I use an Anker PowerCore 20,100 with dual ports as my Primary power source.
https://www.amazon.com/Portable-Charger-Anker-PowerCore-20100mAh/dp/B00X5RV14Y/ref=sr_1_3?ie=UTF8&qid=1545589112&sr=8-3&keywords=anker+20100)
I fly in several different aircraft that do not have the cigarette lighter port, so I need to also consider that I must provide external power to my iPad Pro running ForeFlight, especially if flying on an extended series of XC flights that could total 6 hours or more.
If the iPad is fully charged, it will be at less than 50% on its own battery after 2 hours of flight, so if you are on a series of XC flights totaling 4 to 6 hours our more, the iPad will be near ONLY 10% remaining at arrival and this is not enough safety margin for me!
The Anker will easily power both the Stratux and the iPad for this long flight duration and the iPad will remain "topped off" and still be somewhere between 85% to 95% at the end of the trip.
I also use this PortaPow Charge only cable to power the Stratux from the Anker.
This cable is perfect because it is a true 20 Gauge cable that is very flexible and will provide full power to Stratux. Other cables at 6.5 foot length use thinner gauge wire that can cause power loss that will not allow a full 1.0 Amps to be supplied to the Stratux.
Providing less than 1.0 amps would cause the Stratux to drop off line, then reconnect, only to drop off again and reconnect. Not a good scenario in an aircraft. This was an issue on my first Stratux build a couple years ago and this cable completely solved that problem.
The new Low Power radio may also help with a lower power draw, but I have not yet tested my latest build in flight to confirm.
Hope this helps