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bigvt avatar image
bigvt asked

Multiplus programmable relay wiring

I want to run a 4G router, on DC load to avoid the inverter idle consumption, with an Easysolar 48/3000 so I can remotely monitor it. The router will run on a 48v-24v PoE adapter with max 0.7A.

I was thinking I'd use the Multiplus programmable relay set to disconnect on low voltage. I've understood this is max 1A at 48v.

This might be a stupid question, but do I simply run a positive cable from the battery through the relay (NC port in from battery, coms out to the PoE adapter?) and set it to open/on at e.g. 48v in the Assistant section in VEConfigure software?

Cheers!

MultiPlus Quattro Inverter ChargerEasySolar All-in-OneRelay
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3 Answers
Daniël Boekel (Victron Energy Staff) avatar image
Daniël Boekel (Victron Energy Staff) answered ·

Hi @bigvt

yes you can run it like that, put a 1A quick fuse before it just in case.

But...when the Multi is off, the relays are not working... So depending on the type of battery, you might want to use something to cut-off at low voltage or use 'allow to discharge' signal from bms.

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bigvt avatar image bigvt commented ·

Great, thanks! Am I wrong thinking the multi is always on (but necessarily not inverting unless activated) and only shuts off because of low battery voltage? When I'm not there, I was planning on leaving the system as is with inverting off and then turn it on through VRM to start up e.g. fridge before I get to the cabin.

Can the relay be set to turn off the router load if the Multiplus shuts down? Is there any better way, e.g. use the CCGX relay instead? Or buy a BMV712?

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Daniël Boekel (Victron Energy Staff) avatar image Daniël Boekel (Victron Energy Staff) ♦♦ bigvt commented ·

The multi can be turned on/off etc. throught the GX device (and VRM therefore), off course make sure the internet connection and GX device is powered by DC...

to protect the battery from draining, you can use a Battery Protect.

the Multi is really 'off' when it's off...relays don't work...

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bigvt avatar image bigvt Daniël Boekel (Victron Energy Staff) ♦♦ commented ·

Ok - does that mean I can't avoid the inverter idle consumption of 25ish watts when using that relay?

My BMS got low voltage protect so not overly worried, although I rather disconnect dc loads before it kicks in. How about the bmv712 relay as it, as I understand, would also give some better accuracy in soc?

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Mark avatar image Mark ♦♦ bigvt commented ·

Use the BMV relay, since that is always active and easier to program / more flexible.

But there is a 'trick' with keeping the Multiplus CPU alive while the inverter is off - instead of turning the Multiplus 'off', switch it to 'charger only'.

In that mode the power draw is only ~3w and the CPU will still be active.

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bigvt avatar image bigvt Mark ♦♦ commented ·

Got it. Thanks a lot for the help, both of you!

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bigvt avatar image
bigvt answered ·

Great, thanks! Am I wrong thinking the multi is always on (but necessarily not inverting unless activated) and only shuts off because of low battery voltage? When I'm not there, I was planning on leaving the system as is with inverting off and then turn it on through VRM to start up e.g. fridge before I get to the cabin.

Can the relay be set to turn off the router load if the Multiplus shuts down? Is there any better way, e.g. use the CCGX relay instead?

My BMS doesn't have allow to discharge signal unfortunately. If it had, would it work with DC loads too?

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justme avatar image
justme answered ·

I dont like any load in the internal relays so always use them as a low / no volt switch via another relay to take the full load. Better you wear out an cheap external relay than the fitted internal one.

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