Help Support Candle Power Flashlight Forum
There are NO fuses and the cells themselves are unprotected so the circuit is HOT HOT HOT between the cells!!
You joke, but I'm pretty convinced that his fame comes in great part exactly from that. Had he been one of those who add a lot of "hmmm" "errr" and so on in their movies, spreading his crap on metacafe would have earned him a lot less money.
Make that $6.5 per pair (Trustfires on DX have just had a very pleasant price drop).
Eh, not really. I just modified my EeePC's battery by adding two cells to the pack, and while the circuitry does seem to get a slight bit confused, this doesn't cause problems.
You don't necessarily need to bother with that. Just cut the tabs at the cell terminals and the circuit is de-energised.
While the danger of shorting the pack is definitely there, a slip of your knife or accidental contact with wire cutters is unlikely to do much of anything. LiIon cells really dislike shorts, but once someone does short a pack the "zap!" noise and spark(s) are very likely to make them retract the tool at once. The short is thus very very short, and definitely not enough to start a fire.All it takes is a slip of your knife or shorting wire cutters across the circuit and....
You could put all those in series and zap people with them
Slim laptop packs almost always have prismatic cells, or sometimes even LiPo ones. I guess the space premium that cylindrical cells need is not an option when size is that much of a concern.
). I can't imagine the average joe attempting this kind of a mod.
I agree on this. Worthless as they are, the other contributions by "kipkay" are at least more or less things anyone with opposable thumbs would be able to do. This isn't.
Must have been an interesting sight
it wasn't a lithium cell, was it?Hmm. I remember doing exactly this on my two laptop batteries (one from Acer and one from (if memory serves me right) HP). Then again, I've taken apart two packs and you have taken apart about a zillion, so I'm going to say you're probably right.
True. There should really be a way of reporting those videos and have them removed.
.
I have a lot of experience DIY tweeking and working with electric circuits from my involvement in car audio, RC cars, and guitar tube amps. I was very careful and cautious, yet I still managed to screw up. I work on these outside on my brick patio so if the cells do flame up the flames don't ignite to anything of value (except possibly me
I was cutting a segment of wire to free up a cell and as my cutters were cutting through the wire a sharp backside edge of my wire cuter sliced through the cell heat shrink and shorted + to -. It sparked, smoked and melted the heatshrink for a moment. I have since dremel'd my wire cutters to remove all sharp edges and burs.
Second incident occur'd when I tried to cut through one of the metal strips with my wire cutter. I was not careful in observing the circuit and had not noticed there was a wire behind/beneath the metal strip. When I cut the strip I shorted the wire and strip!!! WOOOHOOO!!! the wire welded to the strip and became a fuse-link between + and -. It turned red hot and lit the insulation, tape and adhesive on fire. I keep a wet towel at my side during the procedure, so I ousted the flames easily.
"You don't necessarily need to bother with that. Just cut the tabs at the cell terminals and the circuit is de-energised."
Easy to do in theory, not so easy in the real world. The way the packs are assembled, taped and glued together you simply can't access those points in the circuit without pulling the cells apart and opening things up far enough to get a wire cutter "in there". Thats partially how I made the two mistakes listed above... trying to shove my wire cutter in between and beneath tight areas to access the points to disconnect the cells.
I get the packs from the recycle program at work.... one mans trash...
The intent of my posting is not to discourage the idea of modding / replacing / salvaging ells, but more to alert CPFers who do take on such a project. There are safety concerns and an element of risk in doing this. The video dismissed the safety concerns all together and made it look no more dangerous than reloading AAs into a VCR remote. Furthermore, the pack used for the demo is unusually well laid out, with cells perfectly side by side.... very low risk of + and - contacts being close to each other. I took apart a toshiba pack just like that, for its 17670 cells and it was relatively easy.
(my favorite)
No. It's important that all cells have the same capacity, so as to prevent reversal. Even if you use cells of the same capacity, you'd be putting brand new ones in series with old ones that have inevitably lost capacity due to use and age.
Not necessarily, if you're swapping all of them. Using better cells will give you improved runtimes, though the battery gauge might be set to the old capacity and go haywire.
Actually no, the parallel configuration is safe for different capacities as long as you connect them when they have the same resting voltage (or bad things can happen). But you do need to replace any in the series, and that means the whole pack.
