Can I use these tools to solder in battery

> is a 15 watt radioshack soldering iron good enough

Ugh.

It can work.

You NEED to practice on some scrap before you globber your iPhone.

What's in your cellar? Old VCR? Dead cordless phone? Anything electronic and useless that can be opened-up without much fuss.

Be SURE it has not been plugged-in for days. (Do NOT use a TV set; these can hold a charge for weeks.)

Open up, expose the PCB (printed circuit board), find some wires to un-solder and re-solder. If the wires are not soldered, cut any wire, strip the end, and solder into any handy PCB hole.

Have a damp rag.

Have a discarded heat-proof candy-dish or large ashtray for the iron. (The bent-wire "holder" is silly and unsafe.)

Warm up the iron. After a minute you smell the factory oil-trace. Wipe the very tip with the damp rag, quickly. Do it again in another minute. When the damp rag sizzles, poke the very tip of the iron with the end of the solder. It will be another minute before solder melts, but you MUST get solder on the iron before the hot tip oxidizes too much.

For this repair, just tin the first 1/8" or 3mm of the conical tip.

When the iron "takes" solder, get a good blob and let it heat another few minutes. The $13 irons will not get "too hot" (even if you heat for an hour). The goal is a fairly hot iron and quick work. Fast melting in a small area does less damage than a warm iron and long melting time.

When iron is good and hot, takes solder readily, tap the iron in the ashtray to remove excess solder. You want just a thin film of solder to transfer heat, not a glob.

The trick is to heat BOTH the copper pad around the PCB hole, AND the wire, to solder MELTing temperature. Un-soldering is easy. If the hole closes-up: re-heat, take the iron off and quickly put a needle through; solder won't stick to cold steel. When soldering, apply solder to the wire and hole, NOT the iron. When BOTH are hot enough solder will flow and "WET" both surfaces. Solder should not glob-up like rain on a waxed car, it should spread and cling like icecream on hot concrete.

> .015 is this enough?

Solder MUST be "for electronics"!!! It should be lead-tin and rosin FLUX-CORE. Hardware store solder might be for plumbing pipes. That stuff either has no flux (needed to clean copper for soldering) or it has a strong flux that will eventually EAT small wires and mini PCBs. Radio Shed has the right stuff. 0.03" is what I like, 0.015" or 0.06" will work. 0.15" is never used in electronics and probably the wrong stuff.