Walkera Dragonfly 4 battery upgrade
Above, the pack and charger (left) and the pack in place (right)
The Walkera Dragonfly 4 electric rc helicopter is a great little helicopter, and doesn't cost a lot for what you get.
The stock battery is a 7-cell NiMH 650mAh pack, which is OK for a while but doesn't take much of a bashing... with regular flying, it won't be long before the pack is discharging quicker than you can get the helicopter off the ground!
An excellent substitution is a 1000mAh 7.4V 15C or 16C Li-Po (lithium polymer) battery pack. My main Li-Po pack is a DualSky but there are many makes out there; my 2nd and 3rd Li-Po packs are cheapie 7.4V 1000mAh 15C ones from eBay (pictured below), shipped from China (search for these on eBay).
A very important point to remember is that if you do purchase a Li-Po pack, make sure you also get the appropriate charger - you CANNOT charge a Li-Po pack with a charger meant for NiMH or NiCD cells!
The E-Sky EK2-0851 (try eBay) is a cheap n' cheerful charger meant specifically for Li-Pos. Beware though, it is powered from a 12V source only - so if you don't have such a source, then make sure you get a mains-12V transformer at the same time, or be prepared to run the charger from a car battery.
Fitting the Li-Po pack in the Dragonfly 4 isn't a big job, but the much thinner size does mean that some modification to the existing battery cage is required.
I epoxied a modeling-grade (1/64") ply base to the front cage support and used a zip tie around the receiver. A bit of sponge filled the gap, and the pack is far easier to remove than the original, as well as being perfectly secure in flight.
If you do make the switch from the stock NiMH battery to a Li-Po, watch out for the change in CG; the Li-Po pack is a bit lighter than the NiMH, so needs to be mounted further forward - another reason why the cage needs to be adjusted somewhat.
With the new Li-Po on your Walkera Dragonfly 4 electric helicopter, you can enjoy flight times of up to 15 minutes or so, instead of the 6 or 7 mins that the stock NiMH pack gives. Because of the extra power available from the Li-Po, you use less throttle, hence the longer flight times.
Related pages
Motor upgrade - fit a better quality brushed motor.
Landing gear & skids upgrade - add a touch of class to your helicopter.
The Dragonfly 4 - what you get and what to do with it all.
Spares & repairs - useful tips for the Dragonfly 4.
Rotor blade balancing - a crude but effective way if you don't have a balancing tool.
Rotor blade tracking - how to get the blades tracking correctly.
Flybar balance and paddle pitch - more ways to stop vibration.
Main frame replacement - guidelines for the worst job of them all!
Index - to all Walkera Dragonfly 4 related pages.
