Building a Rez_arator

[Rez]

So I'm looking at a Car Battery, a old GM alternator and an electric cooling fan.

I hook a voltage gauge to the alternator, plug the electric cooling fan into the battery with a switch. Hold the electric cooling fan motor to the alternator so it turns it.. Voltage says 12 volts.

What am I building?

[Jackass]

A Goldberg machine? A battery charger that requires a battery to run on?

[Rez]

One would think.... but no. haha


Just saw your edit... bingo.. well close.

a self charging battery.. fan motor takes less juice then the alternator puts out. So turn it on and use the battery for camp without it going dead. Theory anyway. May have to turn some wrenches and fire up the welder next weekend.

[Jackass]

Does it apply voltage to the "undercarriage" area?

[Rez]

Hmm... "clears off work bench"

[ygmir]

perpetual motion........*squints at Rez*.........

[Rez]

Well for some part.. If it works. I would prob hook a voltage switch to the fan motor, so when the battery drops to a point the fan motor would turn on until the alternator has brought it back up to voltage. But with a load it would prob run almost constant.

I'm really thinking more for just camp lights and such. but may hook up a inverter with a load and see how it handles it.

[Jackass]

You may want to do some testing and revisit your theory. You can't get something from nothing. There are losses that you aren't accounting for... Energy cannot be created nor be destroyed, only transformed from one type to another . But not at a gain... You will surely but slowly run your battery down.

PS run everything you can at 12V DC, the AC inverter will give you a loss just for being connected to the battery idling with no load. Use the smallest capacity inverter you can also for minimal loss. You'd be surprised what a 400 watt inverter can run. No blender or hair dryer though.

[Rez]

You may want to do some testing and revisit your theory. You can't get something from nothing. There are losses that you aren't accounting for... Energy cannot be created nor be destroyed, only transformed from one type to another . But not at a gain...

this may very well be the case. Basically just bored in my garage. But

I'm really not building a perpetual motion generator. like what has been attempted in the past.

I'm taking a small electric motor "Electric engine cooling motor" that uses a small amount of juice, to turn a generator "Engine Alternator" that puts out a large amount of Juice. And just hooking them up to the same car battery.

PS run everything you can at 12V DC, the AC inverter will give you a loss just for being connected to the battery idling with no load.

Yes i'm counting on it. I really was just planning on trying an inverter to create a heavy load plugging in some stuff. I want to see if the small fan motor would still turn the alternator with a higher load. Not sure if there would be more resistance of the alternator in that case. more of test to find out.

[Jackass]

In that case, I'd like a full report in the a.m. with your findings. I admire your tenacity...

The alternator will definitely feel resistance when it starts producing juice, the more you ask of it the harder it is to turn...

[Rez]

It would be more of a next weekend project ..lol

I'm sure I could just look this stuff up on the internet instead of testing.. But I enjoy benching stuff and testing myself. It a hobby of being able to say Rez your an idiot as much as possible..

[Rez]

The alternator will definitely feel resistance when it starts producing juice, the more you ask of it the harder it is to turn...

I figured this.. So I took the leads from the alternator and hooked them up to a dead battery, and there was a draw on the alternator but the fan motor still turned it. (Keep in mind I'm holding this crap in my hands while I was testing) Plan on rigging something up to mount the alternator and fan motor together next weekend so I can really play with it more.

[Jackass]

Yeah, I goof around in the shop a lot more than I should sometimes too. It's all fun and games until the red-hot toaster wire lands in your lap...

[Rez]

I will spare you the details of when I tried building my own propane powered fridge back in my 20's. Take your visual and run with it.

[Captain Goddammit]

"A fan that takes a small a out of juice to turn an alternator that puts out a large amount of juice"?


Alternators don't "put out" juice. They convert mechanical energy into electrical energy, with major losses involved. You won't gain efficiency, you will severely decrease it.
That alternator you're holding in your hand spins freely and easily because it's not under a load and turning enough RPM to function. They take a lot of power to spin when subjected to an electrical load and they are only about 50% - 60% efficient.
A car alternator like that GM Si alternator you've probably got there takes around two to four horsepower to spin at a load. That's more than your fan can begin to even produce.
See that fan right behind the drive pulley on the alternator? That's a cooling fan, it's there so the alternator doesn't fry itself from all the heat - wasted energy - it produces.
Go ahead and build it if you're that bored, but you will only run your battery down faster than if you didn't hook this junk up to it.
You're putting more current into your fan than you are getting out of your alternator.

The bottom line is you get about half the energy out of an alternator that you put into it. That's the big basic flaw in logic you're not seeing.

[Rez]

"
You're putting more current into your fan than you are getting out of your alternator.

That is what I was afraid would be the result. and what I had wanted to test at a low load. I was thinking it may produce just enough to run the fan motor and enough to have some low voltage lights (DC light strings) going for camp. Not looking to solve the worlds energy crisis here. Just keep the battery good enough to keep my lights strings on for a week...

I was just surprised I was getting anything out of the alternator ran by just an electric fan motor.

[ygmir]

"
You're putting more current into your fan than you are getting out of your alternator.

That is what I was afraid would be the result. and what I had wanted to test at a low load. I was thinking it may produce just enough to run the fan motor and enough to have some low voltage lights (DC light strings) going for camp. Not looking to solve the worlds energy crisis here. Just keep the battery good enough to keep my lights strings on for a week...

I was just surprised I was getting anything out of the alternator ran by just an electric fan motor.

perpetual motion........*squints at Rez*.........

[Skuzzy61]

I think Captain is being generous with the alternator efficiency. Automotive alternators lose efficiencies in multiple ways.

1) They take part of their own output and recycle it to create the magnetic field needed to generate electricity.
2) Thermal losses are higher due to electricity used to generate the magnetic field, as well as the generation of output.
3) Mechanical losses due to friction from bearings, fan, mass....

Basically, they are very inefficient devices. As the load on the alternator increases, the load on your fan motor increases higher. As an example, when there is zero load on the alternator, your fan energy requirements are low, but not zero as you still have to overcome the mechanical losses of the alternator. Right there you are behind.

Now, as more load is placed on the alternator, the load on your fan motor increases faster than the output of the alternator will increase due to its loads. There are also mechanical and thermal losses in your fan motor. What ends up happening is you kill your battery faster due to the motor loads increasing as the battery drains. The loss will be nearly exponential as it runs.

[Rez]

perpetual motion........*squints at Rez*.........

Perpetual motion is a thing.. it can happen.. Damit !!! stomps foot.. crushes juice box..

[Rez]

The loss will be nearly exponential as it runs.

Yeah, I was hoping to get around this by just running the alternator at its lowest output RPM with only using a small load for accessories. But seems not to be the case.

Looked at some motorcycle alternators.. same thing.. even lawn tractor ones.. Only one I did see some hope in is an AC Delco that is supposed to be able to put out more of a load then it eats. But have not seen a case where that is proven.

[ygmir]

perpetual motion........*squints at Rez*.........

Perpetual motion is a thing.. it can happen.. Damit !!! stomps foot.. crushes juice box..

have you ever considered running for president?

[Rez]

I laughed louder at that then what was socially acceptable in my current physical environment. Everyone stared.. I feel like standing up and saying "What!!! The uptight chic in the corner over there farted and it was fuckin funny .. get over it people" Thank god I don't have to glue my hair back down over it.

[ygmir]

I laughed louder at that then what was socially acceptable in my current physical environment. Everyone stared.. I feel like standing up and saying "What!!! The uptight chic in the corner over there farted and it was fuckin funny .. get over it people" Thank god I don't have to glue my hair back down over it.

a description of your current environs would be entertaining, methinks?

[Captain Goddammit]

A solar cell and charge controller would accomplish what you're after.

The mechanical power it takes to spin alternators under a load is the entire reason I use an electronically fuel-injected engine in my Mutant Vehicle, rather than a playa-simple, less-to-go-wrong carburetor.
I use two alternators to get enough power, and if I tuned everything on with the engine idling (like it always is in BRC) it would kill the motor. The EFI automatically compensates and throttles it enough to maintain the right idle under all that drag.
Real-world workin' man's example:
Have you ever hooked up good jumper cables between a running car and a dead one and noticed how the motor gets "dragged down" on the running one? That's the alternator pulling it down trying to make all that electricity.

They sell oversized pulleys for alternators to the hot rod and "tuner" guys, to slow it down and reduce the drag on the engine. (The alternators don't work as well, but hey, priorities).
Some drag racers don't run an alternator at all, figuring they can run for short periods just on the battery. Personally I think that's taking it too far... one of my buddies did that on his 10-second '70 RoadRunner drag car and we were always fighting a weak or dead battery. I convinced him to put it back on and not only did the car always start, but the super-hot ignition system worked a hell of a lot better. But I'm veering off on a tangent. Partially because Skuzzy is here... I knew he was trouble.

[Rez]

Was in a coffee shop "no bars were open yet.." But with it being sunday all the church folks were in there and apparently standard library etiquette is expected. You can't really take me anywhere in case you have not noticed.

[ygmir]

A solar cell and charge controller would accomplish what you're after.

The mechanical power it takes to spin alternators under a load is the entire reason I use an electronically fuel-injected engine in my Mutant Vehicle, rather than a playa-simple, less-to-go-wrong carburetor.
I use two alternators to get enough power, and if I tuned everything on with the engine idling (like it always is in BRC) it would kill the motor. The EFI automatically compensates and throttles it enough to maintain the right idle under all that drag.
Real-world workin' man's example:
Have you ever hooked up good jumper cables between a running car and a dead one and noticed how the motor gets "dragged down" on the running one? That's the alternator pulling it down trying to make all that electricity.

They sell oversized pulleys for alternators to the hot rod and "tuner" guys, to slow it down and reduce the drag on the engine. (The alternators don't work as well, but hey, priorities).
Some drag racers don't run an alternator at all, figuring they can run for short periods just on the battery. Personally I think that's taking it too far... one of my buddies did that on his 10-second '70 RoadRunner drag car and we were always fighting a weak or dead battery. I convinced him to put it back on and not only did the car always start, but the super-hot ignition system worked a hell of a lot better. But I'm veering off on a tangent. Partially because Skuzzy is here... I knew he was trouble.

Was in a coffee shop "no bars were open yet.." But with it being sunday all the church folks were in there and apparently standard library etiquette is expected. You can't really take me anywhere in case you have not noticed.

[Rez]

A solar cell and charge controller would accomplish what you're after.

That would just suck the fun out of it ..

Going into it I knew the alternator would not power much.. This is why I was surprised I got 12 volts out of it running off a fan motor.

Also knew that an alternator has a RPM range along with it an output range. The drag or I guess resistance at the lower end of that range seemed small. Or at least was small enough to be ran by a fan motor. Figured if the fan motor was turning it at that resistance it maybe would produce enough to keep the fan motor running with a little extra to compensate for some low voltage accessories. Now to fully charge a dead battery under a load I knew would be too much, but with a charged battery with a low draw that was slowly compensated for by the alternator might of been a possibility.

But if your all saying the alternator wouldn't be enough to keep the fan motor running then I guess I'm clearing off my bench for some other crazy shit..

EDIT: Skuzzy already beat us and won life.. I mean.. A Cobra.. A freakin Cobra. I had a 69 Z28 with the orig 302 "yup they came with a 302" and a rock crusher.. And I would of traded it in a second for a AC Cobra.

[Captain Goddammit]

You can spin an alternator easily and get 12 volts, the catch is that's at almost zero amps, which is almost no power.

I once bought a nice 327 from a friend in the early '90s because he'd found a correct "DZ" 302 for his '69 Z28 and at that time the car was just starting to get too valuable to not have it be "correct".
I've got a '55 Bel Air that I often think I'd trade for a Cobra. (A good reproduction.... shit I'd trade my HOUSE for an original one these days!)

So enough about what you can't do... what you could do is drive that alt. with a stationary bike and add some power back into your system. It's a lot of work though and it gets old fast. There are YouTube videos of a ridiculously muscley Olympic cycler pedaling such a thing to make a slice of toast (at around 600 - 700 watts) and it about wipes him out.

[Rez]

I've got a '55 Bel Air that I often think I'd trade for a Cobra. (A good reproduction.... shit I'd trade my HOUSE for an original one these days!)

Had a '55 but it was a 4 door and pretty beat back in 94. never ended up doing much with it.. Funny story though. Should of seen me pulling up to the gas station the first time. I'm sure you know the rest. I would def trade my lake house for an orig.. hell even a nicely built kit. I have a 2010 slk 350 and a 2004 slk 320 i'm toying with atm. They are both two seater roadster types but no Cobra.

So enough about what you can't do... what you could do is drive that alt. with a stationary bike and add some power back into your system. It's a lot of work though and it gets old fast. There are YouTube videos of a ridiculously muscley Olympic cycler pedaling such a thing to make a slice of toast (at around 600 - 700 watts) and it about wipes him out.

sounds like perpetual motion.. making toast and burning off the toast at the same time. possibilities are endless there.

[Captain Goddammit]

I've come up with an improvement on the Rez-arator.
Simply plug a battery charger into the inverter. It'll still drain the battery, but I think it'll have less loss than the mechanical alternator setup, so it does improve the situation. It sucks less.