Welcome to Tesla Motors Club
Discuss Tesla's Model S, Model 3, Model X, Model Y, Cybertruck, Roadster and More.
Register

OK to leave USB charger plugged in 24/7?

This site may earn commission on affiliate links.
I have one like this that I plug into the cigarette lighter and run the cord between the passenger seat so it sits on the floor in the middle of the backseats for my kids to use:

Fonus Brand Two USB DC Cup Holder Cigarette Lighter Socket Power Adapter Splitter Double Car Charger Center with Dual Charging and USB Ports for Apple Iphone 5 (GREEN Dash Sticky Mat is included): Amazon.ca: Electronics

I sit it in one of these cup holders:

2007 2014 Tahoe Suburban Avalanche Yukon Console Cup Holder 19154712 | eBay

I keep it plugged in all the time with no problems.
 
Yes I do it, no problem. The USB ports are switched anyway (i.e. power to them is cut off when the car is off). Even disregarding this you'll be fine. I have dashcam hard wired to non-switched (always on) fuse and I left it on for 10 days at the airport (forgot to turn it off) in parking mode and no problem with my 12V battery after that either.
 
I like to joke with people who ask me about the headlights staying on for a while or leaving an accessory outlet item plugged in: "The battery might go dead. In a month or two."
 
The adapter is actually pulling 12v from the port. Internally it drops the voltage down to 5v for the USB ports. So as far as the car is concerned, it's a 12v device pulling up to 24watts of power (assuming both USB ports are used at full capacity). I believe Tesla rated that port at 120watts, so you'll have no issues.
 
The USB ports are always ON (Dec 2014 Model S) contrary to what everyone is saying. Only the 12V outlet is switched off when the car powers off. How do I know this? I have a constant USB charger plugged in one port and the light is always on (the cables with the LED at the tips), the other plugged into my lithium-ion battery pack which I connect to my cell phones and the unit says it's always charging. I've gone as far as plugging a dead tablet into it and come back hours later to find that it is fully charged. Since my dash cam uses 5V, I will be wiring it to the USB also now. And yes it is okay to keep accessories plugged in. If the 12V dips below a certain voltage, the main pack charges it back up.
 
  • Informative
Reactions: wesley888
The USB ports are always ON (Dec 2014 Model S) contrary to what everyone is saying. Only the 12V outlet is switched off when the car powers off. How do I know this? I have a constant USB charger plugged in one port and the light is always on (the cables with the LED at the tips), the other plugged into my lithium-ion battery pack which I connect to my cell phones and the unit says it's always charging. I've gone as far as plugging a dead tablet into it and come back hours later to find that it is fully charged. Since my dash cam uses 5V, I will be wiring it to the USB also now. And yes it is okay to keep accessories plugged in. If the 12V dips below a certain voltage, the main pack charges it back up.

If true on your car, this is a change from earlier cars. My USB ports and accessory outlet all shut off when the car is off. In my Signature car, the USB ports are limited anyway in that they're only 1.0A ports, so we keep a charger plugged into the accessory outlet.
 
If true on your car, this is a change from earlier cars. My USB ports and accessory outlet all shut off when the car is off. In my Signature car, the USB ports are limited anyway in that they're only 1.0A ports, so we keep a charger plugged into the accessory outlet.
My earlier car takes a few minutes to shut off. If you don't check, it might appear that it stays on.
 
I have the energy savings on but with Always Connected checked. Yes, I know the accessories take a bit to turn off once you lock/leave the car but my USB remains on all the time. My dash cam records 24/7 (it uses 5V) only when connected to the USB, not the 12V which turns off.
 
I have the energy savings on but with Always Connected checked. Yes, I know the accessories take a bit to turn off once you lock/leave the car but my USB remains on all the time. My dash cam records 24/7 (it uses 5V) only when connected to the USB, not the 12V which turns off.

If I plug my phone in and turn the car off, it charges for one or two minutes (I've never actually timed it, but it shuts off before I get bored of waiting) and then stops. Energy savings on, Always connected off.