28 replies to this topic

[DarkHand]

Ok, I'm building a battery charger using an alternator and a washing machine motor. The washing machine motor will be used to spin the alternator, which will charge the battery. Not the most efficient system in the world, I know. I've already got the motor-side of the system working, I even re-used the dial from the washer, so it will automatically shut off after a certain amount of time.

I've got a few questions about the alternator though. It's a Civic alternator of course. From what I can tell from the wiring diagrams I've seen, I should only need to connect the ground wire to negative, and the white wire to the positive terminal of the battery? It seems I don't need to use the black/yellow and white/blue wires, but that just dosen't seem right to me, and I'm worried I'm misreading the diagrams and taking the regulator out of the equasion, which I need to prevent overcharging the battery.. So before I go and burn out my alternator or battery I thought I'd ask first. How should I have the alternator wired up to properly charge the battery?

Edited by DarkHand, 11 September 2005 - 03:43 PM.

[b16a87crxsi]

Very innovative Idea. post pics when its done, id like to see it!

[DEIVIONCRX]

if you could post the wiring diagram i could help you a lil better

id try to wire it as if it was in the car, white wire to the + and the ground to the -terminal, wire in the regulator so you dont overcharge like you said, and just skip the ECU wiring if there is any

[DarkHand]

I was going by these pictures and this description.

After looking at it a little more, the black/yellow and white/blue wires control the 'battery' idiot light, among other things. Each wire connects to either side of the light. Normally, both wires are energized, so the light stays off. If something goes wrong with the system, one sides goes to ground, lighting up the bulb.

So at the very least I'll connect a 12v bulb to those wires, and have a little warning light for some extra security in case I screw something up.

Edited by DarkHand, 11 September 2005 - 06:39 PM.

[badpenny]

Wow, and then you could remount everything in the washing machine to fit and make one of the largest non-industrial battery chargers known. All self contained.
I think it is a very novel idea.

[Daveed]

That is a very interesting idea. Maybe consider using a GM 1 wire alternator. Can't hook that up wrong Also, most of the gm 1 wire alts are 100amp or greater.

[Buford]

It's called a motor generator.......has been used since before WWII. on aircraft........we used them to get quite power 400HZ from 50/60hz.......also ones with a humongus flywheel so computers could shut down or wait for back up generators come online......they even have them for vehicles/tractors to get 120v from 12v.......alternative to invertors.......

If you use gas engine power plan on 2hp per kilo watt........also with all alternators that can be disconnected while running (battery cables) you need a big Zener Diode so the voltage won't blow the rectifyer diodes......"ZAP STOP" available from West Marine.

A 4 cycle Honda weedwacker motor with a 30amp alternator works great (I built one) I tried a 100amp alt. and had to start it first before connecting the batt. terms....then if the batt was fully discharged as soon as you connected it to the bat it would over power the engine and stall it.....now you know how to make a small engine brake dyno!!! big alt with a big variable load resistor.....I used fixed ones in a bucket of water for load testing.......

Have fun

[DarkHand]

with all alternators that can be disconnected while running (battery cables)  you need a big Zener Diode so the voltage won't blow the rectifyer diodes......"ZAP STOP" available from West Marine.

Ah ha, thanks for that, Buford. I knew you shouldn't disconnect the battery while the car was running, but I didn't actually know why. But after Googling into the Zap Stop, I found lots of good info on the 'load dump' phenomenon. If the alternator is chugging away charging the battery, and the battery is suddenly disconnected, the alternator can't drop its output fast enough, and all that extra energy's got to go somewhere. And it's usually forced back through the alternator's diodes in reverse, which frys them. The Zener diode in the zap stop essentially acts like a voltage regulator. If the current spikes too high, the zener diode can dump that extra current to ground, instead of back through the regular diodes in the alternator.

After a little more research, I discovered that the Zap Stop is nothing but a wire with a 20 amp slow blow fuse and a MR2535L zener diode. I just now ordered the diode through Allied Electronics for $1.40 before shipping. For the price, this is really something that should be on all of our cars!

Edited by DarkHand, 13 September 2005 - 12:30 PM.

[Gasoline Fumes]

I think you'll need at least the "IG" terminal hooked up.

[DarkHand]

That's EXACTLY what I was looking for, Gasoline Fumes! Thanks a ton!

The charger is pretty much built and the motor side is wired up, I just need to wire up the alternator and it's done. I'll take some pictures sometime this weekend when I finish.

So it looks like I'm connecting 3 wires to the positive side of the battery. B to provide charge, S so the regulator can monitor the current, and IG on a switch to turn everything on. Then I'll connect a 12v bulb from L to IG so I can have a charge warning lamp.

Edited by DarkHand, 16 September 2005 - 09:16 AM.

[Greg Gauper]

Ok......I gotta ask. Why are you building a 'Rube Goldberg' contraption to charge your battery? Is it just because you've got the parts laying around and they're free?

From a practical standpoint, you would be much better off using a proper 'trickle' charger to charge & maintain your battery.

I assume your washing machine motor is an electric one? (gas powered washing machines kinda went out of favor after WWII)

You have the inefficiency and energy loss from converting electrical energy to mechanical energy (your motor) and then converting the mechanical energy back to electrical energy (your alternator) in order to charge your battery.

A real battery charger has minimal energy loss and is much, much more efficient at charging your battery, and will do a much better job at maintaining the battery once it is fully charged. I would be worried about your setup 'over-charging' your battery, regardless of how good your regulator is. Your alternator is designed to always proved some current for all of electrical systems AND charge your battery. Without any other load, you will probably cook your battery. A good trickle charger on the other hand, can sense when the battery is properly charged and will back off to next to nothing to keep a battery in good condition.

Now if you do have a gas powered washing machine motor (or any small gas powered engine) and you you are trying to make a home built gas-powered generator for mobile use, then I agree it's an interesting project

Just my $0.02 worth...........

[DarkHand]

Ok......I gotta ask.  Why are you building a 'Rube Goldberg' contraption to charge your battery?  Is it just because you've got the parts laying around and they're free?

Yes. I'm working on the CRX so rarely lately because of budget reasons that the battery keeps discharging from underuse. I need a way to keep the battery topped up without having to continually idle the car.

From a practical standpoint, you would be much better off using a proper 'trickle' charger to charge & maintain your battery.

That would be the best solution, but if I had the budget for a charger, I'd have the budget for working on the car, too. Since I haven't been working on the car, this is pretty much just something-for-me-to-do, anyway.

I would be worried about your setup 'over-charging' your battery, regardless of how good your regulator is.  Your alternator is designed to always proved some current for all of electrical systems AND charge your battery.  Without any other load, you will probably cook your battery.

I was worried about that as well, and was considering putting a small secondary load on the alternator. Maybe build a spare car stereo and speakers into the thing. I also re-used the washing machine's timer, so the charger can automatically turn itself off after a good spin-cycle top-up charge anyway.

Now if you do have a gas powered washing machine motor (or any small gas powered engine) and you you are trying to make a home built gas-powered generator for mobile use, then I agree it's an interesting project 

I actually considered using a spare snowblower engine I've got laying around, but I already had the old washer apart, and I wanted to be able to use it indoors, too.

So yes it's highly inefficient, and it may cook my battery, but it's a nice little side project nonetheless.

Edited by DarkHand, 16 September 2005 - 12:52 PM.

[Greg Gauper]

So yes it's highly inefficient, and it may cook my battery, but it's a nice little side project nonetheless.   

<{POST_SNAPBACK}>

Gotcha....

I like the idea of the 'spin cycle'

Have you considered building your own charger from old surplus electrical parts? They aren't very complicated. I would suspect you could build one for about $5 - $10 in used parts. Search the website or your library for plans. Even if you aren't electrically inclined, it's an easy 'beginners' project.

Another option...If you have any industrial control houses near you, they often scrap out old used power supplies when retrofitting controls. See if you can find a surplus 12V power supply with an adjustable regulator and crank it up to 13.5-14V. You need a supply rated for 3-4amps minimum.

[DarkHand]

Little update:

The charger TECHNICALLY works, but I don't think the alternator is spinning fast enough; I can't get it to generate more than 0.9v according to my multimeter. While it is a fast motor, the pulley on the motor is smaller than the alternator pulley, so I know my gearing is off. I have a larger pulley to attach to the motor side, but the center hole in it is too big. The options I've come up with so far are to either come up with some sort of adapter to adapt the bigger pulley to the smaller-spindle motor, or take both pulleys to a muffler shop and have them tack weld the little pulley to the middle of the big one, and use the smaller pulley itself as an adapter.

Edited by DarkHand, 17 September 2005 - 11:24 PM.

[Buford]

you need to be turning the alt 3 - 5000 rpm