Part I - Removing DC -> AC -> DC
I have a solar panel connected to a LiFePO4 battery with an in-built inverter to run the Farmbot. The battery is just at the edge capacity-wise. I was using the stock AC->DC block that came with the FB Express XL but it would never last through the night even with X and Y unpowered while idle. There was incredible conversion loss.
DC Power source 12V DC to 24V DC assuming 100W peak
First I had to deal with unidentifiable 2-conductor on the FB 24V input. I have an aversion to proprietary or uncommon connectors so I adapted it to a TE AMP Superseal 1.5 (typical automotive power connector) with a 16AWG cable. Next it the matter of stepping up the voltage. As I have a power box (actually an old mailbox) to house the battery, I decided to use a step-up converter with a display so I can also measure power use.
Step-up with controls
Part II - Camera and Accessory Power.
I have had continued problems with the camera. Sometimes I can get it to latch but most of the time the USB camera is “not found.” I have another boroscope camera with similar cable length and that seems to be always recognized. After finally getting a decent multimeter setup outside it is very clear that power to the camera peaks at 5.05V but is only reliable at 4.8V and will dip to 4.5V when other systems are running. I assume the camera is not found because that dip happens at boot time when the system is likely querying the bus for devices. I also noticed that the cable for the camera is not shielded, which seems like a significant oversight.
Additionally, I plan to connect all manners of devices at the tool end so I need more than the RPi zero offers anyway.
Run a shielded USB extension out to an amplifying hub at the tool end and provide higher capacity 5V.
I have started with a USB hub with a FE1.1 chip that is intended for downstream power distribution. The model selected also has a 15ft shielded cable. The hub is housed in a waterproof box with cable glands on the Y-axis at the Z-axis junction. For more reliable power I have also dragged 24V (from the FB system input) out to a 5V regulator in that junction box. The regulator feeds the hub but can also supply power separately. This also gives me the option to add regulators for other voltages as needed in the future.
USB Hub and Cable
Step-down(buck) from 24VDC to 5VDC