vettdvr

If your batteries are both reading out of circuit 12.6 V then they are ok.

Out of circuit means that if you pull the - lead from the aux bat and check it, it will be 12.6V. Then with the lead OFF you check the main bat in the trunk it also reads 12.6V you have completed a out of circuit engine off test. Given this is what you have done. Reconnect the aux battery and start the car, then measure the voltage on the main battery in the trunk. I would expect to see around 13 volts to indicate the alternator is charging. I normally use a very specific piece of test equipment to test the 3 phases of the diodes but given you don't have this just test the battery engine running with voltmeter. If this is ok, Autozone will test the main battery for no charge. Given you pass all these test the alternator testing is next.

jay m

Hey Y'all,
I'm a newbie to this forum, however, I have been on the rennlist and roadfly boards for a few years. Thanks for all the good info I have obtained in the past while lurking and searching. I have a 2003 E320 that is having the battery-visit workshop alarm. I replaced the aux, battery when the alarm first displayed after measuring 11.2 Volts. Upon replacement, my alarm is still present. The new aux. battery has 12.83 V. I am not showing the aux battery charging when the engine is running (if it is even supposed to). while the main battery is charging at a rater of 14.06 V. Upon searching threads, I have not seen any info on how to troubleshoot the system. I'd like to see if the aux. relay and/or battery control unit are operating correctly. If anyone has any info, please let me know.

Thanks,
Jay

kenikola

The Battery Controller (BCM) will only charge the AUX battery if the systems voltage is above 13.5 volts. If that condition is satisfied, and the AUX battery needs to be charged, the BCM will charge the AUX battery for 20 minutes per ignition cycle.

vettdvr

Correct, which is why I recommend having the charging system checked.

mammothskier

Hi all,

I've got the same message on the cluster today. The aux battery reads 10.4V. When car is running it has 13.6V so it seems the charging system is working.

Now I went to autozone, pepboys, and Kragen. All have 14BS batteries which need acid poured in and I think charging after that.

Is it OK to just put acid in and install on the car. I don't have a battery charger.

2 nearby stealerships want $205 for the OEM battery (part only). I'd probably pay $120 or so to avoid messing up with the acid, etc. but not $200.

BTW, Autozone battery is 14BS, not 14BX. Did anyone bought a non-OEM battery which does not need acid poured in?

vettdvr

Just make sure the battery is AGM type. This is adsorptive glass mat.

You might have to add acid to activate and it can still be AGM. You just won't want a conventional lead acid battery. You should be ok with autozone agm.

JimPurdy

Yes, the Autozone battery is the 14BS and is an AGM. The acid fill isn't difficult at all. I placed a pad of old newspapers under the battery before filling but that wasn't necessary. I only got one drop of acid on the part just beside the filling hole. The instructions for the Autozone battery says to fill and wait 30 minutes before charging. This is to give the acid time to be absorbed into the fiberglass mat. I used a little 1amp battery charger for a couple of hours before installing. The instructions called for 2-5 hours with a 2 amp charger. I don't think the charging would be necessary since the car will use the main battery for starting and then charge the aux battery. I didn't follow the "remove the positive cable from the main battery" instructions. I removed the positive cable from the aux battery first and taped a plastic 35mm film canister over the clamp to prevent shorting. I reinstalled the aux battery and everything is fine. I would suggest removing the black and red plastic covers from the old battery terminals and reusing them since the new battery doesn't have them.

vettdvr

[QUOTE=JimPurdy;3499252]............ I didn't follow the "remove the positive cable from the main battery" instructions. I removed the positive cable from the aux battery first and taped a plastic 35mm film canister over the clamp to prevent shorting. I reinstalled the aux battery and everything is fine. QUOTE]

I didn't disconnect the main battery either. I had the wife hold it the aux + cable.

Unfortunately we didn't have the cross ref bat #'s so I bought a oem from MB at $155. Then I took the old bat. around town to do a physical / electrical match up so next time we would not have to pay the $155. So I am glad my research saved you a few$$.

smb7420

No one at sears could let me know if the DieHard Gold 14BS puts out 170A, it is a 12v with 12aH.
Someone at walmart told me their everstart has only 6aH.

Any idea if this DieHard Gold PowerSport Battery 14-BS battery will do?

http://www.sears.com/shc/s/p_10153_1...icationsAnchor

vettdvr

If it is the same physical size, terminal location, agm and over 12ah then it will work. Note the Diehard is 14 a/hr therefore has more capacity than OEM which would mean it would operate longer. I don't know what the 170A is for?? Means nothing to me. 12 V 14 ah are the two you need to know. So if it fits exactly in the car. and 12 V 14ah I would use it as it is actually larger than origional.

mammothskier

It is 12Ah, not 14. It is mentioned on sears.com

Power Ratings:
Capacity Amp Hours at 10 Hour Rating: 12

kenikola

Read post #103.

Maybe if vettdvr writes something about this, then you people will listen

Assuming the battery needs to be charged from 0% to full capacity, I do think we all agree that charging a new battery for a maximum of 20 minutes per ignition cycle is not very good for the battery. Get/borrow a suitable charger, preferably one with an "AGM" and "motorcycle" (small capacity battery) setting ..."for optimal performance".

vettdvr

Consider the purpose of the aux bat. It supplies power to the SBC system for brakes. If you are driving with the red light on you have no backup brakes.

If you take a agm battery pour acid in it and let it sit overnight it will probably have 12 V but it won't have reserve amps. If you install it the car system should build up the charge and full amperage reserve.

But the caution here is that you will still have no back up brakes while the aux battery is being charged. This might take a couple of days depending on how you drive.

So this is really a safety issue. IF the agm battery sits overnight and has 12V it should not hurt the battery to install it. But warning you will have no back up brakes and we all know they is never a failure of SBC braking system .

Guess it really does fail which is why you have the aux battery.

mammothskier

Thanks to great people of this forum

Got the battery, poured acid in, charged as specified (3hr @1A written on the box, 6hr@1A in the manual ), so charged for 6hr, installed, red light gone for 2 days now, so it seems I've got it fixed.

vettdvr, how much current does SBC brake system draw? Even if aux battery had nothing in it, the alternator is still running and providing current to SBC, right? Just curious.

vettdvr

I don't know the total sbc current draw but it is small given if you have a failure you make 1 stop then get the car towed.

You are right. Even with aux failure the main alternator will power the sbc. Glad it worked out for you. I went through quite a bit of research to find a replacement battery. I pulled my old battery found the mfg name in Italy. Then traced the battery back to US by cross reference of part numbers and the first battery I found was a Harley Davison battery. Then from the HD number I was able to cross reference to other US available batteries.

CLEK500

HOLLY MOLLY GOSH, I just got the hit today, .Yup, as y'all expect, RED battery msg. damn it. gotta go replace it now. *sigh*

vettdvr

Tag you're it!

But at least you can change it for about $70 less than I did.

kenikola

The SBC-pump doesn't rely on the aux battery directly in any way.

The aux battery will provide extra power to ALL of the cars systems, not just the SBC pump. The aux battery is only connected to the car's (entire) electrical system if the BCM finds it necessary to energize the AUX relay (emergency mode), or if the aux battery voltage is too low the BCM will energize the aux battery relay to charge the aux battery. Additionally, in emergency mode, the BCM will likely also activate one (at 11V), or both stages of consumer cutoff (at 10.5V), deactivating your heated seats and stereo system etc. to try to raise the system-voltage.

The SBC-pump will work just fine without the aux battery, but some of the redundancy in the electrical system (required for normal SBC pump operation) is lost without the aux battery. This is likely why a defective aux battery is important enough to trigger a red message in the instrument cluster, even though the situation isn't an immediate problem.

mammothskier

In California you can buy Exide battery at Kragen autoparts. It is also AGM.

valium

I have been following this forum and reading lots of great advices from people here. I need help with my 2003 E320. Last week, the battery warning came on and i changed the aux battery myself. The battery warning light went away and everything was fine for a few days until my car died while i was at a stop sign. After about 5minutes, i was able to re-start the car and drive home. Everything went back to normal again and then today, the same thing happened again. Everytime the car dies, it is very hard to get re-started. Anyone have this problem after replacing the aux battery? Please advise on what might be the issue with the car. Thanks!!!!!

vettdvr

This doesn't sound like the battery.

It sounds more like the CPS that provides the timing signal to the sparkplugs/injection/Powertrain Control Module.

valium

Hi Vett, Thanks for the reply. I notice that this problem occurs after a long drive when the engine is warm or hot. Dont have any issues when the engine is cold. I'll take it to the shop sometime this week so they can check it out. Thanks

vettdvr

Most CPS use are basically a Hall effect sensor to generate a electrical pulse when a magnet field passes through built in coil. If the coil if opening up under heat the CPS will not send a pulse.

Don't know for sure if this is your problem but the cps could cause this problem.

Clinton Horn

More than once I have attributed a failure to a recent event only to discover through much heartache that it was completely disassociated with that event and is due to something else (even to the point of similar symptoms).
I had stalling or near stalling on my 2003 recently. I looked at the CPS and it does appear to be a bear to get to. Yours may indeed be the culprit, but try something very simple relayed by another member. Make sure the air cleaner housing is engaged in all 4 clips. If not, the induction is bypassing the MAP sensor and the engine runs rough / dies at operating temps. It takes 5 minutes and it has fixed mine and at least one other (the member who figured it out) . Good Luck

valium

Hi Clinton, Thanks for the advice. Maybe i didnt tighten the air filter when i replaced the aux battery. Definitely will check it out tonight and see.