Take the battery pack to a Batteries Plus store they will be able to test the battery with a couple different machines to determine if this is the cause of your problems. Also check all yoru wiring make sure everything is secured and connected tightly. I've never liked Nimah's as the life of the packs are not that great. after each use they do get cell depletion and it continues to derteriorate with each charge. When I store my batteries I give them a FULL charge and store them away and after about every 2-3 weeks pull them out and give them a complete cycle. a full discharge and then full charge and put them back up. it's work fine for me but seriously if your content with 4-6 minute flight times then stay with nimah. if you want longer times look into Li-po packs. I have a 3s cell Thnuder Power 1325mah pack and I can get close to 25 minutes out of this pack. You just have to either install a voltage meter to make sure your not over discharging the pack on my 3 cell the cutoff is 9.6v or like I do let the heli rest and motors cool down after about every 10 minutes and check the voltage level with a volt meter. I know they seem expensive but they are a well worth while investment for this kind of high powered-draw machine. I flew the stock battery for 1 flight it lasted maybe 5 minutes. I happened to have an extra lipo from my rc car stuff so I just soldered up a connector to make the Ultra deans connect up to the Micro deans conneter on the copter and that's it. took maybe 5 minutes for the soldering. well worth the time and effort. Not to mention it's alot more powerful than the stock batttery. I don't know I'm very new to the helicopter. As I just bought my first a coupel days ago. But I've had a lot of experience with batteries. And this is just my 2 cents.