B2B with Split Charge Relay

[Twinsdad]

I've fitted a Renogy B2B to my Hymer Exsis which comes with an EBL system. I've wired the Starter battery ( +/alternator) to the B2B input and B2B output to the EBL (starter in) with a fuse in both lines. The EBL output has been left connected to the Leisure battery. So the B2B is effectively in series as follows, Starter - B2B - EBL - Leisure with all the negatives connected together or to the chassis
Renogy instructions are not to connect the D+ wire except on a smart alternator as the unit can detect the engine running on a standeard alternator.
I've followed numerous instructions from Renogy, and Votronic and from forums such as this but I am puzzled about what to do with the Split charge relay built in to the EBL. When the engine runs this will surely connect the EBL starter input to the EBL leisure output. Is this right?.

 

[headlight]

I've fitted a Renogy B2B to my Hymer Exsis which comes with an EBL system. I've wired the Starter battery ( +/alternator) to the B2B input and B2B output to the EBL (starter in) with a fuse in both lines. The EBL output has been left connected to the Leisure battery. So the B2B is effectively in series as follows, Starter - B2B - EBL - Leisure with all the negatives connected together or to the chassis
Renogy instructions are not to connect the D+ wire except on a smart alternator as the unit can detect the engine running on a standeard alternator.
I've followed numerous instructions from Renogy, and Votronic and from forums such as this but I am puzzled about what to do with the Split charge relay built in to the EBL. When the engine runs this will surely connect the EBL starter input to the EBL leisure output. Is this right?.

Yes you need to disable the split charge. Someone will be along and explain how to do it on an EBL system.

 

[StillGoing]

How many amps is the B2B?
Depending on the answer, if it’s about 30A then all you needed to do was remove the stater battery + wire from the back of the EBL and put it into the B2B then run a new + wire from the B2B to the EBL.
I would always use the D+ and not rely on the B2B to work out when the engine is running.

Attached is the wiring for a Votronic B2B. Yours should be similar.


.

 

[Pausim]

If your B2B is feeding into the EBL instead of the original direct engine battery connection then the split charge relay does not need disabling. However this is putting all the Amps through the relay which need to be limited to a level the relay can cope with. I did this on my Hymer but used the Votronic B2B settings to limit the flow of Amps. The arrangements on my Carthago had to be different because it had a CBE DS and not an EBL.

 

[LostInSpace]

Our new Hymer does not use the split charge relay.

There is no connection to the Starter Battery input of the EBL 30.

The factory fitted B2B is connected with the input from starter battery/alternator and the output direct to the leisure battery - with settings for different battery technolgies. (both fused)

I am puzzled about what to do with the Split charge relay built in to the EBL

Ignore it. Let the B2B completely by-pass the EBL as Hymer have done on our Exsis-i 580.
i.e. No connection to the Starter Battery input of the EBL.

Use the D+ signal regardless of what sort of alternator you have.

The hook-up charging of the starter battery is done using a different ouput from the EBL 30.

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