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Old 07-17-2009, 03:08 AM
Rockenstein Rockenstein is offline
Motorized Bicycle Elite Member
Join Date: Feb 2009
Location: Ontario, Canada
Posts: 442
Lightbulb 6 volt 3 watt dynamo regulator

I happened by this dynamo regulator circuit while looking for some info on an LED conversion\replacement bulb for my headlight. My headlight takes a 6v 2.4w E10 type died earlier tonight while I was out and I think the vibration and bumps is what did it in after maybe 4-5 hours of use while powered by 4 rechargeable AA's.

Anyway I thought maybe the info and schematic might be of use to somebody so I'm posting it. I ponder the thought that maybe something like this could be used with the magneto white wire output...

This is a regulator for a 6V/3W bicycle hub generator system. The purpose is to manage the powering of bicycle lights from the hub generator and from rechargeable batteries, to charge the batteries using excess power from the generator, and to provide intelligent charging of the batteries from an AC adapter, when needed.

The switch has three positions: charge-off-light. In the charge position, the bicycle dynamo charges five AA NiMH batteries if those are drained. If the batteries are reasonably full, then the circuit draws virtually no power. In the light position, if the dynamo’s average voltage is below some threshold value, then the bicycle lamps are fed by the batteries aided by the rectified dynamo If the dynamo voltage is high, the lamps are fed directly by AC from the dynamo and the dynamo excess power is used to recharge batteries. The direct use of AC maximizes efficiency. Additional circuitry is provided for an intelligent charging of the batteries from an outlet using a 12V AC or DC adapter. Practice shows that that additional circuitry may be redundant. A flickering green LED indicates the activity of the dynamo in the charge mode and the fact that the light is fed by AC in the charge mode. A red LED indicates the fast charge state when the charging is done from an outlet.

Last edited by Rockenstein; 04-17-2011 at 02:10 AM.
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