I bought a battery charger/tender/minder with my car storage capsule. Came at a discount. The seller says it's the best but it does have a true "float" feature. My battery is on it as I type...ask me in the spring!
Charger12 Volts, 3 Amp Constant Current
(Equivalent to 6 Amp tapered charger in charging time)
Input 115 VAC (range 90 VAC to 132 VAC)
Suitable for U.S., Canada, other 115VAC countries & Japan (100VAC).
Automatic Cut-off and then true Float.
Can be left connected indefinitely without harming the battery
Increases battery life by de-sulfating the battery
UL and cUL (CSA) Listed
Meets FCC Class B. High level of electro-magnetic interference filtering
Suitable for off-board application.
Size, only 4 ½” x 2 ¼” x 1 ¼”, and very lightweight, only 11 ounces