I see a lot of mixed views on this topic. I guess there is a right and wrong though. I hear people say to parallel, the batteries need to be the same. Then I see people running a 1500mah and a 2200mah battery in parallel. From what I have seen, that seems to be okay. The batteries will always drain to the same voltage no matter the capacity of each, it is how batteries work apparently. The bigger battery will pick up the slack from the smaller battery. From what I read, just make sure the voltages are the same when connecting, and charge them separately with balanced chargers. Hard to know when I read so many different statements. What if you had a 30 amp draw and wanted to parallel a 20 amp capable battery with a 10 amp capable battery. Together that makes 30 amps. Does it matter that neither one alone can produce enough? This might be a dumb question, IDK. I've seen a guy with a 1000mah, 800mah, and 1200mah paralleled inside his stock. Ill never parallel lipos anyway. I was just curious about it after I saw what that guy did. If anyone could explain dos and don'ts with a little science to back it, that would be great. Everyone talks about upgrading, gears, springs, motors, ETUs/Mosfets...... I then see people go 12:1 SP120 and 16TPA motor, puts a 1100mah 15C lipo in his PDW stock because it is the only thing that will fit. Then wonders why his lipo is hot or puffed up. You got the con artists at Titan battery selling crap batteries for airsoft to people. Batteries seem to be the most uninformed area in airsoft.