Battery - slow crank

[jdwis]

Hello guys
I hope and wish everyone is keeping safe in such Covid times.
Recently I have noticed some Battery related issue so thought I would take some pointers and advice from here.

The car is nearly 13yr old.
Somewhere in January 2020 the alternator was replaced as the main battery went dead and couldn't charge.
Then in next month Feb 2020 the original Merc battery was replaced with Varta battery (4 yr warranty) as it could not hold charge for more then 8-9 days.

Now as like quite many people I also work from home and doesn't need to go out for quite even 10 days.
Just recently after the gap of 10 days when I started the car, the sound of crank was quite slow and it felt like the battery has not held enough charge, though the car started on first time. I then ran the car for quite 30 min so making sure the battery is charged properly, all consecutive starts on the same and following days were good powerful enough, again drove for next 5 days.

Then again car was left for nearly 9-10 days and when started the car, the sound of the crank was slow but it started first time.

Like others, I have driven this car so much on regular basis, I know the sound of a powerful crank - the first crank. But the thing is even though the car starts on first try, from the last 2 incidents, it clearly shows the symptoms as the battery is not holding good power and shows the weak start.

My other friends who has got Merc E220 when they leave their car for even 15 days, and on the first start, the crank is still good, even though their battery was not original and quite few years old.

Before I get into any major issue/repair work I thought I would take some suggestions. pointer to check this.

Should the new battery be like this - after quite good runs, leaving it for 10 days without run and then the first crank would b slow?

Also, just for the info, in case when I think of something draining the power, there are no accessories connected to it apart from the Stereo (not original but single din - Alpine) which is connected as per standard connections and the dashcam - which would turn ON only when ignition is ON.
I see no other lights ON when I leave the car (not even in the night time).
I appreciate your help.

Forgot to mention, checking the battery voltage in the morning, it does show 12.1V and I also checked it through the Display Menu that once the car is started, the alternator does provide 14.1V

 

[optimusprime]

Jdwis you might think this is silly for an aged motorist that repaired and service his own car I had to remove my battery to charge it some weeks ago .I have to do this every few months , due to the alarm . The alarm will go off if the battery is to low - car is standing most of the time . So i charged the battery and before i fitted it back , i could see that the post were black , this being a new battery , so i cleaned up the posts with a fine wire brush .Fitted the battery back in to the car wth a dab of copper grease on each post .I fitted the clamps back in place locked them up . So when i started it up the engine turned over much faster than it ever did , a lot faster than before . I think the reason was , because it was a new battery , and i never cleaned the post on it to start with.. I have always made sure my battery posts are clean and greased . But this battery being new i never chacked it .

 

[jdwis]

Jdwis you might think this is silly for an aged motorist that repaired and service his own car

There is nothing silly as such in repairing or servicing our own car, I really appreciate you could do that, its just my place where car stands on road and anything is difficult to do and as per the age, it does bring the experience
But you made a good point, I do remember the guy who put the new battery in, he did it in quite rush, and also I didnt pay much attention as was replying on him to fix this, so not sure if the posts are cleaned and if he really put the copper grease in as well.
I would get this checked soon

 

[jimbg]

Forgot to mention, checking the battery voltage in the morning, it does show 12.1V and I also checked it through the Display Menu that once the car is started, the alternator does provide 14.1V

12.1 volts is just about 50% charged.

 

[jdwis]

12.1 volts is just about 50% charged.

So how much should it show?

 

[jimbg]

So how much should it show?

 

[jdwis]

So thats quite interesting
Seeing I had only 12.1 today morning, even though the day before in the evening I started the car and left it to run in its ideal for at least 20min, it showed 12.1 today morning...
So the question still is, what could b draining this as the battery is just 9 months old and it seems Merc original battery was Varta as well

 

[jimbg]

Can you charge the battery either out of the car or terminals disconnected to make sure that you are not unlucky and have a duff cell on the battery?

 

[Petrol Pete]

Hi JD

This should be posted on the 'Battery' related part of the forum ...but seeing as we don't have one yet 'Electronics and audio' is close enough You have only posted 17 times but have been around on here for a few years so you might have seen how some MB owners on here swear that the only way to make sure your Mercedes Benz starts after being stood still for more than 43.25 hours it MUST be plugged in to a battery conditioner unit or the world will end.

Some of us (me) call a healthy car that can not start itself after a week of standing still a broken down car. I am (or appear to be) very lucky because my old and very analogue C class can stand for many weeks in all weathers and will start up , no problem, but I appear to be in a minority as all of the talk on here is about battery conditioners, someone will be along soon to recommend one to you.

Answering your query I would say with a new battery and a new alternator your car should easily be able to stand for a week or more and start at the touch.

You say you 'run' the car for 30 minutes ? is that just stood still ? If so that's not the best way to get charge into the battery, you need to drive the car. You have warranty left on the battery, get it load tested (multimeter will not do) and if its faulty ask them to replace it. 'They' do not need to be told of the previous alternator issues.

For a decent DIY test of the alternator , start the car switch everything on light's , heated seats, rear window , everything and check the voltage on the battery posts with an accurate multimeter . And check the battery terminals are tight. Best of luck

 

[OneForTheRoad]

Jdwis you might think this is silly for an aged motorist that repaired and service his own car I had to remove my battery to charge it some weeks ago .I have to do this every few months , due to the alarm . The alarm will go off if the battery is to low - car is standing most of the time . So i charged the battery and before i fitted it back , i could see that the post were black , this being a new battery , so i cleaned up the posts with a fine wire brush .Fitted the battery back in to the car wth a dab of copper grease on each post .I fitted the clamps back in place locked them up . So when i started it up the engine turned over much faster than it ever did , a lot faster than before . I think the reason was , because it was a new battery , and i never cleaned the post on it to start with.. I have always made sure my battery posts are clean and greased . But this battery being new i never chacked it .

thats just silly.

 

[OneForTheRoad]

Hi JD

This should be posted on the 'Battery' related part of the forum ...but seeing as we don't have one yet 'Electronics and audio' is close enough You have only posted 17 times but have been around on here for a few years so you might have seen how some MB owners on here swear that the only way to make sure your Mercedes Benz starts after being stood still for more than 43.25 hours it MUST be plugged in to a battery conditioner unit or the world will end.

Some of us (me) call a healthy car that can not start itself after a week of standing still a broken down car. I am (or appear to be) very lucky because my old and very analogue C class can stand for many weeks in all weathers and will start up , no problem, but I appear to be in a minority as all of the talk on here is about battery conditioners, someone will be along soon to recommend one to you.

Answering your query I would say with a new battery and a new alternator your car should easily be able to stand for a week or more and start at the touch.

You say you 'run' the car for 30 minutes ? is that just stood still ? If so that's not the best way to get charge into the battery, you need to drive the car. You have warranty left on the battery, get it load tested (multimeter will not do) and if its faulty ask them to replace it. 'They' do not need to be told of the previous alternator issues.

For a decent DIY test of the alternator , start the car switch everything on light's , heated seats, rear window , everything and check the voltage on the battery posts with an accurate multimeter . And check the battery terminals are tight. Best of luck

ive left 3 mercs all different types at various airports around the uk for upto 2 weeks , sometimes in november ,december for holidays , on my return they have all started without issue , if they dont start then you obviously have an issue ...

 

[jdwis]

Can you charge the battery either out of the car or terminals disconnected to make sure that you are not unlucky and have a duff cell on the battery?

Sure jimbg thx, I will ask the garage guy to check for a duff cell

Hi JD

This should be posted on the 'Battery' related part of the forum ...but seeing as we don't have one yet 'Electronics and audio' is close enough You have only posted 17 times but have been around on here for a few years so you might have seen how some MB owners on here swear that the only way to make sure your Mercedes Benz starts after being stood still for more than 43.25 hours it MUST be plugged in to a battery conditioner unit or the world will end.

Some of us (me) call a healthy car that can not start itself after a week of standing still a broken down car. I am (or appear to be) very lucky because my old and very analogue C class can stand for many weeks in all weathers and will start up , no problem, but I appear to be in a minority as all of the talk on here is about battery conditioners, someone will be along soon to recommend one to you.

Answering your query I would say with a new battery and a new alternator your car should easily be able to stand for a week or more and start at the touch.

You say you 'run' the car for 30 minutes ? is that just stood still ? If so that's not the best way to get charge into the battery, you need to drive the car. You have warranty left on the battery, get it load tested (multimeter will not do) and if its faulty ask them to replace it. 'They' do not need to be told of the previous alternator issues.

For a decent DIY test of the alternator , start the car switch everything on light's , heated seats, rear window , everything and check the voltage on the battery posts with an accurate multimeter . And check the battery terminals are tight. Best of luck

Yes Pete, I looked for Battery section first and couldnt find one, so used this.
Yes I did put only few posts as most of the time I could find good answers from this forum and so it was not necessary to duplicate my issues in the past, and like I mentioned - "good forum" thats the reason I have put my issue question here first though I m member of other forums too.
Also the mention of Merc standing still for 43.25hrs it needs maintaining outside the car would be quite disappointing and harsh, though I know this is from all experts so cant and dont want to argue, but seeing this 43.25 hrs, its not even 2 days straight, and if thats the case then majority of those group would be out and about calling rescue ppl just to fix the battery, but hey.. anyways.. got the point.
About the "run" - "30 min" - yes it was stand still, though I dont generally do that and go for a good run.
And finally regarding the load testing and a full test with all accessories ON, will do that as well and see how it goes, and mainly the battery posts be cleaned and tight...
Good points, will bring these points with the garage guy and see what he has to say.

 

[jdwis]

ive left 3 mercs all different types at various airports around the uk for upto 2 weeks , sometimes in november ,december for holidays , on my return they have all started without issue , if they dont start then you obviously have an issue ...

I would agree with this, I left my Merc with its 13yr old original battery on the airport for 12 days and on return it started on first go, without any issue

 

[OneForTheRoad]

big engined diesels with alot of overnight gizzmos will drain a battery any battery new or old if its not driven enough miles to put the cranking start power lost back into it , say it takes 5 amps for instance to start a car and you only drive enough to put 4 amps back in, after 10 days youll of lost 10 amps from its capacity , eventually it will fail .

especially winter time , when you use lights, heated screens , heated seats . etc etc . driving 10 miles each way isnt enough , hence the battery conditioners come out to play .a flat battery to full charge requires 500 miles of alternator charge so i hear ??

 

[Petrol Pete]

ive left 3 mercs all different types at various airports around the uk for upto 2 weeks , sometimes in november ,december for holidays , on my return they have all started without issue , if they dont start then you obviously have an issue ...

I am very happy that it is just not me that can leave his Mercedes Benz parked outside airports for weeks on end without issue. For a few years or more I thought I was alone !

Maybe we should start a private members club. "www.mymercstartsafterafewweeksofstandingstill.com" ?

 

[optimusprime]

Well another bit of silly information that some might think ! You wont charge a discharged battery thats in the car if you drove it 20 miles .You only put back wats there to start with .So a good charge on a battery charger will be needed.