Power Problems
After the power problems I faced at the dark sky site, I decided that a ‘proper’ power distribution setup was required. Easy, right?
Nope.
There are plenty of commercial offerings out there - software controlled power distribution boxes with in-built USB hubs and other fancy widgets. Cheap? Oh no, most certainly not.
So I ended up making my own - some DC power sockets, plugs, wire, and a small plastic box to cram it all into. It’s not pretty but it works. I contemplated fitting fuses as a safety measure, and I still think I should, just in case. Maybe they can go into v2 of this thing.
The large port at the left is the inlet - screw threads so that the 12v supply cannot come out. The 4 DC sockets are standard 2.5mm DC power sockets and the leads will have 2.5mm plugs at one end and 2.1mm plugs at the other. I’ll colour-code which end goes where to save me the frustration of trying to fit the cables the wrong-way around.
As an added bonus, the holes in the box’s mounting flange line up perfectly with the threaded holes in my scope’s dovetail. Meaning I can mount the distribution box under the scope, where the battery bank (used to power the dew heater) would go. The USB hub will be attached to the distribution box by a piece of velcro.
All I need now are some cable-management clips. And a bigger box to store the scope in because when the power distributor is mounted, the scope won’t fit into it’s box. (I’ll need to get a bigger box when I purchase the EAF anyway, so nothing really lost there.)
Update - 2022-09-01
It was a clear night last night, so I thought I’d drag everything outside and run the rig through it’s paces with the new power box and new USB hub on board.
Nope. It wasn’t going to happen. There was a fault somewhere in the power box. So I spent the rest of the night (after taking everything down and then back inside the house) debugging what was going on.
Those DC power sockets have a switch inside them, that is opened when a socket is inserted. Which changes the connectivity of the socket. I had happily soldered the ground wire to the wrong connector, so when the plug was inserted, it wasn’t actually connected to anything. This was easily fixed - just solder the wires to the correct socket connectors. (I really should re-wire it. It’s not a good example of soldering in there.)
Once I had 12v (14v, actually) coming from all 4 sockets when a plug was connected, I found that one of the custom-length power cables was a short circuit. Which was strange, as I’d tested them when I’d assembled them.
Oh, look. A manufacturing flaw in the plug. When the backshell is installed, it squeezed the plug by a hair’s breadth, which was enough to push the connectors in the plug together. A quick twist with some pliers got that sorted out easily enough.
After testing everything repeatedly, I now have a rig with a stable power supply, better cable management (although I still have to create custom looms, or to use lots of velcro cable straps and cable ties to bundle everything together) and room for expansion.
What’s up next? Probably debugging the guide camera to see why the image preview is so bad when the guide camera is connected through the USB hub. This one could be “fun” to debug - it could be a cable issue, or it’s picking up interference from somewhere, or it’s a setting (or several) in Ekos that needs tweaking… This could take a while to resolve. I also need to resolve the issue of dew on the guide scope, too.