dead battery

[sheward]

I finished all my brake upgrade and spring pad work last night and went to test drive this morning. Battery is dead. I left the key on after turning the wheels from side to side for better access. I have always held the idea that running a car battery down completely will damage it. Does anyone know if there is any truth to this? The key was on for days.

drew

 

[Maui]

Just have to charge it up and see. I have discharged batteries and they came back after charge. I guess it kind of depends on how old the battery is.

 

[Glen]

Just have to charge it up and see. I have discharged batteries and they came back after charge. I guess it kind of depends on how old the battery is.

+1

 

[gsxr]

+2. A total discharge isn't good for the battery, but if it's relatively recent, it may charge back up and be ok. In some cases you may need a "dumb" charger to begin the process, I've had some "smart" chargers refuse to charge a totally dead battery, but the dumb charger worked fine.

 

[gerryvz]

My experience has been that if you have a new or relatively new battery (<3 years old) you can get 1-2 "chances" with it in terms of still being good and holding a charge, after running it down completely. If the battery is more than 3 years old, I'd just replace it. If it gets totally run-down more than twice, then it will never be as good as new, no matter how new it is. This is with traditional lead-acid batteries, not the newer style, GSXR-approved/endorsed AGM batteries.

Cheers,
Gerry

 

[sheward]

Thanks, guys. My neighbor has an older "dumb" charger. I'll try it when he gets home. Battery is a genuine Mercedes unit and not that old so I would like to be able to keep it. I put my float charger on it a couple hours ago to get it started and the trunk light won't even light.

drew

 

[txbrit]

Although I wouldn't normally go near Manny, Moe or Jack, Pep Boys does sell Bosch Car Batteries, and they have the Group 49 for $113.99 - AND if put in "Merry20" in the Promotional code Box, you get 20% off - select 'In Store Pick up" and you are good to go!

Here is the link

http://www.pepboys.com/product/details/9073755/1629/

 

[Glen]

Those Bosch batteries are ok. I have one in my daughter's 190E (2 years old) and one of my E500's has one (just under a year old) and they've been fine. For under / around a $100, I think they are great. Otoh, the Optima in my wife's wagon is 10 years old now and is going strong (knock on wood). But that car is used daily, with 45 minutes commutes each way...about perfect to keep a battery in good condition.

 

[sheward]

Although I wouldn't normally go near Manny, Moe or Jack, Pep Boys does sell Bosch Car Batteries, and they have the Group 49 for $113.99 - AND if put in "Merry20" in the Promotional code Box, you get 20% off - select 'In Store Pick up" and you are good to go!

Here is the link

http://www.pepboys.com/product/details/9073755/1629/

Good price, and a Bosch no less. Thanks for the tip.

drew

 

[TerryA]

Drew,

If you do have to buy a battery get an Interstate. They have one for the 500E. I can get you the part number a little later tonight.

I just replaced my last one. It was 8 years old. I wouldn't buy anything else. It did cost $160.00 but worth every penny.

Take Care

 

[gerryvz]

Drew,

If you do have to buy a battery get an Interstate. They have one for the 500E. I can get you the part number a little later tonight.

I just replaced my last one. It was 8 years old. I wouldn't buy anything else. It did cost $160.00 but worth every penny.

Take Care

http://www.500eboard.com/forums/showthread.php?4588-Maintenance-Heads-up-Maintain-your-battery-!!

 

[sheward]

Interstate is what I've been using in my truck for years. I actually have two spares but they are 1 inch taller than our cars use. I'm going to hook up the charger tonight and see if I can raise my old one from the dead.

drew

 

[samiam44]

Any tricks to charging a AGM battery? I have a charger which has 3 modes- wet, gel, and AGM. Putting it on AGM, 2-10-15 amp, it all goes into the same mode. I'm showing 6-7 volts. It's less than a year old, but been sitting for months.



Here's a trick from Optima :

Here's all you need to do: Grab another car battery with a decent charge on it (12.4 volts or better) and connect it in parallel to the problem battery using a set of jumper cables. Then activate the charger and charge the battery normally, being careful to follow the manufacturer's instructions for current and voltage limits. It's as simple as that. The second battery supplies the voltage that tricks the charger into supplying the necessary current. After an hour or so, you can remove the second battery and continue charging. We tried it and it works. No matter how deep the discharge we applied, we were able to bring the battery back to a full state of charge using our cheap but trusty bulk charger. ​

Michael

 

[sheward]

I'll try it, Michael. I thought I had it going last night (trunk light came on - charger showing charge). Woke to find it quits after a few minutes. I swapped it out with another I had and all is good for now. Two different smart/float chargers wouldn't even get started. Even though the original was working fine, even under limited use service, I now believe it is older than I originally thought.

drew

 

[samiam44]

I can tell you it Works...@!

 

[sheward]

I should have disconnected the battery from the car on the first attempts. Followed your tip and the battery is up to 12.2 volts after 5 or 6 hours. Interesting. I've never discharged a battery so completely before.

drew

 

[sheward]

The battery has been on the charger for a couple of weeks now and it's holding 13.8 volts. Time to put it back in the car and see if I did any damage.

drew

 

[Glen]

Hopefully you dodged the battery bullet. Good luck!

 

[Roma_500E]

The battery has been on the charger for a couple of weeks now and it's holding 13.8 volts. Time to put it back in the car and see if I did any damage.

drew

Usually it is a day or two max ? Or you got some different charger/strategy ?

 

[sheward]

The battery has been on a trickle/float charger while I was away for the holidays. I temporarily installed a spare I have that doesn't fit into the hold down plates.

drew