Last year whilst on a driving holiday with friends, they kept the sat nav plugged into the cigarette lighter all the time whilst driving, being removed from the car each evening. It would appear that no other charging was done, is this how this should be done or as another friend tells us you should use your mains charger to charge it up.
Regularly flatten the battery.
Many batteries develop a memory, so if not exercised fully, will gradually cut available duty cycle.
Latest batteries are supposed to be memory-free .. that's what it means, if you see it printed on them.
Mine sometimes switches on all by itself in the drawer and flattens the battery I only know this because I heard a voice from the drawer telling me at the end of the road turn right!!!!!
I don't think many satnavs have mains chargers supplied as standard. Mine certainly didn't, and I never missed it. Why would I have my satnav in the house?