Schumacher now makes their own version called the
Extender SP2. Sort of a cross between a CTEK and a Battery Tender. I have lots of different chargers and maintainers, including a couple of Battery Tenders (a single and a dual channel), the new Optima 1200, older Vectra maintainers, etc. I like the Extender because it is one amp, auto ranges between 6 and 12 volt batteries, comes with the usual clamps as well as a commonly used charging pigtail and most handy, a 20ft power cord. Like any modern maintainer, it has a microprocessor controlled charging process that won't cook the life out of the batteries like a simple trickle charger can. I'm happy with it, I've used it on tractor and generator batteries, random vehicles, and it is currently keeping the battery in my parked-for-the-winter MINI Cooper S happy.
Pros: Small size, odd but convenient shape, three different color status LEDs (they form the big "X" on the unit), nice clamps and charging pigtail compatible with Battery Tender and other accessories, 20ft power cord and 6 foot charging cord, not sealed shut like some other brands (can be repaired).
Cons: Not waterproof, but can be left under the hood while connected in the weather, no cigarette lighter adapter included.
I recommend this unit. I monitored the operation with my pile of test equipment and found it does follow the typical4-stage charging and maintaining cycle, but not sure if it adjusts for temperature extremes. I bought mine from Wally World for about 40 bux, recently I picked up another at $35 dollars to give as a gift, I think that is the current regular price. Amazon wants $45 last I checked.
If you are looking for a charger that has more oomph but can also be used as a long term maintainer as well, the new Optima 1200 is the dog's ********.
