6V Nimh and 2.4 Ghz Spekrum reciever?

[cjcyclesrc]

T-ster,
It's good to hear you fixed your problem before you lost anymore planes.

If you had The Elite HR1650AAU NiMH packs, they have an Internal Impeadance of 25 mOhms. That would make them one of the worst Nimh's at holding volatge. Just for comparison The Sanyo HR-1950 FAUP is rated at 4 mOhms which is equal to that of a Sub C Nicad.

Do you fly at the grapevine field?

[T-ster]

I had the Sanyo cells, but had the issue.

No, I fly at a renegade field in Allen at Exchange Parkway, just East of 75. I have flown at Grapevine before with my heli's, but that has been awhile.

[bmoney69]

t-ster.....4 or 5 cell batts?

[JoeAirPort]

T-ster, do you know what exact Sanyo cell it was?

In general you need to use only the low impedance/high discharge NiMh cells. They are out there, you just need to know which ones they are. The 1950 FAUP and Elite 2000 cells are very good. I always use a single 5-cell NiMh for rx and Elite 1500 4-cell for ignition. I've never had battery issues with those packs on 50cc 3D aerobats with all high torque servos. They are setup on Spectrum.

[cjcyclesrc]

	Quote: Originally Posted by T-ster
	I had the Sanyo cells, but had the issue. No, I fly at a renegade field in Allen at Exchange Parkway, just East of 75. I have flown at Grapevine before with my heli's, but that has been awhile.

We have probably bumped into each other. I used to fly Heli's behind Mike's a couple years ago and planes a couple times at Grapevine when I lived in Dallas.

[T-ster]

I was using 5 cell packs. They are the: NiMH Sanyo 6V HR-AAU 1650mAh. That sounds like it may be the type of cell that is questionable..... That would be surprising as the company I purchased them from are extremely knowledgable and seem to be a very respectable business.

No other receiver I know of has a low voltage light, so other 2.4 Ghz systems may be running on the edge and you wouldn't know it. I had been flying those type of batteries for several years now and been ok until one time. While I don't know it was the battery (after the crash it still had over 1,000 mah left in it) once I started seeing the low voltage light it scared me enough to want to eliminate that as a possible failure point.

cjcyclesrc, I used to fly at the North Dallas club for years, but once they moved north adjacent to Denton, the travel time was an issue.

[bmoney69]

that's exactly why you had lights out with those cells.....they have an internal impedance of 25, put a big load on them and good night. you need cells that have a low internal impedance, around 5-7

[wildhare]

May I suggest that you do a little testing? It may save your plane, the cost is nominal and it's educational.

Buy a Hangar 9 watt meter, and make up something that will put a load on the batteries. I used a brushed electric motor with a 35 amp speed control and an old FM receiver I had laying around (who doesn't have most of this stuff in a box). I mounted the whole thing on a board and put a prop on the motor, I can adjust the prop size to vary the load to get it into the range I want.

Now I just hook up the battery I want to test and watch the meter. For a 50cc size plane you must be able to maintain about 6 amps for the length of the flight and about 12 amps for 3-4 second bursts, all this without going below about 4.5 volts. This type of performance is necessary to avoid any chance of brownouts.

The watt meter will report amps, volts, instant watts used and totalo watts used, this is all the information you need.

If you set this up then you can test any new or questionable power setup before you risk your airplane.

TF