JetJock

Recently, I came home after a few weeks on a business trip,only to find my battery completly dead on my 2004TL. I've only got 8000 miles on the car, so I don't drive it every day. I've never had a problem with the battery over the past few years. When I found the battery dead, I hooked up a charger, but it didn't want to take a charge. After fooling with the charger, I managed to get the battery to charge. The charger showed 100% charge after it finally managed to take a charge. The little "eye" on the battery never showed "green" even with 100% charge showing on the digital charger. I drove the car, with no problems. After I let the car sit for a few days, the battery was down t o 60%. I took the car to the dealer to see if there was something draining the battery. They said everything checked out OK with their test equipment, but the "eye" on the battery still doesn't show green.
Has anyone else had this problem with their car with infrequent driving, also, why would the charger show 100% charge, the battery test OK with the dealer test setup, but still not hold a charge? I've only got 3 weeks remaining on the battery warranty, so any thoughts would be appreciated. I'm not that familiar with batterys, how they hold charge, and how they test on the dealers equipment, but time is running out, so I need help. Thanks in advance guys...I really appreciate your comments.

Ron A

The battery may take a charge, and it may show good on the tester if they don't do a complete test, but what is happening is it will not take a load, like when you start the engine. That's what I meant about a complete test, because some shops don't test it under load.

This is usually caused by one or more dead cells, which drain the power from the good cells when they are called upon to start the car or run the headlights or other high current requirements.

Bottom line-you need a new battery.

And don't worry about the 3 weeks left on the battery warranty. After all this time you have no warranty at all. The manual says the warranty gives up to 100% credit towards a replacement battery, but this is prorated on the length of time it has been in use, so you probably won't get enough to buy a cup of coffee. But check with the dealer to be sure of the exact amount.

Walmart does a great job of checking the battery, and usually it is without charge. They can tell you for sure if it has a dead cell or something else preventing it from holding a charge. Most of the major auto parts stores will also do the same thing.

Wid-TL

Slightly off topic but worth mentioning - my brother works at BMW and their cars (I think the Mini's) are shipped via freighter - so they come into the dealership with this contraption that is a solar panel with suction cups for window mounting - and plugs into the cigarette lighter. I guess to keep the battery charged during the trip for offloading.

He gave me one and I've been using this on my Ford pickup since I don't drive it that often - and it really works at trickle charging the battery.

Luckily I got it for free - but there has to be a manufacturer that makes these for public sale.

Brettg

I have a solar charger, it worked great on the passat as that car had a power outlet in the trunk, and I put the solar charger in the back parcel shelf with velcro.

On the TL, the windshield would work, put it on the dash and plug it in the power outlet and let it keep the battery charged.
That of a battery tender.

If the green eye does not show after a charge, the battery is bad.

Brett