Conflicting battery voltages.

[gearsincorg]

I've notices that depending on where you look, the "battery Voltage" is giving different values.

I understand that various power paths may have protection devices etc that effect the actual voltage at that point, but we probably should decide what is the "Battery Voltage" and what is "some other internal voltage".

I charged a battery and measured it's output when powering the system.

I measured 20.57 Volts at the output of the battery (and at the motor terminals). (Fluke DVM).

The small display on the System Core says 18.1 V
The Driver Station says 18.2 V
The SystemCore web page says 18.1 V
The MotionCore web page says 20.1 V (while the 18.1 V is also displayed at the top of the page).

It seems to me that if there is a MotionCore attached, the "Battery Voltage" should be the number measured by it (since it's actually attached to the battery) and this is what will effect the operation of the motors.

Also related: the Driver station Voltage display goes RED when the Battery Voltage drops below 16 V (It appears). I assume this must just be for FTC, but it's not actually valid.

[ThadHouse]

Can't really answer the where measured question, other than the DS displays the voltage where Systemcore measures it (Which is why its the lower one). What do you get if you stick probes at the Systemcore input.

16V is the cutoff for low battery, thats just what we programmed. We can lower that. Note the system detects 12V vs 18V batteries, and changes the cutoff for what is considered low battery.

[Kevin-OConnor]

I think this is a dupe of #306. The battery voltages should match which would eliminate the issue and allow us to continue using the single SC measured voltage which works cross program.

[gearsincorg]

What do you get if you stick probes at the Systemcore input.

The Systemcore input measures the same as the MotionCore input.