RE: How to attach leads to batteries?
do not put them in the freezer whtever you do.
it is not the wattage of the iron that matters but the size of the head. Wait for the head of the iron to heat up properly!! I always use a small piece of tissue paper around the terminal with a bit of water on the tissue. ie damp this way if i overheat the terminal the tissue will cool it down sufficiently for me to work for 5-10 seconds at a time. good luck!!