Salmo-
If cold weather affects your battery it has seen its best days and should be replaced. I don't know what charger you have but all batteries should be charged at the slowest rate possible. They also should be kept as close to fully charged as possible at all times. A full discharge and recharge effectively "produces" a half life in a battery. This means that fully discharging and recharging a battey twice cuts the "new" life to 25%. If you call Jacobs Electronics they will sell you a charger equipped with the ability to periodically pulse the battery with a reverse polarity charge. This acts to de-sulfate the grids (or plates) and prolong the life significantly. Jacobs has had a long history in the automotive world while maintaining a very good reputation. They also have an ignition system with money back guaranteed power and mileage improvements. I would also suggest the highest quality battery you are able to aquire (not just the best you are able to find at the nearest store). The quality of the "guts" can vary greatly and will make a huge difference in the long run. Best of luck.