The tip size of the soldering iron is just as, if not more important than the temperature. You need the tip to transfer a ton of heat as quickly as possible to do the solder job in the shortest amount of time.
You can have a 1500 degree tip that is the size of hair, and it won't solder anything bigger than the hair because the temp will go from 1500 degrees to room temp on something the size of a battery. Or you have to hold the tip on the battery for 5 minutes to get the solder to melt, which happens long after the shrink wrap is melted from the cell............ Pretty much killing the cell.
But if you have a 1/4" chisel tip or bigger at 600 degrees, it will have enough thermal mass to melt a solder on a large battery and bar without cooling below the solder melting point. I use 80 watt weller with a 3/8" chisel tip. Will do a battery bar joint in about 2-3 seconds.
It just kills me when magazines show battery soldering 'how to's' using a 40 watt iron with a teeny tiny pencil tip. Idiots.
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