Possible Bug Cerbo GX - D.V.C.C

DIY
1

I was advised to post here about a behavior I have seen with D.V.C.C on a Cerbo GX as a possible bug.

I have a system with a single Multiplus 12/300/120-50 (v556) connected to a Cerbo GX(v3.55) via V.E.BUS, with a BMS V2(v113) inline. There is also a SmartSolar M.P.P.T 100|30(v1.64) connected to the Cerbo via V.E Direct. An IP65 BMV Smart Shunt is also connected via VE Direct to the Cerbo GX. D.V.C.C is active and configured on the Cerbo GX.

On turning off the BMS V2 remote switch, and then back on, the D.V.C.C current limit value set on the Cerbo GX no longer seems to have authority in the system. Adjusting the D.V.C.C limited current up or down by any amount seems to then reassert the authority of the D.V.C.C. Cycling the D.V.C.C on and off also has the same effect.

As an example I set the current limit to 30A, watched it regulate charge at that. Then cycled the B.M.S off/on, on resumption of charging I witnessed maximum charge of over 100A from the multi-plus. Simply moving the current limit to 31A immediately resulted in the system then returning to normal behavior.

Thanks for your help and any feedback.

Matt

2

Noted!

We’ll look into it

3

Thank you. :folded_hands:

4

What was the result of the investigation into this?

5

The GX device is supposed to be powered through the GX Power pin on the VE.Bus BMS v2. When you switch off the BMS with remote control, the GX device will switch off as well. The BMS then implicitly stops controlling the solar chargers, and the solar chargers will go into error #67 after a short amount of time. This maintains a nominal voltage on the DC bus, but won’t charge the batteries.

So the problem here appears to be that @PetrelMarine has his GX device powered in some other manner.

The second issue noted was fixed in Venus 3.67.

6

A colleague pointed out that the v2 BMS has an auxiliary power supply option which allows the GX to remain on. So there is an oversight in the implementation right now.

I reproduced the issue and consulted with the developer. Thanks for reporting!