Both Ni-Cad and NiMh use a constant current technique to charge and most of
these constant current chargers have a high saturation voltage to accomplish
this. The cell voltages are identical for all practicable purposes so the
added capacity of the NiMh should only take longer to charge.



"RP" wrote in message
...
Hey, thanks for the tips George. I misspoke on the L-ion thing. I want
to rebuild some nicads w/solder tabs. I upgraded my newest kit to the
18v makita l-ion gig and i'm real happy with that. They say you cannot
upgrade to nimh and charge with a nicad charger because it won't reach
full charge ever. I'll check out Red's battery clinic. Muchos
Grassyass

RP


On Nov 9, 3:06 pm, Max George
wrote:
In message
, RP
writesAny you guys rebuild your own NiCad's or NiMh
power tool batteries?
I'm going to do a few batteries of my own and maybe someone has some
tips or possibly some "look out fors". I ordered 100 sub c's to
rebuild a few batteries I've had kicking around.. I've been asking
around my area to see if anyone rebuilds them and everyone says no.
Maybe that's an open market for me. It would help keep me busier in
the winter.

Try looking on sites associated with electric powered model aircraft. We
have been making batteries out of nicads and Nimhs for years.

In fact we have been known to buy power tool batteries and cannibalise
them to provide our RC plane batteries!

Try Red's Battery clinic.

http://www.hangtimes.com/redsbatteryclinic.html

Also

There is a section there relating to soldering cells.

I have built quite a lot of packs in my time and all have been OK.

One thing I have found useful is to use the desoldering wick that is a
rope of copperstrands. If you manage to leave a little bit of the wick
where it hasn't fluxed up the solder it allows a little flexibility
which can help with vibration.

Use a big soldering iron, 100 watts or so and get it hot at the start.
Do not use the sort that heats up for each individual joint it puts too
much heat into the cell case while it heats up.

Make sure you clean the cells carefully and tin them quickly using the
large iron. Then attach the wires with just a quick dab of the iron.

Have some electric freezer spray to squirt on the tinning and on to the
joint after soldering to clear the residual heat.

I echo the point about the new lithium cells. They need special chargers
otherwise they can be dangerous.

I have not tried making lithium cell packs as yet. However I do believe
they sell them with tags on and you can solder the cell tags OK.

One thing you need to do is to hold the cells together and a good way to
do that is to push them together and use a blob of hot melt glue to
stick them.

HTH
--
Max George