Quick Battery Question - Please

[lindajane]

Hi...

Well, my battery has died a couple of times, but I've left my lights
on all night. But today I went out, and It won't start.
I have not left any lights on, it's just dead.
The light that usually lights up before you turn the key all the
way to the right dimly blinks. All the other lights work.
I'm thinking it's finally time to get a new battery (?).
If I call triple AAA to try to start it, Should I do it today?...or
if I wait till tomorrow, will it just get harder and harder to
charge?
The last time It charged, he just barely got it to...
Just basically wondering if I can wait till tomorrow to try
and jump start.
Also, If any type of battery I should get or avoid pops into
anyones head, I'd appreciate the info as well.
Thanks!
Lindajane

[sixto]

What car?

You have to figure out what happened to the battery. How are the alternator and voltage regulator?

Sixto
98 E320s sedan and wagon

[Mxfrank]

Once the battery is flat dead, it's unlikely that a charge will hold for long. If you have AAA, they can deliver a new battery.

[rocky raccoon]

What kinda car LJ? That annoying buzzer doesn't faze you? Since you are not self-disciplined enough to turn your headlights out, an inexpensive jumpstarter box may be handy for you to buy and keep around. You can get one that will do the job for less than $100 unless you are driving a diesel.

Regarding your battery, it is probably toast and as colder weather approaches will get worse.

[lindajane]

It's a Diesel, 300D, 1984, and the lights weren't on.
It makes a buzzing sound when I try to turn over the engine,
but not the same sound as when the lights are left on.
There is a tunnel i have to drive through during the day,
and you're supposed to turn your lights on, it's easy to
forget to turn them off when you get through during
the day...

[lindajane]

Thanks Sixto...

But not knowing much about these cars, other than constantly
changing the fuel filter, I have no idea how to check the
alternator and voltage regulator. I've read various things about
getting a good batter for the diesels...a Bosch or Varta, prob.
pricey. Do you happen to know if triple aaa would supply
a decent battery?....thanks

[SD Blue]

To check the Alternator and Regulator, you would need a basic digital multimeter. I believe Lowe's, etc... sell them for about $30.

Place the meter in DC volts mode and connect to the battery terminals while the engine is running. You should see something better than 13 Vdc but not over 15Vdc.

Then place the meter in AC volts mode and connect to the battery. You should see something less than 100mV AC.

Too low DC volts is usually a regulator failure. Too high DC volts and/or AC volts is usually a sign of a failed rectifier diode in the Alternator.

Most auto parts places will do this check for free. They usually have a tester that checks this with a simple switch.

Once a starting battery has been drained flat, it usually is not long for this world. From what different mechanics tell me, the AGM (glass mat) batteries are the worst for not taking a charge after going flat.

[OM617YOTA]

Auto batteries don't handle being run down dead flat at all. Doing so causes permanent damage that can never be repaired.

At this point, I would go ahead and give it a good charge up. I would NOT jump start it and then depend on your charging system to charge the battery. With the mediocre stock alternator on these vehicles, that could take several hours at highway speeds to do, and you may damage your alternator in the process. They're only designed for max output for a short period of time, then just handling the car's electrical loads.

After the battery's charged, pull out a multimeter and do the usual checks. It should hold 12.7ish volts overnight. I've seen batteries reading 12.5v after sitting overnight still start the car in the morning, but they were on the way out for sure. Don't check straight off the charger, it'll show 13+. Engine running, it should be 13.5v minimum, with accessories on. Less than that means you're not charging, or are drawing more power than the alternator is producing.

How old is the battery, and what's your driving cycle like? If you deeply discharge, then start, drive ten minutes, shut down, repeat repeat repeat, you may never have a fully charged battery.

For replacement, I have a Duracell from Batteries Plus in my specialized application, which is the only 617 battery I have experience with, but I can recommend it. It has started my 617 just fine down to waaaayyyyyyyyy colder temps than you'll ever see in the Bay Area. I have read that some people have gotten surprisingly good pricing and service from an MBZ dealer - comparable to auto store pricing. Or slightly more for MUCH better quality.

Edit: I would get that battery charged ASAP. It sounds like it's probably toast already, but the longer it sits discharged, the more damage is done.

[tyl604]

You should buy a battery charger; Sears has a good one. In any event you should own one. I have had a Sears for over forty years and it has never failed me. I also use Sears DieHard batteries and have always been happy with them.

This thread might help: http://www.peachparts.com/shopforum/tools-tricks-supplies/372473-shopping-battery-charger.html

[torsionbar]

x2 on get yourself a charger. The "Battery Tender" brand is popular with enthusiasts and works very well. Keep in mind that you'll need a higher amperage model to charge up a dead battery, while the low amperage models are more for maintaining an already healthy battery to prevent it from going dead.

Pep Boys has a good deal right now, $115 for Bosch Premium. This is the size for my w210, your w123 may take a different size, I'm not sure.

https://www.pepboys.com/parts/batteries_accessories/automotive_batteries/00087/1998/MERCEDES%2520BENZ/E300TD/0/6-2996%25203.0L%2520Dsl

[CDTurbo001]

After a battery is run stone dead the first time it's anybody's guess whether it's worth its salt again or not. With any age on it, run down several times, or both, and it's almost certainly not dependable. East Penn is a good brand and makes Napa, Deka, etc. My 300CD has an interstate in it that's a couple years old and, even having been run half down several times, is still starting the car - but I still carry jumper cables and it hasn't sat more than 2 days in a row since I got it.

The best remedy for leaving the headlights on is, simply, have the presence of mind to check every time you get home. Any vehicle I get out of, I do a quick check of all lights and accessories and leave as little on as is practical. Keeps something from getting left on, and gives the charging system a second of reprieve before being shut off. I've yet to have a battery last less than 4 years, most of the time more.

And besides, I usually turn around and look at my stylish ride as I walk away, anyway.

[ESchwab]

The first question when you have problems with a battery is: how old is it. If it has been in the car for seven years or longer, just buy a new one. Most of the time, that is all you need to do.

[tyl604]

I thought all MB's had a buzzer which went off if you turned off the engine and left the lights on??? My '81 300SD does.

[sixto]

The buzzer was disconnected by a P.O. or stopped working in my ‘83 SD resulting in the occasional drained battery. Maybe rewiring the fog lights to work without the headlights and with the high beams bypassed the buzzer trigger :/

Sixto
98 E320s sedan and wagon

[BillGrissom]

Once you get it started, drive to Autozone and have them run a free load test in the parking lot. If it shows bad, buy their "H8" size. I did that in my 1985 300D. It was $50 less and 10 lb lighter than the spec'ed "Frame 74" size. My son said Autozone even showed that in their computer when he had to replace the battery in our 1984 300D. I always buy the gold model for the better warranty and have replaced ~3 in various vehicles under full warranty. A strange lot of "bad batteries" lately or perhaps that is common today (1 wouldn't hold charge after just 6 months). Other auto parts offer similar "free test". They can also test your alternator. For future, buy a cigarette lighter voltmeter (Amazon, ebay). You should see 12.6 V with engine off and ~14 V when driving, if the alternator is fine.