Originally Posted by
dirtybird
Acid flux is not a good idea for any electrical soldering. The acid will creep up the wire under the insulation and cause corrosion of the wire.
Scoring the end of the cell with any kind of abrasive will remove the coating and make it very hard to solder to. They have always had a coating.
You cannot touch the end of the cell quick enough to transfer heat as small as spot welding.
DirtyBird, its just a smear of flux on the end of a Q-tip, not enough to wick under anywhere... besides, the area in which you are applying the flux and solder to, has no insulation to wick under... just a few wipes with a 3M scotch brite pad and a smear of the flux and the solder flows very well... then a couple drops of mild dish soap in some water and scrub the ends with an old tooth brush to get any flux residue off.
My inlaw and I have been doing this for over three years, he longer than I, as he and I were sharing his aircraft for a while, until I got something large enough to fly for myself while I refurbished my Sig 1/4 cub... the amount of heat transferred into the cell casing is very small...the solder will pass more current than 4 small spot welds will... I'm extremely confident that the integrity of the battery is in no way compromised... the battery temperature at the ends after soldering is no where near as hot as if you where to pull 30 amps through the cell for a few minutes... now if you lay the soldering iron on for too long, you going to damage the end cap insulators inside the casing, but once you see how quickly they solder with the right iron, solder and flux, you won't have any concerns
Jon M,