In article , mike wrote:
| Doug McLaren wrote:
| In article , mike wrote:
|
| | You MUST have a spot welder to connect the cells. DON'T LET ANYBODY
| | TELL YOU OTHERWISE!!!!!
|
| Here, I'm going to tell you otherwise.
|
| I just love it!!!!
I thought you might.
| snip
| But you can certainly solder your own battery packs together, and once
| you get the hang of it, the odds of a bad pack are very low.
| snip
| I've made lots of them -- for radios, for R/C planes and transmitters,
| for power tools, and have not had any problems beyond a small
| percentage (10% ?) not making the grade once I ran them on the cycler.
|
| There you go. 10% INITIAL failure rate. That's sure the way I want to
| run MY business....
You may not have read my post very carefully, so I'll reiterate the
really important part -- I wouldn't want to make a business out of it.
It's too labor intensive. I've already said that a few times, but
there, I've said it again.
As for the 10% failure rate, that's the number of packs that don't
cycle to their rated capacity. It could be that I ruined a cell, or
there was a cell bad to begin with, or I just didn't form the pack
properly (which is easy enough to fix), but unless I'm pretty
convinced that a pack is good it's not going up in an R/C plane.
(I might use it in a cordless phone or something, however.)
But I'm perfectly happy with not using a spot welder for my packs.
Things work quite well most of the time.
I also tend to use the cheapest batteries for non critical
applications (power tools, cordless phones, etc.) -- 700 mAh AA NiCd
cells from Harbor Freight Tools for $0.60/cell? Pretty cheap! I'm
not surprised if most of the failure rate is the fault of that.
For R/C packs, I prefer to get cells for a somewhat more reliable
source, and cycle them a few times before I use them -- the
consequences of a failure are higher there.
As for the 10% initial failure rate, once I get past that, I've found
that the failure rate is not really any different than cells that I've
bought at full price from people with spot welders. Batteries don't
last forever, and mine aren't any exception.
| If you're afraid of soldering directly to the battery itself,
|
| this is just nuts!!!
FUD often is. It's perfectly possible to make good battery packs
without a spot welder.
| Probably true. I certainly wouldn't rebuild somebody else's laptop
| battery for them, but I might try it for my self.
|
| The above is the most telling part of your whole soldering suggestion.
Laptops cram lots of little LiIon cells in there, with wierd sizes
(read: hard to find) and then they have more circuitry than anything
else to deal with. And if something fails, it could ruin an expensive
laptop. I'd risk my own laptop, but probably not somebody else's.
I don't have special insurance. (Remember, it's not a business.)
| Somehow I thought that rebuilding someone else's pack was necessary to
| have a business...soldering is NOT acceptable.
Again, I was just giving my personal experience -- I've probably made
at least 50 battery packs of various sorts by now. I've only done a
handful of LiPo packs, however, and found them to be harder to deal
with.
No, it's not a business. I wouldn't want to make a business out of it
-- the pay per hour would be too small to be worth it. But when I
rebuild a battery pack that would cost $40 for $6, I feel good about
it, even if it all took 30 minutes.
Now I've lost track ... how many times have I said I've not made a
business out of it, how many times have I said I don't want to make a
business out of it? Hopefully enough times.
| If you listen carefully, you can hear the sound of me beating a dead
| horse...
That's nice.
--
Doug McLaren,
The beatings will continue until morale improves!