?? on soldering batterys need help FAST!!

[beason]

ok I'm at work, i got a laptop that came in with some errors.. traced the errors to the cmos battery.. take it out and seems someone has tried to scotch tape the pig tale leads to the battery........
its a flat watch style battery and the pig tale has a small 2 pin plug on one end and flat spade ends on the other. the spade ends are supposed to be tacked somehow to the battery, it has to be a machine that does it cause its two tiny spots and they hold good. but someone took them off (I'm guessing to change the battery) and just layed the spades on there and taped it up (with scotch tape) now on to my problem.....

i need to solder the spades back onto the battery. BUT the solder wont stick to the battery!!!!! i tryed a bunch of times and even took a flat blade and scratched it up a bit. i can't keep the iron on there to long or the batt will asplode (trust me, dont ask) but i can't get it to stick.!!

is there a trick? what am i doing wrong???

 

[FastEddy]

First off get a new battery. This one is most likely toast.
On the old one, try to sand (220 or finer) the place where the solder will go.
Put a bit of solder on the tip of your iron then hold it against the battery till it slides off the tip and seals to the battery. This is called tinning. Tin the wire, then hold the two tinned parts together and apply your iron till they melt together.

 

[beason]

man the only part of that i didnt do was the sanding.. i used a small flat screwdriver to rough it up.. i dont know why but the solder wont stick.. it looks stuck, all spread out, then you move it and pop it comes off with NO solder left on the battery..

i finnaly got it to hold long enough to tape it up with ELECTRICAL tape by driping some hot solder on it then sticking the wire to that.. and its only a cmos batt so the solder job isnt to important..

the big thing is makeing sure not to over heat the battery.. its very small so it gets hot fast!!

 

[vbgagnon]

Are you using flux? That helps with sticking.

 

[FastEddy]

Using sandpaper will give the solder little grooves to grab.
Yes, rosin core solder or flux will do wonders.

 

[beason]

the solder i was useing is the thin coreless stuff used for small electrical jobs. but i had a bit of rosin core and tried that, it just left a brown stain on the battery, with no other results..

i put some grooves in it with the screwdriver, it still wouldnt stick..

 

[niggle]

I use a fibre-glass abrasive pencil to clean up and roughen the area to solder when I want to solder wires to nickel plated battery terminals, although I must admit that soldering wires to coin cells is much more tricky than soldering to NiMH pencil cells.

If you have a local electronic parts supplier you might be able to obtain the same size coin cell with a PCB mounting. These are more expensive than the plain coin cells that you get from the the local electrical retailer or watch repairer but they have PCB pins spot welded onto the cell and it is very easy to solder wires onto the pins.

Make sure the coin cell is electrically insulated before you stuff it back into the laptop.