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4thumbs???? · 10-17-2009, 08:59 PM

Have new 450 sport. Set up with sperate bec running 5v. First 5 hovers went ok.(Hovers is all I can manage at this time) After that at about 3 minutes in to flight get this rpm pulsating, up and down, enough to make the tail turn until the gyro puts it back straight. This happens in either normal or throttle up mode. Set it down and come to a stop, start back up and its ok for less then a minute, keep shutting down and restarting and it gets down to 15 sec., and it goes back at pulsating like you were running the throttle stick up and down. Motor or speed control are not hot at all, speed control set at 1-2-1-2-3 does it with 2 different batterys, both batterys charge up fine and check out ok. No crashes, rx is AR6100E, tx is DX6i. Align sent new speed control, changed it and its just like before. Anyone had a problem like this? What is the fix?
Thanks

Brick · 10-17-2009, 09:06 PM

have you tried it without the seperate BEC? i don't use one on my Sport, and i've had no problems. i also programed my ESC for low voltage cutoff...as i use a timer on my TX to time my flights

Wolfpackin · 10-17-2009, 09:10 PM

Are both of the batteries that you're using new?
Have they ever been run down too far?

Sure sounds like Low Voltage Cutoff (LVC).

4thumbs???? · 10-17-2009, 09:19 PM

I haven't tried not using the BEC. Align said it should be no problem the way I have it, I will try it tomorrow without the BEC. Both battery packs are near new less then 15 cycles on each one, was using them in my B-400. They are 2200 mah, I also use my timer and set down at 6 minutes, have never used more then 60% of the capacity.

mightymouse · 10-17-2009, 10:11 PM

Try checking to see if motor is overheating or binding, also if the tail rotor belt is to tite. there sounds like some is deffenitly not right. My trex 450 with a bell 222 scale body I get 7 mins with scale flying. The only time I everhad my heli's pulse was in my hurricane and my canope was touching the motor and causeing it to over heat--had to dremel it back abit and then all was well. don't give up keep looking and you'll find the problem.

4thumbs???? · 10-18-2009, 07:56 PM

Thanks to everyone for the help with my problem. Wolfpackin appears to of had the answer to my problem. Changed the program on the esc on battery protection from high cut off to middle cut off. Just finished hovering 2 packs without a issue. Had 35% left in packs before charging. Figured it by the mah put back into battery at end of charge. About the same as it was before I had the problem, still don't know what changed.

Again Thank You Everyone.

punkie · 10-18-2009, 08:41 PM

what sort of voltages are you left with across the cells after a flight? 35% in a pack after being charged sounds too low to me, i start with 4.20v in each cell (12.60v total) and there is usually about 3.7 - 3.8v after 4-5 mins flying mild 3D, takes the total battery to about 11.4v after a flight. you can probably go a fair bit lower than this... but i don't like to.

what kind of "c" rating do your batteries have, if you're going under 3.2v on any cell, that is too low i think and you may damage your batteries.

4thumbs???? · 10-18-2009, 09:06 PM

Thanks for the reply Punkie, I end up pk voltage looking at my battery log of 11.39v to 11.54v as about average. Looked the last time the pk hit the charger the cells were 3.77, 3.77, and 3.79, all very close before charge. My pks are 25C 2200 Mah. Any other ideas I,m here to listen and learn.
Thank You

punkie · 10-19-2009, 12:03 AM

seems fine to me, if that's what your pks are ending up after you changed your low voltage cutoff then as long as you're not having any more problems.... try not to crash!!

works for me!

mostly...

marcosp · 10-19-2009, 02:06 PM

I had this issue on my Pro. I was using a 25C pack. It killed it, puffed and now receives lower than 1200ma on recharge (this happened after the very first flight). Bought new 35C batts and works like a charm. Mind you, the 25C was working great on a 450 sized less demanding heli. I don't know if it's the motor or the ESC, but evidently it stresses the batteries more.

ttrip06 · 10-19-2009, 07:37 PM

I notice the same thing on mine, plus I am no longer seeing any rpm gain from idle 1 to idle 2 (80% to 100%) flat line. I think maybe the esc is going cause I am running a scorpion 6 motor with one 45c TP pack, the rest are 25c packs.

The tp pack has 4 cycles, the 25c pack are old.

Tim

10-17-2009, 08:59 PM	#1 (permalink)
4thumbs???? Registered Users Join Date: Sep 2008	450 Sport-Pulsating RPM?? Have new 450 sport. Set up with sperate bec running 5v. First 5 hovers went ok.(Hovers is all I can manage at this time) After that at about 3 minutes in to flight get this rpm pulsating, up and down, enough to make the tail turn until the gyro puts it back straight. This happens in either normal or throttle up mode. Set it down and come to a stop, start back up and its ok for less then a minute, keep shutting down and restarting and it gets down to 15 sec., and it goes back at pulsating like you were running the throttle stick up and down. Motor or speed control are not hot at all, speed control set at 1-2-1-2-3 does it with 2 different batterys, both batterys charge up fine and check out ok. No crashes, rx is AR6100E, tx is DX6i. Align sent new speed control, changed it and its just like before. Anyone had a problem like this? What is the fix? Thanks Last edited by 4thumbs????; 10-17-2009 at 09:13 PM.. Reason: Make post more clear

10-17-2009, 09:10 PM	#3 (permalink)
Wolfpackin HF Support My HF Map location Join Date: Nov 2007	Are both of the batteries that you're using new? Have they ever been run down too far? Sure sounds like Low Voltage Cutoff (LVC). __________________ Jonathan Livingston Helicopter Blade 400: E-flite 420H/35X ESC, AR6100e, HS65HB x 3, G401B/DS290G. (Ret.) CopterX 450AE V2: 430XL/35X ESC, AR6100, HS65HB x 3, LTG2100T/HSG-5084MG. T-Rex 550E V1 Classic Flybar: 600MX/BL70G, AR6200, DS610 x 3, Quark/DS650, 16t/520mm blades.

10-17-2009, 10:11 PM	#5 (permalink)
mightymouse Registered Users My HF Map location Join Date: Nov 2008	try this Try checking to see if motor is overheating or binding, also if the tail rotor belt is to tite. there sounds like some is deffenitly not right. My trex 450 with a bell 222 scale body I get 7 mins with scale flying. The only time I everhad my heli's pulse was in my hurricane and my canope was touching the motor and causeing it to over heat--had to dremel it back abit and then all was well. don't give up keep looking and you'll find the problem.

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10-17-2009, 09:06 PM	#2 (permalink)
Brick Registered Users Join Date: Dec 2007 Location: N.Carolina	have you tried it without the seperate BEC? i don't use one on my Sport, and i've had no problems. i also programed my ESC for low voltage cutoff...as i use a timer on my TX to time my flights

10-17-2009, 09:19 PM	#4 (permalink)
4thumbs???? Registered Users Thread Starter Join Date: Sep 2008	I haven't tried not using the BEC. Align said it should be no problem the way I have it, I will try it tomorrow without the BEC. Both battery packs are near new less then 15 cycles on each one, was using them in my B-400. They are 2200 mah, I also use my timer and set down at 6 minutes, have never used more then 60% of the capacity.

10-18-2009, 07:56 PM	#6 (permalink)
4thumbs???? Registered Users Thread Starter Join Date: Sep 2008	Thanks to everyone for the help with my problem. Wolfpackin appears to of had the answer to my problem. Changed the program on the esc on battery protection from high cut off to middle cut off. Just finished hovering 2 packs without a issue. Had 35% left in packs before charging. Figured it by the mah put back into battery at end of charge. About the same as it was before I had the problem, still don't know what changed. Again Thank You Everyone.

10-18-2009, 08:41 PM	#7 (permalink)
punkie Registered Users My HF Map location Join Date: May 2009	what sort of voltages are you left with across the cells after a flight? 35% in a pack after being charged sounds too low to me, i start with 4.20v in each cell (12.60v total) and there is usually about 3.7 - 3.8v after 4-5 mins flying mild 3D, takes the total battery to about 11.4v after a flight. you can probably go a fair bit lower than this... but i don't like to. what kind of "c" rating do your batteries have, if you're going under 3.2v on any cell, that is too low i think and you may damage your batteries.

10-18-2009, 09:06 PM	#8 (permalink)
4thumbs???? Registered Users Thread Starter Join Date: Sep 2008	Thanks for the reply Punkie, I end up pk voltage looking at my battery log of 11.39v to 11.54v as about average. Looked the last time the pk hit the charger the cells were 3.77, 3.77, and 3.79, all very close before charge. My pks are 25C 2200 Mah. Any other ideas I,m here to listen and learn. Thank You

10-19-2009, 12:03 AM	#9 (permalink)
punkie Registered Users My HF Map location Join Date: May 2009	seems fine to me, if that's what your pks are ending up after you changed your low voltage cutoff then as long as you're not having any more problems.... try not to crash!! works for me! mostly...

10-19-2009, 02:06 PM	#10 (permalink)
marcosp Registered Users Join Date: Nov 2008	I had this issue on my Pro. I was using a 25C pack. It killed it, puffed and now receives lower than 1200ma on recharge (this happened after the very first flight). Bought new 35C batts and works like a charm. Mind you, the 25C was working great on a 450 sized less demanding heli. I don't know if it's the motor or the ESC, but evidently it stresses the batteries more.

10-19-2009, 07:37 PM	#11 (permalink)
ttrip06 Registered Users Join Date: Apr 2004	I notice the same thing on mine, plus I am no longer seeing any rpm gain from idle 1 to idle 2 (80% to 100%) flat line. I think maybe the esc is going cause I am running a scorpion 6 motor with one 45c TP pack, the rest are 25c packs. The tp pack has 4 cycles, the 25c pack are old. Tim

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