Hi all, sorry I’m very new so I don’t know if this is a common question or not.
I’d like to set up a Pi instead of a Cerbo so I can customize the OS / interface and do more things with an all-in-one-device. My question is on cabling to the Pi.
I see I can buy VE.Direct to USB cables, but 1) these can be a tad expensive and 2) there may be a lot of devices to connect which can add up in terms of both USB ports but also power draw if you’re connecting many USB devices.
It would be easier, less cabling, less power draw, and potentially less expensive, if there existed an adapter which took in many VE.Direct ports/cables, and output one USB cable. Since VE.Direct is a UART that’s basically RS232, and USB can carry multiple RS232/UART (exposed on the host side as independent VCOM devices), this should be possible.
Has anyone attempted building one of these before? It seems like VE.Direct uses 4-pin JST VH connectors. And I see they suggest galvanic isolation, so you’d want to build that into each input.
The idea would be to have four female 4-pin JST VH inputs, add galvanic isolation to each, and map them to a FT4232H UART USB bridge, and output one USB cable to the Pi. You could then make cheaper, simpler VE.Direct to VE.Direct cables (without isolation), so the total cost should be cheaper, use fewer USB ports, and (hopefully?) draw less power from USB side.
FT4232H Mini Module: Placed centrally to manage USB to UART conversions.
Digital Isolators (ADuM1201ARZ): Each UART TX/RX line from the FT4232H passes through a digital isolator to ensure galvanic isolation.
JST VH 4-Pin Connectors: Positioned on the edge of the PCB for easy connection to VE.Direct devices. Each connector interfaces with the isolated side of the corresponding UART channel.
100nF Capacitors: Placed near the power supply pins of each isolator for decoupling.
Header Pins: Used for additional interfacing needs or future expansions.
Power Supply Input: A dedicated section for the 5V regulated power supply to power the isolated sides of the digital isolators.
Total Estimated Cost: ~$80–90 depending on options and sourcing. This is already cheaper than four VE.Direct-to-USB cables. You then add cheaper VE.Direct cables without isolation as they won’t need them. For 8x ports there’s a different chip to use (CH344). Or you’d double up chips and add a USB hub integration but then it’s questionable how much this saves in the end, still would be more cost effective than the hub + 8 stock cables I think.
Yes, the cost of the USB adapter cables can add significantly to a Venus OS Raspberry PI implementation. Add to that list:
A DC power supply because running off AC isn’t really a good solution in this environment.
Interfaces for digital inputs and relay outputs
Interfaces for any analog temperature or tank sensors (although there are bluetooth alternative solutions for the these).
An HDMI or DSI touchscreen display. (The Victron touchscreens will not work on a PI because of the way these send touch commands to the Cerbo.) HDMI displays will typically not allow brightness control via the Venus OS menus. You must use the dimming mechanism built into the display. (HDMI does not communicate display brightness.) Some HDMI displays blank their displays while others do not. Not all DSI displays work with Venus OS.
The PI runs a Victron-custom Linux kernel (not Raspberry PI OS) which limits expansion to other things you might run on the PI that rely on Raspberry PI OS.
Customization of Venus OS on Cerbo or other Victron GX device platforms is still possible.
Currently, Venus OS on the Pi does not support the New UI. It is being worked on but may be some time before that gets included.
Everything considered, a Cerbo may end up being less expensive than a PI, and is certainly more plug and play.
I wish that VE Smart Network would work with all of them and we could just get rid of the cables. In the small spaces we use for our site charge controllers the USB cables of the VE direct probably take up more space than anything else. All of my devices can talk to each other over the VE Smart Network but the VenusOS device, so I have to turn it off and run VE direct cables all over the box.
