Battery Drain Again

[Tezz]

Ok so hear we go again.

So back in April I had a battery drain, it was found to be rear tail gate handle, new battery fitted by RAC and handle fixed since then no issues with battery, start fine all ok

Used car few days before all fine apart from the Command 20 was turning its self of and on, after a few times it came on and all was fine, used yesterday all was fine. when I got car this unit was disconnected apart from radio, I reconnected all wires ect and been fine since

only thing iv never done before, was about 2 hours later realized I left some thing in car, opened it up, got what I needed and locked again, usually never open with out starting car, this morning car dead to point door locks don't work. opened with key everything dead, no alarm flashing light, no ignition nothing. checked all switch everything off ect.

Points maybe unrelated

So how do I remove the battery to charge so alarm dose not go off ? bearing in mind its totally dead

Is the alarm siren near pollen filter or under a wheel arch?

Any idea how long the alarm will go off on its internal batteries ?

What do you think is the likelihood of the command unit being faulty and getting stuck in a wake up loop of sorts

It only recently did a 180 mile round trip so would think battery would be charged ok and I use it every few days for about 20 miles

I do have an Icarsoft, very recently I plugged in just to check every system 1 at a time to check for any faults and found none.

what ever the drain is was enough to drain battery overnight

Any thoughts


Thanks


Tezz

 

[jimbg]

What is the battery voltage?

 

[whitenemesis]

Alarm will self-cancel after approx 30sec.
You need to get the car on STAR and get the codes read.
That COMAND unit was disconnected for a reason..

 

[Tezz]

Alarm will self-cancel after approx 30sec.
You need to get the car on STAR and get the codes read.
That COMAND unit was disconnected for a reason..

yes, command was disconnected, but its been fine since I reconnected in April, the previous owners may have disconnected it looking for drain without star system, which I found was rear handle in end or maybe it had 2 issues ?

cool so if I remove battery it will only go off for 30 secs? or will it reset and go off again

Thanks


Tezz

 

[Tezz]

What is the battery voltage?

3.95 V

 

[Tezz]

3.95 V

Took Battery off car and checked again was 6.31 V

 

[jimbg]

Are we talking about the main 12 volt car battery?

If so that battery is a goner!

 

[Tezz]

So took battery off car, car alarm did not go off which surprised me as it did last time I removed earth

Its on charge, will leave on low charge for a few days

Why car is completely dead, when I reconnect positive battery is it best to do the current draw there and then using earth and multi meter before I wake car up.

or

Connect both, run car drive ect as normal and let go to sleep and then carry out test ?

cant check for any codes till its charged anyway.

issue I have is if I start car and run, if it is an intermittent issue with command it may clear, where as the car is now exactly in state that drained battery


Many Thanks


Tezz

 

[Tezz]

Are we talking about the main 12 volt car battery?

If so that battery is a goner!

View attachment 106327

yes brand new fitted in April by RAC 74Ah 750a Varta

I will charge and see what it reads after standing for few hours, if I turn charger off for 5 mins reads 10.58v

 

[whitenemesis]

Any warranty on the 'new' battery?

 

[jimbg]

Best of luck, I have never seen a battery go that low and come back,

 

[Tezz]

Any warranty on the 'new' battery?

Yes 5 years

I get that MB are crap when it comes to batteries and issues with them, but last battery was under 2 years old, this one 7 months, there has to be an underlying issue that's causing the drain/ fail of battery in first place


I still think something is keeping the car awake, the hic up with command could be a pointer ?

either way cant do anything till I have a charged battery


Thanks



Tezz

 

[Tezz]

Best of luck, I have never seen a battery go that low and come back,

Thanks ill give it a go, got a low amp small charger will leave it on for a few days, its been on charge since 11am ,turned it off and left for hour it holds 11.58 now, so put back on charge


worst case ill claim for free replacement

LOL maybe owing a MB I should have asked for a booster box for xmas


Thanks




Tezz

 

[Tezz]

Bit of help needed.

Using an old trickle charger, iv got battery up to 12.24 volts, no idea if will hold or not

I still need to find drain.

car has now been standing for a few days with no battery.

So do I connect red, and then put me multimeter on amps and connect in series to check for drain before I do anything else.

Or connect both and if car starts, go for long run to top up battery and wake up all system turn off wait for it to go to sleep and then disconnect earth and connect up multimeter.

also I cant find switch for inside lights on door ect, is this some how controlled by lock ? would be handy if I could have door open when pulling fuses as they all in drivers foot well with battery. could I some how lock the door with it open ? fooling car to go to sleep ?


Many Thanks



Tezz

 

[andy27168]

Hi
On the door and or boot close the latch over with a screwdriver or the like to fool the car its closed.
How are you going to connect the Ammeter? what sort of accuracy/resolution do you have on your meter?
From a personal perspective i would be using a clamp meter, such as this one I bought one exactly the same for sorting the battery drain out on my CLS.

UNI-T UT210E True RMS AC/DC Current Mini Clamp Meters w/ Capacitance Tester: Amazon.co.uk: DIY & Tools

Free delivery and returns on all eligible orders. Shop UNI-T UT210E True RMS AC/DC Current Mini Clamp Meters w/ Capacitance Tester.

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Though I would buy this one now more sensitive and comes with a temp probe too

Bside ACM91 1mA Clamp Meter AC/DC Current True RMS Auto-Ranging 6000 Counts Voltmeter Temperature Capacitance Frequency Live Wire Check V-Alert Tester with Back Clip : Amazon.co.uk: DIY & Tools

Bside ACM91 1mA Clamp Meter AC/DC Current True RMS Auto-Ranging 6000 Counts Voltmeter Temperature Capacitance Frequency Live Wire Check V-Alert Tester with Back Clip : Amazon.co.uk: DIY & Tools

www.amazon.co.uk

According to MB WIS instructions the car requires to remain dormant after locking for a period of approx. 30 minutes, also bare in mind it wakes up if a door is opened.
As you have a substantial drain observing these sleep times might not be necessary as you will be dealing with a drain that should be quite obvious, and almost certainly a fault on one of the CAN Networks.
Also be-aware that it isn't really advisable to be pulling/replacing random fuses as this can introduce fault codes that might give spurious results in identifying a drain.
I will look for the WIS document it might give you a few pointers.

 

[Tezz]

many thanks for your help much appricaited


Tezz

 

[Tezz]

charged battery up to 12.5 V

car had no battery fitted for 3 days

I refitted it to car + side only , I latched the drivers door

I connected my meter in series on the earth side (it sparked) so something was wanting power.

only thing I could hear was the radio cd spin up for about 30 secs, command did not come on

I could only get a reading on the 10amp setting and it was 1.82

I left it untouched for 15mins and it dropped to 0.91

I pulled fuses and only one that made a difference was 33 (command) reading dropped to 0.00

with the hick up I noticed with command turning its self on and off a few times, looks likely it could be the drain

I checked every section one by one on my Icarsoft and only faults anywhere were all to do with low voltage

I checked voltage on icarsoft and was charging at 13.58 and 14.3 ish

Car started and run fine, I left the fuse for radio removed, guess I will know in a few days if it was the command unit

I would have liked to test in a lower range but I could only get reading on 10amp setting, I think I will invest in a clamp meter after xmas


Tezz

 

[Tezz]

over 3 days not driven it has dropped from 12,61 to 12.54 is this Normal ? command unit is still disconnected

Thanks


Tezz

 

[jimbg]

Probably OK

 

[Jockcl500]

over 3 days not driven it has dropped from 12,61 to 12.54 is this Normal ? command unit is still disconnected

Thanks


Tezz

That battery voltage sounds ok, I would use it without command, it was obviously found to be the problem before and the reason it was left disconnected.