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Ask Scott W. Your Own Question
Scott W.
Scott W., ASE Certified Technician
Category: Car
Satisfied Customers: 3288
Experience:  28 yrs. experience in automotive repair
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attached a new rebuilt car alternator..tire..smooth

Customer Question

i am 12 years old working on a science project. i have attached a new rebuilt car alternator to my rear bicycle tire to spin a smooth surface pulley to create electricity. when i am pedalling my bicycle, my dad is only measuring 1-2 volts of electricity produced. the shaft of the alternator is spinning very fast. i was hoping to get 10-12 volts. What am i doing wrong?? how many volts would the alternator produce under normal conditions in a car? Any thoughts would be helpful...
Submitted: 4 years ago.
Category: Car
Expert:  Scott W. replied 4 years ago.

Steve W :

Hello my name is Steve W, is this project alt hooked to a battery source also, wired up?

JACUSTOMER-msnlyt07- :

we have attached the positive lead to a 12volt deep-cycle battery. when i check the voltage, its reading 12.5 which is coming from the battery. there is also a voltage regulator on the alternator which I'm not using. Should I be?

Steve W :

What is the alt you are using, Ford, chevy ect.?

JACUSTOMER-msnlyt07- :

not sure. we purchased it @ autozone because it was the cheapest. its a valuecraft. #7127. it reads delco-bemy on the alternator

Steve W :

Ok, let me see if I can find some info how this is wired, how many total wires are hooked up now?

JACUSTOMER-msnlyt07- :

just the positive to the positive of the battery and the negative post of the battery to a ground.

Steve W :

Ok, give me couple minutes

JACUSTOMER-msnlyt07- :

ok :)

Steve W :

I am not having much luck finding a diagram, how many terminals on the alt and are they marked?

JACUSTOMER-msnlyt07- :

there is just the one red marked positive post. no connections for a negative and a 2 pronged voltage regulator built in on top.

Steve W :

Does the 2 prong say I or B?

JACUSTOMER-msnlyt07- :

not that i can see... i dont see an I or B.

Steve W :

Ok

Steve W :

Does it look like this?

JACUSTOMER-msnlyt07- :

yes it looks like the 10Si

Steve W :

Ok, good

Steve W :

You can wire all three of the terminals together, hook to the output of the alt along with the 2 terminals to the positive battery wire, just dont leave them all hooked up overnight or it will run your battery down. I will try to look for a printable diagram for you so you know how it works in the car. Another thing, when you get this alt turned on ready to charge you will know it because I don't think you will be able to pedal it, these alt's pull alot of energy required to turn them, give me a few minutes and hopefully I can give you some more info. Hopefully everything will work ok.

JACUSTOMER-msnlyt07- :

what i want to do is measure the voltage coming out of the alternator while I'm pedalling and to light up a bulb which will fluctuate as i pedal faster and slower. i dont want my power to come out of the battery for this part of the experiment. i want it to come out of the alternator.

Steve W :

Here is a car wiring diagram, notice how all the terminal are 12 volts, normally there is a ignition switched wire to turn on and off alt. I am not sure if you were going to install a switch or just hook and unhook.

Steve W :

I see, you might be better off going to a cycle shop and look for a wheel mounted generator. Let me look online to see if I can find what I am talking about.

Steve W :

Check this out, maybe a idea here

JACUSTOMER-msnlyt07- :

one last question. Do you have any idea how many volts i should be producing while pedalling? again, we are only getting 1.5 volts pedalling in high gear on the 10 speed.

Steve W :

I am afraid with a alt you won't be able to pedal it.

Steve W :

With a generator, the faster you pedal the more output you have, depends on the generator how many volts, with a alt max is 14.4 volts.

JACUSTOMER-msnlyt07- :

we were going with a dc generator but it was too expensive ($400) thats why i went with a car alternator which had been used in previous experiments i had reviewed online.

Steve W :

Here is a deal that may make your parents day, see if this looks like something you might try.

Steve W :

Wiring diagram click here Here is how the 10si alt is wired in a car.

Steve W :

Let me know what you think or if you have any more questions, Thanks Steve W