SMALL - espritmodel.com SMALL - Telemetry SMALL - Radio
Reply
Thread Tools
Old Sep 28, 2009, 10:33 PM
c/f
Registered User
Joined Jan 2004
3,315 Posts
Help!
Weird motor/ESC response to differant batteries.

I have a MicroDan Velocity motor which is basically a 600watt 33gram motor I run a APC 4.1X4.1 prop. I use a ThunderBird 54 esc.

Statically this little beast needs 60 amps of 3s power to produce 600 watts..

The weird thing is I have been using Korean cells of 2300-2500 MAH at 20C 30C,40C in the past year to feed this little monster, volts stay around 11VDC WOT.

I had a chance to try out a 2250 45C ThunderPower on this setup and it would peak out at 50 amps with volts of 11.5VDC and acted as if the ESC had a rpm governor.

We then tried a differant ESC and it did work and proved to be of lesser volts under load. Not impressed......

What was going on with the TB54 to act up strange on the TP 3s 45C pack that it would not supply the 60+ amps?
c/f is offline Find More Posts by c/f
Reply With Quote
Sign up now
to remove ads between posts
Old Sep 28, 2009, 10:48 PM
Registered User
Dr Kiwi's Avatar
Chattanooga, Tennessee, United States
Joined May 2003
27,206 Posts
Could it be because the TB54 is over-amped at 60A?

Maybe the TB54 can't cope with the rpm @ 11.5v?
Dr Kiwi is offline Find More Posts by Dr Kiwi
Reply With Quote
Old Sep 29, 2009, 08:48 PM
c/f
Registered User
Joined Jan 2004
3,315 Posts
Not really Phil, With a Korean made 40C 2300 3s the watt meter using the TB54 is showing: 62amps, 11.1VDC, 680watts and running strong with ear peircing rpms.

With a ThunderPower 45C 2250 3s new from IRCHA, it will only pull 50 amps, 11.6VDC
580watts and the RPMS are noticably down.

Using the same batteries in another model same motor and differant ESC Hobbywing Platinum 60, the Korean 40C is same as the TB54, 62amps, 11.1 VDC, 680 watts.

Using the ThunderPower 45C it ran it up to 58amps, 10.9VDC, 600 watts.

It was producing less numbers than the Korean 40C.

So I am wondering what is the laws of electronics we are dealing with here. Is it internal resistance of batteries in play or is it limitations of ESC components? or what?
I think theres something to learn in this experiment that may be usefull to understand.

Phil the motor in play here is the Micro Dan Velocity 4800KV with a 4.1X4.1 APC if you care to experiment. The new ICE controllers show promising results equal to the newer platinum series Hobbywing ESC with faster processor speeds to track rpms better.

Dan says he thinks the motor can handle 800watts but we have had no ESC to handle rpms at these amps on 3s till recently. Going to max it out, Are you going to be at the Tolluhoma electric event??? If so come see how a motor performs on a real teststand.....
c/f is offline Find More Posts by c/f
Reply With Quote
Old Sep 29, 2009, 09:39 PM
Registered User
Challenger 413's Avatar
Dickinson, Tx.
Joined Sep 2004
5,373 Posts
Could it be the TP is new and hasn't seen enough cycles?

Challenger413
Challenger 413 is online now Find More Posts by Challenger 413
Reply With Quote
Old Sep 29, 2009, 10:53 PM
Registered User
United States, NJ, West Orange
Joined Aug 2007
799 Posts
Based on the results with the HobbyWing, it sounds like the TP's internal resistance is higher. Could be external resistance too... did you check the connector?

The only thing I can think of with the TP54 is you might be hitting the 9.0V cutoff during part of each phase. You could disable the cutoff and try it to verify.
nybbler is offline Find More Posts by nybbler
Reply With Quote
Old Sep 30, 2009, 03:08 AM
Registered User
vintage1's Avatar
East Anglia, UK
Joined Sep 2002
29,703 Posts
I think that is the issue. That current is not being pulled all in one go, its being pulled as a lot of very high current pulses, slow enough that even the onboard capacitor on the ESC wont be able to smooth it out.

Minute differences in inductance and series resistance will change behaviour.
vintage1 is offline Find More Posts by vintage1
Reply With Quote
Old Sep 30, 2009, 11:15 AM
c/f
Registered User
Joined Jan 2004
3,315 Posts
aprreciate the input, the only thing I change is the battery, which was the odd thing to me how it could act so strange.

The TB54 does struggle to get to full rpms on any battery without slowly ramping up in small increments, to soon and it shut downs, so the governing effect with the TP pack must be this same thing with a different result, I will soon be switching to the ICE lineup with more detailed recordinging of data possible.

Thanx.......
c/f is offline Find More Posts by c/f
Reply With Quote
Old Sep 30, 2009, 11:52 AM
Registered User
Chicago 'burbs
Joined May 2006
1,706 Posts
Quote:
Originally Posted by c/f
aprreciate the input, the only thing I change is the battery, which was the odd thing to me how it could act so strange.

The TB54 does struggle to get to full rpms on any battery without slowly ramping up in small increments, to soon and it shut downs, so the governing effect with the TP pack must be this same thing with a different result, I will soon be switching to the ICE lineup with more detailed recordinging of data possible.

Thanx.......

I wonder if you are hitting the current limit earlier with the TP battery. Recall that 50A at 75% throttle is actually pulling ~67 A instantaneous (and giving you 30% more heating than an average 50A current would give).

So in this scenario, the other batteries are pulling less current at 75% throttle (75% just chosen to make a concrete example), and that allows you to creep up to WOT. The TP could already be way over the limit.

Just a WAG!
Alan Hahn is offline Find More Posts by Alan Hahn
Reply With Quote
Old Sep 30, 2009, 10:34 PM
c/f
Registered User
Joined Jan 2004
3,315 Posts
But the TP pack actually does not shut down the controller as do the others if I dont creep up WOT. The TP just stays running but acts in some weird rpm governor mode.

With the Hobbywing ESC it was actaully running fine but less static spec the 40C.
c/f is offline Find More Posts by c/f
Reply With Quote
Old Oct 01, 2009, 12:54 AM
Registered User
USA, CA, Long Beach
Joined Jun 2004
124 Posts
Quote:
Originally Posted by c/f
But the TP pack actually does not shut down the controller as do the others if I dont creep up WOT. The TP just stays running but acts in some weird rpm governor mode.

With the Hobbywing ESC it was actaully running fine but less static spec the 40C.
That weird gov like mode is either the esc hitting current limiting or low voltage cutoff. I would guess your esc is shutting down because the TP has lower internal resistance and is providing more current at higher voltage. The old batteries were the over stressed component in the system before, now since the batteries are up to it, the controller has to govern the current to save itself.
Klogg96 is offline Find More Posts by Klogg96
Reply With Quote
Old Oct 01, 2009, 08:59 AM
Registered User
cjbucher's Avatar
Raleigh, NC
Joined Sep 2004
2,636 Posts
Quote:
Originally Posted by c/f
We then tried a differant ESC and it did work and proved to be of lesser volts under load. Not impressed......

Did the other ESC get over 60 amps? Kind of sounds with it might be a ESC issue.
cjbucher is online now Find More Posts by cjbucher
Reply With Quote
Old Oct 01, 2009, 07:04 PM
c/f
Registered User
Joined Jan 2004
3,315 Posts
No, actually on the Hobbywing Platinum 60 it was less amps using the TP 45C and less volts 10.9 as compared to the Korean 40C where as the amps were 62 and the volts were 11.1

Seeing as the TP is almost 60grams lighter I feel as if a 2650 45C would actually be the comparable battery and run as strong as the Korean 40C. It appears to me TP has figured out the labeling scheme others have been doing to gain market share and are a tad bit aggressive. It seems to me most all premium cells are now weighing equal amounts for a given energy density to produce watts in a given setup. The gap has now narrowed........02
c/f is offline Find More Posts by c/f
Reply With Quote
Old Oct 01, 2009, 10:10 PM
Registered User
Chicago 'burbs
Joined May 2006
1,706 Posts
Here's a suggestion. Put on a somewhat smaller prop, one that definitely draws less than 50 amps lets say.

Now see if the problem goes away.
Alan Hahn is offline Find More Posts by Alan Hahn
Reply With Quote
Old Oct 01, 2009, 11:15 PM
Registered User
cjbucher's Avatar
Raleigh, NC
Joined Sep 2004
2,636 Posts
Hmm... I think you're right. Sounds like the TP is not putting out as advertised...
cjbucher is online now Find More Posts by cjbucher
Reply With Quote
Old Oct 02, 2009, 04:25 AM
Registered User
vintage1's Avatar
East Anglia, UK
Joined Sep 2002
29,703 Posts
Quote:
Originally Posted by cjbucher
Hmm... I think you're right. Sounds like the TP is not putting out as advertised...
No? Really?
vintage1 is offline Find More Posts by vintage1
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Sold Parting Out Hornet - Motor ESC Gyro Servos Rx Batteries Arthur Knowles Aircraft - Electric - Helis (FS/W) 2 Jun 12, 2005 02:49 AM
Vortex CC w/motor, ESC and batteries neilo Aircraft - Electric - Airplanes (FS/W) 3 Sep 09, 2003 03:17 AM
Batteries, Misc, Motor, Esc stealthy Aircraft - Electric - Airplanes (FS/W) 7 Oct 21, 2002 04:14 PM
540 motor, ESC, 9.6 v batteries and charger Befudled Aircraft - Electric - Airplanes (FS/W) 0 Mar 27, 2002 03:08 PM
JR VoyagerE Motor & ESC, 2 7-Cell batteries on EBAY Inverted-3D Aircraft - Electric - Airplanes (FS/W) 1 Nov 18, 2001 11:00 PM