Changing the battery

[14emerc]

I need to replace the battery in my 2014 E Class as it has now gone flat and will not charge via my Smart battery charger, have had to charge it a few times when the car not been used for months. This is the battery under the bonnet. Can I ask, is there anything that I will need to do after fitting a new battery?
Thanks for any pointers
Pete

 

[AMGeed]

I don't know about the W212, but the W211 E class needs the windows resetting and electric sunroof.
If your windoes don't work properly on the door switch after the battery change, just open each window fully in turn on the door switch, then close and hold the switch at fully closed for a couple of seconds. Same with the electric glass sunroof.

Hopefully your later model won't need anything done afterwards.

 

[Skd884]

If the car is still under warranty phone mobilo they will replace it foc.

 

[richard]

My usual warning. Remove the negative lead on the battery completely first (it is brown) and then remove the positive. Fit the opposite way round - and tighten the positive fully before even connecting the negative.

This is because negative connects to the vehicle body, so whilst it is connected if you use a spanner on the positive and it touches the body you will get a big bang. Worse if it touches a ring or watch that is also touching the body of the vehicle.

Richard

 

[14emerc]

If the car is still under warranty phone mobilo they will replace it foc.

Goog point, thanks but the warranty has run out, the car is now over 3 yr old.

 

[14emerc]

My usual warning. Remove the negative lead on the battery completely first (it is brown) and then remove the positive. Fit the opposite way round - and tighten the positive fully before even connecting the negative.

This is because negative connects to the vehicle body, so whilst it is connected if you use a spanner on the positive and it touches the body you will get a big bang. Worse if it touches a ring or watch that is also touching the body of the vehicle.

Richard

Thank you Richard. I will do as you say and take extra care.

 

[toolman1954]

Hi,
I appreciate that you now wish to replace your battery as opposed to recharging it.
Modern day chargers require some battery power left in the battery to start the charge process, and anything less than about 7 volts will not accept a charge. This is why your smart charger is ineffective, good for topping up, but no use for a recharge. However, you may still wish to charge the battery and find another use for it, rather than chuck it out. (Cue the 100 uses for an old battery thread).
What is needed is a good "old fashioned" type charger, that just uses rectified DC from an AC transformer inside it.
The old Selmer type chargers, which all look the same inside, which often you can buy for a few quid off of a Car Boot sale, or someone you know might have one you can borrow.
These old chargers will often charge up a completely flat battery and give it a secondary lease of life.
Handy also to have a small multimeter to keep your eye on the voltage. Normal caveat about no smoking etc etc when charging a battery applies.
Another top tip from "my house and garage is full of rubbish ".

Steve

 

[Railwayman]

Very strange that a lead acid battery failing after only 3 years, should get approx. 9 with care.

 

[Gallon]

Does the car have Start Stop. If it has & is using an AMG battery then I believe that the battery has to be calibrated to the BCM (battery control module) to achieve correct charging. Might be worth checking out.

 

[14emerc]

Very strange that a lead acid battery failing after only 3 years, should get approx. 9 with care.

I think the main problem has been that the car has been left, unused for too long a time and thus the battery had drained.
I should have trickle charged it when I was away.

 

[14emerc]

Does the car have Start Stop. If it has & is using an AMG battery then I believe that the battery has to be calibrated to the BCM (battery control module) to achieve correct charging. Might be worth checking out.

Yes it is Start Stop AMG battery.
BCM, I need to find out more about this, can you add anything more?

 

[14emerc]

Hi,
I appreciate that you now wish to replace your battery as opposed to recharging it.
Modern day chargers require some battery power left in the battery to start the charge process, and anything less than about 7 volts will not accept a charge. This is why your smart charger is ineffective, good for topping up, but no use for a recharge. However, you may still wish to charge the battery and find another use for it, rather than chuck it out. (Cue the 100 uses for an old battery thread).
What is needed is a good "old fashioned" type charger, that just uses rectified DC from an AC transformer inside it.
The old Selmer type chargers, which all look the same inside, which often you can buy for a few quid off of a Car Boot sale, or someone you know might have one you can borrow.
These old chargers will often charge up a completely flat battery and give it a secondary lease of life.
Handy also to have a small multimeter to keep your eye on the voltage. Normal caveat about no smoking etc etc when charging a battery applies.
Another top tip from "my house and garage is full of rubbish ".

Steve

I have the Smart type charger for the wife's and my car and it's been good so far. I got it because it gave the impression that it could recharge a flat battery and that AMG batteries need this type to recharge, or at leased that is what I think it said. I will dig out the charger manual and double check.
Thanks for your very interesting post, much appreciated.

 

[toolman1954]

I am not being picky and just to keep you right, but the battery is called an AGM (Absorbant Glass Mat ) Battery. Not AMG, that is a brand name , confusing acronyms !
In these batteries the electrolyte is held in Glass Fibre Mat between the plates by some sort of capillary action.
Good for short bursts of high current --ergo start / stop driving. Also makes them a tad expensive.
As your car is 2014, I would have thought you should have gotton more years out of it than 3. Even Halfords give a 4 year guarantee with their batteries.
I would try an old type charger, that and a small prayer and you might resurrect it. Save you £150 plus if you can. Just remember to arrange to keep it topped up while you are away.
Good Luck

Steve.

 

[14emerc]

I am not being picky and just to keep you right, but the battery is called an AGM (Absorbant Glass Mat ) Battery. Not AMG, that is a brand name , confusing acronyms !
In these batteries the electrolyte is held in Glass Fibre Mat between the plates by some sort of capillary action.
Good for short bursts of high current --ergo start / stop driving. Also makes them a tad expensive.
As your car is 2014, I would have thought you should have gotton more years out of it than 3. Even Halfords give a 4 year guarantee with their batteries.
I would try an old type charger, that and a small prayer and you might resurrect it. Save you £150 plus if you can. Just remember to arrange to keep it topped up while you are away.
Good Luck

Steve.

Not a problem Steve. Was a bit late last night when I did reply and mixed up the AGM. The smart charger can be set to 2, 6, 8 or 12amp charge rate as well as automatic. I have only tried to recharge in auto. As I'm in no great rush, I now thinking to give it a try at 2amp for a couple of hours. The battery is out of the car and in a dry, safe area. As you say, might save me £150+

 

[AMGeed]

^ If the battery was really flat, get a good 6amp charge on it for 24hrs to fully charge it. Hopefully it can be saved.

 

[markjay]

The section below is from here: How To Charge an AGM Battery - Hot Rod Magazine

'Here’s all you need to do: Grab another car battery with a decent charge on it (12.4 volts or better) and connect it in parallel to the problem battery using a set of jumper cables. Then activate the charger and charge the battery normally, being careful to follow the manufacturer’s instructions for current and voltage limits. It’s as simple as that. The second battery supplies the voltage that tricks the charger into supplying the necessary current. After an hour or so, you can remove the second battery and continue charging. We tried it and it works. No matter how deep the discharge we applied, we were able to bring the battery back to a full state of charge using our cheap but trusty bulk charger.'

 

[Gallon]

Yes it is Start Stop AMG battery.
BCM, I need to find out more about this, can you add anything more?

Found this on a battery suppliers website:
Finally, once the battery has been changed, reset the battery management system (BMS). This will be done through the on-board diagnostics port. If you skip this step, the stop/start system might not work and the battery’s operational life could be shortened or system faults could develop.

 

[14emerc]

The section below is from here: How To Charge an AGM Battery - Hot Rod Magazine

'Here’s all you need to do: Grab another car battery with a decent charge on it (12.4 volts or better) and connect it in parallel to the problem battery using a set of jumper cables. Then activate the charger and charge the battery normally, being careful to follow the manufacturer’s instructions for current and voltage limits. It’s as simple as that. The second battery supplies the voltage that tricks the charger into supplying the necessary current. After an hour or so, you can remove the second battery and continue charging. We tried it and it works. No matter how deep the discharge we applied, we were able to bring the battery back to a full state of charge using our cheap but trusty bulk charger.'

Thanks, this is very interesting. I now have a battery on order but I'm very tempted to give this a try after it arrives. Thank you for taking the time to find and post.

 

[14emerc]

Found this on a battery suppliers website:
Finally, once the battery has been changed, reset the battery management system (BMS). This will be done through the on-board diagnostics port. If you skip this step, the stop/start system might not work and the battery’s operational life could be shortened or system faults could develop.

Thanks for this bit of info Gallion. I will see if the stop/ start works after fitting the battery. Got to say, I've got , been given great bits of info from you all. Much appreciated!

 

[Gallon]

Just a quick update 14emerc. Just had a look in WIS & there is no mention of having to calibrate the battery after replacement so maybe on Mercs you don't have to do this?