question

That happens when your Pi's power supply is not big enough.I had the same issue which I solved by using a 3A USB power supply for the Pi. The powered USB-Hub could also help, but it sounds like your Pi still does not have enough power.

My Pi3+ GX now run 7 USB connections (using an unpowered hub) without issues.

The Cerbo is a good option if you don't have all the cables and Pi already. It draw it's power from your batteries directly so does not have a limit from any USB psu and that also means it does not need AC power.

But the cheaper option for you would be to just upgrade your Pi's PSU to at least 3A or more.

I had USB issues from a cheap USB hub (powered) that disappeared when I swapped the hub out for an expensive one or went direct.

You can also power the PI from your battery bank with an inexpensive DC-DC converter. There are many with a USB port for output that'll plug into the PI's power port. I ran Venus OS on a PI for a while using a DC-DC (5 volt output) converter with USB-C that plugged into the RPI 4. Never had any issues.

Thanks everyone but it doesn't look like it's the power to the Raspberry Pi. I tried a few different beefy power supplies, finally going to bed last night with the Pi plugged into my 91W Macbook Pro USB-C power supply.

But I woke this morning to this:

:(I also tried with a different hub and then the 3 x USB direct into the Pi, but the same result just with varying failure times.

I was hopeful yesterday evening after 5 continuous hours of data, but when I checked again at 9pm it had failed.

Then 3 hours and disconnection at midnight.

Would the Cerbo GX with VE.Direct connections be more stable?

i run my Raspberry on a DCDC converter direkt to the 5V and GND pins, i also supplies the USB HUB with the 5V DCDC , ncreasing the voltage a little bit over 5V also helps.

I actually have a similar setup, MultiPlus, SmartShunt and SmartSolar all going to a 4 port (unpowered) usb hub. This one. The hub is on a 20ft USB extension going to my RPi4 (rev 1.5). The Pi is powered off an 18w USB port on this device. The 90W USB C port powers my MacBook 15, mobile hotspot, and about 6 little devices charging like iPhones etc.

The only overload I had with this setup was when the Pi was also plugged into the same hub as my computer, when I initially plugged in the computer the Pi would see a power sag and restart, so I switched its power source...

Maybe give that 4 port hub a try?

Maybe your USB RS232 converters are faulty or wrong wired.

I have no problems with a Pi4B powered by a single active USB hub on 12V, together with a 7" touch display, gps mouse, several VeDirect inputs, a MK3 Interface, RS485 interface for my BMS, wireless keyboard & mouse dongle, WLAN stick, USB Thumb drive for data logging when offline, several I2C and 1-Wire sensors etc.

Of course if you only have Victron gear, a Cerbo is great, but if you are into modifications and 3rd party sensors, a Pi is easier to modify and much more powerful.

UPDATE:

thanks all but I ran out of time, patience & talent so I gave in and bought the Cerbo GX.

Same USB -> Serial adaptors on the outside boxes (Smart Shunt & 100/30 MPPT) but made a VE.Direct cable for the 12/800 Phoenix Inverter.

Rock solid for 48h now.

https://vrm.victronenergy.com/installation/212669/share/946c6dbf

As most of you suggested, I suspect it was a power issue somewhere along the line but I couldn't find a combo that worked reliably.

Thanks again

Mark