Hydro.. these are the batteries I've been buy'n. cheap, free shipping.. 2200 - 30C's... Never had an ounce of trouble with them at all... supposed to be made in Japan... who knows.. I've never had any issues with them and for me thats all that counts...

http://www.ecpower.com.hk/index.php?...roducts_id=218 - $43.00 for two batteries delivered isn't bad at all... I have 6 from them...

As for maintenance... always... its a heli with tons of spinning, vibrating bits... it will shake itself to pieces if you don't go thru and tighten stuff up regular... also anything that can be loctited.. loctite... the blue non-perm... not the red...

hope this helps some...

happy christmas