strange issue with battery maintainer: weird noises

[jdcooper]

I've searched the forums and the web and can't seem to find anyone that's experienced a similar issue, so I thought I'd ask y'all about this.

I left my 2001 996 for a bit too long without driving it or hooking up a battery tender. (A month, maybe longer.) The battery is discharged as a doornail.

I purchased a Ctek 3300 battery maintainer / charger and cigarette lighter adapter. When I plug it in and hit the mode button to switch to car battery mode, the charging light comes on in orange, but a very strange thing happens:

The car makes odd noises, all over, cyclically, with a period of about 1/4sec. It sounds like solenoids trying to move and failing. the sounds are especially prominent in the engine compartment and door panes near the window actuators, and under the hood.

Needless to say, I unplugged it and won't plug it in until I figure this out!

Has anyone experienced this? Is my best bet with such a flat battery to remove it from the car and charge it there? (Note: via the cigarette adaptor I am unable to get enough power to pop the hood!)

Any thoughts would be much appreciated.

Thanks,

Jon

Edited May 4, 2011 by jdcooper

[JFP in PA]

Your problem is the dead battery. With a battery that is really discharged, some of the normal items powered by it when the car is off (alarm system, immobilizer, etc.) tend to react to there suddenly being a source of power; that is the sounds you are hearing. Pull the battery and fully charge it, let it cool and then have it load tested; chances are better than even money it won't pass muster. If that is the case, put in a replacement (or just do that without testing if the original battery is more than a couple years old) and the car should recover fine, although you will still have the usual battery replacement woes (no radio presets, alarm will promptly go off, etc.).

[jdcooper]

Thanks for the reply.

Do you think it is worth borrowing a traditional 12V charger and using the power point in the fuse box to try to pop the hood, or will I have the same issue if I provide 12V there?

In that case, I guess my only option is to dig out the mechanical release in order to pull the battery?

(That is a not-very-easy thing to do because I'm parked in a garage quite close to a car on one side and a wall on the other.)

[JFP in PA]

Thanks for the reply.

Do you think it is worth borrowing a traditional 12V charger and using the power point in the fuse box to try to pop the hood, or will I have the same issue if I provide 12V there?

In that case, I guess my only option is to dig out the mechanical release in order to pull the battery?

(That is a not-very-easy thing to do because I'm parked in a garage quite close to a car on one side and a wall on the other.)

That would work, as would attaching another battery via that method.

[jdcooper]

Just for clarity, that would work while using the CTEK via the cigarette lighter adapter doesn't, due to the fact that a 12V charger will provide more amperage?

[JFP in PA]

Because of the high internal resistance of a fully discharged battery, you need current more than voltage, in fact, as little as 9V will do it with enough amperage..