Programming and charging teensy off one usb port.

[Waterme11on]

Hey there so I'm pretty certain my plan will work but I need some confirmation before I melt any more ICs.. :S

I'm planning to power my teeny+Prop shield with a rechargeable 3.7v 18650 boosted through Sparkfun's Power Cell board, which will boost to 5v. (https://www.sparkfun.com/products/11231).
I also have some DIY female micro usb ports (https://www.adafruit.com/product/1829) which I want to rig up as a universal port.

So im wondering if these connections will work:

1. 5v and Ground from DIY usb port into charging pins on the Power Cell board.
2. D+ and D- from Diy usb port to teensy
3. Boosted 5v from Power Cell board to Teensy Vin or Vbat (I believe i can leave them connected since i'm not plugging usb into the teensy directly?)
4. Connect Ground Power Cell to Teensy

So with that set up should I be able to plug a usb cord into the diy usb port to send data to the teensy and also charge the battery?
Also do I need to connect the ground from the usb port to the teensy or is it okay the way I have it?

Thanks.

 

[PaulStoffregen]

Teensy vbat is for a coin cell that keeps the RTC running when power is off. It is NOT for powering Teensy. You need to use VIN for that.

Teensy LC & 3.x have a connection between VIN & VUSB which you can cut. If you leave this connected, it's possible for power you apply to VIN to flow backwards into your computer. That's generally considered a bad thing, though actual damage is very rare. Still, be careful and consider whether external power is able to go back into your USB cable.

 

[Waterme11on]

Oh sorry that was a typo with the Vbat, I was talking about Vusb.

As for the backwards power, I should be fine since nothing is connected to the vusb? Can i send data through the D+ and D- pads without having to power Vusb, whilst having the teensy being powered through Vin?

Cheers