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Hello Joy-IT Team,

I'm running Strompi3, Rev 1.1 with V1.8 firmware, with the XL battery HAT, to power a Raspberry Pi Zero 2W. The Pi is running the Bullseye-based Raspbian OS Lite, 64-bit. Although the Pi Zero 2W isn't officially listed as compatible, it seems to work fine. I'm accessing the Pi from a Linux desktop in the same local network, via SSH with X11 forwarding. The serial communication (Strompi3 console) is working, and the GUI configuration script too. Here's my current configuration:

The problem I'm having a problem with the Strompi3 is shown by the following experiment:

- I start with mUSB (main supply) connected, and also the battery connected and partially charged. The serial command "adc-output" says:

(which is to be expected: main supply is On, so that's being used to power the devices, and the battery is being charged. The battery HAT shows an orange led and the strompi3 shows a red LED on mUSB.)

- Then, I cut-off the main supply. "adc-output" says:

(so far so good: the strompi3 detected a power failure, gave a warning, and switched to the fallback power source, the battery. The battery is now no longer being charged, instead it's being used. The battery HAT orange LED went off, and the strompi3 now shows a green LED in Bat, and no longer the red LED in mUSB. So far, so good.)

- Now, the problem. When I turn the main supply back on, nothing happens! The serial console does not give a "power-back" warning, the LEDs remain unchanged from the previous step, it's exactly the same as if I hadn't plugged the main supply back on at all. "adc-output" says:

(which is not true: the strompi3 thinks, incorrectly, that the main supply is not connected, but it is!)

- Now, I can "force" the strompi3 to re-evaluate the situation by powering it off using the serial "poweroff" command, waiting 30 seconds, and then "pressing" the poweron button, that is, shorting the two terminals that make up said button. If I then go to the console again, "adc-output" says:

(that is to say, by effectively restarting the strompi3, it corrected / refreshed its assessment of what power sources are available, and correctly decided to prioritize the primary source and charge the battery).

My project consists of an autonomous small mobile robot which is always on, taking trips around the house relying on battery power, and then returning to a docking station to recharge (the docking station connects to the mUSB input through a magnetic USB adaptor cable). Therefore, ideally, the strompi3 should immediately recognize that the mUSB input is back on, and switch from the battery back to the main supply on its own, i.e. switch from using the battery to recharging the battery. 

If this problem persists, the resulting behavior will be silly in that, upon returning to the docking station, the battery will continue to discharge until it's depleted < 10%, then the Pi will shutdown, restart, and only then will the strompi realize that it's actually plugged in to the main supply and start recharging.

Is this hardware defect, firmware problem or am I just misunderstanding the way the configuration options work?

Many thanks in advance!

Hugo

Update:

I tried flashing the Strompi3 several times, with V1.72 main, V1.73 and then V1.8 again, to no avail, the process described above gave the same results as before, not the expected results. 

But then, I tried just using a different USB wall adapter to power the Strompi3 via mUSB, and it worked correctly. By that I mean, with this other adapter, the process above worked as per expectation. I was using an official Raspberry Pi power source before, and then the adapter that worked is just a vanilla USB cellphone charger.

It looks like it was "hardware defect", but not the Strompi3. Please keep up the post anyway if you believe it may be useful as reference for others. If so, it's worth asking: what's the ideal wall adapter to power the mSUB port of the Strompi3 ?

Thanks,
Hugo

Hello Hugo,

Normally, we recommend using the official Raspberry micro USB power supply.

But any USB power supply with 5.1 to 5.25 V output, capable of providing enough current for your setup, should do the job.

Best regards 

Tim (Joy-IT)