LiPo cells for UM planes & helis - comparison tests
The question of which LiPo cell is the best for the UM planes & helis comes up often in the ultra-micro forums. Many of us have found that Hyperion cells outperform most of the competition, and that Thunder Power & Intellect UM cells perform as well as, or very close to the Hyperions. Objective tests back up our experiences.
Remember - loaded voltage is what determines the performance
of a battery - not usable capacity. Loaded voltage is a function of the cell's internal resistance (Rint). The lower the Rint, the less power will be dissipated within the cell as heat, and the lower the voltage-drop will be under a given load. The cells with the highest voltage under load will provide the most thrust & speed in a given application. Also of importance is the voltage slope over time. The shallower the slope, the more power the cell will deliver over the course of the flight. Also, a shallow slope means that more power will be available toward the end of the flight.
It has been proven many times that Hyperion cells maintain voltage under load better than nearly all of the currently-available LiPo cells. The notable exceptions are the Thunder Power 160 & Intellect 130/160 UM cells - which perform similarly to their Hyperion counterparts. The Hyperions can be charged @ 5c for hundreds of cycles with no reduction in performance or longevity. 300+ 5c charge cycles with no reduction in performance is common. Of course, this assumes than the cells have been properly stored and that they have not been discharged below 80%.
The Intellect & TP cells are also rated for at least a 5c charge. More long-term test data on the TP & Intellect cells is needed to determine how they perform over time; but so far, the reports have been favorable. John & Natterjack have done some excellent UM cell comparison testing.
See John's report here:
See Natterjack's report here:
My favorite sources for Hyperion cells:
All e RC: http://www.allerc.com/batteries-lith...-c-3_4_93.html
Aircraft World: http://www.aircraft-world.com/shopdi...-Po+-+HYPERION
Hyperion Australia: http://www.hyperionaustralia.com.au/?stg=878
Thunder Power 160 mAh 'UM' cell:
All e RC: http://www.allerc.com/thunder-power-...or-p-5784.html
RCBabbel's plug & play Hyperion 180 mAh 2s packs for the UMX Beast & Sbach: http://www.rcgroups.com/forums/member.php?u=54990
In Sept, 2010, Hyperion announced that a bad batch of 160 mAh 'UM' cells made it to the sales channels. Hyperion pulled the bad batch from their shelves and told their vendors to do the same. See the post below: