Battery Woes - the Plot Thickens…

[markben]

Christmas Greetings all.

Another Battery query in case any of you are tuning-in in between the Festivities....

To recap: New battery fitted 3 weeks ago when the previous one failed (after 6 years). New battery failed after 2 weeks, recovery service called out twice within 48 hours to start the car, battery replaced under warranty in case it was a ‘bad’ one. 48 hours later even after a 2-hour fast journey in daylight, second / new battery was dead this morning. So.. not the 2nd new battery, more like a battery drain problem?

Co-incidently (?), for the past few weeks my manual boot release button hasn’t worked so I’ve been using the remote button on the key fob.

I spoke with a helpful auto electrician by phone today (Indies etc are all closed for the Hols), gave him the recent battery failure history AND mentioned the boot opening button problem in case it’s relevant. Immediately he said that probably… (stress Probably), if the manual boot release button was stuck / faulty, the boot / trunk interior lights (2 x 5w bulbs) could be staying ON when the is boot is closed & the car is switched off / left overnight. So.. remove the bulbs to stop a possible parasitic current draw, charge-up the (second new) battery and see how it goes. The PSE pump works ok on all the other functions and is silent when the car is switched off.

The latest problem.. a few hours' trickle charge today and the battery voltage won’t go above 5.9v. It’s a lead acid 90mA lead acid OE spec (before you say it.. yes an AGM would be the ideal choice but the Nat Tyres / Halfords recommended one was an expedient). And... both new batteries may be ok if not for the suspected parasitic drain problem? You tell me...

Any thoughts & ideas welcomed

Many thanks and YO-Ho-Ohhh… No-No-NO!?

MB

 

[AMGeed]

Sorry to hear of your battery woes. It does sound as though you have a pretty serious battery drain.

If the battery was fully discharged it need at least a 6amp charger put on it for 24hrs+ to bring it up to fully charged (12.6v)
A trickle charger just isn't up to the job with a fully discharged battery as I found myself previously.
Once its up to 11v+ a trickle charger can take over.

 

[markben]

Sorry to hear of your battery woes. It does sound as though you have a pretty serious battery drain.

If the battery was fully discharged it need at least a 6amp charger put on it for 24hrs+ to bring it up to fully charged (12.6v)
A trickle charger just isn't up to the job with a fully discharged battery as I found myself previously.
Once its up to 11v+ a trickle charger can take over.

View attachment 81271

Thanks AMGeed, that's really helpful. Fortunately I don't have to travel anywhere over the next few days so I'll try what you suggest and report back in case it helps others in a similar situation.

Best wishes for a Happy, Safe & peaceful (or whatever!) Christmas

 

[AMGeed]

You too Mark
If your battery drain is still continuing after removing those bulbs, I'd suggest an appointment with Steve at Avantgarde Automotive Clevedon to trace the drain.
It will have you pulling your hair out until its traced.

Clevedon Mercedes Specialist | Avantgarde Automotive

Avantgarde Automotive is a Mercedes-Benz independent specialist offering par excellence quality of service to owners of Mercedes cars in Clevedon

avantgarde-automotive.co.uk

 

[markben]

You too Mark
If your battery drain is still continuing after removing those bulbs, I'd suggest an appointment with Steve at Avantgarde Automotive Clevedon to trace the drain.
It will have you pulling your hair out until its traced.

Clevedon Mercedes Specialist | Avantgarde Automotive

Avantgarde Automotive is a Mercedes-Benz independent specialist offering par excellence quality of service to owners of Mercedes cars in Clevedon

avantgarde-automotive.co.uk

Thanks again. Yes, I went to Steve at Avantgarde about my (never resolved) hard damping issue when I first had the car - that was 6 years ago but he was very helpful at the time. Since then I've had masses of other work done to the suspension (more locally), but If the battery prob isn't resolved (I'm in Dorset atm), I'll certainly go back to him about both issues when back at home in Somerset.

 

[markben]

Quick update..

Hooked-up the battery to a more powerful 9A charger for a few hours today. The 6A charger clearly wasn't powerful enough and / or it would have taken days to recharge the battery.

Result: BINGO! Battery now registering 12.5v (negative terminal disconnected) and it started first time with no problems! Drove the car for 30 mins in daylight to warm it up generally, my pal suggested leaving it on charge overnight (says his charger has a monitor / safety cut out & cannot over-charge / do any damage etc.

Hopefully, the parasitic drain was due to that faulty / 'stuck' bootlid manual release button which might have kept the interior boot lights on when the boot was shut & car asleep. With the (3) bulbs removed and a 2 hour drive in daylight tomorrow, hopefully it will be ok when left overnight at home. Then, I'll get the release button fixed & all should be well again. Phew.... after 3 weeks & 3 battery fails!

I'll report back with progress in case it helps anyone here - many thanks all for your thoughts & ideas in the meantime.

MB

 

[mioba]

If a battery goes too flat for a charger, a jump start gives the battery the required kick up the bottom to enable it being charged.

Funny think is my sister in law has a VW tiguan. Her car was sounding sluggish the last few weeks (cold weather) then ine morning it was dead. I jumped the car with leads and its obviously done something as the problem has not returned.

Now I have no idea how such batteries work - but giving them an ommpf does some good.

 

[markben]

So.... this morning after a couple of hours' more top-up, the 9A charger was registering a static battery voltage of 14.4v and 'fully charged'.

The car unlocked using the remote key and started with no problems, I drove 90 miles across a blustery Dorset / Somerset with headlights, wipers etc on constantly and parked-up a couple of times locally before returning home. So far, so good - fingers crossed after 3 weeks of flat battery Woes & hassle.

My best conclusion? If the (second) new battery continues to perform at 100% in daily usage over, say, the next week, it will most likely confirm the probable cause of the battery drain issue: i.e. a faulty (note: manual) boot release button which operates via the PSE pump & causing the interior lights to stay on when closed (even though the remote boot release / closure works ok).

And..(?) after disconnecting the 3 x 5w boot light bulbs it has probably fixed the battery drain issue pending getting the manual boot release button fixed. Fingers crossed in the meantime...

Hey ho.. 'on we go' and thanks all for your kind contributions to this thread.

 

[markben]

Famous last words...

So: 24 hours later the (second) new battery has DIED - again. Car unlocked using the remote key fob (just..), but the engine turned over slowly a couple of times then kaput. Had to lock & secure the car manually using the blade key but at least it's parked up safely.

Clearly, the battery drain WASN'T caused by the faulty boot release button / interior lights staying on after all. The first roadside rescue & recovery agent (3 weeks & 3 flat batteries ago) said the alternator was working, so who knows WOT the problem is?

To compound things, my local Mercedes Indie, auto electrician and a couple of garages are all CLOSED through the Xmas hols until Tuesday next week..

TAXI..!

 

[malcolm E53 AMG]

Try taking the NAV CDs out of COMAND this has a habit of not shutting down, a common fault apparently

 

[ajlsl600]

Drill a hole in rear wing fit a batt isolator. Turn off end of each day prob over. Mining motors all have. no more electronic electrical drain. Those issues do my head in. Hrs, days, weeks wasted. No thanks.

 

[markben]

Thanks all

So... (again!). I've ordered a NOCO Boost 'X' 125 amp Jump Starter kit from good old Halfords. Suitable for diesel engines up to 4 litres, so should be strong enough to bring my 3.2 cdi battery back to life? Free home delivery tomorrow, and of course, useful to keep on board until or unless the mystery battery drain issue is fixed. Plus, probably a good idea to fit a battery isolator switch for the same reason?

After 3 weeks of flat battery hassles and in view of my local Mercedes Indie, auto electricians etc being closed until 4 January + a local roadside rescue quoting a minimum of £120 for 24/7 callout (I've used my Motor Insurers 3 times recently for the same thing f.o.c. so they would probably refuse next time) I even considered hiring a car for the next 6 days just to stay mobile over the new year Bank Holiday - but the cost would be £220 + a £250 deposit.

It dawned on me that the investment of £120 or so on the Jump Starter kit + a battery isolator switch will at least prevent me from being stranded in the short term, will be useful to have in the long term, and much more cost effective than the expedients?

Hey ho, as always, 'we'll see'.

 

[SL63 Mark]

In my experience, Batteries need to be correct items from MB. Hallifords specials won't do. Although Hellifuds say they will.

That may be the problem. However, approx 9,720 other things may also be the problem. While it is fun guessing, you really need to get it to a recommended Mercedes specialist for diagnosis. There are quite a few, your nearest is probably MBS Southampton.

These are specialist sensitive high tech cars, not like the MKII Cortinas of our youth, where a bit of educated guess work went a long way.

 

[LostKiwi]

Do these have a block heater like some of the 220s do?

 

[markben]

In my experience, Batteries need to be correct items from MB. Hallifords specials won't do. Although Hellifuds say they will.

That may be the problem. However, approx 9,720 other things may also be the problem. While it is fun guessing, you really need to get it to a recommended Mercedes specialist for diagnosis. There are quite a few, your nearest is probably MBS Southampton.

These are specialist sensitive high tech cars, not like the MKII Cortinas of our youth, where a bit of educated guess work went a long way.

Thanks Mark, good points.

Re. OEM spec batteries (Bosch, Varta etc?), yes I've read that AGM are the best especially for heavyweight (electrically) Mercedes. For better or worse I went for a Halfords recommended Lead acid 90 Ah battery as an expedient when I needed to keep mobile. In fairness, the manager said that it would be fine but swapped it for a new one under warranty after the first failure, in case of it being a 'bad' one.

I also agree about those 9,720 other possible causes of the (second new) battery drain - especially on an 18 year old but otherwise immaculate & well maintained W220. As soon as my most local MB Indie (W-s-M North Somerset) is open again on 4 January I'll book it in for thorough investigations via SDS. But the booking date could be a couple of weeks later as they are always busy. Hence the 'stay mobile' contingency plan in the meantime.

I fondly remember 1970s / 80s Cortinas et al (my first car was a Mk. 1 Triumph 2000) when these types of mystery electrical issues were almost unheard of - but often easier to solve!

Thanks again and I'll update with progress in case it helps anyone on this friendly & helpful forum.

 

[markben]

Do these have a block heater like some of the 220s do?

Yes....ish. On the W220s it seems there were 2 factory options for what's called the 'Auxiliary ('block'?) Heater' depending on the sales market for which they were destined. From what I've read: in colder climates, they had an electrically operated Webasto heater (powered by a separate battery?).

But for the ('warmer'?) UK market, as far as I can see, the 3.2l cdi engine auxiliary heater was somehow powered via the HVAC system and not dependent on a separate electrical supply. But I might be wrong about this...

That said: my UK version of the W220 Owners' Manual is quite confusing around such things and all that I've gleaned from it is that, on my 2004 S 320 cdi, when the Aux Heater is switched 'OFF' (button to the LHS of the gear shifter) a red beacon stays ON. Confusing or WOT?!

 

[LostKiwi]

But for the ('warmer'?) UK market, as far as I can see, the 3.2l cdi engine auxiliary heater was somehow powered via the HVAC system and not dependent on a separate electrical supply. But I might be wrong about this

If yours has a block heater powered by the vehicle (and not by an external power supply) that may not be turning off. I seem to recall this being an issue on some of the 220 engines and it quickly results in a flat battery if it is.

On the 220s it's located under the inlet manifold but I have no idea if one is fitted or where it might be on a 320.

 

[SL63 Mark]

Thanks Mark, good points.

Re. OEM spec batteries (Bosch, Varta etc?), yes I've read that AGM are the best especially for heavyweight (electrically) Mercedes. For better or worse I went for a Halfords recommended Lead acid 90 Ah battery as an expedient when I needed to keep mobile. In fairness, the manager said that it would be fine but swapped it for a new one under warranty after the first failure, in case of it being a 'bad' one.

I also

I buy the correct Mercedes Batteries from a Mercedes Dealership, they are no more expensive than any of the "OEM" makes. The friendly Halfords branch manager is an expert salesman, that's his job.

 

[markben]

If yours has a block heater powered by the vehicle (and not by an external power supply) that may not be turning off. I seem to recall this being an issue on some of the 220 engines and it quickly results in a flat battery if it is.

On the 220s it's located under the inlet manifold but I have no idea if one is fitted or where it might be on a 320.

That's interesting and it reminds me of something which might be related to the flat battery issue.

During 6 years' ownership of my S 320cdi I've never paid much attention to the Aux Heater switch / never felt the need to use it and assumed that the light being 'off' it meant that it was disabled. But, recently, after consulting my Owners' Manual, I flicked the switch to 'Off' - with the indicator light (perversely & illogically?) indicating 'On'. It's the same paradox with the HVAC switch: when 'OFF' the switch lights up. When 'ON' the light goes out .

But you have a good point: maybe (just maybe...?) a fault in the Aux heater and / or the switch light remaining 'on' recently could contribute to the recent mysterious battery drain? Another thing to look into tomorrow, and thanks again.

 

[markben]

I buy the correct Mercedes Batteries from a Mercedes Dealership, they are no more expensive than any of the "OEM" makes. The friendly Halfords branch manager is an expert salesman, that's his job.

Thanks Mark. I can't argue with that, especially as a former MB Sales Exec (35 years ago - how time flies!) and latterly external Senior Sales Training Consultant for MB UK with many happy memories of training in the Art of ....