Battery drain problem

[digisatman]

Hi all,

I normally only drive my e270cdi(53) on the weekends, and have been finding that the car need a jump start on saturdays (first day after about 5 days break). I even put a new high power battery a couple of week ago and seemed to do the trick, but tryed to start today, and needed a jump start again.

If I drive a short distance after jump starting, then switch engine off, it starts fine.

I am wondering what could be the problem, is there any check I can do to figure out whats up?

thanks,

 

[television]

The last 211 that had a problem it was the rear SAM (Glojo)

Is there a lamp staying on, boot, the Comand may not be going to sleep and could be the OHC panel also

Only with a ammeter can the drain be found

 

[BTB 500]

If the car is only being used irregularly for short trips it could be as simple as the battery not being fully charged?

 

[DansSlk]

Battery control module, seat control modules and signal acquisition modules are the common ones.

Check you have a good charging current and leave the car parked up (key out) with a door open for 30 minutes or so then get in and have a listen for any running fans or pumps.

 

[Dragon]

I have been told by MB dealer you are supposed to use your car regularly. The SBC consumes a lot of battery power. There may be a fault in the wiring of the battery charger. This needs to be done by MB workshop. Check out the auxiliary battery in addition to the main battery. Hope you know where to locate the auxiliary battery.

 

[digisatman]

Can anyone tell me how I can check if the boot lights stay on while boot is closed, as I cant rell when boot is closed. Can I switch off using onboard computer?

thanks

 

[television]

I have stolen this from elsewhere

close the boot, then open it after 5 mins and see if the bulb is hot

 

[crockers]

Or climb in boot yourself and shut it........... hope your mobile phone works...

 

[digisatman]

thanks for all help so far, thinking of testing the amps out tomorrow, do i just Disconnect the negative from the battery, connect it to the - on the meter and connect the + on the meter to the - terminal on the battery? what the ball park range for amps this kind of car should be using while off, and how long should I wait for it to settle down?

Secondly, what setting should i set meter at first, to avoid blowing the fuse!, milliamps, etc?

finally, how am I going to check amps, without closing boot, or should boot close with wire hanging out of it?

 

[CiaranMcKeown]

Put your mobile in the boot facing the bulb or at least towards the light, record a video, close the boot...open the boot...watch the video...simple.

 

[crockers]

Put your mobile in the boot facing the bulb or at least towards the light, record a video, close the boot...open the boot...watch the video...simple.

Thats called thinking outside the box....or should that be outside the boot...

Still prefer sticking one of neighbours kids in boot for a few hours.....



OOps is that the NSPCC pulling up............

 

[Ade B]

I climbed in the boot and shut myself in and fortunately my wife let me out when I asked her..

With hindsight, the mobile phone trick sounds better.

Not sure how it works with newer cars but I isolated the boot circuit by leaving the battery connected and removing each fuse in turn and measuring across the fuse clips with the ammeter set in series mode. The current reading on the boot circuit was much higher than anything else.

Unforunately I can't remember the settings, I'm sure someone here could tell you.

Also my car has basic old school electrics, so I was (perhaps naively) fairly confident I was not going to upset any delicate electrical trickery. Might be worth checking with someone more knowledgeable about yours before you wade in with the ammeter probes.


Ade

 

[television]

Let the car go to sleep, circa ½ hour, remove the bulb from the boot

disconnect the neg lead from battery and take one lead from the meter to the battery and the other to the lead or ground.
The meter must be switched to the max amp range, then turn the meter to a lower range until you get e usable reading.

There are snags with the above method in that the path of the leak could be lost by disconnecting the battery.

A meter with 3 leads is the best way . I should do a sticky on this as it takes so long to write out and I have done it at least 10 times this last 9 months

 

[DansSlk]

Just an addition to Malcolm's informative post, if you have another battery and a 2 lead meter connect them in parallel with the current battery then disconnect the current battery that way you wont wake the car up.

If you have no choice but to wake the car make sure you meter has the capacity to carry the loads that it will generate, I'm always surprised with the otherwise good units that simply don't have enough current capacity for a wide awake car.

 

[television]

Just an addition to Malcolm's informative post, if you have another battery and a 2 lead meter connect them in parallel with the current battery then disconnect the current battery that way you wont wake the car up.

.

Thats a brilliant way to do it and would fit into the link that I posted earlier,, there are some points here that could be used on a 203 http://forums.mercedesclub.org.uk/showthread.php?t=37364

 

[Dec]

Hi all,

I normally only drive my e270cdi(53) on the weekends, and have been finding that the car need a jump start on saturdays (first day after about 5 days break). I even put a new high power battery a couple of week ago and seemed to do the trick, but tryed to start today, and needed a jump start again.

If I drive a short distance after jump starting, then switch engine off, it starts fine.

I am wondering what could be the problem, is there any check I can do to figure out whats up?

thanks,

Going back to the original post, I would be inclined to think that you don’t have any abnormal drain on the battery, the fact that the car is driven for only 2 days a week and then left standing for 5 days in cold weather maybe the problem.

If you are jump starting the car, driving, even a few miles, is not sufficient to recharge the battery, so you still have a flat battery the following weekend. A flat battery will restart a hot engine after it has been driven a few miles.
.
You would need to give the battery a full charge on a battery charger and some trickle charge during the week.
I would expect the same problems as yourself, if my car was idle for 5 days in cold weather.

If you have an alarm, that will draw about 50ma ?, the radio will be drawing a very small amount, plus whatever is drawn when the car is “sleeping”. I know some people will say the battery should survive for 5 days, but the reality can be much different in a cold climate.

As others have said, the explanation of a drain on the battery is possible but given the irregular driving of the car, a battery in poor condition would seem the most likely cause of the problem.

Dec

 

[crockers]

So heaven help those who go away for a 2 week winter holiday and return the airport where their car has been sitting in the cold unused...unloved...and therefore gonna repay you by not starting?? -- Perhaps....

 

[Dec]

-- Perhaps....yes if there car was parked with a battery that is in poor condition.

Dec

 

[Satch]

Note this bit:

"The electronics on pre-2005 models are more fickle than on later versions of the E-Class, but the manufacturer changed the voltage control to get round this problem"

http://www.autoexpress.co.uk/carreviews/usedcartests/217638/mercedes_eclass.html

That was not actually a recall but a service campaign. You might ask MB to check if it has actually been done on your car.

You might also want to consider switching off the "welcome lighting" feature if it is set and the "auto" function on headlights if it lives in a garage and so puts the headlights on when you put the key into position II. These put a big drain on the battery even before you have started it!

What with the SBC pump pumping, glow plugs glowing etc etc that puts a big initial load on the battery. (If you put the key to position I, set the display to show speed and then rapidly press the trip reset button three times, when you put the key to position II an extra voltage display is available in addition to mph, temperature, etc and you can see the effect)

If you do not do many miles and are weekend only driver then may want to consider a good quality battery conditioning device.

 

[television]

Just an addition to Malcolm's informative post, if you have another battery and a 2 lead meter connect them in parallel with the current battery then disconnect the current battery that way you wont wake the car up.

If you have no choice but to wake the car make sure you meter has the capacity to carry the loads that it will generate, I'm always surprised with the otherwise good units that simply don't have enough current capacity for a wide awake car.

Using another power supply (battery) is the perfect way,,if the circuit is broken when joining up then the path of the short can be lost,, also cars with get ready to go would wake up and you would have to wait for them to go back to sleep.
As Dan says, then the problem is finding a meter that has a range up to around 30 amp that this can all surge at,, most meters without getting stupidly expensive only go to 10-15 amp.

I have always done this by using a meter with 3 leads, but one slip and all is lost

the 12v alarm type battery would do