# Electric drive for alternator



## spanky6510f (Feb 12, 2010)

Could you use a automotive electric cooling fan motor or blower motor to drive a 105 amp GM one wire alternator? I'm a auto mechanic by trade and not a electrical guru, but since the cooling fan draws less than 30 amps and an alternator will reach full output at less than 3000 rpm, if it's geared right it seems like you would end up with a ton of amps left over. Can one of the electrical wizards out there please poke some holes in my idea or tell me if it'll work so I can free some room up for drooling over new baits and gear( I miss my Bass Pro catalog ).


----------



## thudpucker (Feb 12, 2010)

Interesting Idea. 
There are other boat forums where some long haul ocean cruisers have actually created a wind driven generator which is used partly for propulsion. 

Watts in = Watts out! or in planer English, Work to drive the alternator will equal the output of the Alternator.

So you have to convert the effort to drive that Alternator at 2500 Rpm, to KWH (Killowatt hours) or BTU's and then find a wind driven device that would produce that with a 10 Kt wind, and you have won the battle.
All except for fitting it the boat somewhere.

I put up a thread of using a Weed-eater motor to drive an Alternator some time ago. I did that on three forums.
Holy Cow, the other people who've done that came out of the woods like Bat's out of a Cave.
But along with them came the nay-sayers etc.

The Weedeater is a noisy Sumbutch but it will do what your thinking of doing. This photo is one of the early efforts. Kinda big n' bulky. I'm sure we could do better nowadays.


----------



## spanky6510f (Feb 12, 2010)

Yeh, but what I'm after is a quiet way to run a Duracraft 1536 on a 2 week camping trip in southern Louisiana with me , my boat, and a 50 lb thrust Minn Kota and not have to carry fuel. I've got the best of both worlds coming up. Vacation and the wife is taking the grandkids to Florida for a trip. WHEEEEEEEEEE!!!!


----------



## thudpucker (Feb 12, 2010)

You'd need a pretty big Solar panel for that. You don't want to be down there in Atchafalaya when the wind is blowing hard enough to make a Fan charge a Battery. :lol:


----------



## spanky6510f (Feb 12, 2010)

Sorry about the confusion here. The motor that I'm talking about is the one that runs the radiator cooling fan. The other possibility was the motor that drives the heating and a/c fan. Either one is 12 volt powered and will turn in excess of 3000 rpm.


----------



## thudpucker (Feb 12, 2010)

Yeah I am confused. Are you talking about making an air boat?
Or are you talking about making the boat go fast enough to use the fan motor to charge a battery?
Make a sketch of your thoughts. That might help.
I envy you on your vacation. I've always wanted a multi-day trip through those swamps.
Dick


----------



## spanky6510f (Feb 12, 2010)

What I'm looking to do is make a on board charging system for my two deep cycles that will keep the batteries charged even if I decide to run the trolling motor for hours at a time. I do not want to carry a generator and the fuel to recharge my batteries for a two week stay in the Atchafalaya (?spelling?) Basin. Due to terminal lack of computer skills I don't know how to put a picture up. What I want would look similar to the weedeater setup, but would use a 12 volt motor to turn the alternator. That way, if I decided troll and fish all day for days on end I've still got plenty of punch left in my batteries(just in case a big gator decides to add some fat to his diet). Won't be able to outrun him, but maybe I can beat up on him a little bit with the prop.


----------



## thudpucker (Feb 12, 2010)

OK, so you'd like to go two weeks on the two batteries.
Part time running the TM on some kind of 'green' device.

Physics says: You can't have an electric motor run by the battery, charging the battery.

So if you had some other way of turning the alternator, your plan would work!


----------



## Captain Ahab (Feb 12, 2010)

So you want to run a 12 volt motor to an alternator to charge a 12 volt battery? 


Unfortunately while I like your ambition this will not work. The amount of power (watts) that you will draw from the battery to run the electric motor will be less then the amount of power (watts) then you will receive from the alternator. As thudpucker said above "Watts in = Watts out" By which he means that even the most efficient system cannot create more power out then the amount of power in.

You need an alternative energy source - right now you have, a few options 

1. a small gas engine or generator;
2. Wind power;
3. Solar power; or
4. Hydro (water) power.

Essentially you need something that will spin that alternator or generate some electric charge. You best bet is going to be solar power from a weight standpoint is solar panels. You can constantly trickle charge your battery so long as it is sunny. 

A wind turbine will require winds - which are not good for small boats

a water or hydro systems will require some moving water - either by gravity (a river) or by steam pressure - pretty complex stuff 


Here is what you need:

15 watt solar panel 
https://www.amazon.com/Sunforce-50032-Solar-Battery-Charger/dp/B0006JO0X8/ref=pd_bxgy_auto_text_b

Charge controller (to prevent battery damage)
https://www.amazon.com/Sunforce-7-Amp-Charge-Controller/dp/B0006JO0XI/ref=acc_glance_auto_ai_-2_t_1



Keep in mind that this solar system will give you a small trickle charge and might take a very long time to fully charge your battery even in optimum conditions


----------



## S&amp;MFISH (Feb 12, 2010)

Spanky,you being a mechanic,think about this one.
With the headlights on,wipers on,A/C and fan running,an alternator in a car keeps the battery charged,right. Why wouldn't a blower or fan motor not do the same thing?When you have only one current draw instead of 4or5.
Being a former ASE-Certified Mechanic myself,in my opinion it should work.Your motor draws 20a-alternator puts out 55-65a.No brainer.
Go ahead and give it a try.What can it hurt.Let us know how it goes.


----------



## Captain Ahab (Feb 12, 2010)

You get this to work and I will get you $10,000.00! https://www.phact.org/e/freetest.html

As I tried to explain above the laws of physics will not allow you to create more energy then you use!


----------



## wasilvers (Feb 12, 2010)

You will lose efficiencies in the tranfers... The motor is not 100% efficient, there is some loss of power turning the motor. The Alternator is nowhere near 100% efficient, so you are using a fair amount of power to create a little amount of juice from the alternator. It sounds great on paper, but it will not work. If it would work, we wouldn't need the electric companies as we'd each have our own 'renewable' resource.

To charge the batteries, a small Honda generator is pretty darn quiet and should do the job. It would weigh in at about the same as the alternator and fan setup. Though it's not quite as unique as the weedeater and alternator setup. (Great idea by the way! I'm going to try this later!)

Will


----------



## S&amp;MFISH (Feb 12, 2010)

You all seem to forget or not even get the fact that we are talking 12voltsDC, not 100volts,which is the minimum they request for the prize.You are drawing 20amps-replacing with 55-65amp. A 20amp motor will not draw more amps just because more amps are being produced.If that was the case all the wiring in you auto or truck would burn up,being overloaded.At full load 55A alternator will have 40-55 amp output.We're talking automotive electrical system not National grid.


I am going to do this.I will let everyone know what my findings are.This won't happen overnight,but it will happen.And if I'm wrong,I will definitely admit it.


----------



## Captain Ahab (Feb 12, 2010)

wasilvers said:


> If it would work, we wouldn't need the electric companies as we'd each have our own 'renewable' resource.




Exactly!


----------



## Jim (Feb 12, 2010)

S&MFISH said:


> You all seem to forget or not even get the fact that we are talking 12voltsDC, not 100volts,which is the minimum they request for the prize.You are drawing 20amps-replacing with 55-65amp. A 20amp motor will not draw more amps just because more amps are being produced.If that was the case all the wiring in you auto or truck would burn up,being overloaded.At full load 55A alternator will have 40-55 amp output.We're talking automotive electrical system not National grid.
> 
> 
> I am going to do this.I will let everyone know what my findings are.This won't happen overnight,but it will happen.And if I'm wrong,I will definitely admit it.



If you get this to work, you can become a billionaire. Just remember me, that's all.


----------



## Bugpac (Feb 12, 2010)

You ever hear a engine load up when the alternator kicks in? There is a certain horsepower factor there that needs to be considered, And i dont believe your 20 amp motor will create it.. By the time you gear it deep enough to handle the work load, you likely will only be spinning about 1/100th of the needed rpm to make the power..


----------



## wasilvers (Feb 12, 2010)

Bugpac said:


> You ever hear a engine load up when the alternator kicks in? There is a certain horsepower factor there that needs to be considered, And i dont believe your 20 amp motor will create it.. By the time you gear it deep enough to handle the work load, you likely will only be spinning about 1/100th of the needed rpm to make the power..



LOL - you beat me to this comment. Theres a reason generators in the 4000-5000 watt range use a 5-7 hp motor. A 20-30amp fan motor will not have the power to turn the motor under load. But I would seriously like to hear how the project works out. I always thought an electronic car could be powered by batteries supplemented by an onboard generator. Last year I read an automaker did just that. No like the Prius with supplemental gas power, but a generator on board to recharge batteries and provide power.

From Wikipedia - https://en.wikipedia.org/wiki/Alternator

_"Efficiency of automotive alternators is limited by fan cooling loss, bearing loss, iron loss, copper loss, and the voltage drop in the diode bridges; at part load, efficiency is between 50-62_%"


----------



## Jim (Feb 12, 2010)

If it works or does not work the cool thing is the thinking outside the box. :beer:

I learned a bunch of stuff from this thread, and that my friends.......is what matters. :USA1:


----------



## thudpucker (Feb 12, 2010)

I think another way might be to boil water with some mirrors aiming the sun at a collection of water.
Steam from that could run a generator or Alternator.

Down in the Atchafalaya you got plenty of 'heat' energy!

What I'd do with the Weed eater charger is let it run while I was off on the beach cookin' or sumpin.
I'd never want to be in the boat with that Beast running. It violates the whole premise of Vacation in the worlds greatest pursuit. That kind of noise is akin to taking your horse along. The one that keeps up with 'Nag Nag nag'...


----------



## Brine (Feb 12, 2010)

How about just a really long extension cord? 

You guys are talking over my head so carry on....I'll keep rootin for a billionaire! 

=D>


----------



## Bugpac (Feb 12, 2010)

Nothing wrong with thinking outside the box, I do it every day, I have come up with some crazy ideas, I am having one put to use right now to see if it works, It may be a big flop, But my buddy is a machinist and believes in it as well, so there is no cost involved in getting it from cad to product. If it does work, yall will be the first to see it...


----------



## S&amp;MFISH (Feb 12, 2010)

The thing is that you are not generating extra power,you are recharging the battery.Wtih an automotive charging system,it doesn't so much have to do with horsepower per say,it's about RPM.If you accomplish the required rpm,horsepower is a non-factor.A blower motor will run an auto cooling system(just ask any Drag Racer),why wouldn't it run an alternator?It takes more to run a cooling system than a charging system.

As soon as I aquire the parts.This is a done deal.


----------



## Bugpac (Feb 12, 2010)

Keep us informed please.


----------



## Captain Ahab (Feb 12, 2010)

S&M - no one is doubting that you can spin the motor - just that with only a 12 volt battery you will generate less power then you draw off the battery - thus you will drain the battery faster then you can charge it.


----------



## Bugpac (Feb 12, 2010)

Think of this while your at it... a 4cylinder motor will generate 6000 rpm, A v8 engine generating 6000 rpm, which do you think will handle more work? A alternator does not just free spin, do a simple test and power it up and see how much harder it turns?


----------



## KMixson (Feb 12, 2010)

Captain Ahab said:


> As I tried to explain above the laws of physics will not allow you to create more energy then you use!




This is the answer. There is no way you can create more power than you put into the system. If you do find a way, you will be very rich.


----------



## cubanredneck (Feb 12, 2010)

As long as you can turn the alternator It will work. all he is doing is using a small draw from the battery to cause the fan motor to spin at 3000 rpm at that point the alternator will produce the amps to recharge the battery. It will work just like on a drag car. The alternator has three main components: The Stator, Rotor, Diode and a voltage regulator. When the alternator belt or V-belt spins the pulley on the alternator, the rotor inside the alternator spins ... fast. The rotor is basically a magnet or group of magnets that spin, with all that speed, inside a nest of copper wires. These wires are called the stator. The next step in the chain is a diode assembly that changes the electricity from AC to DC current that your battery can use. There is a final step in the chain, the voltage regulator. In modern alternators, this is a built-in component. Back in the day voltage regulators were big black boxes that had to be bolted somewhere under the hood and wired into the system. The voltage regulator is basically a gatekeeper that will shut off the flow of juice to your battery if the voltage goes above a certain level, usually 14.5 volts. This keeps your battery from getting overcharged and cooked. That's it! As your battery is drained, current is allowed to flow back into it from the alternator and the cycle goes on and on.


----------



## Bugpac (Feb 12, 2010)

Nope.. I got a little tiny motor that draws about 1 amp that will spin 3000 rpm.. There is no HP... Electric motors have a hp rating for a reason, And there is no way imaginable a 1/4 hp fan motor is gonna spin even a 50 amp alternator generating a load...


----------



## Bugpac (Feb 12, 2010)

Here is a very good article...

https://www.w8ji.com/electical_system.htm


----------



## Bugpac (Feb 12, 2010)

Here is another, Heck i even wasn't thinking about the watts it takes to make the alternator itself work, so there is another factor...

https://www.jettyfishing.com/topics/?topic=17


----------



## cubanredneck (Feb 12, 2010)

The alternator tester in my store is just a electric motor with a pulley so I can hook up to the alt. then it mesures the voltage on and off load I still think it will work. It will be interesting if he does build the thing. Im almost tempted to dig through my cores on Monday and build one myself.


----------



## Bugpac (Feb 12, 2010)

It will be interesting, Check and see what your HP rating or amp draw is on that motor when you go back to work..


----------



## spanky6510f (Feb 14, 2010)

Wow. Thanks for all the info guys. Still gonna take a run at it (combination of redneck and coonass heritage so how can I not try something crazy), but if it doesn't work, maybe I'll just use a bicycle chain drive type set up down by the foot of my camp lounge chair. If nothing else, the huffin and puffin should keep the critters freaked out and wary. Jumper cables and budweiser go a long ways down here.


----------



## thudpucker (Feb 14, 2010)

Y'a know, Snakes and Gators cant hear. They feel vibrations though.
So the Weed eater or the 5 hp B&S running the alternator, making all those vibrations while your snoozing aint all that bad of an Idea! :?


----------



## nbaffaro (Feb 15, 2010)

I vote that you hook up a chainsaw motor to the alternator. It would sound better than a weed eater.


----------



## thudpucker (Feb 15, 2010)

nbaffaro said:


> I vote that you hook up a chainsaw motor to the alternator. It would sound better than a weed eater.


I agree with that too. Chain Saw's have 'Boss' sound. An all for business attack sound.

You can make a sound proof or limiting cover on the operation too. That way you can catch a Nap while your laying out trying to lure a Carnivour into your camp! :LOL2:


----------



## nbaffaro (Feb 16, 2010)

I actually like the idea for a remote camp. If you had the parts, then it would be cheaper than a generator but, if you had to go get them and wire it all up a small honda generator would be a better idea. Then you'd have 120v to power a charger and anything else you'd need.


----------

