question

nebulight avatar image

Power MPPT from ve.direct?

I'm trying to figure out the best way to disconnect my MPPT in the event of a BMS over voltage event from my third party BMS. I know victron makes a ve.direct on/off cable:

https://www.victronenergy.com/cables/ve-direct-non-inverting-remote-on-off-cable

that I was planning on using as it would go to my charge disconnect signal from my BMS (that I'm going to run to the multiplus for as well), but I ended up going down the Raspberry Pi rabbit hole, and now plan on using that VE.Direct port to connect to the Venus. I don't know if there is a way for the Venus to take the input signal from the BMS and just shut off all chargers (since the BMS isn't CAN). Since I doubt this will work, I was planning on running the MPPT through a battery protect and just us the BMS single to turn on or off the battery protect. My only concern is that I want MPPT to always talk with the Venus and I know that VE.Direct cable provides 5v power. If the positive battery terminal is disconnected, will the MPPT still be powered on?


Thanks!

MPPT - Solar Charge ControllerVenus OSVE.Direct
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2 Answers
wkirby avatar image
wkirby answered ·

The VE.Direct USB cable is isolated, so it will not keep the MPPT powered

In my ESS system, I have my BMS (on / off contacts) wired in to the MultiPlus. I use the "Two signal BMS" option within the ESS assistant. I wire allow to charge and allow to discharge contacts into Aux and Temp inputs on the MultiPlus.

My MultiPlus stops charging if the BMS signals so. My MPPTs stop too as they are in a networked state.

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I won’t be using ESS as this is an off grid application (camper van) plus the mulitplus will be off most of the time. As Guy stated I may need to move up to a larger controller which stinks as I only currently have 300w of panels (though I may upgrade to 600w). Even so it’ll be about $180 more just for a on/off switch. Hmmm I gotta think about this.

Guy Stewart (Victron Community Manager) avatar image
Guy Stewart (Victron Community Manager) answered ·

The MPPT can be powered by either the solar, or the battery terminals.

It will not be powered on by the VE.direct port.

Some MPPTs in the range have a dedicated on/off port, perhaps consider one of those.

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Thanks for the info. I currently only have 300w of solar (might upgrade to 600) so I feel like these controllers may be over kill. I’ll have to think about it more.

Does the remote function just cut off charging or does it power off the unit? If it does the same thing I may just go the bp route.