Help Me Think Through A Solar Build

[JOsmund999]

I have a 40 X 60 Pole Barn without electricity. I use it to store trailers, seldom used equipment, etc.

Running power and setting up electrical would be costly. I don't even have electrical on the property so it would require starting from scratch. In another shed, I do have some equipment with batteries where I have 25 W panels hooked to little individual maintainers and they work beautifully.

For this shed, I'm thinking I'd like to store a boat with a starting battery and two deep cycle trolling batteries. They will need to be charged / maintained. I'd also like to have some LED lights and perhaps the ability to run some small electrical tools / appliances.

So if I build the traditional system with: panels - charge controller - battery - inverter, it seems like it would be silly to plug a 110V on board charger into to an inverter to maintain my boat batteries. Why not skip the inverter to 110 and then the on board charger back to 12 Volt?

Could I somehow use the Charge Controller to charge / maintain the boat batteries and the solar system battery together and then when using the barn lights or other barn appliance use, isolate off ( Unplug ) the boat and just use the solar system battery?

I hope that makes sense. Am I thinking of this correctly?

 

[dcg9381]

I've done "off grid" solar for remote gates, largely starting like you are thinking - deep cycle batteries and a panel or two.
When you're stepping up to the ability to invert to 120V power, now we're talking about at least one deep cycle and an inverter that you turn off/on when you need to use it.

What I don't like about using a "110V board" (IE, and inverter) to charge your batteries is that the inverter is always on and you're going 12V -> 120V -> 12V again. I'd rather see you drop individual wires from individual panels to individual battery charge controllers for individual vehicles. Or, worst case, one 200 watt panel to multiple 12V charge controllers.

I think the barn lighting and 120V inverter system will be it's own thing.

Vitron is probably the leading manufacturer of this stuff.

You're in KS, you put panels on the roof be ready to recongize that you may go weeks in the winter with no solar power (snow covered).

 

[sjvicker]

check out: https://diysolarforum.com/ and anything Will Prowse's youtube video's about small solar systems. Also, he has several examples on his website of systems with component lists that should be everything you'd need. https://www.mobile-solarpower.com/

What you do kind of depends on your budget. As dcg mentioned Victron is the leading manufacturer but there's several other options out there that are good enough. Because you want to run AC and DC loads and you mention small tools and appliances then I think feeding an AC panel with something like this would suit you best: https://www.mobile-solarpower.com/2000-watt-24v-solar-system.html. You can get some trickle chargers for your boat batteries and yeah, there's inefficiencies in converting DC > AC > DC its also "free" power and keeps your solar system separate from the loads.

You need to make these decisions:

1. Do you want to run sensitive electronics? Yes = Pure Sine inverter, No = cheaper general inverter
2. Do you want to use a lithium battery or more than one lithium battery? Yes = higher cost and can't charge/discharge below freezing but more power per battery & better longevity. No = cheaper
3. Do you want a 12v, 24v or 48v system? Higher voltage = smaller wires & more power, lower voltage = lower startup costs
4. how many W of panels do you want to buy?


I have about $2k into a system in a shipping container that feeds a panel and does everything you describe. During the summer it stays on 24/7 and running starlink and a camera I have about 55% battery capacity every morning. My goal was to be able to run a miter saw or my 120v welder. Here's what I have and it works great.

2 cheapo amazon LI batteries in series = 24v
Giandel 3000w inverter
Victron 150/45 charge controller
Victron battery balancer
2.25kw of used panels from SanTan solar - 3x3 series/parallel config

 

[bluedog225]

solid advice above.

I’ve gone years with a 12 volt system. Ryobi makes a 12 volt charger for scores of hand tool batteries. Lights, rv stuff, etc. I imagine there is a battery maintainer off 12 volt.

but the step to 48 volt and an inverter opens up a bunch more everyday stuff. E.g. a 32” costco flat high def tv for $120.

victron is top notch.

freezing LiFePO4 is a real concern. Lead acid can take very cold temps. Trade off. I just got tired of nursing my trojan for 15 years. I bring my LiFePO4 home for the summer heat and disconnect for the freezing.

currentconnected.com has some kits. But maybe more than you want.