On Sat, 03 Nov 2018 21:39:57 -0000, danny burstein wrote:

In "Steven Watkins" writes:

It turns out that a local vendor ("Batteries Plus")
can rebuild the battery assembly for about $10,
which is well worth it...

What do you mean by "rebuild the battery assembly"? Put in new cells? Or construct the shell to put them in?

The design is just three cells nose to toe in series, with
soldered connections and wires from top and bottom.

The one at the heel runs alongside the cells to
the top, so to speak, and..

hmm, there might (might...) also be a thin plastic
(think electrical tape/shrink wrap tubing) cover
that circles the area where the cells meet up.

This slides into the handle of the screwdriver.

I had a _lot_ of trouble trying to rebuild one of
these myself. I hate, hate, HATE, "modern" solder.

(plus, to be honest, I've had decades of aging eyes
and hands since the last time I did any soldering)

The folk at the counter there had the nifty high
temperature quickie/instant solder zapper tool

I managed to build a new battery for my drill easily enough. And that had 12 cells!

The only problem is in charging them up. Have to
remember to pull the unit off the charger after
just an hour or two, otherwise the batteries fry.

Must be a way to rig up a sensor, or even easier just
use a plug in timer.

The basic charging circuitry is dumb, designed back
for the days of "overnight" at a 0.1C [a] rate.

So why is it now an hour or two?

I foolishly left some on for days at a time way back and
while they probably could have survived just 24 hours,
they got killed by a week online...

Odd, I've had 16 hour chargers left on for a week with no problem. But then those cells were snuggled together to get too hot.

And again, I wish I'd have kept the units. Back then
they were $15 or $20 dollars, and I thought they'd
be available forever.

Like with a thousand other tools and products we could
all name, it was a terrific value and worked perfectly,
so they stopped making them.

I never throw anything away that works, or could be used for parts. If I really really think I won't need it, I give it away, not throw it out.

[a] that's "C" as in charging rate, not "C" as
in speed of light...

0.1 of the speed of light would be quite dangerous for a battery, and also the person it came into contact with.