Rad Pro: Continuously powered operation

[ge0rg]

When operating the device as a permanent probe attached via USB, it would be great to be able to limit / disable battery charging altogether and operate solely from USB power. I'm not sure if the CPU can actually control that, but if it's possible, it would be a great way to extend battery life.

Related: SunboX/radpro-wifi-bridge#4

[Gissio]

This would require a hardware mod. But I don't think it is worth the effort.

[ge0rg]

Thanks, I feared so much.

[ge0rg]

In fact, something weird is going on and I don't know yet what. I'm running the GC-03 permanently connected to the USB-host port of the ESP32 S3. The battery voltage as reported by RadPro floats around 4.147V for most of the time, both devices together consume 100-160mA at 5V from the power source, which could provide up to 500mA.

Then, suddenly, the voltage report from RadPro falls to 0.002V and slowly rises again. At around 0.150V reported voltage, the GC-03 shuts off. I can turn it on again (without disconnecting) and the battery level keeps rising again, slowly:

This has been happening every few days, as you can see in the voltage graph. The jumps back to >4V happened when I briefly disconnected the GC-03 in order for it to actually measure the battery voltage without a USB power source.

[ge0rg]

I wasn't logging data, only voltage, and so I don't know when it happened exactly, but eventually the GC-03 turned off because of "low battery". This was during the rising battery voltage line, some time about 1.2 Volts probably. When I tried to turn it on while still connected to USB, it showed an empty battery. I disconnected it, waited a minute and turned it on without plugging it in, the battery was reported as full, and it has been operating from battery for a day since.

So there is apparently some bug in the battery management that prevents continuous operation.

[Gissio]

On the GC-03, USB power is wired directly to the charging circuit without software control. So this has to be a hardware issue.

[ge0rg]

Is there any software logic to shutdown on low battery? If yes, can we disable that when on USB power?

[Gissio]

The charger IC tells the MCU these two things:

* USB connected
* Battery charging

The MCU does not talk to the charger IC.

Sorry, I misread your message.

When Rad Pro detects USB is connected, it does not attempt to shut down the device. See

radpro/platform.io/src/system/power.c

Line 327 in 122154b

bool usbPowered = isUSBPowered();

The issue you report can only occur if the hardware is incorrectly reporting that USB is disconnected, or if there's a bug in isUSBPowered. That said, I remember it was passing tests correctly.

Unfortunately, you will have to find your way through this yourself. I won't have any time in the foreseeable future.

[egormanga]

Doesn't the charge control IC have any commands? Some do, allowing to change charging current and sometimes even states.

[Langoor2]

I'm a bit unsure if this is the right place or if I should open a new topic.
I run a GC-01 flashed with radpro. It's also connected continuously to a radpro WiFI bridge (ESP32-S3-DevKitC-1-N16R8).

What I notice, is that the GC-01 seems to "trigger" the charging/plugged in state often. Which results in the screen turning on and it vibrating briefly. Sometimes this happens in a few second intervals, and sometimes it only happens after multiple minutes or hours.

I've tried several combinations of cables, connecting the radpro to the esp with several usb C-C cables, or C-A-C, which makes no difference.

The ESP needs to be powered by an A-C cable it seems, as a C-C and modern PD charger doesn't seem to trigger power delivery. Here I also tried several A-C cables and chargers, but that doesn't make any difference either.

I don't have the fancy graph yet, but this is the data from the bridge

[bombcheck]

Yeah, running the same device and noticed that, too.
Is the GC-01 able to operate with disconnected battery (just powering via USB)? That would prevent this and also prevents the battery from overcharging over time.

[ge0rg]

Yes and no. If you try to power on the GC-01 while attached to USB, it will go into boot loader mode, not into normal operations. And it won't turn on without USB and a battery ;-)

So the steps are:

1. Connect battery, disconnect USB
2. Power on GC-01
3. Disconnect battery without touching the 400V parts

In that mode, the GC-01 will operate without a battery permanently connected. However, it will still switch between showing "charging" and "discharging" and vibrating every few minutes.

[bombcheck]

Ah ok I see... So maybe disconnection the vibration motor would help...

[ge0rg]

I think this could be disabled in the RadPro source code - stop monitoring for battery changes, force reported battery voltage to 0V or something ;-)

[Gissio]

Next version shall have an option to disable power-off on low battery.