The Juice 1800 got 10.8-12.6V 1800mAh
I tried with a EasyAcc 12000 which got 5V 12000mAh
The Juice can handle a Alfa extra but the EasyAcc don't, the Pineapple is in a bootloop :(
So I guess, if you just using the Pineapple a 5V source is fine, unless it have 2Ah output
I've got some Lipo's lying around from my older Helicopter, maybe i make a batpack out of them ;)
I'll report when its done