Bad JuJu - 3 ESCs and one LiPo in one day

[Skipster]

First a simple lesson in Ohms Law

Power (in Watts) = Voltage x Amps - a directly linear relationship

We all know a motor delivers a certain wattage (power)
if the voltage goes down the amperage must go up.

So I was running a Prince 25" mono with an Ammo 30-50 2300kv
on 3s - yielding a free running prop speed of 25530 RPM
First run on a 435 was a dog (GPS 32 MPH)
Running 3s2p 30c total 10,000 mah

Got wild and put a 437/3 made it 1/2 lap and the Hacker Navy 77 went poof.
The drive is a very free running system with no binding.
Figure it pulled more amperage than the Navy could handle.
See Ohms law above.


Mean Machine - suppo 200A modified - Aveox 1421/1.5Y
4s1p 3600 mah ran a x442 to a rousing 34 Mph.
Driveline spins with no binding.

Went with a X445 made it one half lap and the suppo went
"I will go no mo senor"
Will not arm or make any motor chiming

Replace suppo with a turnigy 100a HV
Ran 5s [a 3s and a 2s (same c rating) in series]
made it 10 FEET and major smoke - dead short in the ESC
even burned a cell open in the brand new Turnigy 3s lipo
Battery now shows 0 voltage.
I hate that smell!!

Went to fire up my favorite Delta Force Vortex.
Has been running just great
on 3s with a suppo 125a turning an Ammo 36-56
Now
It will not arm and run unless I feed it 5s - less voltage it will arm
but will not turn the motor.



Some days your the windshield and some days your the bug.
I feel like a SPLAT.

Sorry for the rant, but I'll have a better day tomorrow..
I hope.

__________________

[Alexgar]

Went to fire up my favorite Delta Force Vortex.
Has been running just great
on 3s with a suppo 125a turning an Ammo 36-56
Now
It will not arm and run unless I feed it 5s - less voltage it will arm
but will not turn the motor.

check the lipo cutoff

[Fluid]

Mean Machine - suppo 200A modified - Aveox 1421/1.5Y
4s1p 3600 mah ran a x442 to a rousing 34 Mph.
Driveline spins with no binding. Went with a X445 made it one half lap and the suppo went "I will go no mo senor"

The problem here is likely exceeding the ability of the battery to deliver. 4S1P/3600, even 35C, is just 125 amps safely. That setup likely drew more than that, the cells couldn't deliver and the ESC croaked.

Replace suppo with a turnigy 100a HV Ran 5s [a 3s and a 2s (same c rating) in series] made it 10 FEET and major smoke...

Lets me see if I get this straight...you blew a 200 amp ESC running 4S, so you put in a 100 amp ESC, increased the cell count 25% and you expected the ESC not to blow? The first ten feet can be the hardest on the ESC of the entire run. The amp draw from a dead stop once the prop hooks can draw very large amps, and if the packs can't deliver....

Regardless, I am sorry for your loss. Sometimes you just can't win.


.

[keithbradley]

That sucks skipster. I somewhat understand replacing the 200A esc with the 100A, just because a suppo 200A isnt quite the same as a lot of other 200A escs. They arent really know for their toughness.
How do you know the short in the mean machine is not the motor? I have had motors do that before (motors that seemed fine and turned freely) and if thats the case you will fry your next esc in 10 feet as well. Its possible the motor went on teh first esc, and simply made short work of the second one.

[ray schrauwen]

That is what happened to a Turnigy 100 HV running a 1521 Neu 1050Kv on 8S, super fast for a little bit and then Smoke on the water. Cells were really high in resistance and I was only running 1P. That motor was an amp hog! Keep some overhead in your setups.

[Make-a-Wake]

Yea..................but has anyone accidentally connected the wires on two 3s 5000 40c batts in series.........then connected the last two to CLOSE the circuit...................man.................it was ugly...................and loud..................and my hands were black...................and i ruined one of the lipos. Just got in a bit of a hurry with a new boat/setup and wasnt methodically thinking it all thru and watching what i was doing. The intense shock desoldered one of the bullets thank goodness..........so one lipo survived.......................oh, I did too.

[Skipster]

Guys I want to thank you for taking the time to reply

I will try and answer some of the questions

Alex:
The Vortex: why would the LiPo cut off change while it sat on my rack?
I tried to reset it and the motor made some strange chimes I've
never heard before.

Fluid:
The Aveox "says" right on the can 100 A max, I thought (bad move yes)
the Suppo could take it (it was a modified version so I blamed the failure on that)

I forgot to put in the post I also down sized the prop to a 437 for the Turnigy
HV esc attempt (it will not arm on less than 5s)
I thought the higher voltage would
reduce the inrush and constant current. Wrong again.
I do not remember if I nailed the throttle, but I normally do not launch that way.
I appreciate your insight it is always welcome and
is used to further my knowledge of this sport.

Keith:
Good point, I will investigate that possibility. Thanks again for the offer.
I am out of ESCs now and may not want to use that motor to test another.
The Aveox has always been a good runner but it is old.

Ray:
Will do in the furure.


BTW: no belaboring but I lost another today.
THIS was my dumb fault (so were the others but I digress)

Bringing the Vortex in (after a short 45 sec run) to check temps.
(I changed the ESC to my best ESC
(A Shultz 105woc)
The boat flipped , I recured it with my tugboat.
Felt good ,tape looked good, so I stupidly ran it again.
without checking for water.
I had taken some water
and the Shultz shut off.
It's drying out but with
my stupidity, I doubt it will return.

This has NOT been my favorite boating weekend!!

[785boats]

Skipster.
I'd just like to say that the X437/3 prop is what I & a few other club members run on an ammo 2300 in 25" & 26" boats on 4s. And that's with the Aquacraft 45A ESC from the SV27 fame. I wouldn't consider it a 'wild' prop on that set up on 3s. So you may have had a different problem there than the ESC.
But man the 'Pond Gods' were bad to you on that day. I feel for you.
All the best.
Paul.

[mpg43]

If you are having esc's blow in one boat set up in particular, I would disassemble the motor and check the magnets. If a magnet becomes loose and it can move around it will cause a bind causing a overload at the esc. I would check the motor just to be safe. I had this happen to me before.
And as for the motor that is making the funny noise, Make sure you don't have a loose wire between the esc and the motor. If one connection is broken sometimes they will make a funny noise.