battery drain

[oldnick]

in the middle of my test to check the voltage drop on the battery while it sits in the barn

this morning opened the boot , lights came on , tested battery , shut boot , walked away then realised I needed the torch I had left there

opened boot , lights DIDN'T come on ; suddenly realised that normally they don't !
if I understand correctly , if the battery is connected the lights should ALWAYS come on ; tried pressing the buttons which get pressed when you shut the boot ...no reaction
is there something here I don't understand , could this be the answer to a maiden's prayer [ so to speak ] ?

[HPsauce]

Faulty microswitch in boot latch?

Quite easy to take out and dismantle or just disconnect.
IIRC I have one, maybe two, spare such microswitches from my own "expeditions" in this area.

[oldnick]

Originally Posted by HPsauce

Faulty microswitch in boot latch?

Quite easy to take out and dismantle or just disconnect.
IIRC I have one, maybe two, spare such microswitches from my own "expeditions" in this area.

spot on HP , just gave a spray with wd40 , opened and shut a few times et voila

ta muchly

[HPsauce]

Hmmm, that's how mine started and the latch innards were damaged and eventually broke. I'd take it out and have a look.

[oldnick]

here's the result of my voltage drop test
first result a couple of days after charging , they daily
12.80
12.70
12.66
12.60
12.54
12.52
12.50
12.48
12.46
12.44
12.42
12.40

at which point I gave up and put back on charge ...as you will all know sulfation really takes hold if your battery gets below 12.40

so I seem to have a fortnight , well maybe , who's to say the alternator will charge up as much as the battery charger did
anyway , I went to amazon and invested £4 or so in a 500mA battery charge maintainer , switches off when fully charged , cuts back in again when the voltage drops

[oldnick]

just to add , somebody here advised contacting Audi at milton keynes so without much confidence I sent them an Email with my problem

had a phone call , nice young person said have checked your OE spec on our computer , your radio aerial/CD stack /concert radio is as factory fitted , we didn't fit either sat nav or phone , and if disconnecting what you have doesn't cut the drain we can only suggest a visit to an audi dealer who can plug in his computer and maybe find the problem

ok , didn't fix the problem but very helpful anyway to somebody with a 15 year old car

looks like my solution is going to be to run a cable from the fuse to the dash , fit a switch [ got a blank space ] to isolate the loom wiring that feeds the ICE , must be a leak from that !

[oldnick]

the 8 not being in use for much of the last 12 months resorted to just disconnecting the battery for much of the time
however now back in fairly regular use so am going to re-address this problem as it is a PITA !

just had a thought ; the radio doesn't lose it's code when the battery is disconnected [OE ] ....why not ? [ probably because I still have the nice tear out strip from the owner's manual ! ]

could this possibly mean anything ? is this normal on an early FL ?

I suppose I could just hot wire to the ignition circuit but that would mean turning the key to put on the ignition when parked ...hardly a good idea ! have given up the idea of putting a switch in the circuit , would certainly forget to switch it off !

[tc4332]

How about putting a latching relay to supply the offending kit?
If you use the correct one and feed it from the ignition then it will cut off when you switch ign off.
To switch the relay on and therefore supply the radio etc. you press the button. To turn it off you can either press the button again or switch ign off.
This means you cannot forget @cos the latching relay does it for you.

http://www.ebay.co.uk/itm/Latching-relay-board-with-single-pushbutton-input-to-latch-unlatch-relay-/111978409246?ha.
sh=item1a126eed1e:g:rbQAAOxyVLNS3kXv

The same supplier does a plastic box for it to fit in
I have used two of these in our buses and have another one ready to put in my A8.

[oldnick]

thanks ray , sounds like a plan , didn't know that existed
when I have the battery fully charged again will pull the radio , disconnect the live feed , leave the main fuse in and double check that this cures the drain [ have already done that with the CD stack to no effect ]
if that works will get one of those gizmos
if I read the spec correctly one needs just a flash of electricity to start up [ a bit like a bell push rather than an on/off switch ] ; got a spare slot in the row of switches on the dash ....is there a matching switch for something else that could be used ?

incidentally , rear seat entertainment ? have forgotten such days !

[tc4332]

Correct.
I use a momentary push button from Maplin. It has a LED in it that I connect to the relay output (as well as the load, in effect in parallel) to denote that the relay is latched in the "On" position.
I'l try and find the Maplin part number when I return home.

RSE is for when we have the grandkids on long journeys.