Possible Battery Maintainer Failure? - 986 Forum - The Community for Porsche Boxster & Cayman Owners

Guys, Could use a little help, please ... I'm away on business for several weeks. My car is in winter storage. The guy who is storing it for me sent a note saying that the red power light on my (brand new) Porsche Battery Maintainer (see model example below) is out. Just black. It may have been out for as long as a month as this guy has been away. 2 questions. 1) Does the red light on this model always stay on or does it go off when the the charge is at an optimal level? Is that what they mean by the statement " It will automatically cutoff to avoid overcharge ." 2) Assuming that the charger has not been in operation for 4-8 weeks, at what point should will/would I begin encountering problems. Thanks for any insight! http://www.pelicanparts.com/cgi-bin/smart/more_info.cgi?pn=980-611-981-00-OEM&catalog_description=Porsche%20Battery%20Maintainer

According to this post, the light only comes on when the charger is powering the battery, unlike my tender (which shows a green light when fully charged). http://forums.pelicanparts.com/porsche-911-technical-forum/516532-battery-maintainer-question.html Sounds like you're good to go...

Thanks a lot! But wow, the light turning off when the battery is charged is an odd piece of engineering -- talk about a stress-inducing "feature." Red/Green or blink would have been a bit more reassuring. If anyone else has experience with this maintainer, love to have a second confirmation. Thanks.

1) Does the red light on this model always stay on or does it go off when the the charge is at an optimal level? Is that what they mean by the statement " It will automatically cutoff to avoid overcharge ." My ans: I have the same maintainer. I just walked out and checked on my maintainer's single red light and it is OFF. It has been connected for a week and so the battery is charged. The light also goes off when the plug is disconnected from the "lighter" socket (even if the maintainer is plugged into the wall socket and the wall socket has power). So it is vaguely possible that something happened to loosen the plug or cause it to come out of its socket entirely...but doubtful. I'll bet you are just fine. The red light comes on when the maintainer has power from the wall socket and the maintainer senses the battery voltage initially, and is on when "charging". I use that light to be sure I've got the "lighter" socket plug in straight and making contact when I initially plug it in. 2) Assuming that the charger has not been in operation for 4-8 weeks, at what point should will/would I begin encountering problems. My ans: You'd already be in trouble at 8 weeks, at 4 weeks you'd have a very small chance only if the battery were new and powerful to begin with and you didn't have any aftermarket accessories drawing power and if it were nice and warm outside (which it probably isn't). My experience is I feel the struggle at 2 weeks off the maintainer if the battery is at all marginal so by 4 I assume you'd be unable to crank the car over but I don't want to draw the battery down to test that theory since doing so hurts the battery. I like the blinking when charging and on when charged that my camera battery charger uses to signal the state of things with one light. The Ctec more expensive maintainer has multiple lights (but does the same job). So relax, enjoy being away. All will be OK when you go to start it if it ever warms again.

I have the same Porsche charger and it's been in use since Dec.1st. I have only seen it on once, I assume to 'top up' the battery. I tested the car's battery after one month recently and all is working well. After opening the car and trying everything (ie. radio and dash), the charger light came on again. I haven't seen it on since though. Relax and enjoy your 'piece of mind'.

Ditto, mine seems to turn off and on as needed.

my battery tender light glows green when full. We have a solar brand trickle charger at work and it went dead in 3 months. it was replaced under warranty

Thanks a lot guys -- this gives me great piece of mind!

I have the Porsche maintainer and the light goes off when the battery is charged. About every other week I open the passenger door so thewindow drops and the dome light comes on just to see the charger instantly light up and verify it's still working. After a short time the maintainer shuts off again, and I feel comfortable that everything is good.

The worse that can happen is you will have to replace a $60 - $80 battery....

Good idea Dave...seems like a simple, quick test. A question for Paul with the last quote "worst is a $60-$70 battery", if your battery dies, I heard you can't get into the front 'trunk' to replace it as the power release won't work(????).

You can unlock the door with the key manually, or use the emergency pull cord in the front fender to connect a charger to the battery. You can also connect a battery to the connectors on the fuse panel. See your owner's manual.

I remove the negative cable on the battery and leave the front trunk on the safety catch. If the car is going to be stored for a month or 2 I remove the battery and take it home where I charge it once in awhile.