Off Grid Garage

[dmelvin]

G'morning everyone!

After deliberating and discussing things with my girlfriend. My desire to own a garage, and her desire to be as earth friendly as she can have collided in a beautiful idea.

Right now, we have an ugly ariel line running to the current "garage" (one of those old model A garages that works good to hold my mower). The line is knob and tube in the house, and spliced to the 4ga that goes to the garage. I'm fairly sure that this is the only live K&T wiring in the house, so this is also a way to get rid of that as well, and the ariel.

Plans are, I'm going to build a couple 18.5V @ 10A panels, charge controller to a small battery bank (batteries haven't been decided on yet). Pure sine inverter for the garage door motors and small gas furnace. 12V LED lighting throughout the whole garage, automotive CD head unit for sound when I'm wrenching on my vehicle. I'm sure I'm forgetting something that she had in the plan, but that's the gest of it.

Thoughts? Ideas? Concerns?

I know, my post count doesn't look promising lol, I'm far from a genius at this, I have a solid fundimental understanding with no actual experience as far as install or build. but I am open to criticizim, and I learn fast

[russ]

Hi Buddy, The first thing you need to do is to determine how much power you really need.

The best way is to measure actual consumption with something like a Kill A Watt.

Without decent consumption numbers anyone trying to assist would be making a WAG - as in Wild A**ed Guess.

Russ

[dmelvin]

Russ, I would love to do that, but I currently just have power ran to my "garage" it doesn't have electric garage door motors, or lights, or anything... well, a single outdoor outlet. I honestly don't know why anyone even bothered to run power to it to begin with. It's literally just big enough for my riding mower, and some extra storage space, my pickup won't fit through the door, and even a mid sized car would be a tight squeeze.

I'll have to cruise around and see what other people's consumption is for similar things.

Basically, 2 garage doors with electric motors, typical is 1/2 - 2/3 HP, 1HP = 746W iirc. 1/2hp = 373W, plus losses we'll say 500W each... but could be up to or even past a 1500W surge.

I don't even know where to begin with the furnace math, I haven't done enough research on it to do any calculations. My dad has one in his garage that's the next size up from the one I'm looking at, maybe I'll be able to throw a Kill-a-Watt on his and use the figures from his, that way I'll be able to have a little overhead too.

[Mike90250]

The furnace is a killer. It likely has at least a 0.5 HP motor for the air blower, and that alone would pull 1,000 Watts. And it will need pure sine AC, mod sine will eventually overheat the motor and it will pull 20% more power on mod sine.

A single 200W panel could easily run a 12V system, with a couple wall wart chargers for cordless tools, and some LED / CFL lighting. Adding door opener motors will start to drain the batteries, and they will need a beefy inverter too, to power them. Using the opener 1x a week, no trouble, but 3x a day (6 activations) will really suck some power.

I've heard of an off-grid / battery backup garage door opener, but have no idea who makes it.

[dmelvin]

Actually Mike, my dad saw one of those battery backup garage door motors the other day and it actually sparked off an invention that we're trying to get patented right now.

Anyway, I don't think the doors would be seeing 3 times a day, one of them maybe twice (leave for work come back from work). I figured the furnace would be the tough one, not only to plan for, but also to run. I'm gonna crunch some numbers and see what I can come up with, if nothing else, I can run everything but the furnace on the solar.

Here's where it's time for an expert, or someone more knowledgeable than I am. While looking at batteries, I'm getting an 8, 24, and 100 hour, I've read about this before, however I must not of understood it too well because I can't remember it. I'll search around, but if someone can shoot me an answer on here as to what I need to be doing to figure out Amp hours, I would appreciate it.

[Mike90250]

The battery mfg figures out the amp hours, and labels the battery, like a car mfg does for the Horespower rating.

All batteries should be identical, preferably from the same production batch/lot. When you mix batteries, the entire bank will degrade faster, than if they were matched.

[LucMan]

Take a look at the Cozy brand wall heaters (LP or natural gas) they only draw 2-3 amps, they should get you wattage down while providing sufficient heat.

http://www.cozyheaters.com/products.php

[GreenPowerVideos]

Nobody mentioned this

Melvin-

Ahh, the elephant in the garage is "Build my own solar panel".

I can tell you that panels you build from individual cells will fail in time.

Solar power systems want to fail... all electronics will fail in time. Power systems
like these are really prone to failure if they are not done with full respect of electrical
principals. Yea, it might actually "come-up" and light a light bulb... and in 6 weeks, it will be dead. How? One of the 214 solder connections you made in the home-brew panels will have "opened-up". Which one? You have to un-seal the silicone on the panel and look at each connection!

Buy commercial panels. They have dropped 65% in two years. Get some good basic info on wiring and procedures before you inadvertently let all the smoke out of your batteries and electronics. See, we engineers know that the factory puts smoke inside electronic parts- and if you let the smoke out, it doesn't work anymore.

The info out there on the net is superficial and very poor in general. My goal is to teach everyone who wants to know- exactly how it is really done. I'm going to answer all questions here until I nod-out.

Calculate your actual energy usage using a Kill-A-Watt meter. Then add 20% for losses. Then buy a commercial panel and MMPT charge controller. Then determine the wire gauges you need between the panels and the charge controller and the batteries and the inverter using the charts in the charge controller manual. Install fuses or circuit breakers of about 1.25-1.4 times the value of the maximum amperage you expect at that point (between each item in the setup). Wire it up using the thickest and shortest wire you can afford (looking at the charts). Ground the system with it's own ground rod and less than 6 feet of 4 gauge copper bare wire.
Use sine wave inverters for compressor items and standard-types for lighting (ice-cream bulbs only please). Use something other than solar for heating.

Best of luck!

Bob Nagy

[Naptown]

Melvin-

Ahh, the elephant in the garage is "Build my own solar panel".

I can tell you that panels you build from individual cells will fail in time.

Solar power systems want to fail... all electronics will fail in time. Power systems
like these are really prone to failure if they are not done with full respect of electrical
principals. Yea, it might actually "come-up" and light a light bulb... and in 6 weeks, it will be dead. How? One of the 214 solder connections you made in the home-brew panels will have "opened-up". Which one? You have to un-seal the silicone on the panel and look at each connection!

Buy commercial panels. They have dropped 65% in two years. Get some good basic info on wiring and procedures before you inadvertently let all the smoke out of your batteries and electronics. See, we engineers know that the factory puts smoke inside electronic parts- and if you let the smoke out, it doesn't work anymore.

The info out there on the net is superficial and very poor in general. My goal is to teach everyone who wants to know- exactly how it is really done. I'm going to answer all questions here until I nod-out.

Calculate your actual energy usage using a Kill-A-Watt meter. Then add 20% for losses. Then buy a commercial panel and MMPT charge controller. Then determine the wire gauges you need between the panels and the charge controller and the batteries and the inverter using the charts in the charge controller manual. Install fuses or circuit breakers of about 1.25-1.4 times the value of the maximum amperage you expect at that point (between each item in the setup). Wire it up using the thickest and shortest wire you can afford (looking at the charts). Ground the system with it's own ground rod and less than 6 feet of 4 gauge copper bare wire.
Use sine wave inverters for compressor items and standard-types for lighting (ice-cream bulbs only please). Use something other than solar for heating.

Best of luck!

Bob Nagy

And what's wrong with this? excluding something that is electricity intensive like resistance electric heat what is wrong with an air collector which would be much more efficient and cost effective?