12.53 right now and just disconnected the headunit. Also fully removed the parrot handsfree that was in there but not powered. Will see how quickly it depletes. Is it easy enough to find the draw of various connections? I'm a bit of a multi-meter novice.
12.53V is not all that bad if its stood for a day or two, does it start at that voltage ?
To check with your multimeter you will need to select amps or milliamps, do you have a manual for the meter, read up on how to connect for current readings (amps). it's easy to blow fuses or meters if not careful.
Sometimes there will be a zap type spark as you disconnect or connect the battery, capacitive discharge by a component, can look worse than it is, but a warning.... some components don't like it and won't tolerate it, I had an auto headlight switch fail because of it one time, it's why newer jumper leads have an "anti-zap device" built in.
Connect the meter leads to the appropriate meter terminals, then select the 10A scale first.
Disconnect the negative cable(s) from the battery, Connect the meter in series (in line) with the earth (negative) cable(s). Wait for at least 35 minutes before recording the readings, giving the CAN lines time to have all gone to 'sleep'. It will now require switching from the 10A scale to a milliamp scale for a more accurate reading. DO NOT try and start the engine with the meter
Once established if a 'more than normal drain' then start checking by disconnecting fuses and consumers one at a time and checking the meter.
Thanks both.. @OSTY unfortunately 12.53 was a reading taken the morning after charging it. Its drops to 12.3 after a couple days and continues. Only looked into this because it was left discharging for 5 or more days and prob went sub 12 and then woudnt start. I'll grab a coffee and have a read, thank you.
Ours was doing pretty much the same. A couple of days sat doing nothing and it would fail to start. Got a portable unit to allow jump starts and even that wouldn't start it. Checked with the multi meter and it had dropped to 10.3v. Decided it was perhaps time for a new battery, got it from Euro Car Parts with 45% off so was only £44. Admittedly it is only a Lion battery so probably not great but all good now. Also have invested in a solar battery maintainer to help with the constant draw you get.
I had the same issue after eplacing my head unit
I had to turn my stereo system off using the power button on the unit which I thought was fine
Essentially it leaves the entie unit live and it need a switched pos so that it goes off when the key is removed. The CanBus has a seperate feed as does the unit which is purely for memory
Yes but see Osty's post above. There is a nice easy explaination here. My early 2.5 shows 30mA after about 15 mins. Some systems take longer to shut down fully. You can fool the bonnet switch into thinking it is closed for the test with a screwdriver but remember to release it again before slamming it shut!
Thanks, thats the exact vid i saw earlier, good explanation. Had no idea keeping the bonnet open would cause some draw as well. Will test soon. Does it matter if the test is done on a battery at 50% as many are saying fully charge first
Fully charged battery only. I can't actually remember if the bonnet open warning on the dash would even work without the igniton on (which you won't have of course) but some vehicles will allow that. The the current draw would be tiny anyway but it's better to be certain about what you are measuring. If 15 mins still leaves you with a big current draw, leave it longer and test again. Your drain is going to be obvious if it can flatten a battery in four days. Are you sure the battery is good and holds up under load as suggested above?
After viewing Eric the car guy video one would think one of us copied the other,
almost word for word the same, like we had the same instructions.
btw - lock the rotary latch of the driver door and the bonnet is stated on page 5 of the TPL.
Anyway generally it's good, but for us VW owners the TPL bulletin is more VW specific,
(in the video a dome light switch is left on, a VW will switch that circuit off after 20-30 mins)
so I would recommend using that TPL and any other relevant material, pretty much for any
late VW, (maybe not elect. sliding doors), for diagnosing and fixing abnormal current drain.
And VCDS can substitute for diagnosis equipment.
This thread and similar interested me because of a current leak in my van some time ago,
in mine was a faulty air suspension valve control, took a while to track down.
For member chatlow if you follow these procedures you will eventually find the problem if it
is current drain, but I have to ask the same as T5TDI - Have you had the battery load
tested and is it good ?
Hi guys, thanks again for the help on this. No I haven't had the battery properly load tested - just been monitoring, charging and testing what I can myself during lockdown. Full battery 8am this morning. Went for a cycle and tested it an hour later. Load did show .35 for a few seconds, but this quickly dropped to 0.05 ish and not much higher.
bit of a late reply, but the following might be of interest when looking at starter battery values ...
I have a fairly new (just under a year old) battery in my LT.
The only drains would be the radio, any internal courtesy lights and the tachograph that is constantly ticking away.
I have a setup that allows the Starter Battery to charge from the Solar for upto 1 hour per day (08:00 - 09:00). This means I can get quite a good idea of the battery drain over the remaining 23 hours a day.
Last 2 full days were:
Start - 12.71V; End - 12.63V
Start - 12.66V; End - 12.61V
Todays Start is 12.65V.
So I see a drain of under 0.1V on my LT, but it is a pretty basic in terms of vehicle electrics to keep running so a more modern vehicle could likely be above 0.1V
have just found that I left my bluetooth OBD adaptor plugged into the van. Prob been in there weeks FFS. Guessing / hoping it's this that's caused the drainage.If so, then I'm sorry to waste everyone's time but also glad I've learned a few things!!