bernard farquar

The battery that you have to fill with acid is going to last much longer. Once a battery is activated (filled with acid) it begins to age, there is a natural self-discharge and the cells begin to get a layer of sulfation as the internal charge gets lower through time. a battery that is stored on the shelf dry (without acid) does not go through these chemical changes.

If you buy a battery that has been activated, it could be six months, or a year old, sitting in the warehouse, then the store's shelves until you bought it. You are giving away a fair sized chunk of it's lifespan, for the convenience of not having to pour a few ounces of liquid from one container into another.

vettdvr

What I have found on relays in PCM's and other on board computers is most of the time the relay mechanically works. But if you check close you see the contacts are riveted to the plastic material. This heating and cooling on the primary contact results in loss of pressure on the main contact that opens and closes. Then it fails to function but when you check it hasn't burned out and open and closed may work sometimes but the frequency of poor operation continues until current doesn't flow through the primary contacts.

Celicasaur

Can anybody confirm if the relay part number is :
A 002 542 38 19 / V23132-A2001-X14 PA

Celicasaur

I just did some tests.

So when car is dead/off the front battery is at 12.6 and the rear is at 5.4 (poor thing, lol. FYI it's a new battery, like 2 months old or 6 weeks)

When jumpstarted and running by itself, rear battery is up to 13.8 but the front is still at 12.6 and refuses to budge.

Red battery message is up.

My guess is it sounds like the front relay, right? What are thoughts on this?

novae500

If the front battery is still the same voltage, could be a bad isolator relay (which i had to replace). And def get a new rear battery, covered under warranty.

Celicasaur

When fitting the relay I need to remove the rear battery ground, for safety, right?

I'll have a go at changing it this week.

ASHBURY04

Thanks

konigstiger

Attachment covers dual battery system explaining part function i.e.: relay, BCM, etc.

Celicasaur

You can always count on Konig for useful info

Cheers man.

FYI I ordered an aux battery relay today. Should be with me by Thursday for fitting.

Celicasaur

Update:

So I fitted a new aux battery relay and it has solved the problem - no more red error message, yay!

My main battery got down to 2.2 volts after having sat for 4 days straight. It took a good 10 minutes just to get it to struggle n start and then it took a further 40 minutes to 'fully' charge the battery ie, get rid of the convenience functions message. Worth noting that unlike before, once the engine was running, the aux battery was now showing 14+ volts, wheras when I jump started it the other day and the main battery was showing 14+ volts, the aux battery didn't move from 12.6.

I've been driving it a fair bit this evening and the main battery is kinda at 12.2 or 12.3 volts, so perhaps the massive draining has compromised it's life a little bit, who knows. I'll give it a few days to monitor how it fares and then take it from there.

Bottom line - problem solved. Thank you MB World

vettdvr

Well done on the solving. 12.2 probably means your main battery is damaged and has lost some reserve cranking capacity. It may last for a while but in very cold winters it might be an issue. I have had one drop to 11.8 and still start but it wasn't pleasant.

novae500

good to see that the battery relay was the solution to the red battery code. I would replace the rear since it got down to 2.2v...Esp if you have winter weather where you are. Also good to have a battery charger (ctek) handy to charge the car when you dont drive it for awhile.

Guess the cars are at the age that these parts are worn out with all the electronic modules on these cars. Never ran into this with acura/lexus/toy/honda.

Celicasaur

Thanks guys

I checked the battery voltage an hour ago and it was showing 12.7 or 12.9 so it's getting higher I'll give it the benefit of the doubt for the next few days and monitor it's behaviour.

As for the car on the whole, yeah, it's such a shame that it looks like with these cars, it'll be the electrical components that die out quicker than the core mechanics of the engine/tranny. It's a very fussy car, I must say. But....for that 5 minutes when it finally does work properly...it's one hell of an epic car with the power, looks and interior to match even some of the best that today has to offer. Long live W211 AMG.

jjleonard

Guys its Aug 24 2012 - just had to replace my front battery - my car is a 2003 E500 - manufactured in late summer 2002 - This was the "original" battery - had 34 02 which I interpret means manufactured 34th week of 2002 - ten years is above & beyond expectations and I had replaced the battery in the trunk last April - again the original battery - just short of 9 years. As a result of the longevity, I decided to purchased another MB battery - don't know if I get a repeat, but for $140 plus tax wasn't worth the time for me personally for procuring, filling, charging, etc that came with some of the batteries and Interstate didn't want to warrant the battery, because they didn't have it as an "approved" application and it was $119 - thanks to all who contributed to this thread - oh, followed Vette's procedure for changeout with no problems - just as noted had to reset/synchronize the clock, date, windows, sunroof.

jjleonard

Forgot to mention, the changeout took me about 40 minutes - but I have a bad back which slows more to a crawl - a healthy guy could do easily in half this time. Asked the MB dealership (in Mytle Beach, SC) and they wanted to charge $105 (1hr of shop time) for this job which is ridiculous and told them as such . .

selen1um

Ugh I get the same message here is the video of what's happening when I start the car https://www.youtube.com/watch?v=NbBD...yer_detailpage

I replaced the AUX battery, I replaced the CPS and the car still has same message. What should I try to replace next?

jjleonard

Replaced the 2 batteries in a little over a year from each other. First, the main battery in the trunk was bad and I would receive the malfunction code "Battery Protection Conven Functions Temporarily Unavailable", however did not receive the other malfunction code your getting in conjunction. The red malfunction picture with the picture of a battery "visit workshop" i got only with the front battery as i can recall - i would start by checking voltage of main battery and go from there. hope this helps

jjleonard

Looking at the video again - seems the Visit workshop is probably not being counted as a malfunction code and seems you've got possibly something going on possibly with one of your headlight lamps (as your 2nd malfunction) - again, though they could possibly be interconnected if you have low voltage but worth checking your lights as well.

Celicasaur

Guy I need help please

So a couple months back I changed the aux battery relay and got rid of the red message etc and all was well. Then a few weeks after, my car died (electrically) again. Main battery had been drained stone dead to 3volts (this after driving it every day that week with no sign of battery power issues at all). Upon inspection, and a jump start, the car fires up, but the little battery doesn't show ~14v like the main battery does, it still shows 12.6 (lol it's been sat dormant for a few weeks now and it's still 12.6!!). I tried another aux battery relay, but when the car started, it still showed 12.6v, so I didn't bother running the car much longer as it's clear there is another fault.

Does this make sense to anybody? When the car is jumpstarted now, the main battery shows ~14v, but the little one shows 12.6 on my 'new' relay and on another one. HELP!

vettdvr

It is still possible the main bat. is internally shorting.

Celicasaur

I'm not really sure man, but all I know (and this from previous experience) is that the little battery is meant to show normal voltage once the car is running. If not, it causes a drain on the big one and causes it to go flat. Whatever it is, it's related to the small one I think...?

Diesel Benz

You only measured (at least only reported) the main battery voltage when the engine was running. Did you measure the main battery after switching the engine of (after a while)?

The isolation relay is not always closed when the engine is running. 12.6 V is not that bad for the small battery when it is not charged.

Celicasaur

To be fair, no I didn't....however, the car was happy to perform all the usual lock/unlock, start/stop, start/stop operations after being jumpstarted. Only problem is, after a few hours, it drains fast to the point that if I simply hit the button to unlock it, that's too much for it to handle and it just goes flat again. I'm not getting the red battery/workshop message as I had in August though.

Yeah the small battery seems good at 12.6v. Only problem is that it doesn't jump up to 14v like normal when the engine is running. Apparently the 'new' relay I tried has been tested and works fine, but I don't know how to check this with my voltmeter. I'm guessing I need to connect the pos and neg terminals to a battery and touch the voltmeter terminals on it, but doesn't this one need to be connected to the loom/ecu to operate, or...?

spinn

My main battery at standing shows only about 12.0V; at running about 14.0. I don't get any message that some convenience consumer devices will be shutdown; I do have the red visit workshop battery light present.

Wondering if it's just my main going bad or my aux; I'm thinking it's the main at this point...after jumping it 4 times in the past year. I had checked the aux battery disconnected and was getting readings all over the place; thinking maybe my multimeter battery needed changing.

vettdvr

It is still possible the main bat. is internally shorting