enjracing

My car was not driven for about 6 weeks other than 2 start-ups where I let it idle for about 5-10 minutes each time. I did not remember to put it on the charger during those 6 weeks, stupidly. When I did finally drive the car, it started up normally (the cranking power from the battery was normal), and ran as it always has. A minute or two after start-up the SRS light popped-up as well as a message regarding that. I then got to the gym 5 minutes later and when I got back into the car to go home, the CEL then came on, so then I had both lights showing. No battery or charging-system light was nor is now on. I then put the car on my charger and it read only 1 bar of 4 as far as battery charge percentage, so roughly 20% charged. I allowed it to fully charge and then drove the car, hoping that the SRS and CEL lights may clear on their own, but no luck. I then bought a scan tool to clear the codes, but no luck there either. The car runs normally and seems to have all of its normal power (JB4 map 3 tune), but I am noticing one very odd thing happening (actually, NOT happening)....on cold-start, the car immediately goes to idle RPM as soon as it fires, and does not do the normal cold-start "choke" fire-up where it jumps to 1500'ish rpm and then slowly comes down to idle rpm within 30 or so seconds. That is extremely odd. The scan tool did not give me any codes regarding the battery nor the charging/electrical system, only a P00A8 and P00A7 code to do with the fuel system, but that code has been throwing for ages on my JB4 app with no issues, so I do not think it's related to what I'm now experiencing, and clearly has nothing to do with the SRS light. The scanner did pick up a B0090 code, which was for the SRS. As these cars are so battery dependent and low-output can result in codes being thrown. do you think that all of these issues are stemming from the battery, especially as I have never had these lights come on before I let the car sit for 6 weeks without being on a trickle? I've now charged it multiple time on my MB charger and it shows that it fully charges, but as soon as I drive it and pull back into the garage and put it on the charger, the charger reads only 50% charge. Any thoughts?

G. P

I have seen some odd issues with the electric distribution control unit, couple of time. Try to disconnect the positive lead from the battery for about 30 min, so all controllers loose power and reset. Reconnect, and see if problems solved. You may need to read/clear the prior OBDII errors as well.
Hope this will do it

enjracing

Thanks. Yea, I have been wondering about doing just that. It seems like a logical thing to try.

G. P

BTW, if your ECU is tuned. Put it back to stock and then do the battery disconnect. Some tuners change some OS info and when you regain power and the rest of the CANBUS items come to live, they may not "like" the ECU changes and act on it. If everything come back OK in ECU stock mode, you can then put back the tune. (I got this reading an AMG tuner blog some time ago)

enjracing

luckily, i have the JB4 piggy back tune, so all good.

have you done this battery disconnect/reset on your car? anything odd happen after?

G. P

Sure, several times. Nothing will happen. Just connect the battery back, wait a minute or 2 and start the car. Just clear any error codes after that, because some of them will not automatically go away.

enjracing

awesome, i'll go do it now......

G. P

I hope this will solve the issue. Let me know

enjracing

bummer.....no change, i think the battery is toast. i'll do the 1-week trickle as directed by stenzel, but i may be buying a new 1,000 dollar battery. uuuuggggg.

G. P

Sorry to hear that.

enjracing

me too, but thanks for the help!

Stenzel-Germany

Hi,


Do not give up. All is not lost yet. :-) I still have hope....

When you start the car or drive it is quite normal that the charger no longer shows "full". The GT also has charging management that initially discharges the battery to 80% and keeps it there. Basically a very, very small hybrid.

The aim here is to save a few ml of petrol (Co2).

The battery is only charged to a maximum of 100% when there is excess kinetic energy (e.g. braking, zero load, cruise control). From 100% to 80% the alternator is then completely off again and therefore does not consume any power.


Kind regards.

Stenzel

W205C43PFL

Interesting information thank you

enjracing

Excellent info, Stenzel, as always. Thank you. I will keep it on the charger and see if it can be brought back to life.

MBNRG

Give the Trickle Trial at least 2-3 Weeks - allegedly, i believe there is *still* a severe shortage of OEM Lithium batteries, with many saying no one has stock.

If unable to resurrect the dead OEM battery, another option is to buy an AGM battery, and have BenzNinja code out all the SAM/module requests resulting in error codes, etc.

Stenzel-Germany

To make it complete, from PM.

[/QUOTE]

Oh wow, thanks for the picture. I had the positive in the correct spot, but had the negative going directly to the battery post/terminal. As soon as I switched it to the correct negative connection point, the charger went from showing full charge to only 1/4. Now it is at 3/4 (in 15 minutes or so). I hope this helps deliver more charge to the battery now. I

Interestingly, now that the negative connection is in the correct spot, I only had to hold the reset button for 3 seconds before the light flashed.

How many days should I keep it on the charger without driving the car (I don't need to drive it)?

[/QUOTE]


Hi,

There is a German saying:
Once you do it right, suddenly it works. :-) :-) :-)

That was exactly my experience too. I also had a dead battery. Different connection, (the charging socket, left in the trunk, also works) other chargers, (I still had 12 of them in 3 types in very good quality) no "RESET Button" and nothing worked.
Only the original MB Charger “awakened” the battery.

Don't know exactly what's happening there. The battery definitely has a LIN bus!!! and can probably also “communicate” with the front SAM.
I SUSPECT that the electronics (front SAM) recognize the charging process through the external sensors on the battery and send this to the battery electronics.
Apparently only than, the battery electronics (there's a lot in there) "reacts" to this.
Upper statement are not scientifically tested findings. More like assumptions based on logic and personal experience.

You can leave the charger on the battery as long as you want. Nothing can happen.
In your specific case, I would charge continuously for a week.
Then another 2-3 weeks. This time no longer necessarily has to be in one go.
IMPORTANT: Just always press the reset button when reconnecting.

For understanding: It's not about charging the battery. Only for charging, 12 hours would be enough.
This is primarily about balancing the individual cells with each other. This can take a very long time.

The cells are all connected in series. It's like a chain. It is only as strong as its weakest link.
Balancing means: Making all “chain links” equally again.

Why does this suddenly happen?
The problem is that the weakest cell is unfortunately automatically put under the greatest strain. This is a self-reinforcing process.

That's why I recommend connecting the charger for a few days every 4 weeks.
If you don't drive for a longer time, this is definitely necessary.
But even if you use the GT daily. Must see this as maintenance.



(Minus = Ground = Black)

For charging/balancing only connect like this. (the charging socket, left in the trunk, also works)
Always push "Reset" Button for 5 sec. (Until a yellow LED lights up)

ABSOLUTELY connect like this even with a “jump start”. Not directly on the battery as usual.


Best regards

Stenzel