C class 250

[Sarah'sdad'scar]

Hi, can someone advise me please. My folks had new battery on their car by halfords. Halfords said it needed coding so my folkes agreed. Halfords guy came out and fitted the battery. Didn't code it in which my folks asked and the guy said the vehicle didn't need it.
They used it a few times over the next day then it won't start.
Halfords sent someone out to replace that battery but didn't have anything to code it or reset the vehicle computer.
Is this halfords fault or something else with the car?

 

[Chrishazle]

Am I correct in thinking this is a 2010 C250 thus a W/S204? I have a 2008 S204 C220, new battery needed no coding when it was fitted (also as it happens by Halfords).

Don't know if the following applies only to cars fitted with comand NTG4 or all 204 series C Class, but on my car, key in ignition and turned to position 1 (firsdt click), press and hold 3 steering wheel buttons (answer phone, hang up phone and OK) simultaneously for about 5 seconds and the dash display shows a nebu, top item is something like Vehicle Data. Press OK and it will show batttery voltage and amperage - and will continue showing these as you start and drive the car, thus checking the alternator. engine running, it should show 14V, maybe a bit more, if the alternator is OK. Halfords also should have a battery and alternator test kit.

Also under the bonnet NS IIRC there is a small red plastic cover over the emergency +ve jump strt terminal and a small brass post which is the _ve terminal, you can connect a charger or jump start pack to these if you cannot access the battery.

 

[Sarah'sdad'scar]

Wow. Thankyou so much for this help. I was about to Google anything on coding with the ignition as I had to do that with my volvo when I had a voltage drop.
just called my dad to have a try at this . He thought he would try the car again before doing that. As hes my dad and its what he does! It started no problem. So can only assume it needed to have a settle time from the battery change, before starting up again. Hes not travelling too far for now just in case it happens again. Thankyou again For this help.

 

[Chrishazle]

Did your Dad try the 3 button trick I mentioned? A brand new and fully charged battery should show something over 12V - IIRC 12.3-12.6 but don't quote me on that! - and before trying to start the car it will probably show something like -9 amps. For the second or so you use the starter motor, the voltage will drop and the amps will go -100 or more, then it should quickly go to 14+V and +20 amps or more as the alternator kicks in.

 

[Blobcat]

Buy him a battery conditioner for Chrispymouse

 

[Chrishazle]

Not a bad idea Russ as long as he has a handy power supply where he parks the car! If it's an estate like mine a Lidl battery conditiion monitor hung in the load area where it's easily visible would be another idea if he does not have a power supply handy to where he parks.

 

[Blobcat]

Not a bad idea Russ as long as he has a handy power supply where he parks the car! If it's an estate like mine a Lidl battery conditiion monitor hung in the load area where it's easily visible would be another idea if he does not have a power supply handy to where he parks.

Even a solar charger if no mains available makes a difference

 

[Sarah'sdad'scar]

Did your Dad try the 3 button trick I mentioned? A brand new and fully charged battery should show something over 12V - IIRC 12.3-12.6 but don't quote me on that! - and before trying to start the car it will probably show something like -9 amps. For the second or so you use the starter motor, the voltage will drop and the amps will go -100 or more, then it should quickly go to 14+V and +20 amps or more as the alternator kicks in.

No. I will probably have to do it myself now he has it working he won't worry about it until it stops working again.

 

[Sarah'sdad'scar]

Buy him a battery conditioner for Chrispymouse

I would happily but this is a brand fire new battery from halfords. Fitted by halfords.

 

[Sarah'sdad'scar]

Not a bad idea Russ as long as he has a handy power supply where he parks the car! If it's an estate like mine a Lidl battery conditiion monitor hung in the load area where it's easily visible would be another idea if he does not have a power supply handy to where he parks.

Yes he parks it on the driveway.

 

[Chrishazle]

Even a solar charger if no mains available makes a difference

None of the 12v outlets on my 204 are live ignition off, which is a royal PITA! Even the one in the load area, which would be useful for a cooler on picnic days! So, how do you (neatly) wire a solar charger with the panel inside the car and the leads connected to the battery??

 

[Blobcat]

I would happily but this is a brand fire new battery from halfords. Fitted by halfords.

Doesn’t matter if it’s a new battery, if it isn’t getting regular >30 minute runs the battery will discharge and he’ll have problems again.

I’ve 8 battery conditioners in use on brand new and 20+ year batteries - all work perfectly because they’re on conditioners.

Modern vehicles really work the batteries hard and there is almost always a current draw going on even with the car “off”

 

[Blobcat]

None of the 12v outlets on my 204 are live ignition off, which is a royal PITA! Even the one in the load area, which would be useful for a cooler on picnic days! So, how do you (neatly) wire a solar charger with the panel inside the car and the leads connected to the battery??

I’ve used the “permanent live” going into the back of the radio for a solar setup on an R170 SLK that had very infrequent usage. Worked well.

 

[Sarah'sdad'scar]

Doesn’t matter if it’s a new battery, if the behind getting regular >30 minute runs the battery will discharge and he’ll have problems again.

I’ve 8 battery conditioners in use on brand new and 20+ year batteries - all work perfectly because they’re on conditioners.

Modern vehicles really work the batteries hard and there is almost always a current draw going on even with the car “off”

Yeh I get what you're saying. My original problem was Halfords said the battery needed to be coded in the car so the car knew that the new battery was on. The guy didn't code it. Within 24hrs my dad's car wouldn't start.

 

[Blobcat]

Yeh I get what you're saying. My original problem was Halfords said the battery needed to be coded in the car so the car knew that the new battery was on. The guy didn't code it. Within 24hrs my dad's car wouldn't start.

Hellfrauds aren’t known for their knowledge… I wouldn't let them do anything to my car - fine to buy bits from (when you can get a deal) but don’t let them touch even a pushbike

 

[AMGeed]

Yeh I get what you're saying. My original problem was Halfords said the battery needed to be coded in the car so the car knew that the new battery was on. The guy didn't code it. Within 24hrs my dad's car wouldn't start.

Halfrauds got it wrong.
A 204 C class doesn't need any coding after a new battery is fitted. There is nothing to code.
I wonder if he has a big current draw flattening the battery.
It may need the help of a Mercedes specialist to investigate a possible fault if the new battery isn't holding the charge.
As in Post#2, try the 3 button method to check voltage and charging circuits.

If you post your location maybe someone can recommend a Mercedes specialist if needed.

 

[sonic]

Doesn’t matter if it’s a new battery, if it isn’t getting regular >30 minute runs the battery will discharge and he’ll have problems again.

I’ve 8 battery conditioners in use on brand new and 20+ year batteries - all work perfectly because they’re on conditioners.

Modern vehicles really work the batteries hard and there is almost always a current draw going on even with the car “off”

My 2011 212 E350CDI still has the original battery. Yes I use a battery conditioner.

 

[Chrishazle]

All good advice above, even parked up these cars have a battery drain due to things like the anti theft alarm. If something is not properly "going to sleep" (like Comand, glove box light, puddle lights, all of which have been the culprit in the past) then the battery will drain. Also many short runs will cause problems as the alternator does not get the chance to refill what the starter motor takes out at each start. I find that, after starting at the house and driving 1/4 mile to get the papers, then driving 2-3 miles the long way to get home, the alternator is still putting 10 amps back into the battery by the time I get home (using the "3 button trick I mentioned earlier!!"). Even a Sunday drive out for an hour with a 20-30 minute drive home does not turn the condition monitor light from amber (25-75%) to green (>75%)!!

 

[rf065]

Yeh I get what you're saying. My original problem was Halfords said the battery needed to be coded in the car so the car knew that the new battery was on. The guy didn't code it. Within 24hrs my dad's car wouldn't start.

I've got a later car that does need the battery coded, but didn't bother when I replaced it and the car has been perfect ever since. so forget about the coding aspect, that's not the problem.

 

[Chrishazle]

I'm guessing the problem is 1 or more of :
1. There is an unknown (at this time) current drain when the car is parked up - unless the battery Halfords fitted was not fully charged.
2. The alternator is goosed. As part of fitting the new battery Halfords should have checked battery voltage and alternator performance, if not, take it back (maybe book online) and have them use their alternator check machine. 3 button trick is another check of this, has the advantage of ability to do it live while driving. Just make sure you retain the Halfords receipt for supply and fit of the new battery, it will probably have a 5 year warranty!!!
3. Short runs draining the battery without suitable long run opportunity for it to decently recharge.