Ive noticed an electrical humming sound coming from the back left of the driver.
It only happens when in higher revs (3k or higher). Im not sure if this is just a sound the car makes or something to keep an eye on. I tried recording audio but its not loud enough for a phone mic to pick up. Knowing the battery is in the rear left, I'm not sure if its related, but it is a fairly new battery (8 months old).
Anyone else experience this?

 

An intermittent buzzing sound? Your car has an electric vacuum pump which is used to close the active exhaust valves. Mine sounds like a buzzing heat shield. It’s located inboard and behind the left rear wheel.

 

The fact that it seems tied to engine speed to me indicates it's not an electrical sound, but a vibration of a panel. I've had a buzzing from the panel just behind the drives seat. Pressing on it to reseat the clips cured it.

If it is buzzing due to vibration you can find it using the sound system and a tone generator app on your phone. One that allows easy and gradual adjustment of frequency will be preferable. I noticed the buzzing has returned so will go through my process again and report. As I recall, I set to sine wave, left speaker, and adjusted frequency until I heard it. Alternately, you can have a passenger press on the panel (or do it yourself, carefully) when driving in conditions that reproduce it.