P38A USB connector/voltmeter installation.

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Datatek

Well-Known Member
Posts
43,970
Location
Near Poitiers SW France
Not sure if this will be of interest.

I have always missed having a voltmeter on the P38, finding something that could fit without altering the appearnce of the car meant I had done nothing about it todate.

With the lockdown and bad weather I had look at what could be done.

Some time ago, I think it was Dopey, mention was made of USB sockets with an integral volt meter, so I ordered a couple.

They will not fit the switch blank positions on the dash, so as the ash tray is unused, I decided to mount one in there, it has the advantage that I can shut the lid at night as the display is quite bright.

The ashtray just pops out. I made a mounting bracket from a bit of scrap 32mm x 2mm alloy bar, it's a bit rough but is not very visible. Normally I would have painted it mat black, but no paint available so just buffed it up. No measurements, I just bent it up by eye.

The USB connector is held in the bracket with a few blobs of hot glue. Before fitting the bracket, pop out the little window in the side of the ashtray to route the cables. I taped the window in the bottom of the ashtray so it would not get lost. I soldered and sleeved the wires to the socket as there was not enough clearance for the connectors.The bracket is held in the ash tray by 2 countersunk M3 screws. Self tappers would do.

To refit the astray it's necessary to remove the gearlever surround, first remove the 2 screws holding the window switch pack, lift it up enough to access the single screw holding the gear lever trim. Put the ash tray back in then lift the trim out which will expose the cigarette lighter connections. I spliced the feed into the cig lighter with soldered joints and heatshrink Scotch locks will not do because of the current draw IMO but crimps are OK. Careful to get the polarity right.

Then it's just a matter of turning on the ignition to see if it works followed by reassembly.

The car had been stood for 5 days and the battery showed 12.6 volts where it tends to stay, engine on I got 14.4 volts at idle.
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The photo's will hopefully make things clear, write ups are not my thing.
 
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Nice one, i was looking at fitting one off them an was going to replace on of the switch blanks but that is much easier and hidden away :)
 
I don't smoke cigars, so I replaced the cigarette lighter with the same kind of socket, but circular ie 2x USBs and a voltmeter. I agree - it's a great fix, and nice to be able to tuck away behind the lid when not needed. https://www.ebay.co.uk/itm/12V-24V-...199795?hash=item26390227b3:g:i5oAAOSwIxVemqML I think I needed to take off about 1mm of ABS from the hole for the cigar lighter (one thread's worth), but you may not even have to do that if you use a different unit
DSC_3503[1].JPG
 
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I think they should be made mandatory fitment, to give our self's a fighting chance on impending doom :D.
Easy of checking alternator out put with out even opening the bonnet:)
How many times have we all ask on here whats you battery voltage at 2000rpm and got dont know and how do i check that:(
 
True - best mod I did, that and the one that disables the headlights when the ignition is off, which runs off the same wiring
 
You mean 1x, or 2x? Are you running a battery charger: o)

The cigar lighter is powered via the BeCM, not sure I would want to push it with that routing
 
Why the hell is the fag lighter attached to the BECM at all???

Because it comes off the fuse box there.

You mean 1x, or 2x? Are you running a battery charger: o)

The cigar lighter is powered via the BeCM, not sure I would want to push it with that routing

5A at 5V is only 25W, which at 12V is a shade over 2A - not that much to be pulling from there... the cigar lighter/accessory socket in the loadspace (on later models) comes off F8 at the BECM which is 30A rated, and the wiring to the cig socket is pretty hefty...

new new nav.jpg


I added one aswell when I put my new nav unit in - though I don't think the volt meter in mine is the most accurate!! Though I am in the process of upgrading the ground/+ve cables from alternator to the battery - and this was after awhile of poking about with the nav system...
 
Because it comes off the fuse box there.



5A at 5V is only 25W, which at 12V is a shade over 2A - not that much to be pulling from there... the cigar lighter/accessory socket in the loadspace (on later models) comes off F8 at the BECM which is 30A rated, and the wiring to the cig socket is pretty hefty...

View attachment 212445

I added one aswell when I put my new nav unit in - though I don't think the volt meter in mine is the most accurate!! Though I am in the process of upgrading the ground/+ve cables from alternator to the battery - and this was after awhile of poking about with the nav system...

Where's your headlights switch gone?
 
"5A at 5V is only 25W, which at 12V is a shade over 2A"

granted - but with 2 slots... I have wired another socket into the towing socket wiring on the LHS of the loadspace for heavier stuff (was for a solar panel on the parcel shelf, which I have since concluded is a waste of time).

Nobody got the battery charger joke : o)
 
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"5A at 5V is only 25W, which at 12V is a shade over 2A"

granted - but with 2 slots... I have wired another socket into the towing socket wiring on the LHS of the loadspace for heavier stuff (was for a solar panel on the parcel shelf, which I have since concluded is a waste of time).

Nobody got the battery charger joke : o)

I've got a similar setup. Added a power-socket above the light cluster in the boot on permanent 12V for solar panel and other stuff. Never needed the panel but have used it for other stuff.

I also added a power outlet in the rear ashtray piggy-backing off the one in the front ash-tray. The family uses it constantly for devices. With hindsight I would have done better removing it and putting a whole bank in.

Odd to think cars used to have ashtrays everywhere. I've never smoked but I do use them for parking money and for holding bits when working on the car.
 
Not sure if this will be of interest.

I have always missed having a voltmeter on the P38, finding something that could fit without altering the appearnce of the car meant I had done nothing about it todate.

With the lockdown and bad weather I had look at what could be done.

Some time ago, I think it was Dopey, mention was made of USB sockets with an integral volt meter, so I ordered a couple.

They will not fit the switch blank positions on the dash, so as the ash tray is unused, I decided to mount one in there, it has the advantage that I can shut the lid at night as the display is quite bright.

The ashtray just pops out. I made a mounting bracket from a bit of scrap 32mm x 2mm alloy bar, it's a bit rough but is not very visible. Normally I would have painted it mat black, but no paint available so just buffed it up. No measurements, I just bent it up by eye.

The USB connector is held in the bracket with a few blobs of hot glue. Before fitting the bracket, pop out the little window in the side of the ashtray to route the cables. I taped the window in the bottom of the ashtray so it would not get lost. I soldered and sleeved the wires to the socket as there was not enough clearance for the connectors.The bracket is held in the ash tray by 2 countersunk M3 screws. Self tappers would do.

To refit the astray it's necessary to remove the gearlever surround, first remove the 2 screws holding the window switch pack, lift it up enough to access the single screw holding the gear lever trim. Put the ash tray back in then lift the trim out which will expose the cigarette lighter connections. I spliced the feed into the cig lighter with soldered joints and heatshrink Scotch locks will not do because of the current draw IMO but crimps are OK. Careful to get the polarity right.

Then it's just a matter of turning on the ignition to see if it works followed by reassembly.

The car had been stood for 5 days and the battery showed 12.6 volts where it tends to stay, engine on I got 14.4 volts at idle.
View attachment 212401 View attachment 212402 View attachment 212403 View attachment 212405 View attachment 212406 View attachment 212407 View attachment 212408 View attachment 212409 View attachment 212410 View attachment 212411 View attachment 212412
The photo's will hopefully make things clear, write ups are not my thing.
Niiiice job sir :cool:
 
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