How-To install DC-DC charger to replace VW Split Charge relay

[Loz]

Thank you. Yes, of course you are right, my bad wording.

I've not tested that signal wire yet, is it an open collector type output? If so then I imagine it would hook into the "L" connector on the Victron, thus bringing the L terminal down to 0v when the alternator is charging, and enabling the DC DC charging on the Victron?

It’s a +12v to energise the relay.
643 is the trailer supply voltage relay, do you have tow bar prep?

 

[rod_vw]

Thank you. Yes, of course you are right, my bad wording.

I've not tested that signal wire yet, is it an open collector type output? If so then I imagine it would hook into the "L" connector on the Victron, thus bringing the L terminal down to 0v when the alternator is charging, and enabling the DC DC charging on the Victron?

No it provides +12v as the activate signal. The other side of the relay coil is at 0v Brown wire DIN standard 31.

 

[a892374923874]

It’s a +12v to energise the relay.
643 is the trailer supply voltage relay, do you have tow bar prep?

Thanks. Yes I have a removable towbar.
Why would it activate on EHU? Is that to charge a connected caravan leisure battery for example?

 

[a892374923874]

No it provides +12v as the activate signal. The other side of the relay coil is at 0v Brown wire DIN standard 31.

Great. simple enough, so that will go into the "H" input on the Victron.

 

[a892374923874]

Here is my setup.

That is a really nice setup.

 

[a892374923874]

Thanks. Yes I have a removable towbar.
Why would it activate on EHU? Is that to charge a connected caravan leisure battery for example?

I wonder if I could use that "EHU activated" signal to energise either the battery isolation relay or another new relay connected to both batteries so that starter and leisure batteries can be charged together?

If using the Victron, then the additional relay would bridge the input and output terminals. I wonder if that would upset it!?

 

[Sp0_0k]

Here is my setup.

View attachment 63515
Plug and play lead is top right ( 2 red cables)

View attachment 63516

Does that lifepo4 have internal bms? Do you at least have access to cells voltages reading?
There were many ready built lifepo4s from China with some not reliable electronics recently. Even sold by big local brands.

 

[Mike Currie]

Does that lifepo4 have internal bms? Do you at least have access to cells voltages reading?
There were many ready built lifepo4s from China with some not reliable electronics recently. Even sold by big local brands.

The battery has an internal bms with cell balancing etc. Performance, so far, has been good. I guess time will tell. TN power has just signed a partnership deal with Total S.A. to make and sell Lifepo4.

 

[a892374923874]

Product Page | travelvolts

www.travelvolts.net

You can buy a plug in relay with loads from the above.

That plug in connector is exactly what I would need, but seemed expensive at £35.

Have you found any 9.5mm male spade connectors anywhere? I've looked and cannot find any. I may try buying a relay and butchering it for the connectors.

I've now bought the Victron, so looking forward to installing it when we next have the van out of storage. It is bigger than it looked in the pictures. Has anyone been able to fit it under the passenger seat, or does it need to go under the driver seat?

 

[Mike Currie]

That plug in connector is exactly what I would need, but seemed expensive at £35.

Have you found any 9.5mm male spade connectors anywhere? I've looked and cannot find any. I may try buying a relay and butchering it for the connectors.

I've now bought the Victron, so looking forward to installing it when we next have the van out of storage. It is bigger than it looked in the pictures. Has anyone been able to fit it under the passenger seat, or does it need to go under the driver seat?

Think you may need to butcher a relay to make the connections. I found it impossible to fit the Orion under the passenger seat if I followed the installation instructions. DC-DC chargers can run quite hot and need a well ventilated area. The driver seat was perfect for me. Just needed longer cables. It's also worth bearing in mind any future accessories such as battery protects and shunts etc that are better installed close to the battery and wiring under the passenger seat.

 

[a892374923874]

Installed mine now under the driver seat.



I didn't need to disconnect or remove any batteries, or disconnect any seat wiring, or remove seat bases. I undid the 4 bolts per seat. This is possible using a normal socket set by swivelling and moving the seat to get access to each nut/bolt. Then I lifted each seat off the base and tilted it backwards so that the headrest rested on the rear bench. There was enough slack on the seat wiring to do this.

I was able to push a fibreglass rod through from the passenger side and pick it up on the driver side. Then a simple matter of taping each cable to the rod and pulling back through.

I made my own relay "plug" to replace the VW relay. I got a dead relay from a local motor garage, removed the insides and soldered 1.5m of 10mm cable to the connectors. Then replaced the casing and filled up with hot melt glue. Epoxy would have been better.

I used a piece of 11mm OSB as a mount for the charger, bolted into the existing holes in the seat base. I used glue gun to lightly stick the nuts on the backside of the OSB as they are not accessible when the OSB is in place.

The grounding point is easily accessible under the driver's seat.

I fished through a few extra cables. 10mm for a future Pure Sine Wave inverter, and a power feed for a van Plex server and WiFi router.

The App does not display charging current which is very annoying. It displays starter battery voltage, and only shows leisure battery voltage during charge.

I have ordered a Victron battery shunt to get a better handle on state of charge.

 

[a892374923874]

Do these settings look ok? Single leisure battery Beach.
Cheers!

Charger



Shunt

 

[a892374923874]

Is 14.7V the correct setting for absorption voltage? Or can it go up a bit more?

 

[a892374923874]

@Mike Currie (or anyone else!) were you able identify all your cables at the positive battery terminal? I'm fitting a Victron Battery Protect, and need to make sure the charging cables are on the "In" terminal, and the load cables are on the "out" terminal.

I can see 1, possibly 2 thick cables, and a few smaller cables. I guess the thick cable will be the feed to the fusebox, and the mains charger feed will be one of the smaller ones. Not sure what the others are yet.

 

[Mike Currie]

@Mike Currie (or anyone else!) were you able identify all your cables at the positive battery terminal? I'm fitting a Victron Battery Protect, and need to make sure the charging cables are on the "In" terminal, and the load cables are on the "out" terminal.

I can see 1, possibly 2 thick cables, and a few smaller cables. I guess the thick cable will be the feed to the fusebox, and the mains charger feed will be one of the smaller ones. Not sure what the others are yet.

I used a dc clamp meter to identify which cables were charging the leisure batteries when dcdc charger and ehu charger were running. Then connected the dcdc charger directly to the battery. I isolated the ehu cables because the inbuilt charger is very basic and doesn't have a Lifepo profile.

 

[a892374923874]

That's good info thank you. That sounds like, 1 cable to Fuse Box, 1 cable from Split charge relay on fuse box, 1 cable from EHU charger. Did you originally have any other cables coming to your +ve battery terminal?

 

[Mike Currie]

That's good info thank you. That sounds like, 1 cable to Fuse Box, 1 cable from Split charge relay on fuse box, 1 cable from EHU charger. Did you originally have any other cables coming to your +ve battery terminal?

Yes I did. Any charging cable and inverter is connected directly to the +ve battery. The only other connection to the +ve battery is the input for the Smart Battery Protect. Any remaining cables that were originally connected to +ve battery are connected to the Smart Battery Protect output. This ensures that the current only flows in one direction and does not destroy the Smart Battery Protect.

 

[Addison Liu]

Thanks for the post Loz! Great information.

I have a 2018 T6 California ocean with duo leisure batteries that are not performing. My plan is to install a Victron DC to DC charger and upgrade both battery to Victron 60ah Lithium Superpack.

Since I will need to remove the factory split charge relay. If i just leave the signal cable (circled in red) hanging, would it trigger a error code?

 

[Sp0_0k]

I used a dc clamp meter to identify which cables were charging the leisure batteries when dcdc charger and ehu charger were running. Then connected the dcdc charger directly to the battery. I isolated the ehu cables because the inbuilt charger is very basic and doesn't have a Lifepo profile.

Almost all modern batteries are charged with CC-CV method. Only top voltage varies. I don't see any problem charging Lifepo4 battery with the Lead-Acid/Agm charger if it has BMS and it always should have one. This is why I would never buy sealed lifepo4 and always build my own.
All the battery cares about is the current going it's way. Lifepo4 has max 14,6 v (3,65v per cell)
Cali charger has a simple profile of CC-CV 14,8V and then trickle charge 13,8v
So Lifepo4 BMS accepts all the way to 14,6V or lower (14v which I recommend to set in BMS), it just ignores the trickle charge phase, as BMS will cut the charging completely.
Can of course waste money and listen to "experts" that you need a special charger for everything.

 

[rapido]

Installed mine now under the driver seat.

View attachment 64570

I didn't need to disconnect or remove any batteries, or disconnect any seat wiring, or remove seat bases. I undid the 4 bolts per seat. This is possible using a normal socket set by swivelling and moving the seat to get access to each nut/bolt. Then I lifted each seat off the base and tilted it backwards so that the headrest rested on the rear bench. There was enough slack on the seat wiring to do this.

I was able to push a fibreglass rod through from the passenger side and pick it up on the driver side. Then a simple matter of taping each cable to the rod and pulling back through.

I made my own relay "plug" to replace the VW relay. I got a dead relay from a local motor garage, removed the insides and soldered 1.5m of 10mm cable to the connectors. Then replaced the casing and filled up with hot melt glue. Epoxy would have been better.

I used a piece of 11mm OSB as a mount for the charger, bolted into the existing holes in the seat base. I used glue gun to lightly stick the nuts on the backside of the OSB as they are not accessible when the OSB is in place.

The grounding point is easily accessible under the driver's seat.
View attachment 64571
I fished through a few extra cables. 10mm for a future Pure Sine Wave inverter, and a power feed for a van Plex server and WiFi router.

The App does not display charging current which is very annoying. It displays starter battery voltage, and only shows leisure battery voltage during charge.

I have ordered a Victron battery shunt to get a better handle on state of charge.

Nice solution since it retains the original cabling (warranty) can you forward a scheme with contact-pin numbers and perhaps the type-nr of the donor-relay please?

 

[egena]

Hi, just want to add validation to this solution. I've just installed the same under passenger seat to assist in charging the two AGM leisure batteries in my 2017 T6.

I removed the four bolts holding the passenger seat and rocked it towards the drivers seat - length of cable connecting the airbag and seat heater were plenty long enough and didnt need disconnecting.

I unscrewed the bracket holding the split relay charger to the seat base then undid the two screws holding the split relay charger to the bracket itself.

For me, I am full-time van living so I'm confident with electrics but not a professional but I'm so very happy with the result. EU6 smart alternator is no longer an issue, when driving it charges automatically without the need for the controller cable that was plugged into the split relay unit. I've left that velcro'd to a bracket under the seat unused.
Victron unit detects the small surge in power with engine running and automatically begins the charging process.
These are my app settings - apologies it's in French

I hope this helps/encourages others.

Envoyé de mon SM-N950F en utilisant Tapatalk

 

[leeb]

I appreciate I am coming to this party very late indeed. BUT have any of you experts here have any experience of this conversion (split relay to dcdc charger) in the grand California?

 

[JMStockholm]

Any experience on a Cali T6.1 Ocean?

 

[jaydisc]

Any experience on a Cali T6.1 Ocean?

I think that if you have a T6.1 with the Max Charge button in your overhead display, this probably isn't worth the effort and expense. At least that was the conclusion I came to.