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?

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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)