How to Solve Voltage Drop Issue in VW Crafter

[Hamboy]

Hi All, Looking for more advise.

VW Crafter 67 plate, stop start

Had Auto Electrician look at van today as i have a problem with leisure batteries not charging in back of van, He was getting 13.5v at van battery and 12.7 at leisure, which is less than 2mts away with 10mm cables between them, The b2b charger needs 13.2v (Stirling bbs1230) to work he tells me, so 1st how am i getting such a Voltage drop over 2mts, and how can i solve problem?, Can VW do anything via software to help?

Thanks in advance for any help.
Cheers

 

[Googlebot]

Sounds like the B2B isn’t working is all.

Has the electrician condemned it? I very much doubt it’s due to the van.

 

[Hamboy]

Sounds like the B2B isn’t working is all.

Has the electrician condemned it? I very much doubt it’s due to the van.

He's still looking into it, The van is euro 6 with smart alternator i believe, i'm not clued up on any of this to be honest

 

[Googlebot]

The B2B goes between the batteries, if the voltage is lower on the output side, it isn’t switching on.

The problem almost certainly is there if all the fuses are okay.

 

[pappajohn]

Sounds like the B2B isn’t working is all.

Has the electrician condemned it? I very much doubt it’s due to the van.

Agreed, either a bad connection somewhere or the B2B has failed.
My money is on a bad connection.

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[Richard n Ann]

Hi All, Looking for more advise.

VW Crafter 67 plate, stop start

Had Auto Electrician look at van today as i have a problem with leisure batteries not charging in back of van, He was getting 13.5v at van battery and 12.7 at leisure, which is less than 2mts away with 10mm cables between them, The b2b charger needs 13.2v (Stirling bbs1230) to work he tells me, so 1st how am i getting such a Voltage drop over 2mts, and how can i solve problem?, Can VW do anything via software to help?

Thanks in advance for any help.
Cheers

13.5v is low for the van's starter battery when the engine is running

 

[Lenny HB]

13.5v is low for the van's starter battery when the engine is running

With a Smart alternator once the initial charge current to the starter battery has dropped to 30 amps the voltage reduces to 13v.

 

[Pausim]

With a smart alternator the B2B needs to be D+ activated. Voltage activation will operate erratically and only when the alternator chooses to charge the engine battery.

 

[autorouter]

What Pausim says. On vehicles with non-smart alternators, it's reasonable to trigger the B2B with the voltage rise of the alternator. When there's a smart alternator, the main reason for fitting a B2B is that the voltage rise is variable, so it's unreliable for switching on the B2B. It should be triggered from the alternator D+ signal, which is definitely on all the time the engine is running, and off when it stops. Does your B2B have a D+ trigger wire connected?

 

[autorouter]

The b2b charger needs 13.2v (Stirling bbs1230) to work he tells me, so 1st how am i getting such a Voltage drop over 2mts, and how can i solve problem?,

You say the starter battery voltage is 13.5V. Where exactly are you measuring the 12.7V? If it's at the leisure battery, what is the voltage at the B2B input terminals (where the wire from the starter battery is connected)? If it's not almost the same as the starter battery voltage, and the wire is 10mm2, then I'd check the connections and crimps. Or maybe corroded terminals on the fuse or fuseholder.

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[Ingersingers]

What Pausim says. On vehicles with non-smart alternators, it's reasonable to trigger the B2B with the voltage rise of the alternator. When there's a smart alternator, the main reason for fitting a B2B is that the voltage rise is variable, so it's unreliable for switching on the B2B. It should be triggered from the alternator D+ signal, which is definitely on all the time the engine is running, and off when it stops. Does your B2B have a D+ trigger wire connected?

Does anyone know where the D+ is located on a 2020 VW Crafter? I'm a newbie and stumped on this. But I can confirm the B2b (Victron) acts really eratic when running on voltage sensing. Any help much appreciated

 

[CAB96]

Does anyone know where the D+ is located on a 2020 VW Crafter? I'm a newbie and stumped on this. But I can confirm the B2b (Victron) acts really eratic when running on voltage sensing. Any help much appreciated

Welcome to the Fun.

Have you tried the Crafter /MAN TGE forum?

 

[Raul]

I have the same van, and no one i asked know about a D+ signal, even a simulated one. Neither I found one. Had same problems to start with. So first I made sure the negative feed for the b2b it is from the chassis, and NOT from starter battery terminal, that way the van bmu can see a draw and tell the ecu to allow charging.
Secondly, i ditched the victron b2b charger and gone for a fixed voltage orion converter. I adjusted the voltage without load at 13.8v for output. The convertor turns on by a ignition signal, you can find them under passenger seat on the fuses. You got hi and low under there, so you can chose either. Hi as ignition is on the voltage turns on, and low when ignition is on the voltage cuts out. These both are suitable to switch the converter on/of by running a wire to low or high signal. I chose the high and works excellent. Also, i fitted a illuminated in line switch, to have manual override and control the converter. If its on, i push the button to disable stop/start as well, that way reminds me to switch the converter off when turn of the van.
If you forget the converter on, the only downside is, it will come on while you wait for the glow plugs before you crank. Not a problem on a healthy battery, here is the switch comes in handy, or a delay relay if you wish. I kept it simple as i only use b2b 2-4 months in winter only. And even then only if I'm low on power, my solar usually covers it.

PS, why i chose a converter rather then a charger? No b2b charger will go low enough to start charging, then to force the smart alternator into work. The converter its a buck-boost and takes anything from 8 to 17v, and WILL force the alternator into charging.
Eddy van bizz runs a buck boost to, lithium can happily charge at a fixed voltage, only lead is problematic and wants the 3stage to charge properly.

 

[autorouter]

The D+ signal is used because it doesn't come on until the engine is up and running and the alternator is producing an output. In contrast to the ignition signal which comes on as soon as you turn the key. This avoids problems of extra loads on the starter battery when it is turning the starter motor. It also avoids problems with a split charge relay, where the leisure battery will be connected to the starter battery during starting, which it is not designed to do.

Also the D+ signal definitely switches off when the engine stops, unlike a voltage sensor which can be fooled into switching on if there's a solar panel connected, etc. A voltage sensor can switch on a B2B when you don't want it to, when the sun comes out and you're charging the starter battery for example.

An alternative to the D+ signal is a D+ simulator like this:

Votronic 3067 D+ Simulator Pro

<p>The Votronic D+ Simulator Pro is used to simulate a D+ signal on vehicles such as motorhomes, campervans and special vehicles. When ba...

www.roadpro.co.uk

It is an electronic gizmo that turns on when it senses engine vibration, and turns off when the vibration stops. It has an adjustable time delay so that it doesn't come on immediately, but waits a few seconds for the engine starting procedure to complete.

Like the standard D+ signal, it will only supply a limited amount of power (about 300mA), so if you are using it for more than one thing (B2B, fridge, awning light switchoff etc) then it's best to use its signal to switch a relay, and use the output from the relay as a D+. Then you can have as much output as you want.

 

[akadingbat]

This may help on locating the D+

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[Raul]

This may help on locating the D+

Unfortunately that crafter is the old type, the newer crafter and man are quite different.