Car alternator?

[PatrickHenninger]

Okay, I'm sure this sounds a bit ridiculous, and being ne wto the whole MB scene, I was just wondering why someone couldn't use an alternator from an automobile to generate power? A lot of the SBC/SBF alternators are internally regulated, why can't those be used on a MB? I can see the weight being an issue, but the resistance from the pulley spinning is minimal and could be used friction drive from one of the tires, belt drive, or just put a sprocket on the dang thing in place of the pulley and run it in line with the drive chain...

I'm sure it's not a new idea, but I'm open to having people tell me why it won't work before I go strap an alternator and battery to my MB and end up sending 60amps straight to my crotch.

 

[PatrickHenninger]

Then again, the resistance on the alternator goes up under load, which probably makes the idea null and void.

 

[happyvalley]

resistance from the pulley spinning is miniman

Not quite, the alt requires something in the neighborhood or 4 or 5 HP IIRC.

This topic surfaces anew from time to time and has been pretty throughly covered if you search the back pages. Still, if you want to give it a try, go get'em!

 

[professor]

No problem getting the car stuff to work. Where do you put it is the problem and finding the power to drive it i the other issue.
If you have the room and the power you only need a small battery to make it work. The good thing is you get REGULATED voltage (around 14v)
The lighter duty route is to do what I did, and drive a small motor to your lights.
I used a motor from All Electronics (www allelelctronics.com). I started with a 24v 250 watt scooter motor but it was overkill, then switched to a 135w 24v scooter motor which I adapted a drive pulley to (all these motors are metric), I think I used a 1.5" drive pulley and 4inch pulley on the electric motor.
The lights (12v) are glowing orange at idle and light up as I rev the engine. When I used the governor the engine came with, a smaller driven pulley brought light off idle and did not over volt the bulbs.
Only thing is you have to adjust the pulley size verses engine rpm and voltage.
A wide rpm range for the engine (like without the governor) will result in a similar wide voltage range and if you go over around 17v you will burn out the 12v bulbs in the lights.

Oh, and about the power required to run an alternator- totally dependant on how much load is on the system and how old the battery is (an old one that is half dead will suck juice like crazy).
Alternators are NOT very efficient too.

 

[IamTheBear]

thought that myself about using one but now learning about the setup professor i have new hair brained ideas to conquer! if i could pick your brain Professor i do have a few questions?

 

[outlawbiker]

i took a stab at this thought a year or 2 ago. the nearest thing i found was an alternator for a honda goldwing that put off 12v dc (with a built in or inline rectifier) the only thing that made sense was to modify either side of the engine covers to accept a pully on the crankshaft and run the belt out to the front of the motor where i would have clearance for the alternator. doing it that way so you have full time 100% charging even at idle.(running it off a tire or the drive chain just doesnt make any sense to me,thats like using a dynamo hub or bottle generator. it just would seem to me that theres going to be more drain than charging time.)

the issue with this is now the crankcase isnt properly sealed and i maybe robbing the engine of some power now to turn the alternator and it was gonna be very expensive.

the most bang for your buck so far seems to be the 12volt mini gen on ebay with a rectifier/charger to a 12 volt or 2- 6 volt SLA batteries

 

[wayne z]

How about a 10 amp Kubota dynamo and an inexpensive mower tympanium regulator? the whole thing rotates ,would be easy to friction drive it

 

[Ruby478]

the answer is yes cause i use one to power my lights and charge my batteries

 

[IamTheBear]

Ruby do you have any pics or info on your setup?

 

[ferball]

One of my projects on the drawing board is a 5hp Briggs and Straton and an alternator from a GMC envoy mated together on a push cart to power a primitive electric bike.

 

[Ruby478]

i dont have any pic yet cause my camera got busted on the last ride but basically i have mine mounted as a chain tensoiner so as my chain drives it rotates the alternator powering my lights if i had a idler underneath it, it could also act as a starter

 

[IamTheBear]

Where did you get the alt. from. Better yet what was it from. and what style bike is mounted to. battery size you used for this setup, and what was it from. last but not least what syle brackets did you use or fabricate for holding the alt. on with

 

[Ruby478]

its mounted on a huffy cranbrook beach cruiser on the very bottom wear the seat tube meet the crank normally the stand would be there but i removed the stand to make room......... using some old tubing i welded the alternator in using 2 "C" or "L" type bends for each side so the alternator wont move i removed the belt drive and replaced it with a sprocket ........ the alternator i got from the junk yard it's from an old jeep i think it was a 94 Cherokee so the alternator is pretty small but it works ........ the batteries i use are 2 heavy duty feeder batteries from Academy sports each 12v 9.5 amp just small enough to mount inside the bike .......after that just gotta wire it up to a rectifier and some resistor and ur good to go .............. i think maybe next time i'll use a friction drive type mount see how that works ............. but thats how i did it

 

[wayne z]

The Kubota dynamo is the smallest self contained ,easiest to adapt for this purpose to a MB thing out there. 10 amps. and uses a tiny simple cheap tympanium regulator
The car alternator made,30 amp, was used on the old Geo Metro's from the early 90's , about the size as a large man's fist.

 

[IamTheBear]

the price on the kubota and regulator is a little pricey for my taste. i also have no tractor salvage yards around here near me to dig one out of. Ruby i don't believe you need to rectify or resist your alt that your using should all be internal. and should be limited to 14 volts and around 30 amps. but i'm no expert just what i have learned from messing with gene to alt conversion on my old school vw's. Friction drive is what i was thinking mounted under a bike rack and a atv/lawnmower battery for it.

 

[microbore]

I am using the Kubota dynamo on a push-trailer that is currently under construction. The dynamo produces a lot of drag even at the low drive ratio that I am using. The result is the engine will not start with tension on the main belt. Since the picture was taken, I have added a belt tensioner that I can dissengage when starting the engine. The simple solution would be to run the dynamo after the clutch and not produce power at idle.

 

[Ruby478]

IamTheBear it's just a safety precaution so i dont burn out my lights

 

[Ruby478]

microbore great job if i decide to use a 4stroke i think ill use ur setup