if i split a battery i use Hyperion taps cause i have a Hyperion charger. I BUY FP packs though and use me little board to convert the FP to Hyperion for all my FP packs (lol which at the moment is only 2) I found that standard rosin core solder has worked on every tsap i have done. Sometimes it does take a sec for it to stick but once it is warm it does fine.

Linc what solder do you use that you find works BEST. I have not experimented so i dont know what works best just know mine works but possibly could be better.

If the al tabs have solder on them you can usually use any solder. I use zinc solder and the matching flux to solder onto bare al taps. Cheapbatterypacks.com sells the solder and flux. I use a specific tip with a 40watt soldering iron.