Is it possible to charge battery and doesn’t power i2c sensor?

[bglazyrin]

Hi everybody.
I’ve connected external LiPo battery to battery connector on the bottom of my TTGO and put on/off switch on plus cable from battery to board.
As far as I understand, when I connect TTGO to USB and put switch to ON position, my battery is charging.
I’ve also connected external i2c sensor to my TTGO, that has limited working lifetime (when it is powered).
So, my question is:
Is it possible to charge internal battery from usb without powering external sensors? What is the best way to do it?
If I’ll put ttgo to deep sleep, will it cut 3.3 power?
Or  I have to add another manual switch to cut off sensor power when I don’t need them?
 
Thank you in advance,
Boris