[T6] Looking for the D+ signal wire in a T6

[Bryn23]

Well, while the flooring is up as I'm currently sound deadening the cab, I'm running new cabling to replace the Factory Relay Aux charger and the DC-DC charger asks for a D+ connection, instead of a ingintion live, so it can't drain the main battery.

I'm assuming this is off the back of the Alternator, has anyone got a pic of it.

Couldn't find it through google or here for a T6

Cheers,

 

[Pauly]

Not sure what D+ means but if you can elaborate I'm sure there will be an answer

 

[Bryn23]

Hi Pauly, it looks like a alternator wire take off, so its only active when the alternator is running to prevent starter batter drain.

The diagram I'll be using is standard connection on page 3, and also a write up of D+ on page 7.

I did fine some reference of D+ connections on the T4 fourm, but they were on T5's and different 5.1/5.2 models seem to have different postion, the diagrams and picture relaying to this were missing due to the photo bucket issue.

I have the Votronic control board, pictured on the bottom of page 14, hence why I'm looking at this, as it fits well with all the votronic gear and sensors i have.

 

[Bryn23]

I believe the Sargent units in the UK, use the same D+ pick up for there unit

 

[Pauly]

I think @travelvolts is the person who will know exactly what's what

 

[Bryn23]

You're right, Travelvolts will most likely know, as he knows his stuff.

it'll be interesting to see where this D+ connection is in the T6

 

[travelvolts]

There is no D+ connection on an intelligent alternator. Use one of the ignition controlled fuses from the centre column of the internal fuse box.

 

[Bryn23]

Well there you go, i've learn't something new today.

Thanks for that

Its not easy looking for something that doesn't exist.

I'll check out the centre row tomorrow and piggyback

 

[Bryn23]

Just one question Travelvolts, With the ignition controlled fuses in the centre column, the mini fuses.

Is there any chance of those feeds linking the board battery and the starter during ignition?

I've got the signal and power feeds through, i will fit the piggy back fuse to the signal feed and put feed it through to the fuse area tomorrow, and will wait until i have the cab back in one piece, so i can check the feeds once the airbag seat connectors are connected and seats are back in place.

Now I'm just waiting for the new control unit to come in from Germany.

 

[Owain]

Hi,

battery/battery is euro 6 charger wants a D+ (IGN+) shown as coming from alternator.

After racking brain/googling for weeks, i have paid for erwin end now see my t6 with start/stop has no D+ connection to alternator.

Alternator has normal negative, B+ and a LIN bus (cheap CAN alternative). So a "smart" alternator.

So what does D+ indicate? Is it a control signal to alternator or a status signal from alternator?

I could imagine the LIN is used to tell alternator to ramp increase/decrease load on engine, for breaking etc, causing power from alternator to incease or decrease.

Any suggestions greatly appreciated.

Don't we all long for the simple/good old days before all this computer shite. And that coming from a computer engineer....me.
,
All the best,
Owain



What

 

[Loz]

Any ignition live will do for the DC-DC charger.
As I was replacing the factory split charge relay for a DC-DC unit I used the trigger feed from the relay I removed.

 

[Dellmassive]

The factory OEM split charge relay has a wire run from the BCM that switched to +12v when the engine is running and cuts out when the ignition is switch OFF.

if you dont want to run the wire to the BCM you can take a +12v ignition feed from the SC fuse box under the dash . . . . (center line is ignition fed)


BCM connection J519 T73a/3 as hsown here > Second battery wiring diagram

T73a 73-pin connector, black
J519 Onboard supply control unit

.

 

[Pauly]

I think the point is the D+ means engines running where as an ign live just means key are turned (not necessarily engine running)
I have used an ignition live on mine and it’s fine just remember if you key on the B2B will try to charge from your engine batt

 

[Owain]

Super guys. So it's just a 12v signal to say its ok to charge from other battery.

After the hassle of tapping into the CAN for the towbar on that J73, I think I will take the easy option of Ignition feed.

Thanks for the quick responses. I'll get to finishing my wiring now.

 

[hodgo10]

Hi Bryn23, I see that you have the Votronic triple, I know this thread is rather old but would love to know how you got on with it and whether using the switched fuse sorted your D+ problem out? Did you use the AES solar output for a fridge?
Looking forward to installing mine this weekend, surprised this unit doesn't feature much in this forum, though there is a lot of brand loyalty here someone on this forum must work for sikaflex

 

[travelvolts]

The Votronic triple is a great bit of kit but it's not everybody's Cup of tea and it can be a bit too bulky for some layouts. Coupled with the fact that the supply in this country has now been monopolised and completion removed the price is no longer attractive might explain why it is not so popular as some of the competitors products.

 

[t0mb0]

I'm never quite sure on the terminology, so I don't know if it's technically called a D+, but the T6 with a factory fit leisure battery uses a 'D+' signal wire for the relay which is only live when the engine is actually running (as opposed to the standard ignition live). Whatever it's called, this is clearly the optimal signal wire for a DC-DC charger because it's live if, and only if, the alternator is capable of supplying current. However, I've no idea where to find this in a standard T6 without the factory fit leisure battery option...

 

[rod_vw]

As said by @t0mb0 above there is also a connection from the BCM that VW use to switch their split charge relay. This is not as easy to connect as picking up an ignition switched wire and also needs coding of the BCM. I have used this in the past on T5s. I have installed this connection when converting my current T6 although don't use it as I have a Battery to Battery charging unit fitted.

 

[Dellmassive]

The T6 "Engine Run" feed from the BCM is shown here:

T6 - Second battery wiring diagram

Second battery for transporter ( not California)

www.t6forum.com

+12v switched on when RPM engine run is detected.

used by the OEM setup to switch a 80A relay that connects the second battery (old skool SCR)

 

[rod_vw]

The T6 "Engine Run" feed from the BCM is shown here:

T6 - Second battery wiring diagram

Second battery for transporter ( not California)

www.t6forum.com

+12v switched on when RPM engine run is detected.

used by the OEM setup to switch a 80A relay that connects the second battery (old skool SCR)

View attachment 70918

Thanks @Dellmassive this is what I referred to above but it does need 'switching on' by coding of the BCM. I'd forgotten that there was a snippet of the wiring diagram on the forum.