Split charge relay advice

[Tombola]

I have a 2019 Autotrail Imala 734 and am in the middle of changing over to Lithium, with Victron 100/30 MPPT, and Victron Orion B2B 30 amp.

Im just confused and my searches for info send me different ways.
The van is on a ducatto and Im led to believe it is a smart alternator , so do I have to find the Split charge relay (or is it a VSR ? ) and disconnect it, or can I just wire the B2B straight in. And if I do have to remove/disconect where is it .

I thought I could go straight in, but then see conflicting videos etc.

Thanks
john

 

[Lenny HB]

If it has a smart alternator it probably already has a B2B.

 

[Tombola]

Really ? right, so I better get looking for that hen? and see what amps etc.

May be best just whizzing it to a local auto elec

 

[Lenny HB]

Really ? right, so I better get looking for that hen? and see what amps etc.

May be best just whizzing it to a local auto elec

Why not give your dealer a ring they should know.

 

[Pausim]

If you are fitting a B2B I think you will need to disable the split charge relay, whether or not it has a smart alternator. The relay creates a loop back to the engine battery which means the B2B is trying to charge both engine and leisure batteries and in effect trying to power itself. It will not be able to monitor the new lithium battery properly if the two batteries are linked by an existing relay.

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[Tombola]

Thanks for the replies, I have emailed the dealer and will also email Victron but....
This is one of the things that are throwing me, so does this mean plug and play, thus no need to disable the Split charge relay ?
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The Orion Smart DC-DC chargers can be used as a power supply or as a battery charger. In charger mode the three-state charge algorithm will increase battery life by properly charging the battery. Especially in the case of vehicles with a smart alternator, or voltage drop caused by long cable runs, controlled charging is indispensable.

Controlled charging will also protect the alternator in lithium systems where direct charging can overload the alternator due to the low impedance of the lithium battery. In fixed output mode the output voltage will remain stable independent of the applied load or varying input voltage (within the specified range). The Orion Smart DC-DC charger can be set up to only provide power when the engine is running.

This is possible thanks to the built-in engine shutdown detection. This also prevents the onboard voltage of the vehicle from becoming too low. It is not necessary to intervene in the system of the vehicle, to install a separate motor run sensor or to intervene in the CAN-bus system. Apart from this detection, the Orion Smart DC-DC charger can also be activated by a forced allowed to charge feature, e.g. connected to the ignition switch. The Orion-Tr Smart DC-DC Charger is fully programmable with the VictronConnect app.

 

[ChrisL]

If you are fitting a B2B I think you will need to disable the split charge relay, whether or not it has a smart alternator. The relay creates a loop back to the engine battery which means the B2B is trying to charge both engine and leisure batteries and in effect trying to power itself. It will not be able to monitor the new lithium battery properly if the two batteries are linked by an existing relay.

I don't understand how you would get a loop, if you leave the split charge relay in place then you would need to disconnect the positive from the relay at the leisure battery end and use that as the input into the B2B you would then connect the positive output from the B2B to the positive terminal of the leisure battery, the negative from the output goes to the negative of the leisure battery which is itself earthed to the chassis and the negative from the input also goes to the chassis, if you need a D+ to trigger the B2B then that can be run from the positive input to the B2B so once the split charge relay opens the input to the B2B becomes live and the B2B will switch on and start charging the leisure battery.

 

[Pausim]

I don't understand how you would get a loop, if you leave the split charge relay in place then you would need to disconnect the positive from the relay at the leisure battery end and use that as the input into the B2B you would then connect the positive output from the B2B to the positive terminal of the leisure battery, the negative from the output goes to the negative of the leisure battery which is itself earthed to the chassis and the negative from the input also goes to the chassis, if you need a D+ to trigger the B2B then that can be run from the positive input to the B2B so once the split charge relay opens the input to the B2B becomes live and the B2B will switch on and start charging the leisure battery.

You can avoid the loop by feeding the B2B output into the relay or by feeding the input to the B2B from the relay but quite often people connect them directly to the batteries. The bigger B2Bs might overwhelm the existing wiring/relay. The installation wiring diagrams given with the B2Bs typically ignore existing charging arrangements (see below) and if wired up as shown will leave the loop in place.

 

[Tombola]

You can avoid the loop by feeding the B2B output into the relay or by feeding the input to the B2B from the relay but quite often people connect them directly to the batteries. The bigger B2Bs might overwhelm the existing wiring/relay. The installation wiring diagrams given with the B2Bs typically ignore existing charging arrangements (see below) and if wired up as shown will leave the loop in place.

View attachment 452773

Similar to what the battery supplier emailed me back with Pausim.

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The answer is dependant on your van set up.

If you can replace the split charge relay with the DCDC charger this works well. But some vans have a built in relay that is difficult to disable.

In these cases you may try installing the DCDC just before the split charge relay. You then set up the DCDC using the Victron app, so it activated when the engine is running only.

Putting there should keep the leisure battery separate from the starter batt even if the split charge relay is open due to higher voltage from lithium.
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[autorouter]

Really ? right, so I better get looking for that hen? and see what amps etc.

May be best just whizzing it to a local auto elec

Measure the voltage of both batteries when the engine is running. If they are always both the same as each other (allowing for a small voltage drop) then there is a split charge relay. If they are at different voltages then there must be some kind of B2B, ie it's not just a direct connection like a split charge relay.

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