Interesting that this thread showed up today....
I help maintain the fire engines for the volunteer fire dept. Today I changed out the batteries on one of the engines and they were 9 years 2 months old. I'm not sure what brand of trickle charger is on the engines, but when the engines are not in use, they are plugged up 24/7, and kept in a station that is semi-heated. Meaning that the thermostat is set at 50 degrees.
One of the things that helps the batteries last longer is that we have master cut-off switches on the engines. You flip the switch and all power to the engine is off. No power anywhere, so the trickle charger is actually doing very little, but the batteries are kept fully charged.
I you'd like, I can check and see what brand of trickle chargers are on the engines, and let you know.
