I used the USB volt/amp meter with the following results.
On battery On AC power
4.98V 4.99V both with no item plugged in.
4.97V/.06A DVD writer idle 4.98V/.06A DVD writer idle
4.97V/.16A spinning no disc 4.97/.16A spinning no disc
4.89V/.5-.6A during disc spin up 4.92V/.5-.6A during disc spin up
4.89V/.31A disc at speed 4.92V/.31A disc at speed
Low Transient Voltage 4.81V Max Transient Amperage .8A
Played a CD and ripped CD no problem. DVD would show content but not play movie, downloaded VLC player and tried again. The movie played ok, window movie player couldn't recognized the file extension.
Connected a Seagate backup plus portable 1TB drive (SRD0SPO), it worked ok. Low Voltage 4.95 High Amperage
The DVD writer was touchy when first started, but seemed to work more consistently as the Writer warmed up. I didn't try writing to a disc so I'm not sure if it will work all the way through the burn. The DVD writer indicates that it uses 5V 1.3A, I never
came close to that much Amperage which might be reached during burning a disc. This might cause a draw down of voltage enough to cause problems maintaining a burn especially when on the battery.