[NJARC] safely weld/solder Lithium battery cells?

Wed Jul 27 11:28:16 EDT 2016

Thanks for the feedback guys.  I suspected it was probably a risk to rebuild, and figured they'd be expensive, but had no idea replacements would be THAT expensive.

I'll check the drill on a bench supply to see if it even works.  If it doesn't i'll write it off as a risk.   if it does work I think i'll opt for the two 18v ni-cads in place of the 28v lithiums.  The drill supposedly runs on both.

I'm clearly not a contractor/carpenter, and I won't use it nearly as heavily as they would, so the risk of letting the older, dumber Ni-cd batteries drain all the way down is easier to cope with and remedy than the lithiums.

I've seen ham folk sell cells (by the seashore?) individually at fests before so I knew I'd hear useful discussion on the subject from you guys.  Thank you.

Regards,

Matt

________________________________
From: radiograveyard at aol.com <radiograveyard at aol.com>
Sent: Wednesday, July 27, 2016 11:00:29 AM
To: dino66 at optonline.net; oldradio at comcast.net; mattr04 at hotmail.com
Cc: njarc at mailman.qth.net
Subject: Re: [NJARC] safely weld/solder Lithium battery cells?

Matt; I am with Bob & John you made a mistake don't make two buy a new one. Only suggestion I have and I think its a bad one is rebuild use a dielectric glue. I checked ebay and no rebuilds offered on 28v whats that tell you?. I have a beautiful Snap on battery impact has served me well orig cost $500.00 batteries are done I can buy a new one cheaper than batteries. Good luck with it Pete

-----Original Message-----
From: Robert Bennett <dino66 at optonline.net>
To: oldradio <oldradio at comcast.net>; 'Matt Reynolds' <mattr04 at hotmail.com>
Cc: 'NJARC' <njarc at mailman.qth.net>
Sent: Wed, Jul 27, 2016 10:40 am
Subject: Re: [NJARC] safely weld/solder Lithium battery cells?

Just remember
Reply = Poster
Reply All = Everyone

_________________________________________________________
Matt -
I checked some "youtube" vids on this subject. Not liking what
I'm seeing. I agree with John and would take the lick and spend the 100
bucks. What's a hospital trip worth?

Bob Bennett

-----Original Message-----
From: NJARC [mailto:njarc-bounces at mailman.qth.net<mailto:njarc-bounces at mailman.qth.net?>] On Behalf Of
oldradio at comcast.net<mailto:oldradio at comcast.net>
Sent: Wednesday, July 27, 2016 9:51 AM
To: Matt Reynolds
Cc: NJARC
Subject: Re: [NJARC] safely weld/solder Lithium battery cells?

Just remember
Reply = Poster
Reply All = Everyone

_________________________________________________________

Hi Matt,

spend the $100 and dispose of the old one.

73, John

I took a gamble at a flea market two weeks ago and bought a contractor grade
Milwaukee 1/2" battery hammer drill. It was in the case with two 28V (yes,
28, not 18) Lithium Ion Batteries and a charger, for 30 bucks. The seller
said the batteries were good, but didn't last long.

Turns out, they are so dead they've gone dormant and won't charge. I'm going
to bench test the drill with a bench power supply to see if the drill at
least works. If it does, I will work on making it cordless again.

Unfortunately, I've found that these batteries are about 100 bucks each (!)
and it turns out (per Batteries Plus\Batteries & Bulbs) it's illegal to
commercially rebuild Lithium Ion Battery packs in NJ.

I've been investigating what my options are, and I'm considering rebuilding
the packs myself, but from what I've read, Lithium cells are very heat
sensitive and it's very dangerous to rebuild them via soldering. Evidently
they are generally spot welded together by the tabs at the factories.

I have at home what I was told is a "thermocouple wire welder" which I
believe uses an arc (presumably like discharging large caps) to weld metal
together. Is this a "safe" way to weld lithium cells? Can you discharge caps
into lithium cells to weld without harming them?

I would be fine with converting the cells to Ni-Cd, but I'm sure the
protection circuitry of the pack won't permit that. The charger that came
with the drill can charge 18v Ni-Cd or 28V lithium, but I'm sure the pack
circuitry is different. I might be better served hunting down one of those
18v packs and rebuilding one of those instead.

I just thought I'd shoot this out on the reflector in case anybody else has
had experience with this. The packs have 7 3.7V "moli cells".

Regards,
Matt

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