Disable deep sleep for nRF and force shutdown for RAK463x on discharged battery

[D4rk4]

Fix for #2022

[github-actions]

🤖 Pull request artifacts

file	commit
pr2040-firmware-2.0.8.72504a5.zip	72504a5

[caveman99]

I'm curious, is this really triggering for you? it wants 10 samples below min_battery and if one of those is above it will start counting over at zero. If it is triggering there may be some underlying problem in the ADC routines.

[D4rk4]

@caveman99 yes it's hit my node =(
Yes, it looks like voltage fluctuation, I'm already soldered supercap in parallel to the battery, but it did not help. So it's not a hardware/18650 issue.

Also it's not correct by a logic - if you battarey is really discharged SDS triggered and kill the node. After battery recharge, your node still keeps SDS state, and you need to reset the board via the hardware button. As result, you can't use NRF hardware as an autonomous off-grid node =(

Please give me time for sanity validation of this fix in different conditions.

[caveman99]

Sure, i converted your PR to a draft, let's get to the bottom of this.

[D4rk4]

@caveman99
I checked 2 cycles with full charge/full discharge. All working like expected (no sudden poweroff and node got online after external power connected).
May you accept this PR? Without this, RAK-based off-grid nodes can't work properly from battery power.

[caveman99]

We need to investigate the measurements further, this will improve user experience for the time being.