I bought a shed, 12X18. I want to install two basic lights and a vent fan. Minimal usage for the lights and the vent fan would be small. As for the amps and usage. I get a bit lost here, but the bulbs are your basic 8w bulbs and vent fan would be 10-15 watt.
You'll need to do a Power Audit. Knowing it's an 8w light doesn't help you if you don't know how long you're going to have it on. 1Hr a day? 10 hours a day? Try to get all your measurements in Watt Hours so the numbers stay straight. About the only time you need to worry about amps is when you calculate things like your battery capacity, which will be Amps * Volts = Watt Hours.
I.E. a 100Ah 12v battery gives you 1200Wh to play with. Once everything is in watt-hours the math gets a LOT easier to keep track of.
I've seen kits on Amazon and Harbor Freight, and I don't know which one would be the best. I have no desire to go and build a massive one. Just a basic panel or two, connect to a battery and then to an inverter. Excuse my ignorance if I missed a part or two, but nothing crazy.
The
Fisher Price My First Solar Harbor Freight kits are absolute krap and will be nothing but waste of money. The kits you find on Amazon ffrom companies like Renology and HQST and such, while basic and simple, are a much better value. Especially for the beginner & small system ends.
I'd like the fan(s) to run on a constant, and the lights would be on for maybe 10-15 min at a time if I need to get something at night.
That's going to require a calculator and some math but is easily do-able.
Any and all direction is wanted. And of course, I don't want to spend a lot of money. Thanks in advance.
If you're working on a budget there are some things you can cheap out on and some things you really, REALLY shouldn't. The more limited the budget the more leg work you need to do.
Some things you can cheap out on for a smaller/beginner system:
Batteries. You can get
Wally-World 120Ah FLA batteries for about $100 out the door. You'll get 60Ah or 720Wh of power out of them, but they're 1/3 the price of even the cheapest LFP comparable battery. If your needs grow, you can always replace it later.
SCC. If you can get a MPPT controller you'll gain upwards of 30% more efficiency out of panels than you'll get out of the PWM's most kits come with. The Victron fanboys will tell you that it's Victron or nothing, but those of us with cats to feed find that an EPEver or HQST or even Renology will do the job of turning solar panel DC into battery DC just fine for 1/4 the cost.
Panels. Search your local Craigslist, ebay, and online places for used panels. A 10-15 year old panel will still produce plenty of wattage compared to a new one but might cost you as little as $0.25/w compared to the almost $1.00/w of a new bog standard "100w Panel". The hardest part of doing that is that shipping a panel is usually more expensive than buying a new one unless you buy a LOT of panels at once. As an example, I bought a pallet of 23 used panels a few months back and the shipping was about $300. That made the panels about $53 each. If I had purchased a single panel, the shipping was the same so it would have cost me $360 for a single panel.
Number of fuses. Some people put a fuse into every single wire in their system. A fuse on every panel, a fuse from the panels to the SCC, a fuse from the SCC to the battery, a fuse from the battery to the inverter, etc. For a small system don't be afraid to just fuse the loads like the inverter and low power fuse blocks. If you want to add more fuses to feel better you're more than welcome to, just use quality trusted fuses.
Things you really, REALLY don't want to cheap out on:
Fuses & Wire. Get the correct type and quality of fuses and breakers. Chinese knock-offs and the tube-style "automotive" fuses look great until they catch fire. ANL is fine for FLA but you really want a Class-T if you step up to LFP. Remember,
Fuses are cheaper than fires!
Inverters. Spend the extra to get a Pure Sine Wave inverter. Yes, that Modified Sine inverter is cheap and you can take all that money you saved and put it to new fans and lights and electronics that burned up because MSW is krap for those. When you plan out your system get the right inverter for the job. The basic rule of thumb is "No more than 250a" because around 300a that fuse becomes a flamethrower. Besides, there's no need to buy a 2000w inverter if you're only running 200w of load, that's just a waste of money and battery power.