I’ve recently switched to using a mini-PC to drive my portable rigs. It is Intel N100 based so it is energy efficient but it consumes more power than the equivalent ASIAIR or a Raspberry Pi running Astroberry. I like N.I.N.A. a lot and wanted a consistent imaging process so it had to be a mini-PC. With my existing 2x 20Ah power banks, sessions longer than than 5hrs were starting to give me worries. A full travel setup combines a phone, laptop, mini-PC, cooled camera, guide scope, mount and two dew heaters. And two power banks is one-too-many.
So I was on the look out for a single 12V LiFePo4 battery with enough capacity and planned to 3d-print an enclosure adding switches and sockets as required. I calculated that 50Ah was a minimum upgrade so went looking to see what was out there. I came across the DC House 100 Ah battery that included a bunch of good features built-in, a carry handle in a rugged case – almost ideal with just a few things needed to make it perfect. With the price they were offering the very small price jump from a 50Ah bare-bones battery to 100Ah with its extra features made it a no-brainer for me.
One 3D print later and this is the result:
I use a laptop, the integral USB-C port of the DC House battery easily copes with keeping it topped up if I need it. The integral 12V 5.5-2.5mm DC port can power the mini-PC directly. The integral USB A port can be used to power phones, fans and lights if required.
The 3D design is available here.
The “roof” to my DC house battery features a switchable 12V fused output (short-circuits can happen when fumbling in the dark!) via a GX16 2-pin panel connector, and a spare fuse holder. It also incorporates a switchable WIFI hotspot.
You need a laptop or some other device to control N.I.N.A on the mini-PC and connecting the two devices by WIFI makes sense. When I operate the power bank near my home the hotspot will also connect to my home WIFI for the internet. When I operate it away from the house my phone provides the internet service. The laptop and mini PC still connect to the hotspot so I do not need to change anything in their setup and the power bank can keep the phone fully charged all night via its USB A or USB C connector.
The roof’s 12V output is fused for 10A. You can fit bigger fuses if you need it, the switches I chose are 20A rated, more than enough for my rigs. It also allows me to plug in a 10A charger when back at home. I like the GX connector – it is deep enough for a secure and waterproof connection that won’t work loose and I can screw the connector down for added security.
I have since discovered that when charging @10A the GX connector gets warm, checking its specification on various websites I see the overall connector is rated @ 20A but the rating is 5-7A per pin. If you are at all concerned you could change out the connector for a 4-pin version and use two pins per wire.
I’m standardising my equipment to use GX connectors for DC from the power supplies. Even for my CEM70 and big Newtonian setup so that they can use the same power bank if necessary.
The power bank will connect directly to my astro-gear but I am designing a power distribution unit that incorporates computer control, switchable DC outputs with PWM optionally for fans and dew heater control. There are “low” cost options off the shelf but for all the features I want they are a few hundred pounds more than I am will to spend.