I've liked the Guest brand units available from the usual marine stores (West, etc.). I use a 3A for winter storage--4-5 months--and have had no problems; I leave the battery connected and simply clip on the charger leads . That said, I've had no problems *without* a charger for a month or two, ever, and that goes back to the 1960's. The only times I've had trouble getting and keeping batteries charged are when the battery's bad or there's a drain that shouldn't be there (checkable with an ammeter). BTW, I've never had a battery go truly flat, for whatever reason, without finding that it didn't do well afterwards and needed to be replaced.

__________________
Craig Bethune

'97 SL500, 40th anniversary edition

'04 Olds Bravada (SWMBO's)
'06 Lexus ES330
'89 560SL (sold)


SL--Anything else is just a Mercedes.
(Kudos to whoever said it first)