uConsole bottom panel to fit 26650 cells

Bottom panel, Battery cover and CPU cover for the ClockworkPi uConsole. 

This is designed to fit my uConsole with 26650 cells and a Raspberry Pi CM5. It is printed in 3 parts - the back panel which replaces the original metal panel of the uConsole, a battery cover, and a CPU cover, which both attach to the new 3D printed back panel. I have updated the back panel and CPU cover to ensure that you can use either the standard ClockworkPi carrier board or the Hackergadgets CPU board (link below)

The back panel attaches to the uConsole using the original screws. The battery cover uses M3 screws in  threaded inserts. The CPU cover is unlikely to be removed frequently, so it is attached using M3 screws into the 3D printed plastic. If you want to use threaded inserts for the CPU cover you could drill the holes out to 4mm or change the model. I have provided the FreeCad source files, though it's my first time using FreeCad v1.1 so they are probably not designed using best practices!

I printed the parts in black PLA with 20% gyroid infill and 3 walls. You can probably see the orientation from the photos, or just use whatever orientation works best on your printer. After printing, you may need to remove a little bit of plastic near the screw holes where the CPU cover is very close to the battery cover. I had to cut off a 1mm strip so that both covers would sit flat against the back plate.

You will also need to do some soldering to remove the old battery holder and replace it with the larger battery holder for the 26650 cells.

I am still in the process of calibrating my battery, so I don't know exactly how much improvement in runtime I will see from the larger cells. But they have a claimed capacity of 5000mAh, compared to 3500mAh of a "good quality" 18650 cell. So we should expect at least 35% better runtime.

If you are using the original uConsole wifi antenna, you will probably see improved performance if you move the antenna from its standard location on the top of the metal chassis to the back of this 3D printed back panel. Photos to follow soon.

Parts

In addition to the 3D files, you will need the following:

1x 26650 cell holder, from Keystone Electronics, part 1107. I bought mine from Digikey for $5.26, their part number is 36-1107-ND.  Note that this holder has polarity markings embossed in the plastic, which will be incorrect for use in the uConsole. It is a good idea to grind off the incorrect polarity markings, or cover them up as I have done, to avoid ambiguity when fitting the 26650 cells. See photos.

2x M3 nylon bolts and nuts, to attach your battery holder to the PCB. You could possibly use glue or tape, that way you won't need to drill holes in the uConsole's battery holder PCB.

2x Threaded inserts, M3 x 3mm. for the screws which hold the battery cover. I used Adafruit part number 4256.

6x M3 bolts, 6-8mm long, to hold the CPU cover and battery cover to the back plate. I used Keystone Electronics part 9191-3, from Digikey, part number 36-9191-3-ND.

Some insulated wire to attach the contacts of the battery holder to the pads on the PCB. I used 2x pieces in parallel for each contact to provide some redundancy. See photos.

The CPU cooler I am using is part number ED-CM5ACOOLER from EDA Technology inc. I bought mine from Digikey, part number 4555-ED-CM5ACOOLER-ND for $9. To run the fan you will need to supply 3.3-5V from somewhere on your uConsole, or use a carrier board with the CM5 fan header on it. For example, the adapter board from HackerGadgets: https://hackergadgets.com/products/pre-order-adapter- board-for-uconsole-ugrade-kit   I like the Hackergedgets board because it adds a couple of nice features like a USB port, expansion headers and a socket to attach a battery for the real-time clock in the CM5.

A sharp knife or a Dremel tool to cut the battery holder. You will need to remove some plastic from each corner of the battery holder to give clearance for the screws. You will also need to cut out a slot to give clearance around diodes D1 and D2, and the fuses F1 and F2. I also needed to file a tiny bit of plastic off the CPU cover, where one screw fouls the screw for the battery cover. See photos.

Philips head screwdriver, 3.5mm drill bit, soldering iron and solder. Optionally, an M3 tap might help to cut threads into the 3D printed plastic.

2x 26650 Li-ion or LiFePO4 cells.

The flip-up screen cover I am using is this one from Thingiverse: https://www.thingiverse.com/thing:6410647

I am also using a glass screen protector like this: https://www.aliexpress.com/item/1005002723381094.html

Things I might change:

I am mostly "happy" with the design and am reluctant to pull my uConsole apart yet again. But if I did choose to make some changes, I would start with the following:

1. Modify the "ear" around the bottom screw on the CPU cover so it doesn't foul the top screw of the battery cover. Alternatively, modify the back plate and one of the covers so the screws are not so close to each other.

2. Make the battery cover a bit shallower. Internally, there is almost 5mm of clearance to the 26650 cells, which is wasted space. The battery cover is presently the thickest part of the device, so slimming this down would make an appreciable difference to its portability. This is done, the updated models have been added to the downloads.

If I ever do make these changes, I will add them here. If anyone else makes changes, please share :-)