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Author Topic: Strange power curve.  (Read 1356 times)

Offline Ty Marcucci

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Strange power curve.
« on: June 18, 2013, 04:12:10 PM »
I don't have the parts list in front of me, but a few weeks ago I was flying my Magnum Plus when at about the vertical eight part of the pattern, the motor started to slow down. Each lap it went a tad slower, etc. I finally let it land under power as it just could not stay in the air. Had to pull the plug to stop it. Any one have this happen?  At least this time it didn't catch fire... LL~ LL~ LL~
Ty Marcucci

Offline Tim Wescott

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Re: Strange power curve.
« Reply #1 on: June 18, 2013, 04:35:48 PM »
It sounds like the battery crapping out.

And yes, people will want the parts list, because it could be an ESC with a soft undervoltage, plus the batteries crapping out.
AMA 64232

The problem with electric is that once you get the smoke generator and sound system installed, the plane is too heavy.

Online Howard Rush

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Re: Strange power curve.
« Reply #2 on: June 18, 2013, 06:02:43 PM »
I had a bad battery that would do this if I overtaxed it.  Flying faster than usual or in high density air (cool, low altitude), or in calm would cause it to wimp out. 
The Jive Combat Team
Making combat and stunt great again

Offline Larry Wong

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Re: Strange power curve.
« Reply #3 on: June 18, 2013, 06:52:27 PM »
How or were does someone dispose of bad battery?    ???
Larry

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Online Bob Hudak

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Re: Strange power curve.
« Reply #4 on: June 18, 2013, 07:41:30 PM »
Drop the lipo battery in a bucket of salt water for about 24 hours(away from flammables)for about 24 hours, it will bubble like mad. You can now safely dispose of it in the trash can.
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Online Howard Rush

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Re: Strange power curve.
« Reply #5 on: June 18, 2013, 07:43:23 PM »
I sent mine back to the factory.  They said they would replace it under warranty.
The Jive Combat Team
Making combat and stunt great again

Offline Keith Renecle

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Re: Strange power curve.
« Reply #6 on: June 19, 2013, 10:47:48 AM »
How or were does someone dispose of bad battery?    ???
Hi Larry, I'm in the process of moving house (bad idea!) and I had a few older lipos that needed to be chucked out. I did not want to throw them with any sort of charge into the bucket of salt water, so I looked around for a load to get rid of the charge. I could not find any load resistors that could do the job in my junk box and then a figured that I have a  number of foam cutters, and I just used one of them. My biggest battery was 4-cell so I just stuck a Deans plug on my longest foam cutters and it worked great. I left the setup somewhere where it could not cause any fires that would hurt anything and just left it. Once they were really flat I still left them the salt water for a few days, and then it's o.k. to chuck these dead lipos in the trash. There are no serious toxic metals in them.

I must say that I was amazed at how much power these batteries of ours have. Even after flattening, some of the cells would recover if the short was taken off, and bubbled for quite a while when put into the salt water.

Keith R
Keith R

Offline Larry Wong

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Re: Strange power curve.
« Reply #7 on: June 19, 2013, 11:15:43 AM »
Thanks Keath I'll try it on my hoop foam cutter, does it get hot enough to cut foam?
Larry

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Offline Dean Pappas

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Re: Strange power curve.
« Reply #8 on: June 19, 2013, 11:28:51 AM »
You're kidding me ...
No one is going to suggest putting it in the street, starting a video camera, and whacking it with a long stick with a nail in the end? S?P

take care, All
  Dean P. (with tongue firmly in cheek)
Dean Pappas

Offline Steve Fitton

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Re: Strange power curve.
« Reply #9 on: June 19, 2013, 12:51:13 PM »
I vote for popping the batteries with a .22.  That should do the job.

I remember when the CRC safety handbook recommended destroying retired compressed gas cylinders with rifle fire.  I always volunteered to do it at the lab, but they have some other way to retire and recycle cylinders now.
Steve

Offline bob branch

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Re: Strange power curve.
« Reply #10 on: June 21, 2013, 06:16:18 PM »
all you need to do to discharge a battery is hook it up to a motor with and esc and turn it on. No special equipmet needed.

bob branch

Offline Keith Renecle

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Re: Strange power curve.
« Reply #11 on: June 22, 2013, 12:57:50 AM »
Thanks Keath I'll try it on my hoop foam cutter, does it get hot enough to cut foam?
It does if there are enough cells with enough energy, but then if this is the case you could most likely still fly with the pack. It all depends on the problem and number of cells. One of my packs did cut foam for a minute or two but then the voltage dropped quickly. You can connect a motor and esc as Bob Branch suggests but this to me is not as basic as the foam cutter, as I do have a few cutters lying around the workshop. The resistance wire acts like a positive temperature coefficient resistor i.e. the resistance goes up when as the temp rises. Car headlamp globes also work well.....same principle.

Keith R
Keith R

Offline BrianW517

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Re: Strange power curve.
« Reply #12 on: July 17, 2013, 10:26:38 PM »
I don't have the parts list in front of me, but a few weeks ago I was flying my Magnum Plus when at about the vertical eight part of the pattern, the motor started to slow down. Each lap it went a tad slower, etc. I finally let it land under power as it just could not stay in the air. Had to pull the plug to stop it. Any one have this happen?  At least this time it didn't catch fire... LL~ LL~ LL~
When that happened to me, I found out that I had fried the motor and the Batt & ESC were OK.  :o


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