| For the Blade CX, you can use any lipo battery with 7.4V, something
| like 1200mah, 1800mah, 2200mah etc ... but make sure they are 7.4V,
| then it is ok.
Hardly.
The CX doesn't have a lot of extra lifting power. If your replacement
battery weighs much more than the stock battery, it won't even be able
lift off.
But yes, the most important part is to get a 2 cell LiPo, but the
weight should not be much more than the stock pack unless you can make
the helicopter lighter by removing weight somewhere else.
| Also, read this information about how long you should fly to avoid
| damage to your helicopter:
| http://www.4-rc-helicopter.com/index.php?action=artikel&cat=5&id=66&artlang=en
The battery on the CX will get warm, but should not get hot, even if
you're flying at full power for a long time. If it's hot, something
is wrong.
As for how long you should fly, it's smart not to run the battery so
low that you don't have enough power to hover anymore. When the power
starts going down, land and recharge, even if you could still fly for
a little bit. If you want more flight time, just get a few packs and
switch them out.

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Doug McLaren, dougmc@frenzy.com
Happiness is nothing more than good health and a bad memory.
--Albert Schweitzer