Battery problems on R320

Little Phil

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Got 2007 model R320L CDi
Might need new battery- I know its under the drivers seat, but looks hard to access.
It starts, but starter motor spins slowly and almost stops before it fires up.... seems as if a couple of cells might be down or on way out.

I'm looking for best place to get new battery
Merc want £296.00 to replace & Halfords (auto centre) want £296.00 to replace with Bosch lead acid type

Thing is, I understand its not an easy battery to replace with carpets needing cut and stuff like that, otherwise I'd do it myself!

Anybody else experience this, & if so, what did you do?
 

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Hello and welcome,,,,well right now ECP are selling batteries far cheaper that anyone else. A cheap voltmeter only cost some £5 and so easy to check the voltage to be sure
 

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Best way is too remove the seat or at least undo all the bolts! the carpet around the rear air vent needs cutting along the two lines which are marked, then remove the air vent by removing the locking plastic pin!! then remove the battery covering, lower clamp holding battery in then remove battery, best battery to buy is from Merc, around £160.........easy to do if you take your time.....
 

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The Bosch and Varta batteries sold by ECP are OE to MB
 

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Anybody else experience this, & if so, what did you do?


I've never had the pleasure, but have been told on here that it's easier to remove the seat, I can't see why you'd need to actually cut the carpet though.

Almost £300 for a fitted battery sounds unbelievable to me though :shock: considering that I'm about to order a 70A/Hr battery for my Omega from Vauxhall for about £70
 
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Little Phil

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Thanks for the responses... much appreciated. I see ECP are very competitive
I'll get it sorted in a day or so

Trust Mercedes to make it awkward to change a simple thing like a battery on my car.
I've had it since 2009 and have had only minor & stupid things go wrong such as rear N/S light bulb holder has to be twisted slightly the wrong way to make good contact (otherwise they dim or go out and your back up bulbs come on)


Right now, I'm having trouble with PDC sensors.
Garage tell me that one of my front sensors is not working hence deafening silence or Red light screechfest...(now and again, they do start working though)

however they wanted £300.00 to put it right as they tell me bumper has to come off, and new sensor to be painted. etc etc

When I can afford it, I'll see if i can find auto electrician locally...

So, I'm learning now that my friendly Merc garage is not for the likes of me now my car is out of warranty!

Garage told me last service that my wheel discs and brake pads need changing for extortionate amounts of cash...(needless to say I will be going to Halfords!)

Having said that, its a good car with plenty of "road presence"...and I cant believe the rear leg room... so, I'll keep it a while yet.
 

EmilysDad

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& stupid things go wrong such as rear N/S light bulb holder has to be twisted slightly the wrong way to make good contact (otherwise they dim or go out and your back up bulbs come on)

......


Not just my R Class then ;) ;) When I removed my tail light cluster to have a proper look, the metal strip, that the bulb holder makes contact with, was burnt due to arcing ........ I cleaned it all up - but I still have to back the holder off slightly :lol:
 

television

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Is your car a 2009 model, if so you should check to see if there is a battery drain, also have you tried a good charge to see what happens, it would be unusual for a 2009 battery to fail so soon
 
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Little Phil

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Is your car a 2009 model, if so you should check to see if there is a battery drain, also have you tried a good charge to see what happens, it would be unusual for a 2009 battery to fail so soon

Its actually a 2007 car which I bought in 2009- even so, its unusual for a 2007 battery to fail so soon either, so will try your suggestion of a good charge first and foremost
 
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Little Phil

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Turns out the battery seems OK.
Works perfectly on a first start up no matter the weather conditions.
Confusion comes from using accessories at night with engine off (interior light, or AC "Rest" or even the radio)
Engine turns over slowly and almost stops before it fires up in these conditions, however, I notice that if I keep the key turned, it works its way thru the slow turnover then fires up.

Other than that, everything on it seems to work! my Parktronic is now working (new sensor at local indie)and I replaced a few blown bulbs, checked Tyre pressures and hey presto! all as good as new.

Any thoughts as to whats causing slow turnover under the described conditions?
 

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You should measure the cranking voltage, the battery could have a short circuit cell. I would have at least tried another battery just to see if it the engine turned over faster
 

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Any thoughts as to whats causing slow turnover under the described conditions?

Battery & 'earth' connections OK? If/when you have starting problems, A N Other battery jumped across the positive post & a good engine earth should spin your engine over OK. If it does, I'd suspect your battery.
 
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Little Phil

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My battery died yesterday due to car standing idle for over a week & then the cold snap

Regarding the charging post under the bonnet:- Am I better off connecting a battery charger for a few hours, or using Jump Leads to get it started?

I know there are resisters and all sorts in the circuitry and am wondering which is the less of the 2 evils as I cant access the battery under the seat as I am thick fingered, useless and borderline incapable of anything other than basic maintenance
 

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Regarding the charging post under the bonnet:- Am I better off connecting a battery charger for a few hours, or using Jump Leads to get it started? .....

I've never had problems jump starting a dead car from A N Other car, however, they do say that modern day electrickery doesn't always take kindly to the sudden addition of the other battery. I connect up to a none running good car, start it and then try the dead car.
Which method you use depends on whether you need the car now, or in a few hours. ;) Neither method is wrong.

Have you decided where your new battery is coming from & who's fitting it? :)
 

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Jumping will start the car but not help that much as the battery needs a good charge for many hours, if a lead acid type then it may not recover.
 
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Little Phil

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I've never had problems jump starting a dead car from A N Other car, however, they do say that modern day electrickery doesn't always take kindly to the sudden addition of the other battery. I connect up to a none running good car, start it and then try the dead car.
Which method you use depends on whether you need the car now, or in a few hours. ;) Neither method is wrong.

Have you decided where your new battery is coming from & who's fitting it? :)

When I can afford it, I'll either use my local Halfords, where I get it MOT'd or a local indie.
Main thing is to get it started without doing any damage to the electrics. Its the original battery and the carpet under the seat is intact so thats why I dont want to mess about with it.

Do you know if this battery is lead acid type as mentioned by another poster?
 

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As this battery is under the seat it should I think be an AGM type and from my experience with them they will charge up again OK.

If the battery is in a partly charged state, then cranking will be slow, if an AGM then they need a fixed rate charge of about 5 amp for some 19 hours or more to get them back up again.

If the voltage is on the low side, then the cranking amps go up by quite a margin owing to the shunt design of starter motors
 
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Little Phil

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I've put the battery on trickle charge this morning- however as I couldn't see an obvious negative earth point, I connected negative to the bonnet strut.

I hope this is OK. I can hear the charger buzzing away, but the amperage meter on the charger hasn't moved like normal...(hope Im not causing any damage!)
Its an old Halfords charger which works fine on my lawnmower!
 

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If the ammeter has not moved surely it cannot be charging
 
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Little Phil

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If the ammeter has not moved surely it cannot be charging

Thats what I would have thought, but it worked! I left it on for about 3-4 hours before I started it. engine turned over slowly, but caught no problem.
I let it run for about 30 minutes before turning off.
I dont need the car till tomorrow, so I might put it on charge for the rest of today.
Im glad it worked as you hear such horror stories about blowing stuff on these cars if you jump start.

I once had an Omega Elite which got a jump start from AA & next thing the auto geabox locked up, which was blamed on Engine management dooo dah (computer) being fried, so was a bit nervous of history repeating it self
 


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