Make sure whatever you use is well regulated; I wouldn't try to use a charger as a power supply for the MkV.
I have to ask... If the provided PSU is working, why are you trying to use something else? And if you need a battery, you'll have fewer probleems if you buy a correct battery.
I am simply trying to buy a batter pack (like pineapple juice) to deploy the pineapple where there is no outlet. If I am using the wrong battery can you give me an example of the right one? I thought this one was okay because it was my understanding that the pineapple operated between 5v - 12v. If you know any that will work, please let me know.
Thank you