B 2 B Ignition Feed?

[jph99]

H

Might indeed end up using ignition feed on the Renogy but I have a few weeks while Jerba stick the roof on so will try and bottom out the wiring.

Hi Farnorthsurfer,
I asked Renology the other day if it needed just ignition feed, as I thought their new charger might do the job with just ignition fed (not engine run), but I recieved a reply I didnt understand.... I replied with some more clarity but not got anything back yet...

"Thank you for contacting Renogy.

When you say engine run wire do you mean it will not be able to use a positive and negative cable from the starter to a DC-DC charger will need?

If so our DC-DC will not work without the direct connection to the battery. It will need the ignition on wire as well to turn the unit on when running the alternator.

If you have any further questions please let us know.
Thank you,
Matthew S."

Cheers John P.

 

[jph99]

There’s a pin out on the BCM that does exactly this. Get the correct repair wire and push it into the empty slot. You’d need VCDS to code that you have an AUX battery fitted but this will do what you want. I use it on mine. The charging light on my B2B doesn’t come on until the engine has been running for a few seconds. When stop start kicks in the light goes out.

Thanks Deaky,
Back to the BCM - but for me, its just too difficult to get to it and then fit a wire into the complex connectors, I dont have a pin out or the tools or a VCDS, so looks like the Sterling is much easier solution. Thanks anyway .
John P.

 

[Deaky]

Here's the repair wire VW Audi Seat Skoda 000979009E Repair Wire Brand New | eBay

The pin is in the Black plug. Position 3 of the BCM under the dash. Pull the plug out, take the cover off and the two halves will slide apart. Click your wire in to slot 3, silde it together then pug it back in. It's just a tick box in VCDS have a look on the forum map for someone local to you with a yellow pin

 

[bmc054]

I’m going to fit the renogy in the next week or two
I’m hoping this thinner cable will be the one to do the job of ign on it’s taped to the aux battery feed from the ebox under the passenger seat

 

[Farnorthsurfer]

I’m going to fit the renogy in the next week or two
I’m hoping this thinner cable will be the one to do the job of ign on it’s taped to the aux battery feed from the ebox under the passenger seat
View attachment 58646

I also have one of the thick red wire clusters under the seat (tow bar factory prep) but haven’t been able to trace the wiring back yet. The thick one is crimped into supply tow bar caravan electrics I think and is fused under the battery.
Have decided to put my own fused 16mm cable in to the Renogy for DC-DC duties. Not sure that one of these feeds is BCM engine running. I think they are Ignition on.
@Deaky has put his finger on the right way to do this I think.

 

[Farnorthsurfer]

Here's the repair wire VW Audi Seat Skoda 000979009E Repair Wire Brand New | eBay

The pin is in the Black plug. Position 3 of the BCM under the dash. Pull the plug out, take the cover off and the two halves will slide apart. Click your wire in to slot 3, silde it together then pug it back in. It's just a tick box in VCDS have a look on the forum map for someone local to you with a yellow pin

Thanks @Deaky great info,
Is there a BCM diagram in the downloads?
I have looked but only found the second battery drawing. I think J519 Onboard Supply Control unit T73a is the bit that controls the OEM split charge relay.
Not my trade though so proceeding with caution

 

[Deaky]

Thanks @Deaky great info,
Is there a BCM diagram in the downloads?
I have looked but only found the second battery drawing. I think J519 Onboard Supply Control unit T73a is the bit that controls the OEM split charge relay.
Not my trade though so proceeding with caution

J519 is the BCM. T73a is the black 73 pin plug in the BCM and pin 3 is the one that controls the OEM relay

 

[Farnorthsurfer]

Thanks Deaky,
Back to the BCM - but for me, its just too difficult to get to it and then fit a wire into the complex connectors, I dont have a pin out or the tools or a VCDS, so looks like the Sterling is much easier solution. Thanks anyway .
John P.

It’s not too difficult to do when we have the instructions that @Deaky has posted. Yes it’s a pain to get into the BCM and a 73 pin plug will look a little daunting but like you said earlier it’s worth doing properly right?
I have VCDS so I am slightly ahead here. It’s worth buying one as you will use it a bit in the future

 

[jph99]

It’s not too difficult to do when we have the instructions that @Deaky has posted. Yes it’s a pain to get into the BCM and a 73 pin plug will look a little daunting but like you said earlier it’s worth doing properly right?
I have VCDS so I am slightly ahead here. It’s worth buying one as you will use it a bit in the future

Hi Farnorthsurfer, Deaky - Points taken - I have worked with cars, bikes, computers, technical stuff, diy, all my life, and if there is a nice and simple way to do something I have found it the best option, the key is understanding the system (I had two BMW motorbikes that tried to kill me recently - due to electronic failures that were not obvious , so I don't trust any of it), so I will take the Sterling route as this creates a system that is easer to maintain and fault find with less to go wrong..... but its still a 'proper job' (nice beer too), as it protects the battery fully, and with all the other advantages of simplicity
Thanks for everyones input...
Cheers John P.

 

[Farnorthsurfer]

I’m going to fit the renogy in the next week or two
I’m hoping this thinner cable will be the one to do the job of ign on it’s taped to the aux battery feed from the ebox under the passenger seat
View attachment 58646

From the second battery wiring diagram (83/2) that I downloaded here the wire to J519 T73a/3 is a Black 0.5mm wire. I don’t think it’s fitted when they do the tow bar prep but will check again next time I take the seat out. Going to be a few weeks away now though. Let me know how you get on

 

[bmc054]

Hi farnorthsurfer
I’m hoping the cables I have are for the aux battery as some have this fitted under the passenger seat from the factory I don’t think they’re for the tow bar wiring as that has more cables in the loom but I will have a root round at the weekend and will let you know as soon as.
Does anyone else have the two red cables to a factory fitted aux battery ?
Thanks
Bob

 

[Farnorthsurfer]

There’s is some info on other threads. My van has these extra wires as well, comes with tow bar fit I believe.
Red Cables Under Passenger Seat

 

[travelvolts]

As most DC-DC chargers will monitor the voltage of the source battery and automatically switch off when a pre determined voltage is reached, usually about 12.4, it is not necessary to use a true engine run signal. Ignition on is sufficient. I have never seen the unit that you are fitting so couldn't comment on whether it has the same monitoring facility as the main stream ones.

 

[Farnorthsurfer]

As most DC-DC chargers will monitor the voltage of the source battery and automatically switch off when a pre determined voltage is reached, usually about 12.4, it is not necessary to use a true engine run signal. Ignition on is sufficient. I have never seen the unit that you are fitting so coul;dn't comment on whether it has the same monitoring facility as the main stream ones.

Thanks @travelvolts like I said earlier in the thread it’s not my trade so I am being cautious and making sure it’s done right.
The manual for the Renogy just says connect the sensing wire to IGN but the diagram in the same manual shows the feed coming from Alternator D+. It also describes charging logic based on starting battery voltage.
If you would install with simple IGN signal from one of the central panel fuses I reckon that’s good enough for me.

 

[travelvolts]

That is exactly how I read their instructions. There is no D+ on an intelligent alternator. It is just a generic way of showing that you should make a connection that will "inform" your charger that you have switched on the engine. Personally, I think that using the output of the BCM is not worth the hassle. There are times when this output will switch off and this is going to reduce the efficiency of your aux battery charging. There is no "backwards connection" of the batteries with DC-DC chargers so power draw from the aux battery under starting conditions cannot happen, unlike with the factory fitted relay which would of course need to switch off under starting conditions.

 

[VeeDubz]

@travelvolts
I am fitting the new CTEK D250SE B2B unit to my van and I believe this needs a ignition feed to it, Do you know if it is ok to take this feed from the 12v cigarette lighter

 

[Donk]

You can take the feed from one of the spare sockets in the fuse box on the right column of fuses. Can’t remember off hand which one I used. I think cigarette remains live all the time.

 

[travelvolts]

@travelvolts
I am fitting the new CTEK D250SE B2B unit to my van and I believe this needs a ignition feed to it, Do you know if it is ok to take this feed from the 12v cigarette lighter

Use one of the empty fuse ports in the centre column of the fuse box. You will need to fuse the connection accordingly. Use 1 mm cable and a 3 amp fuse.

 

[VeeDubz]

Use one of the empty fuse ports in the centre column of the fuse box. You will need to fuse the connection accordingly. Use 1 mm cable and a 3 amp fuse.

Is it ok to just plug a fuse and wire like this (pic just for illustration )

 

[travelvolts]

Yes, that's ideal. Just make sure that you plug it in with cable facing towards the passenger side.