DMyer

My Feedback: (2)

Anyone used the new Lithium Polymer batteries in their e-flight parkflier? If so... which one on what motor and how did it perform. Thanks.


Dan

fishgod

My Feedback: (13)

I have been following the 40+ page post on ezonemag about Li-poly's. A couple of questions you have to ask is how many amps will you be pulling from the pack? and what voltage you need to run. The packs run at a nominal 3.7 volt per cell and something like 4.2 volts fully charged. You can draw a constant 3C from the pack with peaks as high as 5C. All this will determine the Mah pack and the wiring of the cells. What size pack are you looking at replacing?

DMyer

My Feedback: (2)

Plane #1 is an arobatic fun fly type, I am running a 9 cell 720 MA NIMH on a 280 BB Speed with 3/1 gearing and a 9 * 4.7 prop.

On my other plane, a floater, I have an 8 cell 1000 MA running a Speed 400 geared 3/1 with a 10*4.7 prop.

I see were RADICALRC offers a 900/1800 MA LI-POLY packs. The 12.6 volt 3 cells interest me the most.

I am most interested in the additional flight time and if the batteries hold up better than NIMH batteries. All mu current NIMH are near the end of their lives so I need to re-battery anyway.

fishgod

My Feedback: (13)

FMA sells some everything from 145mAh to 3270mAh cells. The amperage is the big thing. The speed 280 would probably work will with the 900's and 1800's from RADICALRC. Or if you are so inclined to make your own packs you could use the 3 of the 1020's and have a pack that could handle 3 amps continuous with peaks to 5 amps. It would weigh approx 2.16 oz. and the 2070's would give you 6 amps continuous, peaks to 10 amps weighing in at approx 4.65 oz I guess to determine what packs would be good you need to know the amperage that you are drawing at full throttle.

Matt Kirsch

My Feedback: (21)

Well, you can look at the battery packs for each plane and pretty much determine what you'd need in the way of LiPolys.

720mAh NiMH packs have a maximum current of about 6 or 7 Amps. Two 2070 Kokam LiPoly cells in series would be my first choice to replace an 8-cell NiMH pack.

1000mAh NiMH, if they are HECell or Wattage packs, can reliably put out about 15A. On that Speed 400, I would expect somewhere between 10A and 12A. In this case, you could gang together two 2-cell packs of 2070 Kokams in parallel, or a single 2-cell pack of 3270 Kokams.

DMyer

My Feedback: (2)

Thanks for the thoughts.... since I have never really been completely happy with the performance of NIMH batteries I think I will give these LI-POLY's a try next. They seem to promise the correct combination of light weight, power and duration we have always been looking for for E-Flight. I am getting really tired of 2 minutes of good performance... 2 minutes of OK, 2 minutes of mediocre followed by 2 minutes of barely flying followed by a landing. I want to fly 15-20 minutes on my terms as I do with gas/glow.

larryflew

My Feedback: (13)

Been using 800 Lions in a modified Tiger Mother and get near an hour of flight time with just a couple grams more weight than 720 NiMH. Doesn't have quite the power of 7 cell 720, but barely perceptable. Mod is using C type gear box and motor from EDF50 which is twice the RPM of standard GWS motor. Will switch to LiPoly when these die for safety.

John M. Bigelow

I have 5 pack of the 1020 they are series /par to give 12.6 volts
i draw 10-12 c maybe too much but we will C I have 20 charges
on one pack at that rate. They are the best expect Hussan gone. CU