Author Options:

Is there a simple way to power both 6 and 12 volt devices from a 12 volt battery? Answered

I wired up my bicycle with a 12 volt battery.  The problem is, I have a Cree MC-E led which requires between 5 and 10 volts with a buckpuck.  One person suggested resistors to drop twelve volts to nine but that would waste too much electricity.  Is there a simple way to cut the voltage in half to six volts which would not loose power in the conversion process.   Cutting the power to 6 volts would be best because there are devices aside from the light requiring 6 volts which I want to install. 


What kind of battery, and are you prepared to commit a violence on it....?


Its a 5 amp/hour sla. Those batteries are dirt cheap. I could do some damage to it.

USUALLY, you'll see some oval bits on the top of the battery, NOT on the centre line of the cell. These cover the connections between the individual cells in the battery. Use a dremel to expose the one between the 3rd and 4th cell: there will be six volts on it.

Its a BAD idea to assymetrically load the battery, so don't use the 6 V side exclusively, or arrange TWO loads, one from battery min to the tapping, one from the tapping to battery +.

If you CUT the link, you could be even cleverer, and make it work as a double capacity 6V cell.


I don't think that there's any way to drop the voltage without some sacrifice. I would reccomend useing a voltage regulator instead of resistors though.

Do you think this would work http://cgi.ebay.com/ebaymotors/12-Volt-6-Volt-Heater-Blower-Motor-Voltage-Reducer-_W0QQcmdZViewItemQQhashZitem4cf23ddab6QQitemZ330481654454QQptZMotorsQ5fCarQ5fTruckQ5fPartsQ5fAccessories#ht_500wt_956

Yes I believe that will work. But it looks like a resistor to me. I thought you wanted to drop the voltage another way?

What about stepping down with some kind of transformer? I do not know where to start but , you would lower voltage and increase amperage.

Get a 'better' buck that supports 12 volts? most efficient option as converting down to 6 and then to 'whatever led voltage' is more work than necessary.