Electric drive for alternator

[spanky6510f]

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]

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]

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]

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]

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]

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]

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]

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]

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&MFISH]

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]

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]

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&MFISH]

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]

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

Exactly!

 

[Jim]

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]

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]

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]

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]

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]

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>