Battery output lower than plug - what effects?

I’ve checked the power at the 12v and AUX screws, and my multimeter shows ~11.9v with the Konnected battery (which is fully charged and plugged in to the wall), and ~12.2v when the board is instead plugged directly to the wall.  This is the same for all three of my backup batteries (within +/- .04v), and switching around the cords for each.

How does this affect the system short term or long term? How about modem and router?  Is it the battery itself, or the male-to-male cord out of the battery?  

I got out my multimeter because I was sure I’d noticed at least a 5’ distance reduction from one of my motion sensors. Perhaps that type of device is more voltage sensitive.  

I also have 4-wire smoke detectors, a CO detector, and glass break sensors that use the 12v taps to run. I would not expect the slight deviance from 12v to affect those (the new 4-wire smoke detectors I used to replace the old original 2-wire units say they are designed for an 8.6-30v range).

The three devices on batteries otherwise seem fine and stable: modem, router, and Konnected Alarm Panel Pro board.