Measured 40mA (0.04A) with supposedly everything off and settled.
Is this fairly normal or do I need to start pulling fuses?
OT: Parasitic car battery drain
Apr 22, 2017
51 Replies
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Information here may be outdated?
AnthonyL explained on 22/04/2017 :
My car = 18mA with an occasional brief pulse up to 30mA, so not that far out.
Fairly normal.
Time to buy a Lidl charger for permanent connection, if the car is not used frequently.
Normal.
40mA from a 40Ah battery = 1000 hours = 40 days from full to flat.
NT
Problem is that charging systems are not designed to give a full battery, so a quarter of the capacity is more likely after a couple of years. My car cannot be left for more than 21 days according to the manufacturer. SILs Yaris claps out after 14 days.
That must be why people buy those 1w solar chargers.
Its probably a grotty ford with one of them there odd batteries and so called intelligent charging from the alternator. Most people I know seem to give up on the intelligent bit! Brian
Remember being told one car maker wouldn't entertain a battery claim if the car was left unused for more than 3 weeks.
Cars may progressively turn off systems (such as keyless entry, GPS if it usually listens to keep a lock on the satellites) after hours/days/weeks to prolong battery.
Wife's AUDI does.
I can remeber my Citroen C5 telling me it was in "saver mode" after 6 days of non use.
My S-Max does, too. It starts with a semi-low mode which means it has a slow response time (keyless entry takes a couple of goes). Then it shuts down some more.
This is a 2009 Mazda 2, fairly unsophisticated I think. Last year battery was dead flat after holiday, put it down to the age of the battery but same again this year. Jumpered to start and went on
100mile run next day. Both events in Feb and very little if any use in 6 weeks but just got round to measuring. So yes 40 days if battery was full sounds about right. The 1.8 petrol Focus had no such problem though - presumably larger capacity.Not seeing a very good solution to this. Solar trickle charger?
Disconnect the battery when you go on holiday.
How do you measure that? Do you have something that will log the readings, or are you using a multimeter and Mk1 eyeball?
I'd like to measure my car's quiescent current, but the battery is in the boot and leaving the boot open may prevent the ECU going to sleep.
I was considering putting together an arduino based current sensor that logs to an SD card using something like this INA219 to do the current sensing:
formatting link
But if someone has got an off-the-shelf solution, I'd be interested to hear about it.
Caecilius wrote on 23/04/2017 :
I was having flat battery issues, so I wired my AVO 8 across (in parallel with) the main bus-bar link. That way I was able to let the car settle to sleep, then disconnect a convenient bolt connecting the bus-bar to the main fuse panel.
Easily done with a storage scope and load resistor.
I tried to measure the quiescent current on my old Sierra, but you had to be careful, since switching it off pulled enough current to blow the 2A fuse in my ammeter.
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