The manual that I downloaded from Innokin, while waiting for my SVD to arrive, has a major typo regarding how to install the battery correctly. As you'll see in this quote, it instructs you to install the battery backwards:

Please install a proper battery before operation. Screw the battery
negative (-) cap off the telescopic tube, then insert battery into the
telescopic tube with the negative (-) end of battery in first and the
positive (+) end out towards the battery negative (-) Cap.

Instead, the Positive end of the battery should go into the tube first, pointing toward the head of the device, and the Negative end cap f the device should screw back onto the tube, making contact with the Negative end of the battery!

While I'm at it, here's something else that I've seen from the manual that might be important for some of us to remember:

Note: Before you make a switch between one battery and two
batteries, please hold the fire button for 5 seconds to release the
remaining capacity in the mainboard. (when you make a switch from
one battery to two batteries, the mainboard will keep the one battery’
settings if you haven’t released the remaining capacity; and vice versa.)

This was important for me to know, since I plan to test the difference in running a single 18650 compared to two 18350s.
This trick (hold the fire button for 5 seconds) may also help with other issues some folks have been reporting.