Yeah like others said, dont ever try charging an E-power on a proprietary battery charger. Thats a very bad idea.
Did you ever consider spending the money on extra batteries, instead of spending $45+20 on a Pila charger+ 12V car adapter or $20+ on an Xtar charger that will allow you to charge your batteries in your car?
One of the main reasons I bought an E-Power is because I wouldnt need to worry about having to charge batteries in the car.
For the price of the cheaper Xtar charger, you could buy 3-4 more 14650 batteries, and for the price of the Pila charger+ car adapter you could buy about 10 14650 batteries. Then all you have to do is keep a few charged at all times, and bring an extra 1 or 2 if you know your going to be out for awhile and youll never have to worry about trying to charge batteries while your out and/or being stuck with a dead battery.
Dont get me wrong, both of those chargers are nice, but personally Id rather have a bunch of extra batteries, then have a nice charger for the 2 batteries that come with the kit.
For my E-Power, I have 4 14650 batteries. I bought a TR-001 charger for only $8.40 shipped off of eBay, which allows you to charge 2 batteries at once. Then all I do is when Im home, charge the batteries Im not using, so they are fully charged when needed. Then every morning I put in a fresh battery before I leave for work, and take a fully charged spare with me for "just in case". I dont normally need to use the extra one, but Its worth taking with you. Then when I get home, I put the 2 batteries I used from the day before back on the charger. They finish charging before I go to bed, and I unplug the charger (Never charge your batteries overnight). Then the next morning Ive got one fully charged battery that goes in my E-Power, and the other fully charged battery goes in my pocket or bag as a backup. And I just continue that rotation.
Doing this works well and allows you to never have to worry about not having a charged battery or trying to charge a battery/find an outlet/hope it charges fast enough while your in your car, etc.