The fact that you must charge an Nixx batteries seperately is very important. Never try to charge NiCad or NiMh in parallel if you want them to both be properly charged. I agree with CGretired, I have never had a receiver/servo glitch caused by using 5 cell batteries (I use both Futaba and Hitec) when they were fully charged. I also fully endorse using the Voltwatch, properly monitored it beats a loaded voltmeter in all aspects as well as giving you warnings of any high impedance paths between the receiver and batteries such as those caused by to small a gage wire, poor switch contacts or high impedance solder joints; almost as good as having a scope on the power system.