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Miro Vidos avatar image

VE.Direct-MPPT in system with VE.Bus BMS, MultiPlus and CCGX

Designing a LiFe/grid/solar powered system with

1.BMS, Multi and CCGX connected via VE.BUS

2.MPPT via VE.Direct connected to CCGX

I have to be able to protect the LiFe battery by BMS switching off charging by MPPT. In documentation we have VE.Direct Remote on-off cable for that.

If I use that port I am unable to connect CCGX to MPPT.

Is it possible for CCGX to switch off MPPT by command from BMS but via VE.Bus connection between CCGX/Multi/BMS?

MPPT - Solar Charge ControllerCCGX Color ControlVE.Direct
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6 Answers
WKirby avatar image
WKirby answered ·

I have ESS on my system. I cannot directly control the MPPT because it is a slave. BMS state will automatically control the MPPT on or off.
Manually, from ESS menu I have an option to limit charge power, I can make it 0W if I want.

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Margreet Leeftink (Victron Energy Staff) avatar image
Margreet Leeftink (Victron Energy Staff) answered ·

I have just tested it in my workshop. And MPPT will not turn off via the VE.Bus-CCGX-VE.direct cable conenction in case of Smart LFP battery over voltage. So use a MPPT with a remote on/off connector and wire this to the BMS. Alternatively add a Cyrix li-charge or Battery protect to the system and drive it from the BMS.

I assume the reason is that stopping charge in case of an over voltage is an important safety feature and should be wired directly to the BMS rather than via a GX device.

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Thank you Margreet!
I'll definately use the charge disconnect ports from the BMS to the MPPTs remote connector.

WKirby avatar image
WKirby answered ·

I'm not sure how your BMS works. If it is two signals - "Battery Full" and "Battery Empty" then you can use inputs on the MultiPlus it's self.
You need to use "Two-signal BMS support" assistant or if you are using "ESS" assistant you will have the option to configure Two-signal BMS in there.

With that, the MultiPlus will communicate BMS state to CCGX.

Downside is that you cannot use the temperature sensor on the MultiPlus because it will be one of the inputs for the BMS instead.


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Natebert avatar image
Natebert answered ·

@Guy Stewart (Victron Community Manager) @Margreet Leeftink (Victron Energy Staff)
This question came up during the webinar this week.
Can either of you confirm that the Ve.Bus BMS will instruct via the Ve.Bus connection to the CCGX that Ve.Direct connected MPPTs (and now Ve.Can connected MPPTs) to stop/resume charging vs having to use any direct 'remote' cables?


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Hi @Natebert,

There was a clear answer to a similar question here -

https://community.victronenergy.com/questions/18991/vebus-bms-with-venus.html

Yes, it works. The VE.Bus BMS will signal to the Multi on the VE.Bus, and then that will be sent to the GX device which will control the MPPTs via VE.direct or VE.Can (>2019 models only) cables.

This answer from Matthijs is also interesting, that the Multi/Quattro is an essential part of making it work, i.e. you can't just connect the VE.Bus BMS to the GX device and have it control the MPPT.

Natebert avatar image Natebert Guy Stewart (Victron Community Manager) ♦♦ ·

@Guy Stewart (Victron Community Manager)

That clarifies things for me, either the Ve.Bus BMS assistant, or ESS assistant, which supersedes the VE bus BMS assistant, (and obviously an inverter/charger to load them into) is ultimately required for the GX to control MPPTs using the signaling from the Ve.Bus BMS.

Follow up question;

If the inverter/charger was turned off, would the assistants no longer be active? Therefore would one want to use the VE.Bus BMS charge disconnect port connected directly to the MPPTs remote switch to control/disable charging?


That's correct Nate, if the inverter/charger is disabled for some reason the assistants would no longer be running to convert the BMS instructions to the GX device.

It would be definitely be a more robust and reliable configuration to have the allow to charge signal go direct to the remote port of the MPPT.

If the MPPT doesn't have a remote port (the smaller units), then another redundancy would be to install a correctly oriented smart battery protect to disconnect the MPPT via the SBP's remote port.

That configuration is shown in the Victron VW van solar installation diagram.

Bathnm avatar image Bathnm Guy Stewart (Victron Community Manager) ♦♦ ·

I am just about to start my Victron Lithium, Solar, Multiplus, etc adventure and install. I have two bits of feedback to Victron.

  1. I find that the detailed information on how the control messages flow lacking from Victron documentation. I am aware that this is a complex set of systems that are being integrated, but I leant a lot from this post and the necessity for the MultiPlus/Quatro Assistant to make this work from this post.
  2. If the Assistant is able to pick up the message from the VE.Bus that charge should stop, the Venus OS should be able to pickup the same message of the VE.Bus. My installation is into a Yacht and will not always have the MultiPlus on, and therefore Assistant to support the required message flow of VE.Bus BMS to Assistant to Venus OS. I agree additional equipment such as SBP or Cyrix Li-charge could be installed, but space is a premium.

I am lucky in that I have ended up with a Smart MPPT that has a remote on/off and VE.Direct port, so can just wire the VE.Bus BMS Charge Disconnect to the remote on/off and VE.Direct port to Venus OS.

I am sure that this is only one of many unknown communication flows that I will face and need to address with additional hardware as I integrate my Victron kit. Another is the lack of ability to control the Multiplus through the VE.Bus from Venus OS when the VE.Bus BMS is installed, and therefore forced to install a legacy Digital Multi Control to perform the function. Please can we get these things addressed for the benefit of all.

Miro Vidos avatar image
Miro Vidos answered ·

I deeply appreciate your assistance in this matter!!

"BMS state will automatically control the MPPT on or off."... Awesome!!!

If you have BMS in your ESS, how did you connect it (through which connection does CCGX see it)..

1. as you described above via Multiplus "Two-signal BMS support" and I guess you have VE.Bus between them as well or...

2. you just have VE.Bus between them that is passing through MultiPlus?

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Miro Vidos avatar image
Miro Vidos answered ·

This is a good and possible resolution to my problem. Thx, very nice

Sorry do not have working (live) model in front of me right now... If you know, on CCGX UI do we have direct option to switch off MPPT on this state/condition change?

Cause this is LiFe, loosing temp sensor at this stage I do not believe is a big disadvantage

BTW..VE.Bus BMS I am using is this design from Victron is already connected to Multi via VE.Bus. Maybe I do not need to use signals "Battery Full" and "Battery Empty"

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