I added an internal battery to my Fates, thought I should document the process here.
- This is not a simple build. I found it fairly quick, but it involves SMD desoldering, drilling out the PCB, physically modifying a lipo battery, desoldering an encoder and a USB port. I’m pretty confident with all those things, if you’re not, I would not recommend doing this the way I’ve done it!
- I did it this morning and haven’t done any long-term testing or tested how long the battery will last. I think it’s at least an hour, hopefully more. I haven’t tested any specifically intense applications, or tried it with grids etc attached.
- You can charge from the Fates USB-C port, and use Fates while it charges, but it seems to crash when you pull out the power supply, so power down before doing that. On the upside, it seems to charge and run happily from my Macbook Pro charger.
- The battery level isn’t visible anywhere, so it will just die without warning.
- I wanted an internal battery without modifying the case
- I realised I also needed a power switch, so removed the 4th encoder and put a toggle in it’s place
- I wanted to be able to charge through the existing USB-C plug
1: Prepare the Fates board
- To make space for the battery, I removed a couple of 10uf electrolytic caps, replacing them with 1206 22uf caps (I didn’t have any 10u), which fit nicely across the pads
- I removed the 4th encoder, and drilled out enough of the PCB to make space for the switch
- I found the thinnest wire I have in my workshop and threaded it through the via on the ‘O’ of POWER. This is the +5v inlet from the USB C socket.
- I cut the trace that runs from the ‘W’ in POWER down to the capacitor. This separates the USB C socket from the rest of the board.
2. Prepare the battery
- I used this 3000mAh pack from Pimoroni
- It’s slightly too long, so I VERY CAREFULLY sliced through the Kapton tape to free the little control PCB and fold it back on itself. If you nick the battery it WILL CATCH FIRE so don’t do that.
3. Prepare the charger board
- I used this MP2636 charge and boost board from Pimoroni
- Higher up this thread I learned that the board doesn’t work unmodified. I made these changes - read the MP2636 datasheet to make sense of these and find the resistors. I made the changes with a soldering iron, not hot air:
- rOLIM limits the output power - by default it’s 42.4k = 2.61 amp limit. I changed it to 36K which is 3amps
- ISET limits the charge power - by default it’s 47.5k = up to 2.5 amps charging. I changed it to 300k, so the battery can only receive 400ma when plugged into power - otherwise the Fates is starved of power while charging.
- I didn’t add an extra capacitor
- I removed the larger USB port to make the whole package thinner and easier to connect. This was a faff because it seemed to be attached with super high temperature solder.
4: Assembly and connections
- Reinstalled the front paneI, put the switch in place - a subminature toggle, with a few washers to make it fit in the bigger hole.
- Taped the battery into place with Kapton tape - and with a few strips beneath it to make sure nothing pokes into it.
- Taped the control board on top of the battery
- Connections - I used wire wrap:
- The skinny wire you put in the via --> The +5 connection on the smaller USB socket. I actually connected it to the ceramic capacitors.
- A ground pin on the USB C socket --> The GND connection on the smaller USB socket (the other side of those capacitors!)
- GND on the larger USB connector --> The spare GND pin on Fates board
- +5v on the larger USB connector --> One end of the switch
- The other side of the switch --> The Spare +5v pin on the Fates board
5. What keyboard is that?
- A Tada68 from KBDfans