Manually remote switching a water heater on L2 out using assistants

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boatgypsy asked Dec 28, '23

Manually remote switching a water heater on L2 out using assistants

Hi, I'm trying to set up my Multiplus to have a water heater attached to L2 output, manually remotely switchable in VRM. So far, although the water heater is powered in this way, I can't find a way to switch it off. I have a Cerbo GX and have connected the Relay 1 (NC, NO, Com) to the same on the Multiplus. I have setup a relay switch in VRM. I can hear the relay switching in the CerboGX, but it has no effect on the L2 output.

I've seen discussions which suggest a combination of assistants are needed to accomplish this, but sadly the documentation has not been of much help and the assistants themselves are not very self-explanatory.

Can anyone offer any help or advice?

MultiPlus Quattro Inverter Charger

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Answer 1 · 2023-12-29T04:51:55Z

Alexandra answered · Dec 29, 2023 at 04:51 AM

@Boatgyps

When you say L2 do you have a split phase system? Could you be a bit more specific as to what Multiplus you have exactly. Do you use a dedicated AC2 output for the heater?

Which no/NC/com did you use the aux?

If using AC2 you can program the logic internally to be on and off with assistants, doesn't need the Cerbo relay.

Are you running voltage/current through the relays? Or just signalling a contactor?

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Answer 2 · 2023-12-29T07:28:35Z

Matthias Lange - DE answered · Dec 29, 2023 at 07:28 AM

You could go from the Cerbo relay (COM and NO) to the AUX input of the MultiPlus and program the "programmable relay" Assistant (one for ON and one for OFF) to switch the AC OUT 2 of the MultiPlus.

OR

The easier way would be to use the relay of the Cerbo to switch a contactor which is than switching the heater.

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Answer 3 · 2023-12-31T17:35:23Z

boatgypsy answered · Dec 31, 2023 at 05:35 PM

The system is a Multiplus 12/3000/120 Inverter Charger, single unit with connection to shorepower. It is single phase at 240vac. The unit has two AC outputs - Line 1 and Line 2 The water heater is directly connected to the Line 2 output. Everything else is connected to Line 1 output. The Line 2 appears to be switching out whenever grid power is off. Ie, it does not connect to inverter power.

The relay 1 connection from the CerboGX is attached to the NO/NC/COM connector on the Multiplus main board - top right edge of the board. Im not sure if this is considered as Aux, as its not marked as such. See picture.Image Caption

1704044021072.png (14.0 MiB)

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Alexandra ♦ commented · Dec 31, 2023 at 06:12 PM

https://www.victronenergy.com/upload/documents/Service-Manual-MultiPlus-3k-120V-(firmware-xxxx4xx)-EN-ES.pdf

According to appendix A that is a programmable relay.

I am not familiar with the 120v versions. The datasheet shows it is off when no ac in is available. But AC out 2 shows it is switchable in appendix B. Normally on the 230v versions you can use the AC2 out relay in the wizard and switch it on and off on SOC and availability of AC in.

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Answer 4 · 2023-12-31T17:38:03Z

boatgypsy answered · Dec 31, 2023 at 05:38 PM

I'm hoping to avoid having to use external power relays when there is clearly a built in relay controlling Line 2 out.

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Alexandra ♦ commented · Dec 31, 2023 at 06:15 PM

Just watch the specs of the relays. For example the Cerbo relay scan take a max of 6A at 125v. (6*125V is 750W). So usually switching a contactor is the preferred option for higher powered stuff.

See the tech specs.

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Answer 5 · 2023-12-31T17:40:57Z

boatgypsy answered · Dec 31, 2023 at 05:40 PM

This is the location of Line 2 out

1704044387635.png (14.5 MiB)

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