Need help debugging mk312 build

I put together an mk312 bt build and I’m having trouble getting it working. I flashed using the t002_bootloader.bin firmware posted to the #estim discord group.

I need your help to get it working.

I’m using the recommended AC power adapter from the BOM.

When my unit boots up it immediately displays the low battery warning on the lcd. The battery has ~13.3V on it. I get the message when using battery but no AC adapter. AC adapter but no battery. And AC adapter and battery.

I left the AC adapter plugged in for 5 hours to charge the battery, but nothing changes.

I looked at the disassembly of the firmware and it looks like it checks the battery status on start up reading through R5 and R3 on pins 37 and 38 of the MCU. I checked R3 - R6 and all look to be the proper values. So I would assume it would detect the battery and AC power levels correctly.

I checked the power at each of the voltage regulators and I get the proper values. I’ve looked for shorts on the mosfets and ensured they’re populated the correct direction.

What else should I check?

Please help!

13,3V should be plenty. IIRC at 12,0V it shows around 30%. My unit is powered with 12V step-up from a USB power bank.

Do you have fuses setup properly? You need a longest startup time possible because the voltage check is done immediately after startup and you need to have the time to charge all big capacitors.

I had this problem because the step-up was not able to deliver enough current to charge them fast enough -> I used lower values to charge them quicker.