How to hook up a battery to my bike generator

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cnodie1

New Member
Jan 27, 2010
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Baton Rouge, Louisiana
OK I just got a bike generator kit off fleabay
Generator

It looks pretty good but I would like to hook up a battery to it to charge when im riding during the day. Being completely electrical stupid I need some tips.

Any help will be greatly appreciated
 

Ted

New Member
Apr 20, 2010
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Leavenworth Wa.
To charge a battery you have to have more amps than is stored in the battery and it's doubtful that this unit puts out enough to do it even with the lights off, if you have a VOM you can check and see, the battery will be rated in amps, look at it this way, if the battery is rated at 12amps and the gen put out 3 amps it can only charge the battery to 3 amps, you would have 12v but only 3 amps, the same as the Gen is putting out and there would be no reserve stored in the battery, you need 14.3 volts to effectively charge a 12v battery,,,good luck with that.:-(
 

BarelyAWake

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Jul 21, 2009
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Maine
urm - I believe yer right on the volts, but not the amps. You do need to exceed the voltage of the batt slightly to get it to charge, but it's not the same deal w/amps - thus a "trickle charge" in which a 12v batt is (usually it's actually 13.5v or thereabouts) is charged at the above "14.3v" and a mere 1-3amps - like a solar cell... ofc all this depends on the batt's size, type & reserve ;)

Bike gennys are often 6v BTW
 
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cnodie1

New Member
Jan 27, 2010
60
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0
Baton Rouge, Louisiana
urm - I believe yer right on the volts, but not the amps. You do need to exceed the voltage of the batt slightly to get it to charge, but it's not the same deal w/amps - thus a "trickle charge" in which a 12v batt is charged w/13.5v (or thereabouts) and a mere 1-3amps - like a solar cell... ofc all this depends on the batt's size, type & reserve ;)

Bike gennys are often 6v BTW
so if this is a 6 volt generator I could possibly use a 6 volt battery to hold a charge (seeing as how the genny will be spinning above normal speed for most of the time)? how long do you think that would power the 6 volt or 12 volt light?
 
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BarelyAWake

New Member
Jul 21, 2009
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Maine
You would wanna use a 6v batt as the genny will no doubt exceed 6v, duration of power output would depend on the batt's amp reserve not voltage... exceed the voltage (or amperage) too much and ya might make a bomb instead of a batt lol

As for actually charging a batt with a bike genny... well... while you could prolly get away with using a SLA directly wired... ya might wanna consult someone who knows a bit more about this stuff, like Deacon whom hangs out in our electric bike section :)
 

jawbreaker

New Member
Jun 30, 2010
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vancouver, B.C.Canada
some ganerator produce AC. if it is you need to change it to DC. The output voltage will go up and down depending how fast you are going so you need to buffer it with a large capacitor and regulate it to 2 -3 Volts above the baterry you want to charge. insulate it with a diode to prevent it from drawing current form the baterry when charging voltage is too low. check out regulator IC 7805, 7812, or LM317. they are quite easy to use.