Inconsistent report of the keyboard battery capacity level of the UHK 80 keyboard

[PYalandin]

Hello,

When charging the left side, right side is not reporting the left side charge correctly.
Here is what I can see in the logs from the agent

uhk80:right$ StateSync: Batteries: 0% 90% (0 / 4079 mV; 3953 / 4123 mV)
StateSync: Batteries: 0% 90% (0 / 4079 mV; 3956 / 4123 mV)
StateSync: Batteries: 0% 90% (0 / 4079 mV; 3960 / 4123 mV)
StateSync: Batteries: 0% 90% (0 / 4079 mV; 3965 / 4123 mV)
StateSync: Batteries: 0% 90% (0 / 4079 mV; 3970 / 4123 mV)
StateSync: Batteries: 0% 90% (0 / 4079 mV; 3978 / 4123 mV)
StateSync: Batteries: 8% 90% (3361 / 4079 mV; 3978 / 4123 mV)
StateSync: Batteries: 8% 90% (3361 / 4079 mV; 3983 / 4123 mV)
StateSync: Batteries: 8% 90% (3375 / 4079 mV; 3983 / 4123 mV)
StateSync: Batteries: 8% 91% (3375 / 4079 mV; 3990 / 4123 mV)
StateSync: Batteries: 8% 91% (3388 / 4079 mV; 3990 / 4123 mV)
StateSync: Batteries: 8% 91% (3388 / 4079 mV; 3996 / 4123 mV)
StateSync: Batteries: 8% 91% (3375 / 4079 mV; 3996 / 4123 mV)
StateSync: Batteries: 8% 91% (3375 / 4079 mV; 4001 / 4123 mV)
StateSync: Batteries: 8% 91% (3353 / 4079 mV; 4001 / 4123 mV)
StateSync: Batteries: 8% 92% (3353 / 4079 mV; 4005 / 4123 mV)
StateSync: Batteries: 8% 92% (3353 / 4079 mV; 4005 / 4123 mV)
StateSync: Batteries: 0% 92% (0 / 4079 mV; 4005 / 4123 mV)
StateSync: Batteries: 0% 92% (0 / 4079 mV; 4005 / 4123 mV)
StateSync: Batteries: 0% 92% (0 / 4079 mV; 4012 / 4123 mV)

As seen, it does not read it correctly, e.g. reports as 0 when the USB cable is connected, but when I disconnect the charging cable, it reads smth odd, e.g. 3375 / 4079 mV, but that is not 8% but rather 80%.

I am using the latest firmware available for the keyboard

[kareltucek]

As seen, it does not read it correctly, e.g. reports as 0 when the USB cable is connected, but when I disconnect the charging cable,

Can you elaborate on the setup? Are you using two usb cables, and are the halves joined with the bridge cable or not?

---

As for 8% vs 80%, battery chemistry is not linear. For LiPo 3.0V is considered completely empty - there the protection circuits disconnect the battery. Dropping under 2.8V leads to irreversible damage of the battery, but the discharge curves drop fast after reaching ~3.3V, so 8% is very plausible that 3.375V charge.

Btw., here are the discharge curves of UHK80:

[PYalandin]

The setup:
Connected via a dongle to the PC
No bridge cable and connected only wirelessly
Have a key cluster and a touchpad

To clarify: It reports as 0 when I have the left side connected via USB cable to, well, charge the half. When I disconnect the cable, it reports the percentage as modulo of 10 (at least what I suspect by looking into mV values in the right half logs of the agent)

[kareltucek]

I haven't managed to reproduce the issue, but the log is loud and clear on it - with connected batteries, it should never show 0mV.

In order to troubleshoot, please flash https://github.com/UltimateHackingKeyboard/firmware/actions/runs/29996869717 and provide left half logs when the above issue (0mV being reported) is present.

[PYalandin]

The firmware attached to the build seems to have solved the issue.

uhk80:right$ StateSync: Batteries: 63% 59% (3888 / 4079 mV; 3659 / 4123 mV)
StateSync: Batteries: 63% 60% (3888 / 4079 mV; 3666 / 4123 mV)
StateSync: Batteries: 63% 60% (3886 / 4079 mV; 3666 / 4123 mV)
StateSync: Batteries: 63% 60% (3886 / 4079 mV; 3664 / 4123 mV)
StateSync: Batteries: 63% 60% (3885 / 4079 mV; 3664 / 4123 mV)
StateSync: Batteries: 63% 61% (3885 / 4079 mV; 3668 / 4123 mV)
StateSync: Batteries: 63% 61% (3884 / 4079 mV; 3668 / 4123 mV)
StateSync: Batteries: 63% 62% (3884 / 4079 mV; 3673 / 4123 mV)
StateSync: Batteries: 63% 63% (3884 / 4079 mV; 3676 / 4123 mV)
StateSync: Batteries: 63% 63% (3885 / 4079 mV; 3676 / 4123 mV)
StateSync: Batteries: 63% 64% (3885 / 4079 mV; 3678 / 4123 mV)
StateSync: Batteries: 63% 64% (3884 / 4079 mV; 3678 / 4123 mV)
StateSync: Batteries: 63% 64% (3884 / 4079 mV; 3681 / 4123 mV)
StateSync: Batteries: 63% 65% (3884 / 4079 mV; 3688 / 4123 mV)
StateSync: Batteries: 63% 66% (3884 / 4079 mV; 3691 / 4123 mV)
StateSync: Batteries: 63% 66% (3883 / 4079 mV; 3691 / 4123 mV)

The left part has started to dump the battery levels as well

uhk80:left$ StateSync: Batteries: 63% 0% (3888 / 4079 mV; 0 / 0 mV)
StateSync: Batteries: 63% 0% (3886 / 4079 mV; 0 / 0 mV)
StateSync: Batteries: 63% 0% (3885 / 4079 mV; 0 / 0 mV)
StateSync: Batteries: 63% 0% (3884 / 4079 mV; 0 / 0 mV)
StateSync: Batteries: 63% 0% (3885 / 4079 mV; 0 / 0 mV)
StateSync: Batteries: 63% 0% (3884 / 4079 mV; 0 / 0 mV)
StateSync: Batteries: 63% 0% (3883 / 4079 mV; 0 / 0 mV)

Zeroes in the right side, i guess, expected as communication is one-sided?

One thing, however: after I have disconnected the left side for a few seconds, the percentage has dropped from 63% to 55%. Is it normal?

Left side:

Cannot write to hid deviceConn: UsbHidLeft: (Disconnected)
StateSync: Batteries: 56% 0% (3838 / 4079 mV; 0 / 0 mV)
Conn: UsbHidLeft: (Ready)
StateSync: Batteries: 56% 0% (3843 / 4079 mV; 0 / 0 mV)
StateSync: Batteries: 56% 0% (3839 / 4079 mV; 0 / 0 mV)
StateSync: Batteries: 55% 0% (3838 / 4079 mV; 0 / 0 mV)
StateSync: Batteries: 55% 0% (3839 / 4079 mV; 0 / 0 mV)
StateSync: Batteries: 55% 0% (3841 / 4079 mV; 0 / 0 mV)

Right side:

StateSync: Batteries: 63% 66% (3883 / 4079 mV; 3691 / 4123 mV)
StateSync: Batteries: 63% 66% (3883 / 4079 mV; 3697 / 4123 mV)
StateSync: Batteries: 63% 66% (3883 / 4079 mV; 3701 / 4123 mV)
StateSync: Batteries: 56% 66% (3838 / 4079 mV; 3701 / 4123 mV)
StateSync: Batteries: 56% 66% (3843 / 4079 mV; 3701 / 4123 mV)

[kareltucek]

Well, yes and no.

Estimating battery capacity based just on the voltage of a device under load is complicated. At the end of the day, charging and discharging states are two completely different systems with completely different properties, needing different calculations, estimations, and corrections.

Given that, different readings when charging vs discharging are expected. It is only the size of the discrepancy that is unusual. With my devices, it fits within 4%, which is further dampened by a stateful algorithm that just suppresses sudden changes of the value, so a 1% change is the most that can usually be observed.

The bottom line is that I don't find it concerning. But it may indicate something like:

• minor damage or quality variation of the battery unit, or maybe just different batch/factory, substituted part in the protection circuit...
• bad connection somewhere uhk-side (bent/broken wire, badly inserted connector)

[kareltucek]

Also, I think the (size of) the drop alone explains the original observations.

Anyways, I don't see anything to be done about it firmware side -> closing. Still, you are welcome to follow up with any questions or concerns.

[PYalandin]

Uhm, i am not sure what has happened, but now the log looks like this.

Left side

uhk80:left$ StateSync: Batteries: 44% 0% (3798 / 4079 mV; 0 / 0 mV)
StateSync: Batteries: 0% 0% (0 / 4079 mV; 0 / 0 mV)
StateSync: Batteries: 44% 0% (3798 / 4079 mV; 0 / 0 mV)
StateSync: Batteries: 0% 0% (0 / 4079 mV; 0 / 0 mV)
StateSync: Batteries: 44% 0% (3798 / 4079 mV; 0 / 0 mV)
StateSync: Batteries: 0% 0% (0 / 4079 mV; 0 / 0 mV)
StateSync: Batteries: 56% 0% (3844 / 4079 mV; 0 / 0 mV)
StateSync: Batteries: 0% 0% (0 / 4079 mV; 0 / 0 mV)
StateSync: Batteries: 56% 0% (3844 / 4079 mV; 0 / 0 mV)
StateSync: Batteries: 0% 0% (0 / 4079 mV; 0 / 0 mV)
StateSync: Batteries: 56% 0% (3843 / 4079 mV; 0 / 0 mV)
StateSync: Batteries: 0% 0% (0 / 4079 mV; 0 / 0 mV)
StateSync: Batteries: 56% 0% (3843 / 4079 mV; 0 / 0 mV)
StateSync: Batteries: 0% 0% (0 / 4079 mV; 0 / 0 mV)
StateSync: Batteries: 56% 0% (3844 / 4079 mV; 0 / 0 mV)
StateSync: Batteries: 0% 0% (0 / 4079 mV; 0 / 0 mV)
StateSync: Batteries: 56% 0% (3844 / 4079 mV; 0 / 0 mV)
StateSync: Batteries: 0% 0% (0 / 4079 mV; 0 / 0 mV)
StateSync: Batteries: 55% 0% (3842 / 4079 mV; 0 / 0 mV)
StateSync: Batteries: 0% 0% (0 / 4079 mV; 0 / 0 mV)
StateSync: Batteries: 56% 0% (3843 / 4079 mV; 0 / 0 mV)
StateSync: Batteries: 0% 0% (0 / 4079 mV; 0 / 0 mV)
StateSync: Batteries: 56% 0% (3844 / 4079 mV; 0 / 0 mV)
StateSync: Batteries: 0% 0% (0 / 4079 mV; 0 / 0 mV)
StateSync: Batteries: 56% 0% (3843 / 4079 mV; 0 / 0 mV)
StateSync: Batteries: 0% 0% (0 / 4079 mV; 0 / 0 mV)
StateSync: Batteries: 56% 0% (3844 / 4079 mV; 0 / 0 mV)
StateSync: Batteries: 0% 0% (0 / 4079 mV; 0 / 0 mV)
StateSync: Batteries: 56% 0% (3844 / 4079 mV; 0 / 0 mV)

Right side

StateSync: Batteries: 44% 79% (3799 / 4079 mV; 3820 / 4123 mV)
StateSync: Batteries: 0% 79% (0 / 4079 mV; 3820 / 4123 mV)
StateSync: Batteries: 44% 79% (3798 / 4079 mV; 3820 / 4123 mV)
StateSync: Batteries: 0% 79% (0 / 4079 mV; 3820 / 4123 mV)
StateSync: Batteries: 44% 79% (3798 / 4079 mV; 3820 / 4123 mV)
StateSync: Batteries: 0% 79% (0 / 4079 mV; 3820 / 4123 mV)
StateSync: Batteries: 44% 79% (3798 / 4079 mV; 3820 / 4123 mV)
StateSync: Batteries: 0% 79% (0 / 4079 mV; 3820 / 4123 mV)
StateSync: Batteries: 44% 79% (3798 / 4079 mV; 3820 / 4123 mV)
StateSync: Batteries: 0% 79% (0 / 4079 mV; 3820 / 4123 mV)
StateSync: Batteries: 56% 79% (3844 / 4079 mV; 3820 / 4123 mV)
StateSync: Batteries: 0% 79% (0 / 4079 mV; 3820 / 4123 mV)
StateSync: Batteries: 56% 79% (3844 / 4079 mV; 3820 / 4123 mV)
StateSync: Batteries: 0% 79% (0 / 4079 mV; 3820 / 4123 mV)
StateSync: Batteries: 56% 79% (3843 / 4079 mV; 3820 / 4123 mV)
StateSync: Batteries: 0% 79% (0 / 4079 mV; 3820 / 4123 mV)
StateSync: Batteries: 56% 79% (3843 / 4079 mV; 3820 / 4123 mV)
StateSync: Batteries: 0% 79% (0 / 4079 mV; 3820 / 4123 mV)
StateSync: Batteries: 56% 79% (3844 / 4079 mV; 3820 / 4123 mV)
StateSync: Batteries: 0% 79% (0 / 4079 mV; 3820 / 4123 mV)
StateSync: Batteries: 56% 79% (3844 / 4079 mV; 3820 / 4123 mV)
StateSync: Batteries: 0% 79% (0 / 4079 mV; 3820 / 4123 mV)
StateSync: Batteries: 55% 79% (3842 / 4079 mV; 3820 / 4123 mV)
StateSync: Batteries: 0% 79% (0 / 4079 mV; 3820 / 4123 mV)
StateSync: Batteries: 56% 79% (3843 / 4079 mV; 3820 / 4123 mV)
StateSync: Batteries: 0% 79% (0 / 4079 mV; 3820 / 4123 mV)
StateSync: Batteries: 56% 79% (3844 / 4079 mV; 3820 / 4123 mV)
StateSync: Batteries: 0% 79% (0 / 4079 mV; 3820 / 4123 mV)
StateSync: Batteries: 56% 79% (3843 / 4079 mV; 3820 / 4123 mV)
StateSync: Batteries: 0% 79% (0 / 4079 mV; 3820 / 4123 mV)
StateSync: Batteries: 0% 79% (0 / 4079 mV; 3818 / 4123 mV)
StateSync: Batteries: 56% 79% (3844 / 4079 mV; 3818 / 4123 mV)

After left side "reset" it has returned back to normal

[kareltucek]

Right. Unfortunately, the log doesn't contain the details that we need. Apologies for that - my overconfidence is to blame.

Please flash this one and supply fresh logs please. //Edit: give me a minute

My guess is that the left half fails to detect battery presence reliably. I am not sure if I will be able to do much about it (this is a one off incident), but without logs, I definitely won't be.

[kareltucek]

Here is the link: https://github.com/UltimateHackingKeyboard/firmware/actions/runs/30272769630