by RCModelReviews » Wed Jun 09, 2010 11:39 pm
Soldering the AA cells is pretty easy but you have to avoid using too much heat.
Here's how I do it.
1. make sure you have a soldering iron that's hot enough (40W is about right)
2. use some wet-and-dry sandpaper to clean up the ends of the cells (get rid of tarnish)
3. apply a hot iron to the end of the cell and feed solder onto the cell, right next to the iron (not onto the iron itself). The solder should melt and flow within a second or so. Don't hold the iron on for more than 3 seconds or so.
After you remove the iron, blow on the end of the cell to cool it as quickly as possible.
If the solder balls-up and doesn't flow then clean the end of the cell again and make sure you've got all the tarnish off before trying again.
Lead-free solder is crap -- use regular flux-cored lead/tin solder for this job, it works much better.
4. repeat step 3 until you've got a nice shiny puddle of solder on each end of all eight cells.
5. take the wire you're going to use to join the cells, cut into suitably sized lengths and strip about 1/4 inch (6mm) of the insulation away on each end.
6. using the hot soldering iron again, tin the ends of the wire so that they've got a good coating of solder. Again, when doing this, don't apply the solder to the iron, heat the wire and apply the solder to the wire -- it should wick-up the solder like string wicks up water.
7. attach the wires to your cells by placing the tinned end of the wire on top of the solder-puddle you've already made on the cell-end then apply the soldering iron on top so as to cause the heat to first melt the solder already on the wire and then the pool of solder on the cell. This is called "sweating" the wire onto the cell. This should take no more than 3-4 seconds. Remove the soldering iron and avoid moving the wire while the solder cools.
Repeat step 7 so as to get all your cells wired in series then connect the wires to the last + and -
8. Now make sure your batteries aren't going to move around -- you can use tape, heatshrink or the odd drop of CA to keep them together.
All done!
The key thing to note is:
Don't overheat the cells. Using a soldering iron that's too small or not cleaning the terminals properly are the main reasons why you might end up overheating the cells. The solder should melt very quickly after the iron has been in contact with the cell for a second or so.
RCModelReviews.com, just the facts.