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Sam's Club is out of stock on the Duracell ETX14, so I decided to desulfate the AUX battery while waiting for stock. After removing it and plugging it up to the battery charger, it instantly read "Float".... So, I assume the charge is not a problem?
The negative terminal and connector does show slight -- and I mean slight -- corrosion. So I scrubbed the post and connector with baking soda, and reinstalled the battery.
Next, I placed the main battery on the charger, and it showed the typical 25% charge for this battery not used for a week or more. I'll give it 2-3 hours charge until it reads FLO, then clear the error message and see where we go from there.
2016 E350 4Matic wagon, 2019 Ford Expedition, 2019 Chevy Bolt EV
FWIW, the original Mercedes aux AGM has a vent hose... an AGM battery shouldn't leak under normal conditions, but they CAN outgas and/or leak if they are, for instance, overcharged. Another name for an AGM is a VRLA, or Valve Regulated Lead Acid. I've not found too many (any?) generic AGMs that have a vent hose fitting.
I just replaced mine last week with a Duralast Platinum AGM Auxiliary Battery from Autozone. It was the closest and easiest to acquire. It does have the vent port.
Well, the AUX Battery Malfunction light is back. So it's time to buy a new one. I think I'll try the Duracell ETX14.
Do you have a Xentry or similar MB capable scanner ?
There is a value I am curious for triggering the AUX battery mailfunction.
The value is read-able at Rear SAM live data and it is called Battery Internal Resistance.
I wonder what value is the threshold to trigger the DTC ?
FWIW, the original Mercedes aux AGM has a vent hose... an AGM battery shouldn't leak under normal conditions, but they CAN outgas and/or leak if they are, for instance, overcharged. Another name for an AGM is a VRLA, or Valve Regulated Lead Acid. I've not found too many (any?) generic AGMs that have a vent hose fitting.
I think this difference is called for the application type.
VRLA are not expected to ever off gas at all but a valve is provided to prevent explosion.
Our AGM are openly vented through a port that is routed to open air.
Normally AUX is strictly on standby except during a 2 to 4 second cranking period.
When things go wrong with voltage control, AUX automatically gets drained then punched back with unlimited current. That can generates a lot of heat.
> The R-SAM calculates an "intermal equivalent resistor" by measuring the voltage drop under load. When the drop is too high the battery is no longer viable because of heat losse.
> To minimize internal resistance:
-- do a cell balance charge cycle (out of circuit)
-- clean the GND path for a good measurements
(desulfating is not applicable to AGM)
> AUX issues originate from the main circuit : ALT + GND + AGM.
Do you have a Xentry or similar MB capable scanner ?
There is a value I am curious for triggering the AUX battery mailfunction.
The value is read-able at Rear SAM live data and it is called Battery Internal Resistance.
I wonder what value is the threshold to trigger the DTC ?
Thanks
I have an iCarsoft V3 for Mercedes. The only errors I get are Gateway types...
I can clear them easily enough, but it doesn't seem to have any affect on the "AUX Battery Malfunction" message. So, I don't think this message throws any codes.
> The R-SAM calculates an "intermal equivalent resistor" by measuring the voltage drop under load. When the drop is too high the battery is no longer viable because of heat losse.
> To minimize internal resistance:
-- do a cell balance charge cycle (out of circuit)
-- clean the GND path for a good measurements
(desulfating is not applicable to AGM)
> AUX issues originate from the main circuit : ALT + GND + AGM.
By a Cell-Balance charge out of circuit, do you mean I should remove the main battery and then recharge it? Until now, I have always recharged the main battery while hooked up in the engine bay.
By a Cell-Balance charge out of circuit, do you mean I should remove the main battery and then recharge it?
Until now, I have always recharged the main battery while hooked up in the engine bay.
Yes, prevent the car from higher than 15Volts. Can it survive, for a while then leaky capacitor disease.
When charging any battery (MAIN; AUX) with a higher voltage 15.xV to balance cell voltage, you want the car not connected to preserve electronics from abnormal voltage levels AND make sure it's a vented AGM battery to release hydrogen. (Non vented AUX should not be used, some ppl do... good for them )
Balancing cells can help reduce the internalresistance if the battery was not too abused too long. Don't off gas lead-acid batteries too long with unnecessary higher charge voltage, trust CTEK.
To take battery out of circuit simply disconnect the (NEG)/GND side is enough - This process will get you a beneficial CAR REBOOT
> SIMPLY PUT:
If your battery has becomed a high maintenance item, there's a root cause doing its number on your dime.
BATTERY TROUBLES MEAN THERE'S AN ELECTRICAL SYSTEM ISSUE SOMEWHERE...
GND STRAP GREMLINS
ECU YOYO
ECO CYCLES
Last edited by CaliBenzDriver; Jan 4, 2024 at 04:44 AM.
Yes, prevent the car from higher than 15Volts. Can it survive, for a while then leaky capacitor disease.
When charging any battery (MAIN; AUX) with a higher voltage 15.xV to balance cell voltage, you want the car not connected to preserve electronics from abnormal voltage levels AND make sure it's a vented AGM battery to release hydrogen. (Non vented AUX should not be used, some ppl do... good for them )
Balancing cells can help reduce the internalresistance if the battery was not too abused too long. Don't off gas lead-acid batteries too long with unnecessary higher charge voltage, trust CTEK.
To take battery out of circuit simply disconnect the (NEG)/GND side is enough - This process will get you a beneficial CAR REBOOT
> SIMPLY PUT:
If your battery has becomed a high maintenance item, there's a root cause doing its number on your dime.
BATTERY TROUBLES MEAN THERE'S AN ELECTRICAL SYSTEM ISSUE SOMEWHERE...
I am very curious on icarsoft method naming of modules :
Is this N93 Gateway at Front SAM or the other gateway inside the cabin, for model with certain options, it is called N93/3 or something... if I remember correctly.
Any time I do not see MB official modules name from non-Xentry scanner, I kinda worry if the mentioned modules has a few variants...like N93 vs N93/3.
==============
DFWdude,
Why do you think the AUX Battery is the cause ?
I am very curious on icarsoft method naming of modules :
Is this N93 Gateway at Front SAM or the other gateway inside the cabin, for model with certain options, it is called N93/3 or something... if I remember correctly.
Any time I do not see MB official modules name from non-Xentry scanner, I kinda worry if the mentioned modules has a few variants...like N93 vs N93/3.
==============
DFWdude,
Why do you think the AUX Battery is the cause ?
You need a second GND Strap mounted high-up to stay dry/clean between (engine <-> chasis).
Here what my version looks like: secondary GND
My version is not the best possible! Others can do better given engine, supplies....
The best straps are the shortest, mine can be improved with a 3rd strap. All straps share the resistance to minimize drop voltage of high currents.
> Additional strap locations:
2x close by locations
between engine - chassis
big size nut
a nonessential nut (Not: strut mount!)
good chunky steel (not fake firewall skirt!)
this is to conduct part of 800Amps!!
Put in a 3rd strap is a perfectly good way to split dynamic current and reduce drop voltage spikes.
Aluminum is known to develop an insulating oxide unlike steel rust is a conductor. Meaning prefer connecting to steel parts... these mordern engine have no steel. This forces us to deploy multiple aluminum straps... Multiples are the best solution.
So, if I install a second ground strap like yours above, are you saying that will moderate (level out) the number of extreme resistance changes in the batteries... and will that in turn possibly minimize the AUX Battery message?
I don't have any electrical cord the gage thickness you show, so I would probably need adapt:
1) A power cord cable from an old PC, twisting all the internal leads together?
2) A heavy gage CAT5 cable (sheith 3/16" thick)
3) other, please suggest... thanks
yes, having a good main chassis strap will lower voltage ripples aka. gremlins.
CAT5 and 14AWG cable zero help here.
You need thick cable like the gauge used in "jumper cables". This is not to pass binary data but high amps under low resistance. Some ppl use welding cable know for low resistance.
For your AUX: check its GND connection is clean and not painted.
yes, having a good main chassis strap will lower voltage ripples aka. gremlins.
CAT5 and 14AWG cable zero help here.
You need thick cable like the gauge used in "jumper cables". This is not to pass binary data but high amps under low resistance. Some ppl use welding cable know for low resistance.
For your AUX: check its GND connection is clean and not painted.
I searched for Welding Cable at Lowe's and this is what came up. Will this cabling work?
What do you recommend for connectors at each end? I assume crimp connectors?
To answer your PM:
Here is what the link shows 4AWG Copper wire
We are talking cable the size of your pinky finger. If 4AWG is near pinky you're good.
Even if it is undersized, it's better than nothing so long you leave existing strap in place.
You can add multiples in parallel to lower resistance.
GND cable can not have issue with shorting to ground... it is GND itself.
The cable I have came with a crimped connector on one side and nothing the other so I simply wrapped it around target. I know it's not perfect but compared to original strap, my addition shines high and dry. No road spray, salt... nothing!
Crimp pliers that size cost a bundle not worth 2 crimps.
Last edited by CaliBenzDriver; Jan 6, 2024 at 09:59 PM.
We are talking cable the size of your pinky finger. If 4AWG is near pinky you're good.
Even if it is undersized, it's better than nothing so long you leave existing strap in place.
You can add multiples in parallel to lower resistance.
GND cable can not have issue with shorting to ground... it is GND itself.
The cable I have came with a crimped connector on one side and nothing the other so I simply wrapped it around target. I know it's not perfect but compared to original strap, my addition shines high and dry. No road spray, salt... nothing!
Crimp pliers that size cost a bundle not worth 2 crimps.
OK, I installed the second ground wire, (same configuration you used above, Post 49). I also removed the AUX battery ground on the back wall and roughed up the mating surfaces with a Dremel tool, and reinstalled the ground.
I've installed a trickle charger and maintainer on the main battery installed in the car. It ran for more than a day in charge mode, and hasn't gone to maintain, yet.
I still have the "Auxiliary Battery Malfunction" message. Any more suggestions?
OK, I installed the second ground wire, (same configuration you used above, Post 49). I also removed the AUX battery ground on the back wall and roughed up the mating surfaces with a Dremel tool, and reinstalled the ground.
I've installed a trickle charger and maintainer on the main battery installed in the car. It ran for more than a day in charge mode, and hasn't gone to maintain, yet.
I still have the "Auxiliary Battery Malfunction" message.
Any more suggestions?
Good to read you have made progress by eliminating known issues.
We're almost good....
Obvious first:
Did you do a REBOOT ?
Troubleshooting:
Did you scan the car for faults?
What's your AUX resting voltage ?
>> AUX resistance is ONLY tested while driving :
Take it out for one or two drive cycles.
This will let the R-SAM analyze AUX when it disconnects MAIN to read AUX under load.
This is tested when iCluster reads "13.0V" shortly after moving...
Last edited by CaliBenzDriver; Jan 11, 2024 at 06:38 PM.
Stubborn me decided I've had enough of this junk. So I drove to Batteries+, removed the AUX (OEM 2017) and had it tested... It showed only 1/2 charge and little potential. Proof enough for me, so I replaced the AUX battery with this one... Works like a champ now, both Brake-Hold function (desired) and ECO Stop-Start (blah) immediately work well...
$99 plus $8 tax. Fits the space, and has a vent hole, too. Same warranty as the domestically made units.
In October I got the Auxiliary Battery replacement warning on the instrument panel of my 2015 ML250 BlueTec. I ordered one from Amazon and put it in. $48.03 with tax. It took about 45 minutes. Zero problems after.
This week I changed the starting battery on my 2011 E350 BlueTec and decided to then change the auxiliary battery preventively. The old one had a July 2010 date code on it, so it was original. I ordered replacement from Amazon for $16.00 with tax. It took about 15 minutes. Zero problems after.
Mercedes SLR McLaren 722 S Is Extremely Rare Example Modified by McLaren
Slideshow: A one-of-one U.S.-spec Mercedes-Benz SLR McLaren Roadster became even rarer after a factory-backed transformation at McLaren's headquarters.
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