Has anyone ever had any issues charging multiple Life or Lipo packs on multi-chargers such as the Hitec X4? Someone told me today that these multi-chargers are known for "common ground" issues. I've gone on Amazon and read the customer reviews and people have put multiple Lipo packs larger than 2000mah and they say it takes about 2 hours to charge all their packs. I have to say, from the days of the Nicads and having to charge them for 12-16 hours, 2 hours is nothing to complain about. Any input here??