Tired of only being able to fly 3-4 min with your Draganflyer baby? the new generation of battery: Litium Polymer or LiPo has just been created for that purpose: extending flying time because of an unseeen yet capacity to weight ratio. You can now expect on an average 15 minutes of cordless and pure flying fun.

LiPo for the Draganflyer


What you need

KoKam 3s 1500mAh
  • High Discharge Cell
    Pack,
  • 3 cells in serie
  • Discharge 10A (15A), Continuous 7C (10C)
  • Charge 1,5A (1C)
  • Weight: 110 g
  • Energy 348Wh/l or 171Wh/kg
  • Dimension (LBH): 75 x 38 x 19 mm

Maybe the best brand on the market for Li-Ion and LiPo.

It's competitor: ThunderPower is gaining marketshare in the USA.

I plan to use them as well on my Hornet 2

Plug for controlling cell on the left, on the right 4mm gold plugs with 2.5mm wire to transmit power...

Charging

LiPo are expensive, LiPo are Dangerous so you must handle them carefuly and charge them safely...
If you charge them too much (outpassing current charge with 100mV) and they can explode. If You store them in a place and forget them, under some condition (less than 2.8V per cell), they will destruct themselves.

A good charger is the
KOKAM LIPO-402, able to take care of Your 1S,2S,3S an 4S pack.

It is mandatory to stop using them if cells go under 3V, (remember at less than 2.8V/Cell they will loose capacity and be damaged), so stopping at 3V is not a bad idea. A lot of device are sold in order to help you watch in realtime the state of your cells. Most of them are made of a single CI (a comparator with a fixe reference at 9V (33S)).

You can also build Your own device (see below and for a lot less). This system has a big high luminosity 10mm LED (but some use buzzer) which blink when it is time to stop. In this case I recommend to land very fast and switch power off.
  • For 2S to 10S pack.
  • Voltage trigger from 2,5V to 3,4V

Sand!

As stated in the documentation, You should NEVER use any water to stop a Litium battery fire, the water is reacting with the Litium and make the things even worse. I recommend to ALWAYS have 1-2Kg of sand in the area. Watching a helicopter burning is not the best way to make the bank officer Your friend...
For the same reason DON'T charge battery inside Your house!

Build it yourself!

  1. Voltage monitor for LiPo
    A PDF that I've found on RC Universe is available here. Cost of buid less than 3euro!!!
  2. Independant Cell charger. So you can charge cells separatly. In the picture below, white plug is the common. Be careful to switch your charger to 1S charge mode (3.2V) when charging cell indep. or you will destruct your superb pack

In the draganflyer...

TODO

Video in-action

............

VIDEO

Before the end of months I will be
able to post a video here

Total Costs

  • 1500mAh LiPo Pack 3s 49.90€
  • Kokam LiPo 402 89€
  • LiPo Protect analog 19€

Links

www.rclipo.de A german site with a lot of battery and choice. The seller has given me good advices...

Future is exciting! hydrogen cell are expected in 2007...