I guess the overcasts you experience are much more severe than here. I only get such bad numbers when it is raining and clouds look dark grey, which only happens here once or twice per year.
 

Thread Starter

Upex

Joined Nov 10, 2013
76
I guess the overcasts you experience are much more severe than here. I only get such bad numbers when it is raining and clouds look dark grey, which only happens here once or twice per year.
Jealous! Lol. Obviously my figures are massively low to start with due to direction, rather them the fact it was overcast etc. I'll still report back on what shows up on next sunny day, but that could be a while lol.

Mrchips thanks for running that through, good to understand it a bit more.
 
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