Installing a Victron B2B charger in a T6.1

[Davidm]

I will shortly be installing a Victron B2B charger into my T6.1. What I need to do seems all OK but my one problem is how to attach the negative cable from the B2B charger to the T6.1 battery. The negative connections on the battery leave no room to attach a 16mm lug. In the photo, see there is a lip above and below the bolt so you can't attach the lug from underneath or above and there is no room from the sides. So I'm not quite sure what to do and would appreciate thoughts.

 

[Pete C]

You need to attach the negative of the charger to the vehicle chassis, not the battery terminal.
Otherwise you bypass the battery monitoring.

Pete

 

[Davidm]

The negative of the B2B charger does go to the chassis via the negative bus bar but this B2B charger needs connections to both the positive and negative connections of the van battery as well.

 

[Pete C]

Can you post the instructions that say that please. My Victron B2B charger only connects to chassis ground.

Pete

 

[Davidm]

You maybe have a non-isolated B2B charger. I have an isolated B2B charger which I didn't mention. It is in the Victron installation manual.

 

[Dellmassive]

As Pete said.

Both negs need to go to chassis.(if you have the twin neg isolated version like I have)


...

[Guide] DC-DC Charger (for leisure battery) -- How I Done It --

DC-DC Charger (for Leisure battery) -- How I Done It -- ************************************************** Dellmassive`s -- "how I Done It" -- Thread ************************************************** Kit List And Stuff -- How I Done It & What I Use --...

www.t6forum.com

....

 

[Pete C]

In which case you connect both -ve connections to chassis ground.
Look here:

Victron Orion - Isolated vs Non-Isolated

Evening all... After lots of going back and forth on my choice of dc-dc charger options for my T6.1 Shuttle, I'm leaning towards the Victron Orion (12/12-30a). However, I'm scratching my head as to why the isolated version is the one most people seem to use in their builds, when a cheaper...

www.t6forum.com

The Victron manual doesn’t deal with VW battery monitoring.

Pete

 

[Davidm]

This is my manual: https://www.victronenergy.com/uploa...34439-Orion-Tr_Smart_DC-DC_Charger-pdf-en.pdf

Also Nomadic Energy who I bought it off say this. Also see this video:

 

[Pete C]

In that video, he makes no mention of whether the vehicle has built in battery monitoring. He’s installing it in a Burstner of an unknown age. He’s also using the isolated version as he probably doesn’t know if the leisure battery shares a common earth with the starter battery. In a T6 that’s easy to sort.

You can install it the way you describe if you want, and it will work, but the vehicle will not be able to properly track the state of the starter battery, and as you have found, it’s more difficult to make the necessary connections.

Pete

 

[Davidm]

I appreciate your help guys - this is not an area of expertise for myself. Is the in-built battery monitoring control the battery warning light on the dashboard or is it more sophisticated than that? So that might not work wiring the charger as Victron suggest?

 

[Samro]

If you are installing a shunt in the LB side it takes a little thought to make sure your shunt knows what is going on.

ALL negatives on the LB side have to go to the "load" side of the shunt. This includes the output neg of the b2b.

The input negative from b2b needs to go to chassis ground.

The non "load" side of the shunt should be taken to the vehicle chassis to combine the grounds,

All you need to remember is that if a bit of kit provides a draw or charge to a battery which has a shunt, you need the respective neg to go to the "load" side of the shunt.

Hope this helps.

 

[Pete C]

I appreciate your help guys - this is not an area of expertise for myself. Is the in-built battery monitoring control the battery warning light on the dashboard or is it more sophisticated than that? So that might not work wiring the charger as Victron suggest?

Wiring the Victron as you suggest initially will not affect the battery wanting light. That lights up under serious fault conditions.

Pete

 

[Davidm]

I misunderstood you Pete and thought you meant battery monitoring of the starter battery. I understand that connecting the BSB charger input negative to chassis ground for an isolated B2B charger will work from what you all say. As a note, this is what the Victron manual says and the second diagram is what I have been advised from the company who sold me all the electrics.

 

[t0mb0]

You’re effectively using an isolated DC-DC in a non-isolated setting, so just hook up both negatives to the closest good chassis ground. This way you both avoid battery monitoring issues, the additional resistance of an unnecessary negative cable run and the faff of the cable run itself.

 

[Samro]

You’re effectively using an isolated DC-DC in a non-isolated setting, so just hook up both negatives to the closest good chassis ground. This way you both avoid battery monitoring issues, the additional resistance of an unnecessary negative cable run and the faff of the cable run itself.

That's only true if no battery monitoring is implemented.
Taking both negs straight to ground will mean that any shunt won't know how many amps are going in to the LB.
The correct way of wiring things is as per the image posted by @Davidm in post #13. The only variance to this, is that the starter neg need will go to the chassis due to the shunt on the van's independent system which is required for start/stop, etc.

 

[t0mb0]

That's only true if no battery monitoring is implemented.
Taking both negs straight to ground will mean that any shunt won't know how many amps are going in to the LB.
The correct way of wiring things is as per the image posted by @Davidm in post #13. The only variance to this, is that the starter neg need will go to the chassis due to the shunt on the van's independent system which is required for start/stop, etc.

No, because the shunt on the starter, and on the leisure battery if correctly installed, will sit between the respective negative terminals and the chassis and therefore, the flow from the DC-DC will be measured along with all other loads if the DC-DC negatives are connected to chassis ground.

 

[Samro]

No, because the shunt on the starter, and on the leisure battery if correctly installed, will sit between the respective negative terminals and the chassis and therefore, the flow from the DC-DC will be measured along with all other loads if the DC-DC negatives are connected to chassis ground.

You're suggesting both "input" and "output" negs go to the same place. This can only be correct in an environment with an unmonitored LB.

The "output" side of the dc-dc has to be connected to the load side of the LB shunt and the "input" neg has to be connected to the "chassis" ground of the vehicle, what is it that you are suggesting is incorrect with this statement?

I agree that if both are grounded to the chassis the dc-dc will charge, but am confident that I am correct in the statement made in post #11 in order for both vehicle and LB shunts to account for the state of charge.

 

[t0mb0]

What you are calling the ‘output’ negative connection from the DC-DC will be connected to the load side of the shunt but it can be via the chassis. The shunt on the starter and the LB should be installed identically, shunt to negative terminal and all loads (including chassis loads) onto the shunt load side of the shunt, not directly to the terminal.

 

[t0mb0]

And yes, the two negatives can go to the same place because it’s an isolated DC-DC run in a non-isolated setting. If going to the same place somehow bypassed battery monitoring then all non-isolated DC-DC designs, which only have a single negative anyway, would fail with shunt monitored batteries which clearly isn’t the case.

 

[Samro]

I refer back to post #13 which is correct.

Edit- Oh my word!.... I have made myself look really •Special" and @t0mb0 has corrected me!
A thousand apologies! My brain has taken the bank holiday weekend off!
The common ground on the load side of the LB shunt means that @Tombo is correct and I feel really daft!