Walkera Dragonfly 4 battery upgrade

by Pete
(UK)

Above, the pack and charger (left) and the pack in place (right)

The Walkera Dragonfly 4 electric rc helicopter is a great little heli, 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 the 1000mAh 7.2V 16C lithium polymer DualSky pack. The 11.1V pack is another option, but costs a bit more and reputedly burns out motors rather quickly.

If you do purchase the lipo pack, make sure you also get the appropriate charger - you CANNOT charge a lipo pack with a charger meant for NiMH or NiCD cells!
The E-Sky EK2-0851 is a cheap n' cheerful charger meant specifically for lipos. Beware though, it is powered from a 12V source - so if you don't have such a source, then make sure you get the mains transformer at the same time!!

Fitting the lipo pack in the Dragonfly 4 isn't hard, but the much thinner size does mean 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, and is perfectly secure in flight.

If you do make the switch, watch out for the change in CG; the lipo 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 lipo on your Walkera Dragonfly 4 electric helicopter, you can enjoy flight times of up to 20 minutes or so, instead of the 6 or 7 mins that the stock NiMH pack gives. Yeah!