RE: Portable power stations
I have not, but many guys use them for small park flyer batteries. If you get into the large capacity flight packs then they dont have enough "juice" to charge many packs. Very conveint for smaller stuff, Have there own charger built in and other do-dads and they are "gelcell type" so can be put in any position without any leakage of the electrolite. Most over here are very reasonable priced also.
Good Luck
Bob