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Real Raptors . Mikado Modellhubschrauber . CanoMod

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e-Electric Conversions > OK What happened to my eRaptor ?
 
 
NZ_Neil
Senior Heliman
Location: Auckland, New Zealand

Last sunday I was out in the field doing high speed low level passes of the airfield with huge climbouts at each end with a few piroettes at the top then back down again. My eRaptor 50 was having fun. She was screaming away like a poor mans Turbine on steriods and with all bling on her she looks like she should be in a beauty contest.

Anyway 8 minutes into my second set of Lipos silence at the top of the climbout ..... I swung her around and autoed down onto the side of the air strip. Walk over to her and notice by this time there is no power to the servos (duh .... what the ...)

a) The batteries are hot (80 degrees celsius, twice max allowed)
b) The Heat shrink has melted on both batteries in places.
c) The Hacker 77 ESC also has most of the heat shrink melted away.
d) Motor was around 80-90 degrees celsius (OK range)

I have been away all week on business so tonite I have carefully dismantled the heli :

a) The two 4S4P6000 Thunder Power Lipos are dead !
b) The Hacker C50 15XL motor looks ok
c) The Master 77-O Heli Esc is dead.
d) No sign that anything shorted out.
e) Nothing binding.

Obviously she was consuming a huge amount of power up in the air and I am sure the ESC was consuming it ? Incidently the ESC is now dead when I apply power to it (so the short has gone)

I have removed the remaining heat shrink off the ESC and the two batts and there are no signs of shorting which I would expect given that I was only halfway thru a normal flight time (normmaly stop at around 15mins)

So what happend up there in the sky last Sunday ?

There were no warnings, no smoke, no change in noise. Has this happened to anyone else ? The heli has probably done 30 flights without incident and I certainley dont do heavy 3D so she does not get over stressed.

I'll probably rebuild her as eRaptorV2 but are dont want a repeat of what has just happened there are too many $$$ involved.

Regards
Neil Harker
New Zealand
04-08-2005 Over year old.
HOMEPAGE  
 
 
chuckhager
Key Veteran
Location: Clovis, CA

Sounds like the ESC to me also. You lost engine power first and still had power to your receiver and servos "shortly" thereafter. A short in the battery more than likely would have taken out your ESC and receiver at the same time. But then again, this is just my theory.
04-08-2005 Over year old.
HOMEPAGE  
 
 
NZ_Neil
Senior Heliman
Location: Auckland, New Zealand

What bugs me is that I was only halfway thru the packs when it happened and now they are dead. Therefore a lot of energy has disappeared ? because I just dont see the damage I am expecting for that amount of lost energy.

OK there is two melted areas on the Lipo backs (Outer Heat Shrink) and ditto on the ESC. Taking the remaining heat shrink of both you would swear they were OK - nothing looks fried.

When you over discharge a LIPO do they normally go open circuit ? Note both mine have. There is no voltage when measured on a DVM.

Maybe thats the nature of the beast

Neil Harker
PS I think Albig is wrong about the dilithium crystal failure, I think I temporarily flew the heli thru a passing Black Hole that just happened to be floating by. Remebering back to my days on Quantum Physics at university I now remember that black holes love gathering energy
04-08-2005 Over year old.
HOMEPAGE  
 
 
chuckhager
Key Veteran
Location: Clovis, CA

You have an open circut caused by the short. That's why you don't have a reading. Think of it like a fuse. When a circut gets hot and begins to overload, the fuse blows and creates an open circut. If the fuse is not the weakest link it will fry somewhere else. Your batteries have an open circut. It still sounds like your ESC began to fry and your batteries acted like a fuse and created the open circut. Otherwise it could have been worse. Fortunately you didn't have a fire on your hands.
04-08-2005 Over year old.
HOMEPAGE  
 
 
NZ_Neil
Senior Heliman
Location: Auckland, New Zealand

If the Lipos acted like fuses they would be in series. Two fuses dont generally blow simultaneously if in series ? In my case BOTH Lipo packs have open circuited.

Regards
Neil
04-09-2005 Over year old.
HOMEPAGE  
 
 
chuckhager
Key Veteran
Location: Clovis, CA

They do if the overload is sufficient. (i.e. a dead short across the leads.) Since both batteries have open circuts I am leaning more towards the ESC being the cause.
04-09-2005 Over year old.
HOMEPAGE  
 
 
QCM
Heliman
Location: Scotland

Interesting, I wonder how much amperage was produced when this happened. Would a high amp (eg 70 amp) fuse in the battery line after the bec feed and before the esc feed have saved the batteries in this situation?

Yes it would have resulted in loss of the esc and motor power instantly, but assuming the bec circuit is before the ESC, the servo's would still work wouldn't they?

The motor hasn't started to throw a magnet has it?

Other than that, I guess the passing starship, just drained all the power, obviously needed it to go fight of those pesky Klingons
04-11-2005 Over year old.
HOMEPAGE  
 
 
chuckhager
Key Veteran
Location: Clovis, CA

Open circut on the batteries = no power to receiver.
04-11-2005 Over year old.
HOMEPAGE  
 
 
QCM
Heliman
Location: Scotland

Chuckhager, was that a response to my question? If so, would the batteries have been prevented from going open circuit if the fuse was fitted as above?
04-11-2005 Over year old.
HOMEPAGE  
 
 
chuckhager
Key Veteran
Location: Clovis, CA

Gary,

Now I'm confused. If you have an open circut at the batteries, how would you get power to the BEC without using a separate battery pack to power them?

I will agree with you regarding the fuse/circut breaker not being able to react fast enough to save the lipos. This is an interesting idea to think about though.

Chuck
04-11-2005 Over year old.
HOMEPAGE  
 
 
chuckhager
Key Veteran
Location: Clovis, CA

Thanks Gary. Now I understand. I thought you were implying that Neil's open circut on the batteries would still be able to supply power to the receiver.

Chuck
04-11-2005 Over year old.
HOMEPAGE  
 
 
NZ_Neil
Senior Heliman
Location: Auckland, New Zealand

An Update On My Problem

OK here's some more confusing stuff.

The ESC was not dead as originally thought. I flicked the wires accross my other set of lipos and there is a big crackle (spark) but then I realised that was just the current being soaked up in the capacitors.

I wired the ESC back into the heli and put fresh "Heat Shrink" over the ESC and went flying. Hovered the Raptor a metre off the ground with m other set of Lipos. 3 Minutes later the motor cut (not a normal soft stop like on batteries reaching the min 3v per cell) .

I would normally be able to hover for 15 minutes+ on charged Lipos.

When I checked the Temp on the Lipos and controller everything was hot.

So I still dont know :

a) Is the controller that is internally shorting when it gets hot ?
Or
b) Is it the motor (Hacker 15XL)

For the 3 minutes before the motor cut everything seems normal, heaps of power in the motor.

Reading the threads above I need to emphasise I had power after motor cut so I can only assume the batts did not die like fuses. They must have a huge power drain on them given that I autoed her all the way into the field and Lipos dies soon after I was on the ground while I walks over to retrieve the machine (I pulled the batteries as soon as I felt the heat)

I'll order a new Hacker 77 ESC and hope that was the problem.

Regards
Neil Harker
New Zealand
04-12-2005 Over year old.
HOMEPAGE  
 
 
NZ_Neil
Senior Heliman
Location: Auckland, New Zealand

What happens when you over discharge a Lipo ?

Can someone tell me what happens when you over discharge a Lipo ?

Say I discharge a Lipo to 2 volts per cell what happens ?

Do they just continue to loose voltage ? (I am guessing this is what happened to my batteries due to the ESC failing internally)

Whats the official answer ?

Regards
Neil
04-12-2005 Over year old.
HOMEPAGE  
 
 
QCM
Heliman
Location: Scotland

That's interesting about the hacker controller. Do jeti make the hacker esc as well? I have a jeti opto 77 bought from the USA running my Actro 24/4.

When I was test flying (thrashing) a scale airwolf (12lbs in weight), the motor stopped suddenly after nearly 5 minutes, but started again almost instantly. I landed the heli and took a look. The motor and esc were hotter than usual but the batteries were normal. I wonder if it has a thermal cut out built in? There was no mention in the paperwork. I wonder if the controller can't take the amperage it is supposed to?

I have since been flying the motor, esc and battery setup in my raptor 50 without incident.

One of my colleagues had a hacker throw a magnet in flight, pretty disastrous Hence mentioning it.
04-13-2005 Over year old.
HOMEPAGE  
 
 
NZ_Neil
Senior Heliman
Location: Auckland, New Zealand

Gary .... thanks for your description, sound more like the chain reaction meltdown of a Nuclear Power Plant

Incidently your Lipo packs have not puffed up they are just dead.


Quote 
QCM Wrote : That's interesting about the hacker controller. Do jeti make the hacker esc as well? I have a jeti opto 77 bought from the USA running my Actro 24/4.


Yes we are talking about the same controller, It used to say JETI on one side and "Hacker" on the other side of the label before the label melted

Regards
Neil Harker
New Zealand
04-13-2005 Over year old.
HOMEPAGE  
 
 
Bill Collins
Senior Heliman
Location: Middletown, CT. U.S.A.

Some insight to the battery question.... I had a Lipo that I left connected for about a week (oops!) and when I hooked it up to my Triton, it kicked it off for being too low voltage. Cells were somewhere around the 2 volt per cell mark and I just kept bumping them until I got the necessary voltage to allow them to charge. Maybe I got lucky, but nothing has happened to this battery and she still flies great with no power or flight times lost. Hope this helps some. Good luck and keep us posted on a solution!
04-17-2005 Over year old.
 
 
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e-Electric Conversions > OK What happened to my eRaptor ?
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