Battery for 3 Liter Mercedes - Cold Cranking Amps, Kilowatt Hours- Capacity Questions

[gunDriller]

I am trying to resurrect a 1984 300D Mercedes. Near-perfect condition except for the battery and the cam-shaft. I know the previous owner because he works at a hardware store I go to all the time. After admiring it for about a year, I was 'on the spot' when it broke. I bought it but now it has sat for a year.


I found a "Euro Battery", it's one they have at junkyards ("auto recyclers" :) ) that is longer & wider than a typical American car battery.

Took it home, long story short it had a bad cell. Hopefully getting my money back.


==> And the new battery costs, $200.


The saleman at the new battery store told me that putting in a different 12 Volt battery could harm the car.

I was wondering how much truth there is in this, or if it's "just another bagel-ly sales tactic."


I was thinking about trying out using a $40 higher capacity used battery from the junkyard. ($30 + core charge)


Specs for the official replacement battery -

12+ Volts (12.6 to 12.8 seems typical)
100 Amp Hour
Cold Cranking Amps 730 Amps @ 0 degrees F
Cranking Amps 910 Amps @ 32 degrees F


Does anybody know - how close does the battery need to be to perform normally in the old Mercedes ?

It's 3 liter, 5 cylinder, diesel.

[ximmy]

funny, I've been studying batteries for my solar set up... Learning waaay more than I wanted to know.

Those specs are standard auto battery replacement, others please chime in? Zap?
Specs for the official replacement battery -

12+ Volts (12.6 to 12.8 seems typical) (12.6-12.8 is a fully charged normal 12v battery)
100 Amp Hour (Doesn't matter too much for a car unless you have a cranking stereo at a burger joint)
Cold Cranking Amps 730 Amps @ 0 degrees F (700 cca or more [800-1000] is fine)
Cranking Amps 910 Amps @ 32 degrees F (Great! It starts in the snow)

[Hitch]

The saleman at the new battery store told me that putting in a different 12 Volt battery could harm the car.

Did the salesman go into specifics? Did he say exactly how could a different 12 volt battery damage the car?

If the battery was a different voltage, I could see maybe damaging the electronics, but the voltage specs you posted show just a normal battery. Even the difference of a wet-cell, gell, or agm wouldn't matter, all you could possibly do would be damage the battery, not the car.

[palani]

The car is already broken. You can't break it further. Go ahead and try things.

[Neuro]

A different 12 Volt battery can't damage the car, salesman was schooled in new math probably, all 12 V batteries are not created equal...

[govcheetos]

Congrats on the 300D, I almost bought one myself a few months ago.

Sales guy is full of it. I went to the Interstate batteries site and they say cold cranking amps for a 300d MB is 720.

In my opinion there is no substitute for cranking amps especially with a diesel. I run an Interstate MTP78DT in everything I own(2 in my diesel truck) even the stuff that could do with far less cranking amps. In my boats I run dual 1000 cranking amp Interstate marine batteries. The MTP78DT puts out 1000 cranking amps and has an 85 month warranty. Also be sure the alternator is putting off the correct voltage, 13.5-14.5 with the engine running and the accessories turned off. Go on their website and buy the biggest cranking amp battery that will fit in your MB.

[gunDriller]

Thanks Everybody !

turns out the diagnosis was incorrect. looks like the camshaft is working.

looks like the only problem is the battery. it is not chargeable, it is DEAD.


long story short there's a fair chance the car will run when it gets a new battery.


i'm sitting here checking my American Express waiting for the credit to show up for the battery i returned.

i just have to get a beefy battery that takes and holds a charge.


i will flip out and do my end-zone dance if it really is that is all it needed. :)

[govcheetos]

Gundriller, any news on your Mercedes?

[gunDriller]

Gundriller, any news on your Mercedes?

yeah ... as it turned out, the cam was broken.

the neighbor took off the cover over the cam, while i watched & learned.

now just need to save the $ for the tow & the cam work. probably cost about $500 to $700.

in case it needs more, e.g. a new engine, i have another 300D with a rusted out body that could contribute the engine.

[govcheetos]

Cool, good to have a donor vehicle for spares. Especially for an older model MB.

I think Ponce should do the same with his Toyota.