Caddy Maxi Leisure Battery Wiring

patmartino93

Guest
Hello everyone!

I seek help and advice installing a leisure battery on my new VW Caddy Maxi!
It's a 2015 model with blue motion technology, therefore smart alternator and break-regen and all of that!

I searched for battery chargers and recently bought a " Schaudt WA 121525" booster because it seemed well priced, had good reviews and was on a German website where I had already a full shopping cart (and therefore free shipping :sneaky:).

NOW, I'm pretty confident about the wiring, but I'm confused about the D+ connection : is it really necessary? And where can I source a wire to it? Diagrams suggest a connection to the alternator, but it looks really tricky to access.. I've seen a few tricks on the internet, like sourcing the D+ from a fuse box or glove box light.. Could this work?
Is the D+ just an "ignition signal" and any 12v signal when the engine is running would do the job?

Or.. Should I just ship back the unit and buy a Sterling or Votronic that seem a little more straight forward to install and apparently don't need a D+ signal?

Thank you all for your help, and enjoy the camping summer!!
 
I think the D+ is used by many manufacturers to operate a relay which switches the 12v supply for a three way fridge so it is only powered when the engine is running. If you join this forum as a full member you will also have access to motorhomebuilder which may be of interest.

Cheers

H
 
The Schaudt is a top quality bit of kit and should keep any battery in good health.
The D+ is the alternator energised connection - I'm not sure whether these modern alternators do have anything so simple.
Stick with it as it will deliver a good reliable voltage.
You may need to rummage the internet a bit I'm afraid.
 
patmartino93 said:
. I've seen a few tricks on the internet, like sourcing the D+ from a fuse box or glove box light.. Could this work?
Is the D+ just an "ignition signal" and any 12v signal when the engine is running would do the job?
Click to expand...
The D+ is just there when the engine is actually running (alternator turning) so picking up a live feed from anything that comes on with ignition wouldn't be ideal. Is there a VW forum
 
Any source that is live when ignition is turned on should work but check fuse and cable ratings. If a fuse box is handy and suitably rated you can take it from there. If it’s like my Votronic B2B it’s not much more than a signal connection telling it to turn on.
D+ is just telling the device the engine is running so it can run without draining starter battery.

Not checked spec on your Schaudt unit but if it says it works with smart alternators it should be okay. Haveyou sized it to provide the power you will be drawing off?
 
It's specifically designed for smart alternators and will provide the right charge voltage from whatever is available at the vehicle battery.
When that battery voltage drops below what the smart alternator considers acceptable it kicks in with 14V.
It's fully automatic and is much more that just B2B on account of its ability to deliver the correct output voltage regardless of input.
 
Just had a look at the manual Mark, it looks like it does the same things as my Votronic B2B, I thought all B2B’s did this? Must admit I didn’t know Schaudt did these or I would have considered one if they do a bigger output in current. It only has one setting for Lifepo4 but it is the right one for mine. I like the way a lot of the Schaudt gear is almost plug and play if you have an EBL.
 
I pulled the D+ for my Votronic triple charger from a terminal on my 2010 T5.1 BCM (Body Control Module) - there should be the equivalent on a Caddy. It did take a fair bit of research, unless you're willing to stump up for access to VW's online technical information. With the D+ signal it will only activate when the engine is running rather than when the ignition is turned on.

On VW there is the 75X terminal which is called X contact relief, this is ignition live, but drops out when cranking. Heavy consumers like the headlights, wipers, rear window, heater blower fan etc are usually fed from this circuit. Usually a fairly hefty black wire with yellow tracer, fed by the X contact relief relay (on a 2010 T5.1 this is located under the dash behind the headlight switch).
 
@wildebus may be able to help with where to get D+ on VW’s, he does quite a bit with the vans I believe.
Wait for someone to correct this but isn’t the radio in a VW only live when ignition is on? If so there must be a D+ on the radio
 
I see they do a WA 121545 which outputs up to 70amp, wouldn’t mind one of them but pricey lol
 
nabsim said:
@wildebus may be able to help with where to get D+ on VW’s, he does quite a bit with the vans I believe.
Wait for someone to correct this but isn’t the radio in a VW only live when ignition is on? If so there must be a D+ on the radio
Click to expand...
I don't know about the Caddys but I am sure it will be pretty much the same as the Transporters. On the Transporters there is a whole bunch of connections under the passenge seat and if you get lucky, there maybe a D+ there. If you are unlucky, the D+ might be in an engine bay fusebox located under the battery (and a right pig to get to and work on if it is like the Transporter).

Ref the radio - depends on the age how it works, but there is no D+ on the radios. The older ones have a standard ignition/accessory input like 'normal' radios. Newer ones are controlled by the vehicles Canbus and receive a signal that essentially tells them the engine is running (and go to sleep after 20 minutes if it is not), but that is not via a D+ as such, but - on the VWs - by, I think, the BCM (the electronic Body Control Module).
Way over complicated :(
 
Markd said:
It's fully automatic and is much more that just B2B on account of its ability to deliver the correct output voltage regardless of input.
Click to expand...
Would you care to expand on that? It seems to me that the Shaudt is exactly the same as other b2b chargers.
 
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