Making battery packs

[SafetyBob]

I think this has been covered awhile ago and I just can't find it, but here it goes.

One of my old Porter-Cable 19.2 volt battery packs has finally bit the dust. Thanks to others here talking about taking battery packs apart, I got the screw driver out and discovered 16 little 1900mAh Sanyo Ni-Cds. They say DF on them, which threw me off for awhile until I went out and measured the batteries.....they indeed were Sub-Cs.

My main question is, can I solder new ones together or do I really need a battery welder (?) to do it? I can come up with a big Weller gun to zap it quick so I don't put much heat into the battery. Or should I just get some with tabs and just solder short pieces of wire between each battery in the pack.

I would appreciate anyone's opinion on the matter. I can get a new battery for around $90 and have noticed alot of options on batteries like perhaps getting higher capacity batteries. Advice please? Any suggestions on where to purchase here in the states?

Thanks all!!

Bob E.

 

[aussiebob]

I have made up battery packs for my cordless phones after the factory batts stoped holding charge. Just used some thin wire and soldered the cells together and attached the conector, with ordinary soldering iron, then wraped in heat shrink plastic and heated with heat gun.
The old cells didnt have any capacity rating but for the new packs i used 900mah nimh aaa and the phones last much longer than the old ones even when they were new. I think factory batt packs dont use very good quality cells to save money so making your own with quality cells is good idea.

 

[aussiebob]

And another thing, the end of the cell you are soldering to must be hot so the solder will stick good, hold the iron on the cell for 10sec or so shuold do it.

 

[Norm]

I'd be contacting member LuxLuthor Custom Battery Packs - Made To Order
Norm

 

[DM51]

That is very good advice from Norm.

aussiebob, I'm very glad you survived soldering cells like that. It is really NOT a good idea to do that.

 

[LuxLuthor]

Bob, just a couple points I can add.

I have soldered NiMH cells, but the key is having a really hot iron (I use a "Hammerhead" tip with an 60W stick iron...or Hakko 936 solder station set at 750°F); lightly abrade the ends of your cells; use flux; pre-tin ends and any wires that may be used. Contact with hot iron is never made for more than 1-2 seconds. Earlier poster who mentioned 10 seconds is either using too low of heat, or does not understand the damage that can occur from prolonged heat. If you need links to a nice video and supplies mentioned, let me know.

Do not solder Lithium Cobalt Ion cells. There are new "safe lithium" battery chemistries that can be more safely soldered...but still not abused with hot iron.

Battery pack welding is fast, reliable, and uses flat, thin strips of Nickel that allow neat/compact packs. 16 x SubC cells is not exactly a small pack though.

There is no problem using higher capacity replacement cells to last longer, and it's fine to use NiMH instead of NiCad as long as you have the proper charger. There are many places to get SubC cells, you can check www.cheapbatterypacks.com or www.batterieswholesale.com

 

[aussiebob]

aussiebob, I'm very glad you survived soldering cells like that. It is really NOT a good idea to do that.

I done it before i had much knowlage on the subject:thinking:. I knew that the cells couldnt get too hot, and they didnt get REALLY hot just warm.
Anyhow those packs are still going strong a year later!:thumbsup:

 

[mdocod]

with NICD you can solder in new cells (order tabbed cells to cut the amount of work in half). be quick about it to reduce heating the internals of the cell. NICD is pretty tolerant to heat. With NIMH the same applies but I would be even more careful as it is less tolerant to abuse (generally speaking).

 

[aussiebob]

Bob, just a couple points I can add.
There is no problem using higher capacity replacement cells to last longer, and it's fine to use NiMH instead of NiCad as long as you have the proper charger.

I got the upgrade NIMH charger from Uniden, (the phones manufacturer) it is for there hi capacity NiMH packs.

 

[SafetyBob]

My charger does not like Ni-MH batteries. I am currently figuring out how to make a little charging port (like FM's on his battery packs) or something, somehow to swap packs or batteries in the phone. Actually, idea bell just went off. I could just glue in 2xAA battery holder, then when batteries get low, swap in fresh eneloops and be done with it. It will take a little Dremel action to get things in nicely, but it should work.

It appears that circuitry in the phone will shut off phone when battery pack voltage drops below 1.8VDC or so. Hopefully that should not damage the old eneloops.

Off to the garage!!

Bob E.