solder for making a battery pack

[savage308]

ive got a old uniden bearcat sportcat scanner that the battery pack gave up, i baught one online it lasted about 18 months before it started dying , i have new AA cells i have the wire and borrowed a soldering iron but the solder he had wont stick to the batterys, what kind do i need to make it stick, thanks any help would be appreciated

 

[n5ims]

Generally those aren't soldered but spot welded (look closely at your old pack and you'll probably find the small circle where the weld is. The metal the batteries are made of do not solder well, which is why you're having problems. If you're able to put enough heat to get the solder to work, you'll probably cook the battery enough to ruin it anyway.

 

[RC286]

Use 60/40 lead-tin solder with a rosin core flux.
I have done it many times and it does work.

First buff the ends of the cell with sand paper, once roughed up the solder will wet better.

The thing with these batteries, (as mentioned above) is they are spot welded.
Soldering them can be tricky, the battery acts as a heatsink and draws the heat from the tip.

Its a ballance of getting the end of the cell hot enough to make the solder wet properly, but not hot enough to damage the venting valves on the cell (keeps the battery from exploding if it gets too hot during charge or discharge cycles) or causing it to rupture. ALWAYS wear safety glasses when working with batteries, especially if you are deliberately applying heat to the cells.

Last pack I made, I merged 2x 3 cell NiMh 1100mAh cordless phone packs to make a 7.2v pack.

 

[slicerwizard]

In order to solder to batteries, you have to break through the plating on each end. Sanding or scratching with the tip of a knife or a screwdriver blade works just fine. The cell ends have to be tinned (coated with a bit of solder); the connecting wires should also be tinned. A hot iron is required and you have to work fast to avoid overheating the cells. One end should be tinned at a time and each cell should be given time to cool down before tinning the other end. After everything has a solder coating, it's easy to connect the wires.

It wouldn't hurt to practice this on the old cells first, but in this particular case, I suspect that the OP has already damaged his new cells.

 

[rescue161]

If you have a Batteries Plus, they can spot weld on little tabs for you on the cheap. I've done it many times for backup lighting power packs that go bad regularly.

 

[moonbounce]

I have a Uniden Sportcat 200. When the battery pack died I took the radio apart and took out the shell that the battery pack sat in. I went to a local electronics store and bought a battery holder soldered the wires together plopped in some batteries and two years later it is still working great.

MB