Join Date: Jul 2008
Location: ellington, ct
Bikes: trek 1200, 520, Giant ATX 970, Raleigh Talon
Gutting a laptop battery to make a light pack?
I have a high capacity laptop battery I bought for an HP laptop that has since gone to laptop heaven.
It worked well when the laptop decided to no longer work well, so I believe the cells are good.
This battery is twice the size of the OEM battery. It is labeled as 10.8V, 8800mAh. Judging by the shape of it, I believe it consists on 12 18650 cells, there are four rows of three.
I was thinking of cracking it open and reconfiguring it as 3 parallel rows of 4. This would result in a 14.4V, 6600mAh pack, if my math is right.
I would like to use this pack as a replacement for my 7Ah SLA boat anchor to power my nightsun halogens. This headlight consists of 2 lights, a 35W and a 10W (I think). I generally run just the 35, keeping the 10 as a spare to get me home if the other blows.
I have a few questions. Is 14.4V too much of an overvolting? I have read some about how overvolting works pretty well. My 35W nightsun does pretty well already, overvolting it ought to make it quite the flamethrower.
How much will this increase current flow? Is it just simple ohms law, meaning about a 20% increase? if so, I can live with it, as my 7A SLA gets me through 2 round trips with ease. It would probably mean having to recharge each trip.
And how much will a charger set me back?
It probably makes more financial sense to just sell it as is on fleabay and buy a new magicshine, but where's the fun in that? My inner geek tells me to give this a shot.
I guess another option would be to make it into a lower voltage pack for an LED light or better yet, a pair of them. And buy an LED light and charger.