Hi Guys,

So my 300SD has been sitting for quite some time. The battery has been charged and discharged a bunch of times.

The battery appears to be from 2008. It really has not seen a lot of miles since then. Maybe 5K if that.

I had the car parked at a relatives' house for a while with battery tender on it. But it got unplugged at some point in time.

My 2A/10A tender won't charge it back up. It reports a "short." So I threw on my 2/10/50A charger (transformer+rectifier type) , let it charge and got the car started and home.

I threw on my 2/10A tender but it would not maintain the battery. The battery was probably still pretty low and the <1 mile trip didnt' help.

Fast forward to yesterday:

I have a 2/10/50A Sears charger when I plug this guy in on the 2A setting. My ammeter reports 10A is being used by the battery. There is some gassing sounds coming from the battery top area. After say 20 minutes of this the battery sits at 8.5V or so. I was not so cautious at my relative's house. I didn't hear the gassing noises if they even were there..

I disconnected it, unsure of if I should let it continue or not.

This morning the battery appears to only have 4.5V left in it.

What do you guys think?

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Cruise Control not working? Send me PM or email (jamesdean59@gmail.com). I might be able to help out.
Check here for compatibility, diagnostics, and availability!

(4/11/2020: Hi Everyone! I am still taking orders and replying to emails/PMs/etc, I appreciate your patience in these crazy times. Stay safe and healthy!)


82 300SD 145k
89 420SEL 210k
89 560SEL 118k
90 300SE 262k RIP 5/25/2010
90 560SEL 154k
91 300D 2.5 Turbo. 241k
93 190E 3.0 235k
93 300E 195k

That battery is ANCIENT, and imo after hearing what you described in your post, the battery is dangerous and worthless.

Just trash it and get a new one. If that thing leaks in the car, it's going to eat away at all of the metal.

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1998 Ford Escort ZX2 5 speed - 279,000 miles My Daily

1992 Mercedes 300D 2.5 202,000 - Pure junk
2000 Mercedes E320 Black - 136,000 miles - Needs repair

Don't forget to grease the screw and threads on the spring compressor.

Buy a new battery?

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TC
Current stable:
- 2004 Mazda RALLYWANKEL
- 2007 Saturn sky redline
- 2004 Explorer...under surgery.

Past: 135i, GTI, 300E, 300SD, 300SD, Stealth

I admit I read to this point and then barely skimmed the rest of your post.

Your battery is toast. At this age it would be done for, even had it been treated perfectly, which it hasn't been.

Batteries are like rubber bits and steel exhaust systems, they continue to age no matter the use/miles.

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617 swapped Toyota Pickup, 22-24 MPG, 50k miles on swap

That gassing sound plus an open spark will usually lead to an explosion. Do yourself a favor and buy a new battery.

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96 E300d

A reconditioned battery from Interstate will set you back only about $45 or so.

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14 E250 Bluetec 4Matic "Sinclair", Palladium Silver on Black, 154k miles
06 E320 CDI "Rutherford", Black on Tan, 172k mi, Stage 1 tune, tuned TCU
91 300D "Otis", Smoke Silver on Tan, 142k mi, wastegate conversion, ALDA delete

19 Honda CR-V EX 61k mi
Fourteen other MB's owned and sold
1961 Very Tolerant Wife

Once the plates get sulfated, the battery will not hold a charge. There is a liquid solution that will break the electolytes away from the plates (look for Charge Battery Power), but in my experience it only works for a while. And, since there is cost associated with the purchase and time in the process of recovery, a typical 12v battery isn't worth the effort.

I have been very successful prolonging the life of expensive 6v and 24v batteries like Trojans, bit they're so expensive it was more cost effective than replacement.

Sent from my XT1585 using Tapatalk

Stick a fork in it... Battery is done. The hissing you're hearing is hydrogen gas escaping, hope there aren't any sparks nearby, that's how batteries turn into bombs.

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Current stable:
1995 E320 149K (Nancy)
1983 500SL 120K (SLoL)

Black Sheep:
1985 524TD 167K (TotalDumpster™)

Gone but not forgotten:
1986 300SDL (RIP)
1991 350SD
1991 560SEL
1990 560SEL
1986 500SEL Euro (Rusted to nothing at 47K!)

I JUST went through the same thing! I bought my battery 7 years ago as a reconditioned unit and it was making sizzling noises for a while even hours after the car was driven and constantly corroding the terminals. Then it suddenly went dead and wouldn't take a charge.

So, yesterday I went to the Mercedes dealer and bought a new battery. The 004 541 03 01 part number EPC shows is discontinued as it's the old lead acid technology. The new AGM (absorbent glass mat) technology is replacing it. The new part number is 000 982 33 08.

The dealer had one in stock and the price was $167 but after my 10% MBCA discount it was $150. That's pretty reasonable considering all the other brands are in the $150-$200+ price range. Now it's all cozy and snug in its new home.

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DON'T MESS WITH MY MERCEDES!


1967 W110 Universal Wagon, Euro, Turbo Diesel, Tail Fins, 4 Speed Manual Column Shift, A/C
1980 W116 300SD Turbo Diesel, DB479 Walnut Brown, Sunroof, Highly Optioned, 350,000+ Miles

Thats what I was leaning toward anyway just based on age. I figured I would post up and see what folks had to say lol.

Poor battery, didnt really do much its whole life!

I'll have to look in a MB AGM battery. All the parts store around me want 180-200 for their AGM battery. If the dealership can do better...

__________________
Cruise Control not working? Send me PM or email (jamesdean59@gmail.com). I might be able to help out.
Check here for compatibility, diagnostics, and availability!

(4/11/2020: Hi Everyone! I am still taking orders and replying to emails/PMs/etc, I appreciate your patience in these crazy times. Stay safe and healthy!)


82 300SD 145k
89 420SEL 210k
89 560SEL 118k
90 300SE 262k RIP 5/25/2010
90 560SEL 154k
91 300D 2.5 Turbo. 241k
93 190E 3.0 235k
93 300E 195k

To last the maximum reasonably expected time. In my opinion and also experience the battery should be kept in reasonable normal regular almost daily service. Todays batteries do not even like to be deeply discharged as this alone seems to shorten their expected life.

I have always suspected that a true battery charger might evolve that duplicates the service seen in a car. It would be expensive though as it would have to duplicate the heavy load the battery normally sees when the starter is used and a normal recharge for the lost amperage. The frequency might need to be three times a week.

It has safety issues but at the same time for a battery not in service. You need a rubber apron, gloves and a face shield. If the acid is then drained out and stored properly. The battery can sit for years. Then when the original acid is replaced the battery has lost nothing in general in storage. In fact you should be able to add the storage time to the normal expected lifespan. If batteries of the lead/acid type become really expensive some may use this approach. The United states navy uses it and it works well.

Also when I buy a battery off of a dispensing shelf. The ones at the back usually have a newer date of manufacturer. They ship them wet and you should see a label that is basically. Best sold by a certain date. The longer term dated ones are usually sitting out front on a dispensing shelf while charged with acid in them are not the best. Years ago during the time they were shipped dry to the retailers this was not an issue.

A guy on Cummins forum runs his house on batteries and swears that he gets 10 yrs of service out of batteries by giving htem a monthly "balancing" charge.

The last time I looked at AGM batteries, they were more expensive than regular lead batteries, had fewer CCA and a shorter warranty. Old technology cars don't need new expensive, lesser performance batteries.

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85SD 240K & stopped counting painted, putting bac together. 84SD 180,000. sold to a neighbor and member here but I forget his handle. The 84 is much improved from when I had it. 85TD beginning to repair to DD status. Lots of stuff to do.

Yes I agree the battery is toast. I too am having problems with batteries lately as seems the smaller the battery like in motorcycles and kids toys the shorter the life of the battery. If they sit with out use any battery will go dead with in a yr. probably. I have read where a lot of people claim they will bring it back to life by putting epsom salt in it well I have tried on 2 batteries and it did not work. My local boneyard will sell a reconditioned battery for $35 with old core I just got one of them will see how long it lasts.

He is correct, I do the same thing and the lead acid house batteries are pushing 15 years old at this point. Take good care of a lead acid battery and they last a LONG time. Once a month seems excessive, though. I do it every 3 or 4.
Cars really trash batteries, they live in harsh environments, heat, cold, heavy loads, etc. 10 years is a good run for a car battery.

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1984 300TD -- summer daily driver
Many others that aren't Mercedes...

Places that sell new so called seconds have become more common. Possibly because of the ever increasing costs. These are new batteries and if one of that type of place has a good reputation in your area. They usually are reasonable in cost and many people use them.


An actual so called reconditioned battery is a crap shoot. My guess is that an auto wrecker would just load test batteries arriving in junk cars and perhaps just sell those that still test okay.