Battery life How long to discharge

[Rick G]

I have been having problems with the battery discharging if the car is left without being run for any more than about 10 days. I don't think the battery is very old and from what I could see was almost new 2 years ago. My 740iL will sit for a month without significant discharge but this heap 01/2004 E53 probably eats it up a bit quicker but I didn't think that 10 days was acceptable. What has been others experience and maybe I need to invest in a smart trickle charger.

[Greydog]

Morning Rick
As I understand it the X5 when in sleep mode should draw 38 miliamps or 0.038 amps enough to keep memory in the things that need it (clock radio nav etc)

Obviously Battery condition will dictate how long it can be left as will any aftermarket parts that are fitted which may need a power draw while the car is asleep over and above the design parameters. BMW use common earth connection points (comb type) make sure they are all clean and seated well. The 4.4 was drawing 1.2amps no wonder it was killing the battery.

My 4.4 had a DVB TV box fitted as the analogue signal here was turned off, about a week was the battery limit without engine running. As I was having other issues with the Radio/Nav system I fitted a Dynavin unit and my battery drain was miraculously cured so I suspect the DVB tuner (non BMW) or something else in the OEM entertainment system was the cause.

Dave

[X5Sport]

If it helps, BMW Dealerships are instructed to recharge their cars in a monthly cycle, and I’m doing the same with all of ours at present. The latest models in showrooms seem to be permanently charging!

I did have a couple of occasions when after coming back from holiday, my E53 would not start after just two weeks, however that may have been down to the on board phone system (yes you could still have them in 2005) periodically logging into the network. I also had a tracking system fitted which slightly increased the overall sleep consumption to charge its own battery..

As said above, the rest will depend upon battery age, condition, and car usage.

[Sandy5454]

Worth checking if you can find what is draining the battery. Plenty of Y/Tube videos which how to check and trace a parasitic draw. A Smart battery charger (Cteck make good ones) would do the job but you should find out what is causing the problem.

[Rick G]

Thanks for the replies I didn't want to be chasing what was perhaps a nonexistent problem.
I am well versed on checking for drain etc so it seems that 10 days is somewhat short of what I can expect from a top notch battery.
I will keep an eye on it for a while as it's only had short runs with the lockdown but I'm doing a 350km (us Queenslanders have been let of the leash) round trip tomorrow so that should top it up well.

[henrym3]

I don’t think 10 days is that bad but there’s certainly room for improvement. I’ve had great success with the CTEK doing a resulphate cycle which took 3 days to get a green light but vastly improved the battery performance

[Alan Gunn]

Recently my 02 diesel has sat for 2 weeks at a time then done a 9 mile trip then a few hours later 9 miles back home.
It starts no problem at all but don't know the age of the battery it was on when i got the car but it's a Bosch with the blue top.
Never had a tank of diesel last so long still nearly full..

[X5-D-Sport]

I have had 3 of these E53 D-Sports on 2004 & 2005...
All 3 of them would give me about 10 to 12 days MAX to do a cold start.
14 days without running & there was no chance of starting them....

My Current Ef3 D-Sport has a 1000 Crank Amp Battery on it - only just fits in the well... and I wont get the vehicle to start at day 14....
10 days Yes, but not 14.

[Graeme]

Well, I don't take the risk of having the battery of my F15 4.0d go flat - so each week for the past 13 I give it 3 hours on a trickle charger after starting it and running the engine for a few minutes. The car's been off the road since mid March but is stored in a garage. The discs are clean - and handbrake off so I hope all will be well - likely to be taxed in August when the shielding I'm subjected to is eased a bit (I hope!!!)

Graeme

[hennabm]

My E53 will go for around 7 - 10 days without going totally dead. It certainly is the worst car I have had for battery drain. Al the usual suspects are OK. Why do I live with it you may ask - because I love driving the beast.
It has a BMW AGM battery in it that is only 18 mths old.

To make it more usable I have installed one of these to it and I can now leave it as long as I want. This has been especially useful given the recent situation.

https://www.ebay.co.uk/p/1380278963?iid=312738567894

There are other suppliers of the same thing on egay.

I too have never had the consumption so good - around 60 days per tank.

[X5Sport]

100A rating for continuous use isn’t high enough for the newer X models. They draw up to 70A before the starter button is even pressed, plus another 180A when it is. 100A is low for the E53

At full load (such as the winter) your alternator is throwing that much (and more) at the battery. It might be 1,000A switched, but for how long does that actually mean? Milliseconds or seconds? It used to be called ‘momentary’ rating and it meant just that, momentary.

As an engineer I personally would want a little more headroom - at least 150-175A continuous on an E53. My X6 generator us rated at 230A.

[X5-D-Sport]

from memory - which is pretty poor these days I must admit...

I fitted a monster battery on my X5 just after Christmas..
I think is was a 1000 Amp battery & 100 Amp hr & 700 Crank amps

meaning 1000 Amps momentary - ie 2 seconds or similar..... 100 amps discharge for a whole hour .... & 700 crank amps available to the starter on demand
or similar.

[cooa99]

How do I confirm if the battery on my x5 is bad or there is a drain?

Since the lockdown started I find that I have to crank for a while before the car starts up. This is usually the case after 2 days of use. I have used the CTEk MX7 a few times but still back to same issue after 2 to 3 days of no use. The Bosch is only about 1.5yrs old and was a warranty replacement for the previous one that lasted 4 /5 yrs.


Thanks

[X5Sport]

That might be fuel needing pumping back up rather than a battery issue. If the fuel rail depressurises then it takes a few moments to get it back up. I can’t remember whether there is a non-return valve in the system that should maintain a certain pressure for faster starting.

There’s no simple way of checking for a battery discharge as you either need a meter in circuit, or better still a current clamp around the +ve, to measure what the current draw is when the car is asleep. It should be a tiny amount - significantly below 80mA.

I recharge all of ours every three weeks of non (or little) use. You can check the volts with a meter and it should hold at least 12.6V when fully charged and 4 hours after the car goes to sleep - measured under the bonnet. It isn’t unknown for batteries to fail early and if it’s an AGM type and has gone flat then its service life will be significantly shortened as they really don’t like going flat.

[Alan Gunn]

I agree with X5Sport on the fuel running back or loosing pressure.
My car stood for 2 weeks again but still started just the same.
Only thing i can think of that might differ from others is i have a android head unit and it shuts down instantly could the factory fitted system drain the battery a bit.