I just don't want to mess up the batteries. I was told that it's not good to charge with the mod. But I can huh will it mess up the batteries in the long run?
It would be best before going a lot farther, to read up on battery safety, Ohms law, Darwin's theories..
You don't want to vape from your batteries. If they say 800mAh, nothing else matters. The Alien is able to ask for 100 watts from each battery, stressful for a 20amp continuous battery let alone a video camera battery. None in the 20a CDR range are 800mAh.
You really need a good charger (I like Xtar), and a half dozen GOOD batteries. For the Alien, a Sony VTC6, Samsung 30Q, or LG HG2 would be great choices. Mooch just tested these as the top 3, in the order I show them.
All of them are 3000mAh and 20a CDR. If your Alien doesn't vape well at that point, it would be your juice system or inexperience. Hang in there, it will come. Get the right gear.