I made a homemade generator.
I recently built a homemade generator. I decided it would be nice to have if we lose power and I want to keep the refrigerator and freezer going.
Here is how I did it:
1) I asked around and got an old lawnmower given to me. It was a Murray with a 4.5 horse Briggs engine. The handle was shot, the wheels were falling off, but I got the engine running good. I cleaned the air filter, which I don't think had ever been done, and changed the oil and sparkplug. It runs fine now.
2) I bought a steel plate for $25 from theepicenter.com. This plat has universal holes drilled for a lawnmower. It also has the mounting holes for the alternator I would need. I bolted the lawnmower engine to the plate. I took the blade off the lawnmower first though. I also used 3 washers between the plate and engine to lift it off the plate a bit. This was needed to insure it could get in "depth" alignment with the alternator, in other words so the shaft didn't stick down to far.
Also, the blade acts as fly-wheel weight, which you lose when you take it off. I've found the pulley and alternator bring enough weight to make it work OK though and start easy enough.
3) I put a pulley on the lawnmower crankshaft. This to run the belt that goes to the alternator. I also got this pulley from epicenter. Theirs is a very good quality one, better than what I saw at Northern Tool.
4) I picked up a GM alternator. You can get the model number needed at theepicenter to from some of the plans they have. I used the alternator where you have a switch in the circuitry so that you can switch on the alternator to charge the battery, or you can switch it off. You can pick-up used alternators at the car junkyard, about $25. Or you can get a newly rebuilt one for about $50 or so. You do need to understand the different types and how they hook-up, which is really very simple. theepicenter website gives a good description.
5) You have to bolt the alternator to the steel plate. I had to go to the hardware store to get the correct bolts and stuff for this. It was easily done though.
6) You have to get a belt to run between the engine pulley and the alternator pulley. I ended up getting one from theepicenter too, as it was about as cheap as anywhere else and I got the right belt. Read their info. to decide on the right belt to use. I put the belt on and tensioned it just by feel.
7) I had gotten some cables that would work to hook the alternator to the battery post of a 12V car battery that I had available to me. Tell the guys at the autopart store what you're doing, they have them. You can also get them from theepicenter too. In this system you have to have a battery because a car alternator needs to be attached to one when it is charging. But that's OK, I like having the battery because I can run small appliances without having to crank-up the engine.
8) Then I ran some wires and a couple of switches, which I got at the local auto parts store, to an inverter that I had ordered. I got a 1200 watt continuous inverter for $99 (and no shipping charge or tax!). You can get small 400 watt inverters for about $25 if you only need to power small stuff.
9) I didn't mentioned that I built a wooden frame for this all to set on. Its a hodgepodge of 2x4's I had laying around. But it does the job of holding the steel plate with engine and alternator, and battery and inverter all together. I have a small wooden post sticking up that has my switches on it, right by where the engine pull-cord is.
Also the other day I bought 4 wheels on sale at Northern Tool, along with 2 axels. I'm going to mount the generator on wheels so its easy to move around.
It runs great. I start it for a few minutes every few days to keep the battery topped off. Its sitting there waiting for an emergency. I've plugged everything from a small microwave (1150 watts) to a drill in it, it powers them just fine. For the microwave though, the pull is more than the alternator can produce, which is about 750 watts, so it is running off the battery some too when the gun is firing. So charge the battery a while after the microwave has been used.
If you decide to make one, good luck. I think next I'm going to build one using a horizontal shaft engine, I've found a place you can get them for about $150+ for a new one.
If you would like to see a picture let me know.