I've replaced the cigarette lighter power with a double usb port. Just pulled out the lighter and removed the earth connector from the plastic holder so that live is still insulated.

 

Before I widen the hole to push the new one down, do you think I should install a switch? Or will the current to power the light on the usb socket by so minimal that it does not matter?

 

Thanks,

 

 

Mark

Ps this is of course in the wrong thread! Mk 2 Octavia.

I'd probably take a new feed from the fuse box to make it ignition switched. If it's left long enough on a weak battery it might be enough to flatten it. You could use a multimeter to measure the current it uses?

 

Well, actually, I'd use a small removable adaptor and not bother removing the 12v socket... That way it can be removed when not needed and also used to power other things car tyre inflators 😉

Is the 12v socket permanent live or ignition switched?

In mine I think switched.

It's permanent live.

 

The current is 11.3mA (0.011A) when it's powered but not charging anything.

 

I'm thinking of installing a little switch still.

 

 

Mark

I'm not sure I see the point. Once you start cutting the centre console there is no going back. All to get the USB ports flush?

 

As suggested above I'd just use one of these...

 

 

They are almost flush and can be removed and reinserted at any time.

That's a good solution, I'm going down this route though as we only ever use usb and it saves the fiddle of an adaptor.

As you have found the current consumed is primarily the quiesecent current of the power supply to the USB sockets.

 

I have fitted a similar one, mine has only one socket, a voltage display and an on/off switch, I bought it primarily to have something small and discreet which could monitor the battery voltage, I have lost one battery through a satnav switching itself on every 168 hours, the MK2 Octavia has plenty of things that can go wrong and wake up the canbus discharging the battery plus I changed the head unit which brought on those problems till I replaced the Can gateway controller.

 

Anyway I have spent the last few weeks obsesively watching every 0.1v drop and can say that switching the thing off makes no measurable difference to self discharge rate of the battery.

 

While I am on the subject, I have a new Varta E44 Silver battery, the LED voltage readout has been checked against 2 other multimeters and confers with them charging voltage while driving is 14vish, when I stop and lock the vehicle I expected it to drop to 12.7v especially in this warm weather but it immediately drops to 12.4v and will be at 12.2v a couple of hours or so later as it will be the next day, it does not seem to drop beyond that more than a further 0.1v over a couple of days.

 

Checked the standby current, its initially say 100ma (cant recall) but after 15 minutes or so (again not sure) it drops to 11ma quiescent, so I dont have a significant parasitic discharge, I'm fairly confident the car will have enough voltage to start after a week but it seems to me that the battery voltage is 0.5v lower than I would have expected, indeed my old batteries on the standby shelf show a higher voltage several weeks after their last charge to the new one after a couple of hours.

 

Do you think that I have a damaged cell or do the new generation of batteries have different characteristics?

 

Its still under warranty and came from a good seller (Batterymegastore.fr) so I can send it back, is 0.5v anything to worry about?

 

The car has always been such a good starter that you cannot tell if a battery is weak or not.

@J.R. - I've just checked my previous autoscans as the HEX-V2 gives a voltage at the end:
 

Log name                   Last log line
Log-203110km-126206mi.txt  End----(Elapsed Time: 01:28, VBatt start/end: 11.9V/11.9V. VIgn 12.0V)-----
Log-216520km-134539mi.txt  End----(Elapsed Time: 01:17, VBatt start/end: 11.9V/11.9V. VIgn 12.0V)-----
Log-242780km-150856mi.txt  End----------(Elapsed Time: 01:17, VBatt start/end: 12.1V/12.1V)-----------
Log-243490km-151297mi.txt  End----------(Elapsed Time: 01:12, VBatt start/end: 12.7V/12.6V)-----------
Log-244620km-151999mi.txt  End----------(Elapsed Time: 01:29, VBatt start/end: 12.1V/12.1V)-----------
Log-253340km-157418mi.txt  End----(Elapsed Time: 01:25, VBatt start/end: 11.7V/11.8V. VIgn 11.9V)-----
Log-255330km-158654mi.txt  End----------(Elapsed Time: 01:16, VBatt start/end: 14.0V/14.0V)-----------
Log-256750km-159537mi.txt  End----(Elapsed Time: 01:13, VBatt start/end: 11.9V/11.9V. VIgn 11.9V)-----
Log-272050km-169044mi.txt  End----(Elapsed Time: 01:15, VBatt start/end: 11.9V/11.8V. VIgn 11.9V)-----
Log-272420km-169273mi.txt  End----------(Elapsed Time: 01:14, VBatt start/end: 12.1V/12.1V)-----------

 

Most of them to agree that 12v is pretty normal for my car but it'll depend how accurate the HEX-V2 is.

 

Never had any starting issues, even when I've left it in an airport car park for two weeks

Looks similar to what I see when hooked up, but to use VCDS the ignition is on and all the other stuff is chatting away to each other so the voltage is always lower.

 

your results above are they with the ignition on and VCDS connected? The elapsed time is it hours and minutes or minutes and seconds?

 

If ever I get to leave my car for more than a couple of days and can check the voltage i will have more faith, I will put the battery on my load tester when I am next in the UK and compare it to the 6 year old but still good Bosch one that I removed.

 

The great thing about this little LED voltage readout is that I can see it through the window from outside, I dont have to open the door and wake up the electronics.

Typically, the ignition is switched on, engine off and VCDS connected.

 

In most cases, the car has probably been sat over night for ~15 hours. Saying that, the 12.7v was just after I turned off the car and the 14v was while it was running.

 

The time is how long the VCDS autoscan took to complete

So 11.8/11.9v after an overnight rest, vehicle unlocked, woke up, ignition on and a minute of so on VCDS.

 

I will check tomorrow but that sounds like what I have seen before.

 

Everywhere seems to say 12.7v for a fully charged battery, the old Bosch one has been off charge for about 6 weeks and it measured 12.45v, the Varta will be at 12.7 when I stop the engine after a run but will fall to 12.4 10 minutes after the doors are locked and be at 12.2/12.1 the next morning then it does not seem to drop any further.

 

I think there has been a slight change in cell voltage with the construction and materials of the latest batteries, just 0.05v per cell would account for the differences that I am seeing.

 

Initially i thought that  the cigarette lighter feed I used for the USB socket and perhaps also the VCDS feed had a diode in line dropping the voltage by 0.7v but i am getting the same readings directly at the battery.

Edited 25 June, 20196 yr by J.R.