I just finished installing a REC 2Q BMS, Cerbo GX/GX 59 display. I have an existing Victron Quattro. I configured the Cerbo for DVCC. I go it all online and cells charged. When I turned off the BMS the Quattro went to bulk trying to charge the now disconnected pack. I quickly turned off the Quattro. Obviously this is not desirable. I saw an unresolved post on the forum for another model BMS. Hopefully someone can let me know how to resolve this. Thanks!
Once the REC BMS passes the CANBus info to the Cerbo, at that time it is treated as any other DC souce so you want to look on the Victron side of things. Maybe verify that your REC is set as your DC source in the Cerbo but I would suggest you talk with your Quattro provider on this one.
@Rick
I've been emailing back and forth with my Victron provider. They are pretty much saying that since the REC BMS is not theirs they can't be of much help.
@Rick
Here is the final word from Victron: "If losing the BMS does not turn off the Quattro, then the communication is not there for this to act.
Most likely, this battery uses some sort of BMS communication that is similar to something that works with ours but is not fully integrated, resulting in this.
If it is not supported, then we cannot guarantee that it will work in every situation such as this."
I'd like to hear how REC responds to this. If what Victron says is true then maybe a firmware update is in order for the BMS.
Hey Chris, I will pass this back to REC head office and see if we can get their input on this one. Thanks for the feedback.
Please keep us updated with what they say and when a firmware update is available.
@Rick To add one last point. Victron say that disconnecting the DC from the Quattro while AC is still connected without first turning it off can cause damage to the Quattro and is not recommended.
Chris
I have pushed this back to REC but it will be after the holidays before we hear back.
Best of the season!
Rick
@Rick I have a new thought about this. When the contactor drops out the Cerbo GX loses power. I wonder if this prevents the Cerbo GX from telling the Quattro to shutdown? From page 69 of the Cerbo GX manual regarding BMS connection lost alarm: "This alarm is triggered once the inverter/charger has received CVL/CCL or DCL from a managed battery and will shut down if the battery is disconnected or communication with the battery get lost." I wonder if the Quattro initiates its own shutdown, or is commanded to shut down by the Cerbo GX? If the latter is the case then since the Cerbo GX was powered off when the contactor dropped out, maybe the command for the Quattro to shutdown isn't given?
@Rick I performed a test today. Rather than powering off the BMS I unplugged the CAN bus connection between the BMS and Cerbo GX. Nothing happed. The Quattro continued to maintain the previously requested float voltage of 54 VDC. After about 3 minutes the Cerbo GX reported a low battery voltage alarm. There was no BMS lost connection alarm and the Quattro continued supplying 54 VDC.
yes, the Cerbo should be connected direct to the battery so it does not lose power on a trip.
Interesting note about the loss of comms. It makes me think the BMS is not the problem.
Did you try the suggestions from my email?
I would first make sure that both my Cerbo and Quattro firmware are updated, then try setting your Battery monitor and Has DC system parameters in System >> Settings
I updated the Cerbo GX firmware. The Quattro is running firmware 497 and I think the latest is 499. I don't think there are any significant differences, but I'll request the firmware from Victron. I also selected "has DC system". I did the same test from yesterday of disconnecting the CANBus. After a few minutes the Quattro reported Low Battery Voltage to the Cerbo GX, but kept pumping out 54 VDC that seemed to be very slowly increasing. No loss of communication alarm. My thought process of powering the Cerbo GX downstream of the contactor is that I didn't want the potential of draining the cells if the contactor dropped out and I was away from the boat for an extended period. I wired the WiFi module the same way. Maybe I'm overthinking this, but if the contactor dropped out due to low cell voltage and there were loads still connected the cells could be damaged. If the BMS lost connection alarm would work as advertised in the Cerbo GX manual and shut down the charger I'd wire it to be continuously powered. One way, or another there needs to be a way to have the Quattro shutdown on loss of communication with the BMS to prevent uncontrolled charging and when the contactor opens to protect the Quattro.
@Rick I did some more experimenting. When the Victron system loses communication with the REC BMS the Quattro goes into "Passthru" mode (this is shown for the Quattro status in Device List on the display), which from what I've read means that the grid is passing through to the AC loads and taking nothing from the pack (not inverting) I'm assuming that also the charger is disabled, but can't confirm this. The Quattro also throws an alarm to the Cerbo GX saying "Low battery alarm". It just doesn't send an alarm saying "BMS communication loss". I'm wondering if this alarm is only related to VE bus BMS systems losing communication, not when using a CAN BUS BMS? I read up on the available firmware upgrades for my Quattro. I'm at 497 and the latest is 508. None of these updates seem like they would benefit my system and are probably not worth the hassle since I have to do it the old fashioned way with VE flash, after first requesting the file from Victron. So, I guess what I need to do is power the Cerbo GX from upstream of the contactor and wait to see what REC have to say about not getting the alarm. It still seems though that if the Cerbo GX were to lose power for some other reason the charger should not go into Bulk as I witnessed when I had it wire downstream of the contactor and switched off the BMS.
Chris
@Christopher
Is the Quattro connected to the BMS via a contactor. IS the contactor in positive or negative?
@tine Yes there is a contactor and it is connected in the positive.
If the Cerbo is also powered on the system side then it does not get the data from the BMS when disconnected.
