The Yotaphone 2 comes with a 2500mAh battery sealed in between those two display, which is a touch smaller than the power packs found in similarly priced competitors.
A slightly smaller battery coupled with an older Snapdragon 800 processor means power efficiency via the main 5-inch display isn't particularly stellar. I found the Yotaphone 2 was consistently running out by the end of the day when the colour screen was predominantly used.
Running the 90 minutes battery test video with the colour screen at full brightness and accounts syncing in the background the Yotaphone lost 20% of life.
It's a shame it's missed out on the Snapdragon 801 chip as it saw big battery life improvements over handsets rocking 800, and considering the processor in the Yotaphone 2 is way over a year old now it seems like a missed opportunity.
Yota isn't overly concerned with the difference in power efficiency between the 800 and 801 chips, as it claims the Electronic Paper Display (EPD) can deliver significantly longer battery life.
Use the rear screen for day to day tasks such as text messaging, emails and social media and you'll only drop a handful of percentage points.
The down side is you'll need much more patience - typing is a bit of a chore as you wait for the e-ink technology to keep up with your taps, and general navigation isn't as fluid as the colour screen.
It's a trade off I was willing to make a lot of the time though, and the fact I can get live information on the low power display makes it great for glancing down at on my desk to get a quick update.
If you do find yourself running particularly low you can always engage the YotaEnergy power saving mode, which switches off various features in a bid to extend life as much as possible.
Yota claims that enabling YotaEnergy when you have 15% battery left will extend life by up to 8.5 hours, versus 1.5 hours if you didn't enable the power saving mode - and it reckons with the mode enabled earlier the handset can last two days on a single charge.
You can set YotaEnergy to automatically come on when the battery falls below 15%, 10%, 5% or your own custom value, plus you can toggle which features it disables.
YotaEngergy can do a variety of things such as throttle processing power, turn off key functions such as WiFi, Bluetooth, GPS and NFC, and enable a 2G only mode which cuts mobile data but still allows calls and texts.
I found by enabling pretty much all the power saving features within the YotaEnergy menu and switching the mode on early that the claim of two days is achievable - but you need to keep off the front display.
The Yotaphone 2 is also wireless charging enabled, so if you have a Qi charging pad you'll be able to plonk the handset on it to refuel.
It's relatively impressive then, but battery life isn't as groundbreaking as I'd hoped. Some of the top smartphones of 2014 can go a day and a half on one charge without the benefit of a low powered display for the menial tasks.
Use the Yotaphone 2 in the right way and two days is possible - focus on the front screen and you'll be lucky to see out one.