Weird thing with battery. Suddenly stopped charging. Questions.

MacBook Pro (see image below).

Was trying to upload a 40GB file to Vimeo. Several fails, but no explanation for why. Tried again yesterday. Let it run overnight. This morning I see that it stopped uploading early on in the night. I'm trying to suss why. Then I see my battery did this weird discharge (see image).

I'm getting my power for the MacBook Pro not directly from the Apple charger but from one of the plugged in external devices (I need all the MacBook Pro ports for external devices and drives). It's been working fine like this for months. I just did a test. I'm getting power from each of the devices: Thunderblade SSD RAID setup, 2 different OWC external patch bays. I unplugged and replugged everything, and any one of these external devices seems to powering the MacBook Pro, while simultaneously keeping the battery charged.

I'm wondering if during the upload (the file was coming straight off the MacBook Pro, not from one of the external drives) somehow all my external devices went to sleep and stopped charging the MacBook Pro? Is that possible? And how they would go to sleep I can't imagine ... the power would still be going through wouldn't it?

I've never seen my battery discharged like this before in this setup. I plugged the Apple charger directly in and got a full charge in an hour or so. Now it seems to be running fine, getting its power from the external devices again.

Any ideas?

Ben