ltoolio

Curious what battery maintainer y'all are using. I'm perusing Amazon and it seems that there are a few that are highly rated, but I'm always interested what's used here by the community.

I'm also planning (hoping?) that I can use this to direct test some of the motors on the car, such as the seat motors and Sunroof motor. I'll be able to do that, correct?

Thanks as always.

LT

jpitman2

Some charger/maintainers wont drive equipment - too much current. Ctek and schumacher are common. Being in Oz I have a local variant - 1.6A smart unit. I have leads direct off the battery via a 10A fuse out through the bumper cover to a waterproof socket under the licence plate- dont have to open any panels, can stay connected while battery is disconnected from car for work.
jp 83 Euro S AT 56k

oldfrat

After researching it on this board, I got through my first winter fine with a Ctek 7002. I just wish I had not wasted money by ordering an accessory that would charge through the lighter outlet. Wrong! Won't charge that way!

Brad

voskian

+1

ctek 7002 , I have two one for the 928 and one for my wife's MB SL500. You can find it on eBay or Amazon, which ever has best price.

Bob

depami

I have a MOTORATT that works very well but it won't run motors. Not because of current but because it needs to measure voltage (3 I think) before it will turn on.

WallyP

Very few of the better maintainers can be used as a power supply. As Denny says, they need to see a minimal battery voltage before they supply any power.

Most newer battery chargers work the same way, which means that they won't charge a battery after it gets really low. The work-around is to hook up the battery charger to the dead battery, then hook a good battery to the dead one with jumper cables. After an hour or two, you can remove the jumper cables and battery.

For some reason, Porsche built part of the '88 cars with lighters that are hooked to battery power, not switched power.

Mrmerlin

FWIW a battery maintainer is not a substitute for a battery charger,
yes it should keep the battery topped off ,
BUT if the battery should see a substantial drain then recharging is necessary,
a 2 to 6 amp charger is good for recharging.

Its not a bad idea to put the battery on a charger every few months.

Landshark87

bought a Battery Tender back in 1997 when i bought my first 928 and it chewed through batteries like bubblegum.

its still working great to this day.

FLYVMO

Optima Digital 1200....a charger and a maintainer, works like a charm.

Cheers!
Carl

upstate bob

sounds like an oil thread I can recommend the MINDer charger/desulfator. With any of these units you should always connect the leads to the battery posts before plugging in. If you only want a little cheapo trickle/maintainer for your lawnmower go to harbor freight. The CTEK and the Schauer are probably ok too but I've had good luck with the MINDer. My battery must be ancient but it still cranks strong.

Rob Edwards

I have a Bosch C7 that I like- has multiple modes for regular, AGM, and deeply discharged batteries and will put out 6A for recharging. Worked when my battery tender wouldn't.

dr bob

The CTEK 7002 has similar features and capability to the Bosch that Rob mentions, plus it will auto-restart if power is momentarily lost. The Bosch doesn't, driving me to choose the CTEK.


Modern digital battery charger/maintainers aren't good for separate loads for the most part, although the CTEK has an available function that can be used to "power" the memory items in the car when you change a battery. This isn't an issue on the 928 equipped with, um, 'legacy' controllers and smarts. If you plan to test seat motors and the like, you'll need a different power supply or maybe a small battery. Adjust your expectations by looking at the fuse sizes for the pieces you anticipate testing, and plan for 1.5 to 2x that capacity just to be safe. Seat motors, for example, have a stiff current inrush as they first start moving. For those things, I have a portable battery powered compressor/power supply that includes a 17Ah battery, Easy enough to use that for testing stuff out of the car.

blau928

4 CTEK tenders and a Schumacher charger..

Works like a charm!

CTEK makes oem tenders for Aston, Ferrari and Bentley, good enough for me..

hb253

Seconded.

My BatteryMINDer 1510 made my lawn tractor battery useful again. I kept my 928 batery on it over the winter without any issues.

Hugo

mdkelly1

I'm with the others on the CTEK 7002. It's a great maintainer and it will bring a low battery back as well.

To Wally's point about some '88's having an always "hot" lighter socket; that's the case with mine as well.