E53 Battery drain

DARTH510 · Post by **DARTH510** » Mon Mar 27, 2017 2:06 pm

Hi all, been having a few battery issues with the X5. Start of Feb i had a flat battery, it failed to jump/booster start, but was still the original battery, so i purchased a new one. All was well until about 2 weeks ago. I came home one night and noticed the front left headlight(not the angel eyes, the low beam) was on, not the rear, indicator stalk was central-battery was flat. I jumped it and took for an hours drive, all was fine for a day or two.

Then the battery went flat again, jumped it and drove round, battery charged fine, parked it up, waited 16 minutes an noticed it went to 'sleep'(P light went out), but battery was very low and would not start the next day.

Not sure if related, but changed the front left indicator bulb the day before the headlight turned on of its own accord??

Anyone had this/any ideas? was thinking the light control units(LMU i think its called?)

DARTH510 · Post by **DARTH510** » Mon Mar 27, 2017 2:07 pm

X5 E53 3.0d, facelift, factory original, apart from towbar.

Horizon · Post by **Horizon** » Mon Mar 27, 2017 6:55 pm

[quote="DARTH510"]
Hi all, been having a few battery issues with the X5. Start of Feb i had a flat battery, it failed to jump/booster start, but was still the original battery, so i purchased a new one. All was well until about 2 weeks ago. I came home one night and noticed the front left headlight(not the angel eyes, the low beam) was on, not the rear, indicator stalk was central-battery was flat. I jumped it and took for an hours drive, all was fine for a day or two.

Then the battery went flat again, jumped it and drove round, battery charged fine, parked it up, waited 16 minutes an noticed it went to 'sleep'(P light went out), but battery was very low and would not start the next day.

Not sure if related, but changed the front left indicator bulb the day before the headlight turned on of its own accord

Anyone had this/any ideas? was thinking the light control units(LMU i think its called?)
[/quote]
I would go back to the indicator build change. Remove the bulb and make sure it's the correct bulb, I guessing it's not an LED? On BMW's when one of the bulbs go in the front they have a safety feature that turns another bulb on instead, i.e. If a front marker light goes the indicator bulb will come on instead. If the new bulb is confusing the system due to having too low a resistance, maybe this could be the cause.
Only guessing really, but it's the first place I would look.

DARTH510 · Post by **DARTH510** » Mon Mar 27, 2017 8:15 pm

The indicator bulb had a silver coloured finish, the one I fitted didn't, but got it from Halfords and was the recommended one from the manual. I changed both front ones was a 2 pack. The light being on was on the side that the bulb failed on and was the night after, which is why Immentioned it. All lights work okay. Not led bulbs, just standard orange bulbs.

will look at changing them.

X5Sport · Post by **X5Sport** » Mon Mar 27, 2017 8:52 pm

It may not be connected with the bulbs at all, especially as the car is going to sleep in the right time. There is definitely a fault with a holder or bulb which is causing the trigger of the other lamp, but that may just be coincidence.

You need to get a voltmeter and connect it to the jump points under the bonnet. Check that the engine running voltage is at least 13.8V DC and no higher than 14.6V DC. 4 hours after last use, again under the bonnet and with the car off, locked and asleep, it should be no lower than 12.6V DC

There is another possibility and that is the starter motor. These are a known weak point (especially 2004/5 builds with Magnetti Marelli starters) and can draw significant excess current which appears to be a flat battery but isn't, it is the battery unable to cope with the demand. The starter should draw no more than 180A however my E53 drew 900A and our E46 drew 540A. Both starters were replaced with Bosch for about £200 ea plus my labour.

It manifests as very slow cranking and even if you recharge the battery the starter will kill it again within one or two more attempts. I had to recharge our E46 every day (two starts and a 60-mile commute) whilst waiting for the bits from ECP and time to do the job. You will need a 'current clamp' rated to 1,000A DC to check it.

DARTH510 · Post by **DARTH510** » Mon Mar 27, 2017 9:17 pm

The battery completely drains though after two days, not just not starting. I still have one of the original indicator bulbs and the packet the replacement ones came in, so will check they are same spec tomorrow (as in boot, and won't open), but I just can't see how the bulb could drain iit its definitely going into sleep mode.

The night after I replaced the left hand front indicator bulb the front lefthheadlamp was on? I never disconnected it either, just pulled it forward and changed the bulb. Strange ccoincidence maybe? .

X5-D-Sport · Post by **X5-D-Sport** » Mon Mar 27, 2017 11:35 pm

Any one had any thoughts that it could possibly be the Cabin blower regulator / hedgehog ??

I had a BRAND NEW battery fitted after similar issues... a monster battery... & kept getting a flat battery.

Turned out that the Hedgehog had failed, even though the blowers worked properly, was allowing a lot of current to dump a fully charged battery.

The interesting thing is that the heat sink on the hedgehog is huge, so it allows the part to get very hot without fire issues, so it can dump huge resistance heat whilst discharging the battery.

Smeeagain · Post by **Smeeagain** » Tue Mar 28, 2017 1:46 pm

yes it could be - we haven't had many FSR/hedgehog posts for a while

Smee

DARTH510 · Post by **DARTH510** » Tue Mar 28, 2017 6:59 pm

I did think about thehedgehog , but heating/fan works fine and doesn't run when switched off. Worth replacing just in case?

X5Sport · Post by **X5Sport** » Tue Mar 28, 2017 7:08 pm

Given how cheap the part is, that has to be a yes.

henrym3 · Post by **henrym3** » Tue Mar 28, 2017 8:09 pm

So are we saying that if you had/have a drain problem that if hedgehog appeared to work fine it could still be the cause and when switched off overnight would there be enough heat generated so that you could feel it if you put your hand in that area in the morning before starting.

X5Sport · Post by **X5Sport** » Tue Mar 28, 2017 8:51 pm

The only real way to check is to put an ammeter into the circuit to see what current drain there is and then remove fuses until it vanishes. You should expect <80mA with the car asleep.

The FSR is a known high current drain source even if the heating appears to be fine. The usual symptom of a fault is the fans running on, but there have been a couple of reports over the last year where everything appears normal with no fans running and the fault was traced to the FSR.

It may not be the case here, and I would have expected it to be warm certainly if it was the cause. I don't know how hot it gets.

X5-D-Sport · Post by **X5-D-Sport** » Tue Mar 28, 2017 9:27 pm

Hedgehog....
My heater blowers ran perfectly & shut off when the ignition switched off... however, this nasty device was killing my battery every night.

henrym3 · Post by **henrym3** » Tue Mar 28, 2017 9:33 pm

thanks, knowledge is power, no matter how little one has

DARTH510 · Post by **DARTH510** » Wed Mar 29, 2017 11:49 am

Right, I shall replace the 'hedgehog' Fsr, where'sbest to get one? Stealership ? Fleabay? Are non genuine ones Ok? Or just try euro car parts etc

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