Urgently Need help with battery drain!

[dasachmo]

Hi guys,
Yup , called my local MB and theyve said 98 for a replacement, will probably get it because like you guys said, it will invalidate insurance and as long as i can fit it myself thats not too bad.

Definately not going to get used because although its a third of the price, it will likely probably be close to the end of its life anyway.

 

[E270 Owner]

Water ingress or battery cells leak.

This one was damaged due to water ingress,
batteries are fine but I just dump them in the bin
and buy new from MB when these faults come up.





very common fault but not the only reason for parasitic battery drain.

 

[dasachmo]

could possibly be water ingress as i did have the car thoroughly jet washed a couple of weeks ago, either way, i think im going to do what you guys have suggested and disconnect it and measure the resting drain using a ammeter and hopefully it falls , im at 1.5A but as you guys have said, should be 50 mA

 

[E270 Owner]

Water ingress would/could be from driving in wet conditions over many years,
typical UK meteorological stuff.

It would be interesting to see how our drier continental counterparts fair in respect of this problem

Probably not as many but some with battery leakage.

 

[dasachmo]

Hi guys. Just an update. I think pulling fuse 8 has helped.
Batteries not gone dead for 4 days. Not bad.
As soon as I connect the battery in series with the ammeter I'm getting 1.7-1.9 amps. After about 2 or 3 mins it's dropping to 0.13 amps... Which is a bit more then the 50mA but not bad... Think it should be okay. Will get the part and follow the vid to replace the alarm.
Thanks guys!

 

[dasachmo]

Hi guys. Not sure if this is related by I thought I'd add it on here.
After changing the alarm siren the car was fine. It lasted a whole month with no issues.
There was terrible rain last night.... Randomly I went to my car and started it, was a bit slow turning over.... It also came up with a warning light sensor or something like that.

Turned it off and started it again twice and it started fine.

Anyway. Tried it now and the central locking wouldn't work. I manually opened the car and the alarm went off and the inside light was dim and flashing.

The cars completely dead now. Put a voltmeter across the battery and at rest it's Showing 4.7v.
Wierdly I took the battery out of the car and it's showing 7v.

Do you reckon something else is draining the car?
I'm going to check for fuses... But what do you think it is?

 

[dasachmo]

Hi guys

Diagnosed the cause- its water leaking into the car and drenched the rear sam.
I've disconnected the wires and was unable to get the number 2 cable out so just wrapped it up and hopefully it will dry!

Hopefully it will fix itself otherwise it appears a new SAM and i think i'll need STAR to programme it!

Not sure how i'll do that because the car doesnt start!