Member Since: 15 Jun 2015
Location: Oslo
Posts: 10
Is this normal battery drain?
I have a 2011 D4 which seems to drain the battery really slow, and I know this is not a new topic and that these cars love to consume power... but, is it above or below normal consumption?
As I understand it the drain should be below 30mA when the car is asleep.
What I'm observing is the amp-meter bouncing between 0 - 2mA and approximately every 30 seconds going up to 40, 50, 60mA. This happens pretty regularly but only for a few seconds.
I have been measuring the voltage on the small blade fuses under the hood and not gotten any readings while the amp-meter has spiked. I have also removed the bigger fuses and the spike continued to show up on the amp-meter.
(I guess the next step is to check the fuses in the car )
Is the behavior I'm observing normal and/or is the spike too high?
It seems to drain the battery from 12.6V to maybe 12.4 in 8-9 days (while in sleep mode)
6th Nov 2024 8:53 am
M3DPO
Member Since: 22 Sep 2010
Location: Notts.
Posts: 8225
Can’t see what your problem is!- except a fully charged 12v battery tested across the terminals should be 13.2v-13.4v, 12.6v is very low.It can when others can't,
It will when others won't,
It goes where others don't.
6th Nov 2024 10:27 am
itsaguything
Member Since: 20 Dec 2023
Location: Manotick, On
Posts: 256
Not entirely accurate. Best read the distinct descriptions of agm and flooded batteries at the varta website.
As for the drain you are noticing, to what period of time did you perform your observations?
This matters as there are a series of operations that are conducted as the vehicle shuts down and systems it continues to monitor. This is very well documented in the Workshop Manual.
One thing to note, If the battery is in good health and fully charged on shutdown, the vehicle may sit for 60 days without any issues on startup. (I do this frequently).2015 LR4 HSE Lux Aintree Green
2013 LR2 HSE Radiance Red
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2005 XJR Jaguar Racing Green
2002 S-Type R British Racing Green
6th Nov 2024 10:52 am
motom
Member Since: 15 Jun 2015
Location: Oslo
Posts: 10
The battery was replaced in August, Exige AGM, but was discharged to under 10V this summer when the car sat for a while. I have tried a slightly older battery (2years old) and experienced about the same drain so even though the batteries are not perfect I still would like to know if the amp's drawn are valid.
The measurements were taken last week. The car was parked up last Sunday and I fixed the hood switch and then I took some voltage readings over the following days. I got a clamp meter last Wednesday and started following Robbie's guide. The car has been asleep (locked, not started, and no key close to the car) the whole time, until last night when I pulled the big fuses, the alarm fuse amongst them, and the car woke up.
It read 12.64V on Monday 18th and yesterday, Tuesday 5th, it was down to 12.43V
6th Nov 2024 11:47 am
motom
Member Since: 15 Jun 2015
Location: Oslo
Posts: 10
I've been reading up on the Service Manual and found this text:
Quote:
The battery drain should be measured using an approved diagnostic system or a Digital Multi-Meter (DVOM). The vehicle should be in the locked/armed state (for example vehicle alarm fully armed), all doors, engine and luggage compartment lids are open and latched (so as to appear closed from an electrical point of view). The test should take place after the vehicle has entered shutdown mode. The time taken for this to occur after the ignition is switched off varies according to model - Refer to Quiescent Drain in section 414-00 of the Workshop Manual.
• NOTE: When the vehicle is armed, the effect of the security system Light Emitting Diode (LED) flashing is to cause a pulsation in the measured current drain. In this case, either the average current should be taken (using a Digital Multi-Meter (DVOM) with an averaging system) or the current reading taken, ignoring the brief high current peaks.
Not sure I have the right equipment to take the average current draw
It also looks like peaks above 30mA is possible, so over what period should one calculate the average?
7th Nov 2024 9:29 am
itsaguything
Member Since: 20 Dec 2023
Location: Manotick, On
Posts: 256
keep reading…2015 LR4 HSE Lux Aintree Green
2013 LR2 HSE Radiance Red
2007 XKR Jaguar Racing Green
2005 XJR Jaguar Racing Green
2002 S-Type R British Racing Green
8th Nov 2024 11:39 am
PROFSR G
Member Since: 06 Mar 2017
Location: Lost
Posts: 5042
12.6v or above is a fully charged battery, 12.06v is a 50% charged battery. yµ (idµ - eAµ) ψ=mψ
8th Nov 2024 11:54 am
motom
Member Since: 15 Jun 2015
Location: Oslo
Posts: 10
Thanks to those offering advice! Was maybe hoping for a little bit more help with how to measure what constitutes a normal vs above normal current draw; i.e. what the manual calls quiescent current draw.
From what I have read the amp usage should be below 30mA over 10 minutes, but it seems like this requires proper equipment to measure and is something many of the great guides out there, like Robbie's, don't go that much into how to measure. The manual also states that with some extra equipment like towing package, the draw can be a little above this as well, and still be within spec.
From what I have seen from my clamp meter and what I can calculate the draw is about right, or maybe slightly higher than the 30mA, but hard to tell from just my own observations. Probably need to get a proper logger.
For now the car seems to behave normal, and as long as the car is regularly driven the voltage seems fine.
14th Nov 2024 9:51 am
itsaguything
Member Since: 20 Dec 2023
Location: Manotick, On
Posts: 256
True enough. Nonetheless, a 30mA draw on a 900 A battery is nothing to worry about for a vehicle sitting a period of nearly 3 months.
As I park in a carriage house, I do not lock the doors nor activate the alarm system. So my draw is minimal.
Every time you open any door however, you are back to square one as the draw will significantly increase.2015 LR4 HSE Lux Aintree Green
2013 LR2 HSE Radiance Red
2007 XKR Jaguar Racing Green
2005 XJR Jaguar Racing Green
2002 S-Type R British Racing Green
Last edited by itsaguything on 15th Nov 2024 9:32 am. Edited 1 time in total
15th Nov 2024 1:24 am
HairyFool
Member Since: 04 Jan 2023
Location: North Essex
Posts: 676
The “sleeping “ current should indeed be down to a few 10s of mA and well within the range of most DMM
Unfortunately as soon as you open a door or do anything to wake the car the current should shoot up and blow the DMM fuse
On mine with the rear screens coming on I measured 15A with a clamp (after I had replaced the fuse ~) )A visitor from the dark side, my other vehicle is an is still an EV. Strictly speaking its SWMBO.
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