Solar Battery

Can a solar powered battery maintainer (1.44 W, or 120 mA at 12V DC) overcharge a car battery?
I have not been able to directly find the answer if a solar powered battery maintainer that charges very slowly can overcharge a car battery? It is for a car that isn't driven very much, and we are in MN and need to have a good charge on the battery to start the car.
Thanks for any help! The product I purchased make no claims that it won't overcharge - it's one of those made in China things from Fleet Farm store.
I keep one in my car (also in MN) and have never had a problem with overcharging.