I want to power some kind of smart home system from the USB ports of the CCGX. Since nothing will take 48V directly, and other things have a standby current, this seems like an efficient way to do it for an offgrid system.
What is the maximum current in mA that can be drawn from the USB ports? And does it need to negotiate USB power correctly, or can I cut open a USB cable and use just the voltage wires directly?
Hi @Freesurfer,
That's not supported and REALLY not recommend. The USB ports are USB2 spec, I'd not draw any more than 100mA @ 5V per port.
It's only intended to connect a USB memory stick, MK3 USB adapter, RS485 adapter, keyboard, GPS dongle, WIFI dongle, and other specifically supported accessories.
You could trickle charge your phone at a pinch, but even then I wouldn't recommend it.
Definitely don't slice a cable to tap the voltage lines, you risk the stability of your GX device.
Far better to get a proper power supply, either running from an inverter - or the Victron DC to DC converter range has 48V models - https://www.victronenergy.com.au/upload/documents/Datasheet-Orion-Tr-DC-DC-converters-isolated-100-250-400W-EN.pdf
You can also find inexpensive DC-DC converters that provide properly regulated USB or USB-C charging receptacles. The ones I've used work on 8-35 volts but I'm sure you can find some that will take 48 volts in. Or you can regulate down from 48 to 12 then use a 12 volt USB receptacle.
