Dwarf 2 BUG – Incorrectly supports bidirectional charging (In/Out ports suck power OUT of the Dwarf)

Update: Firmware 2.0.04 appears to fix this issue.

Last night I ran into an issue where my Dwarf 2 smart telescope was stacking images (running the beta software in 1×1 binning mode, so requiring a lot of CPU power) and as soon as I plugged in a USB powerbank, the Dwarf would freeze up and need to be rebooted.

I finally figured out that my powerbank was sucking power OUT of the dwarf, and combined with the load from the CPU doing stacking, this was causing a low voltage situation that caused the Dwarf to crash.

It appears that the USB-C PD chip in the Dwarf is incorrectly programmed to allow power to flow OUT of the dwarf via bi-directional charging. I confirmed this with a USB power meter. This only happens with USB-C PD powerbanks that have “in and out” ports, which can be used to either charge a device OR charge the powerbank, depending upon if the other end is a source or sync of power.

It appears that when turned on, the Dwarf2 advertises the ability to export power, and does so. Workaround: If you plug the powerbank into the Dwarf when it is turned off, the power flows in the correct direction (from the powerbank TO the Dwarf). Even after you turn the dwarf on, this direction remains correct, so it appears to be necessary to plug in the dwarf before you turn it on. I’ve seen this behavior before testing the Beta firmware and App, but I confirmed it most recently with firmware version 2.0.03 and App 2.0.0 B665.

Video demonstrating the problem:

https://www.youtube.com/watch?v=Zr4WGj41DEQ