18v to 12v

hey everyone, i need help on downgrading 18 volt battery to 12 volt battery, id like to do it for cheap or even free if thats possible. 

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lemonie7 years ago
cheap or even free - what do you need to power with this?

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sirus17 (author)  lemonie7 years ago
 its a radio or more specific a headdeck from a car hooked up to a hifi speaker, it works on a computer powersupply but i dont like the cord so i want to use my broken cordless drill batterys, but they are 18v 3ah
lemonie sirus177 years ago
A lot of people would say "use a voltage regulator", and I'd probably agree with that. You'll have at least one in the computer PSU, but a 6V drop might make it quite hot. For free, you'd hack into the PSU and connect the battery where the roughly 12v power supply comes out of the rectifier.

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sirus17 (author)  lemonie7 years ago
 should i be looking for something in particular on the PSU to connect the battery infront of? i can take some photo's if you dont mind helping me out?
lemonie sirus177 years ago
From the transformer will be some wires (low voltage not mains), they'll hit the board and go through a rectifier (black plastic enclosing silicon) then possibly feed capacitors (big cans) - but for a computer supply the +ve should go through a regulator also - 3 pin black plastic, most likely with a metal heat-sink.
If you replaced the low voltage supply with your 18V it might work, but it may get too hot if the radio takes a lot of current. If you're thinking of adding pictures, I'd do it in a new question - "how do I hack this - will it work?" - it'll pop up in recent and some more people will see it.
The other alternative is to take the 18V battery apart and remove some of the cells, but you'd then need a different charger for it.

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sirus17 (author)  lemonie7 years ago
 the charger does from 12v to 24v i believe, but i dont know if theres something in the battery that reminds the charger that its a 18v not a 12v and i dont wanna blow that cos they are quite expensive lol,
when im finished re soldering all the wires through i'll try hooking the battery up to it, it also has acouple fans in there to help with the heat, but we'll see how we go, if it doesnt work i'll start the new topic.
thanks for you help! =)
its nice to finaly come across a community thats helpfull with all subjects lol
lemonie sirus177 years ago
If the charger will do 12V take the battery apart - you'll find it's made up of a lot of (I don't know but-) 1.5V cells all strung together. That'd be your best bet.
Some people do try to help around here, you're more than welcome to join in.

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