In the specs for this product, which I own and will ikely return before the 30-day return period, says it has a 36-hour 'standby' time for the battery. I believe this is what is killing everyone's battery overnight and when left unplugged. Funny thing is, this IS NOT A PHONE and isn't expected to receive calls, so why does it have a standby mode at all? If it's to allow it to connect to a network more quickly, the painfully long start time shows that it is failing miserably.
I hope a new firmware build can address these HUGE issues that make a promising device, my most hated piece of technology.
I believe they're referring to the device being in low-power mode. If the device is not charging, it will eventually go into low power mode. You can change the amount of time it's idle before it enters this mode through the power settings.
The Overdrive also functions as a router for connected devices, including the ability to share the inserted MicroSD card across the network. This is most likely the reason it has a standby mode. Obviously if you turn it off entirely it won't use power, if you leave it on then it will still be using power. Seems fairly simple to me. If you let it sit idle not doing anything it will be on for 36 hours until it dies. It isn't much different in this regard than the Novatel MiFi 2200.
That is contrary to my experience over the last two weeks. When I see 'Powering off' after charging to 100% and put the OD in a protective sleeve and in my laptop bag, by the end of the day, without any use at all, the unit is warm, only has 40% charge remaining and won't turn on until I remove the battery and wait 15 seconds or so before re-inserting. This is consistent behaviour that has forced me to remove the battery after charging to make sure it's still useful later in the day when I normally need it most. Since Off doesn't appear to be truly Off for the OD, that is what I was interpreting as Standby.
Maybe I'm experiencing a variant of the "Power Off Bug" I've seen in other posts.