I have the sears one, I think I paid $20 for it (on sale maybe?). I use it all the time, no problems.

I just saw them on a motocross site for $30.00. (6 or 12 volt)

Fred Henson Races superstock hemi cars, he lost a very expensive race car, and half a building because of a battery tender. I don't trust them at all. When i put something in storage, i pull the battery out, take it home, use a trickle charger to charge them up before they go in. I never use a trickle charger unless i am in the building. I might be paraniod, but better safe then the alternative.

I bought a bunch of the WalMart specials. The one servicing a pair of big batteries started clicking and after that it then did not keep the batteries charged. I replaced it with another but it did the same thing. Maybe too much battery for its capacity. Another boat has a starter battery and a deep cycle trolling motor battery. The deep cycle battery had the water boiled out three times over the winter and shot craps. The starter motor battery also had the water boiled out once over the winter. I had BatteryMinders on the two jet skis and the batteries stayed fully charged and no drop in water that I could detect after two winters.

I have scrapped all the WalMart specials and replaced them with BatteryMinders. A lot of money up front but for me it is worth it.

I have 2 of the cheap wally world specials and have had no problems with them. I used to have a ~$200 2 bank promariner charger/maintainer in my bass boat and it shorted out somehow
and actually would drain both batteries. :rolleyes:

A great product! I have several brands. They all work, some have more lights than the others. I use one on my car in storage, jet skis and boat.