I would like to build a Combat Wing. I have the kit, Eflight 400 and Phoenix 25 speed controller. I would like to go with the Lipo battery but really dont know what to select. 7.4V or 11.1V, 2000-4000 MAH? Any input from you experienced pilots would be greatly appreciated.

Dale

11.1v for sure! I am unfamilliar with your plane but you should be ok with the 2000mah. Have you used the speed controller yet? If not you may want to have someone do the programing on it for the start and brake. If you got it from a LHS they should have an interface cable.

Hi vicman

Special thanks for your reply. One more question please. Is the different between a 11.1v 2200 mah and a 11.1v 4400 mah a little more weight and more flying time or is their more to it than that?

Thanks for your help.

Dale

Think of what a second battery of the original's size would look like strapped in your bird. So all things being equal (for battery sets) more time = more batteries = more weight

Not all batteries are created equal- some rated for higher C and capacity get quite small when compared to others in the same voltage and capacity, and they can get expensive. I prefer to find a deal on some matched sets out there on the internet based on best price alone

I hope that helps...

T

Hi Ted

I appreciate the input. I believe I will look for a matched set and enjoy longer flight time and still be less weight than the traditional wing battery I am used to using which is a large heavy 1500 mah NiCD battery.

Thanks Again

Dale

Wing, from a VERY basic stance you are correct on both counts, more mah=more # and there is more to it. With limited lekky experience you may stick with what you have experience with. If you were doing good with 1500 Nicads, you will be blown away with lipo.[8D] Save some of your money and try it.

Thanks vicman

I purchased a 11.1v 2150 lipo and Multiplex charger. You are right in both cases, it was a sizable investment and I flew the wing today. Wow!!, what a difference in performance. I get about the same flying time as a 1500 mah with the original 400 brushed motor but I can throttle back the Eflight 400 brushless motor and extend my flying time.

I appreciate your recommendations, this board has been a great help this weekend.

Regards,

Dale

I use a Hobbico MkII. For $49 I can charge everything I have 2 at a time. It seemed to be the best deal with the most options and super easy to use.

What you need is a 11.1V 2100-2250. The 400 likes its juice and will destory anything weeker than 2000mah at full power in a hurry. I run my 400 with a Thunder power 1900mah 11.1v and you dont want to go full power for more than 5seconds otherwise you will begin to damage the battery. Something like Thunder Power 3cell 11.1 2100mah and or go to www.maxamps.com and click on the 2250mah link and look up the 2250mah 11.1 3cell. That would be just about Ideal if the battery diminsions fit your specs. The Thunder power packs are kinda compact. The best combo I have had so far was the 370 with the 1900mah 11.1v thunder power and the Phoenix 25. It will lift something like a YAK, or Tribute off the ground and stright up at 80% throttle. In dealing with the brushless and lipo stuff you always want to be mindfull of what kind of amps your pulling. A 1900mah has a Maximum Continuous Current of: 19A. The Eflight 400 4200kv motor can burst 24amps and continually run on 18amps. The 1900 3cell is not enough to run flat out for anytime at all without damage to the battery. The Thunder power 2100mah 11.1v has a max continous current at 24amps. This is the kind of power cell required to allow the 400 to pull all the amps it needs to run continous without damaging the battery in any way. It will also be kind to the motor while running it at 110%. I know you are thinking what is the difference of 200mah in the two batteries and its a lot. Just look them up and see there max continuous amps. one is like 18 and the other 24amps. Big difference when you are running a motor that pulls 24amps. You must always be mindfull of how hard you run the 400 inrunner because the thing gets extremely hot. Run in the 75-85% range with a little spike here and there and you will be fine. I hope I have helped you and if you have anyquestions just let me know.

For the 400 use 2100mah 11.1 3cell thunder power or better. Something that can discharge 24amps continous. The 400 draws 24amps on the burst and about 19amps avg. You need something that will keep up with that. Using anything less than this will cause battery damage if you burst for more that 5 seconds. Thunder power has a 1900mah 11.1v but the differnece is extreme with only a 19amp continous discharge VS 24amps with the 2100 11.1v. The bat will cost you about 75-80dollas. I cost cutting alternative is to buy and attach your own cells togather but that is for very tech able people. You make a mistake and the battery is no good. I found a site called www.maxamps.com and they have a 2250mah 11.1v 33amp burst for sale 64.94 delivered to your door in a week. THere is a large and growing markett for LIPO and you can find all kinds if you look and the ONE TO LOOK FOR IS 2100mah 11.1v 3cell or 2250mah. You dont want to go any higher than 2250mah. Also make sure its 3cell. If it says 11.1volts it is 3cell. MOST IMPORTANTLY NEVER ARC THE BATTERY. NEVER LET THE BATTERY WIRES TOUCH EACHOTHER OR ANYTHING ELSE THAT IS METAL. THIS WILL DESTORY YOUR BATTERY INSTANTLY AND COULD CAUSE A FIRE. LIPO BATTERIES MAY REACT AFTER BEING DROPED, DENTED, OR UP TO 1 HOUR AFTER ARCing the battery, CAUSING FIRE OR EXPLOSION> IF this happens move the battery to a safe location for a couple hours. If the battery is not bloated or leaking 2hours later try charging in a safe location away from flamable property. The battery will never be the same if it does not catch fire or explode and you will notice a huge difference the next time you charge and fly. Hope I have helped. If ya have any more question in my realm of understanding and I will do my best to answer.

Dale,
The attached curves show the clear choice. Operating the 400 brushless for more than a few seconds at over 15 or so amps will overheat and damage all except the KOK 2000/15C