ESC arrived, success!!! then failure! magic blue smoke come back!

nasukaren's picture
Submitted by nasukaren on Thu, 07/24/2008 - 17:30

The ELF 100 ESC (electronic speed controller) arrived today and I installed it in my Piaggio Boxer. The install was a cinch and everything seemed to be going very smoothly.

I did some test runs with the rear wheel elevated using my 24V SLA batteries. Here is my data table:

Dial Motor Rear Spindle Tire / Speed Amp Draw
0-1 0 rpm 0 rpm 0 rpm 0.03A
2 411 162 14 rpm / 1 mph -
3 1180 335 31 rpm / 2.5 mph -
4 1801 1495 120 rpm / 10 mph 6.6A
5 2390 1950 156 rpm / 13 mph 8.2A
6 2850 2330 185 rpm / 15 mph 9.4A
7 3327 2720 217 rpm / 18 mph 10.16

I ended the no-load test at dial position 7 on the servo tester as I didn't have a secure way of securing the moped on the center stand and if it came off the center stand during the test, the kinetic energy would rocket it off my back deck.

I tried some partial loads and the amps consumed quickly jumped to 30A as the ESC tried to maintain motor speed.

The motor sounded very good and heated up only a very small amount (to 38 centigrade). So everything looked good for a road test. I took it to my front yard and dialed the servo up to 4.

The moped took off and I dialed it to 5 and went down my street at about 15-20 mph. At the end of the street, there is a slight down incline and in order to come to a stop, I dialed the servo back to 0.

The rear wheel skidded to a halt and the ESC beeped menacingly at me then shut up. I tried to dial speed back up again and nothing happened.

I tried resetting the system and it didn't work. That's when I noticed the ESC was getting VERY HOT. I now have a blister on my index finger. I yanked my main system power and pushed the unit back home. I'm just glad it chose to blow near my house and not 5 miles out!

I let the ESC cool down and then plugged it back in again. It quickly started heating up again, drawing 10 A off the battery (240 watts) and not making any sounds (it normally will "sing" to you to let you know it's OK).

Although I didn't see where it went, I have the feeling that I let the magic smoke out of my $30 ebay special ESC. I've since yanked it off the bike and will likely go and buy a "real" ESC (like a Phoenix HV100).

Until then, I'll try to conduct an autopsy on my ESC. I've got the protective shrink wrap off and the chip that seems to be the one getting super hot is marked 78M05 and it has three leads coming off of itIR2101S / 0308. I'm hoping that if I post some good autopsy pix, maybe Fechter can help me diagnose it.

In any case, the moral of the story is that the HXT outrunner will work, but it really really really needs a good ESC. And you should make sure your ESC settings are correct before taking it for a test drive. In the back of my mind, I'm wondering if the ESC was set to brake at throttle 0, which would have been disastrous.

p.s. A quick google reveals that a 78M05 is a voltage regulator chipIR2101S is a field rectifier. Makes sense that that would what blew. My guess is that when the ESC told the motor to brake, the motor said "sure, here's A GAZILLION AMPS in back current to ya!" and that blew out a chip on the ESC.

Topics: 
HXT outrunner
ESC
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Comments

nasukaren's picture

Submitted by nasukaren on Thu, 07/24/2008 - 17:57.

Hmmm.... never try to debug a circuit with a burnt finger, it just doesn't have very good heat sensitivity anymore.

A little more probing reveals that the chip that's overheating is actually an IC marked "IR2101S / 0308."

Mr. Google tells me that it's some sort of rectifier: "High and Low Side Driver, Noninverting Inputs in a 8-lead SOIC package."

Mr. Fechter, do you think this is the candidate for the blue smoke? It's the chip that's getting hot enough to burn skin, even when plugged in for a few seconds. Or could it be another component that's broken and feeding it too much current?

It's a surface mounted component which means it'll be a bear to fix.

Argh. I think I'm just going to have to bite the bullet and buy an Phoenix HV..... $220......... booo hooo hoo. So much for using cheap RC components!

Working on a Piaggio Boxer (mo-ped) EV conversion: http://gpsy.com/ev

nasukaren's picture

Submitted by nasukaren on Thu, 07/24/2008 - 21:01.

Found this info on the net:

What is armature-locked current?

When the car hits the ground, the wheels come to a stop or spin as the car accelerates and/or the airplane prop hits the ground and stops, current can peak at over 100 amps. The resistance of an armature may be as low as 0.01 ohms. READ CAREFULLY: If you lock the armature in the motor with 7.2 V on it, the resulting current will be 7.2 / 0.01= 720amps! That will fry about any ESC. The next best thing is to put a fuse in line with the motor that protects the motor and the ESC until you know all is well, then you can take it out if you want. Next best is to start the car or airplane motor running slowly under simulated light load conditions and gradually increase the speed. Stop periodically and check the motor, the ESC, and the batteries to see that neither is overheating. Most of the ESC’s that come in for service were placed in an unknown car or airplane unit, and run full bore until the motor, the batteries, or the ESC expired!

http://www.fmadirect.com/faqs.htm?category=2

This sounds like what I did.... the only question is, is the ESC blown permanently?

And how can I prevent this from happening next time? My batteries were fused and the fuse didn't blow on them. Should I put fuses on the motor leads?

Working on a Piaggio Boxer (mo-ped) EV conversion: http://gpsy.com/ev

Jeffkay's picture

Submitted by Jeffkay on Thu, 07/24/2008 - 21:24.

Karen, Welcome to the "blowing things up because I tried to cheap out first, club"! I blew 2 Eteks when they cost over 500 bux! Sounds like you will now get a big ESC to try. Good luck--I hear those Phoenix 110's are good. You cheap one should have had the sense to shut down...
I will now wait for round two with the boxer.

Jeff K.

nasukaren's picture

Submitted by nasukaren on Fri, 07/25/2008 - 12:27.

Jeff -

Yes, darn. I'm pissed about going cheap at first on the ESC -- but $30 (made in China crap) vs. $220 (made in USA Castle Creations) was just too much of a difference to pass up.

I'm also peeved because I have this huge blister on my finger from the ESC reaching supercritical temperatures.

And I'm peeved because I wanted to RIIIIDDEEE this weekend!

I ordered an HV-110A (apparently they're on backorder EVERYWHERE) and it should arrive later next week.

So the saga continues! I'm using the downtown to clean up all of my connections and get everything nice and neat looking. I'm figuring that even though it's a test bike, that doesn't mean everything has to be held together by duct tape.

:-)

Karen

p.s. Condolences on the Eteks! The irony of this whole saga is that I went with RC components because I was too cheap to buy a hub motor -- and now it looks like that'd been the cheaper option all along!

Working on a Piaggio Boxer (mo-ped) EV conversion: http://gpsy.com/ev

jdh2550_1's picture

Submitted by jdh2550_1 on Fri, 07/25/2008 - 12:37.

"That's when I noticed the ESC was getting VERY HOT. I now have a blister on my index finger"

yeah, that's how I test for hot electronics too. Will we never learn? ;-)

At least it was only a $30 part, right? Can you get an ESC with an adjustable current limiter?

If you get your Boxer working then I'm really tempted to go out and find a cheap step-through moped like this and try it out myself (I know, I know, I need to write "John must finish project A before starting projects B thru Z" a hundred times - but where's the fun in that!)

John H. Founder of Current Motor Company - opinions on this site belong to me; not to my employer
Remember: " 'lectric for local. diesel for distance" - JTH, Amp Bros || "No Gas.

nasukaren's picture

Submitted by nasukaren on Fri, 07/25/2008 - 16:27.

John -

Yes, it was a cheap $30 ESC from ebay so nothing too much except some skin burnt and two weeks of time wasted waiting for it. I should've gotten a decent ESC from the beginning, one that could handle the load current from this monster motor.

The Phoenix HV is a programmable ESC but I'm not sure if it has a current limiter. I curious about this idea of putting fuses in the motor leads (one of the ESC manuals I was reading suggested this) and wondered if anyone had ever tried it.

Karen

Working on a Piaggio Boxer (mo-ped) EV conversion: http://gpsy.com/ev

Mik's picture

Submitted by Mik on Fri, 07/25/2008 - 19:31.

The Phoenix HV is a programmable ESC but I'm not sure if it has a current limiter. I curious about this idea of putting fuses in the motor leads (one of the ESC manuals I was reading suggested this) and wondered if anyone had ever tried it.

Karen

I think the motor controller fuse in the Vectrix has this sort of purpose.
"Fast acting semiconductor fuse".

But they only act really fast in a full on "short" situation, I think. Your ESC might still have fried even with a fuse. And they cost about $100.- per fuse.

The fuse is located between the positive battery terminal and everything else.

It has been the cause of three complete scooter failures in my case and I know of at least two more cases.

A main function of the fuse is probably also to protect the battery from destruction in case of a short.

The more expensive your battery and other electronics are, the more sense it makes to put in this additional source of potential failures.

Mr. Mik

This information may be used entirely at your own risk.

There is always a way if there is no other way!

Jeffkay's picture

Submitted by Jeffkay on Sat, 07/26/2008 - 10:14.

Karen, Do yourself a favor with the down time. Go to All Electronics site (http://www.allelectronics.com/) and get a couple fans for motor AND esc that run on your pack volts. The current draw is worth it. I run a big fan on Deep Cycle's motor and no problems. My son's e-bike has a 1200 watt motor and without a fan got critical fast--with it--night and day... Your RC stuff ASSUMES a big prop fan in front as a fan. Your motor is now crammed in a less ventilated space. Good luck.

Jeff K.

nasukaren's picture

Submitted by nasukaren on Sat, 07/26/2008 - 12:43.

Jeff -

I had the Venon temp meter on the motor (which is currently exposed to the airstream) and it didn't warm up at all -- barely hit 38C. I'm undervolting the motor by 50% by running it at 24VDC rather than 48. I'm currently thinking of either building a ramjet for the motor or -- because the motor is an outrunner -- turning the motor itself into a squirrel box.

I'll definitely have a fan on the next ESC, most probably get one off a CPU cooler. I think those are rated at 12 V (or I can pull the ESC's 5V line).

Karen

Working on a Piaggio Boxer (mo-ped) EV conversion: http://gpsy.com/ev

Jeffkay's picture

Submitted by Jeffkay on Sat, 07/26/2008 - 21:18.

Hmm, ok on the undervolting but you didn't ride it much. Anyway, you will adjust--good. When is the new ESC coming?
Jeff K.

nasukaren's picture

Submitted by nasukaren on Sun, 07/27/2008 - 04:29.

Jeff -

Hopefully by the end of the week. Right now I have a new toy (Razor e200) to keep me busy -- even though I really should be working on the Boxer's low voltage lines!

Karen

Working on a Piaggio Boxer (mo-ped) EV conversion: http://gpsy.com/ev

Submitted by leopardpm on Tue, 07/29/2008 - 19:16.

Just wanted to give my condolences on your ESC - I am about to try the same thing (RC motor/controller) and appreciate your tests! Please keep the thread going with info when your new ESC arrives. The combo I am going to test is:

HXT 80-100-B 130Kv Brushless Outrunner
Wire Turns: 8
Resistance: 32ohm
Idle Current: 2A
ESC Required: 130A
Input Voltage : max. 48V
Kv : 130 rpm/V
Weight: 1570g
Shaft: 12mm
Voltage Range: 20-48v
Non Load Current: 2.0A
Maximum Power: 6500W
Equivalent: 60-80cc Gas Engine

paired with:

HexTronik PRO 120A BESC w/ PC Programmability
High rate (10 KHz) switching (PWM)
3 to 6 Li-poly cells with receiver.
Dynamic braking ensures prompt prop folding.
BEC (2.0A) provides power to receiver and servos.
Over temperature protection.
User programmable Features.
Low-voltage protection - Programmable
Cutoff can be programmed for motor stop or reduced power.
Brake Type. Throttle Range. Timing Advance.
Safe "power on" arming program.
Low torque "soft start" prevents damage to fragile gearboxes.
Auto shut down in 4sec after signal is lost or radio interference becomes severe.
Microprocessor controlled.
Programmable rotation.

Specifics;
This BESC has an extremely smooth throttle curve and excellent programming features. it is one of the best quality BESC coming from China right now. Item comes with a 12 month warranty
Max Load : 130A
Max Voltage : 6 cell 25v
BEC 2A
Please be advised that BEC should be dissabled when more than 3 cells are used. To dissable BEC remove the middle RED wire from the reciever wire.

I plan to start testing at 24 volts (like you did) and have a fan and as many sensors as possible hooked up. I am rigging up a static 'full load' test stand so if/when I fry it, I won't be stuck 10 miles away in the sweltering heat (110 degrees here in Arizona).

Thanks!

nasukaren's picture

Submitted by nasukaren on Wed, 07/30/2008 - 03:38.

Leopard-san

Not a problem! My super-expensive Phoenix ESC should arrive this weekend so I can do another round of tests then.

The main thing is to have a fan on the ESC and to make SURE THAT THE BRAKE / REVERSE FEATURE is TURNED OFF. The little ESC's can't handle that amount of dynamic energy going through them.

You don't mention getting a UBEC, but you should because the BESC's BEC isn't efficient at doing the job. For my testing purposes, I made a small battery pack from Radio Shack parts, I now have a UBEC that I'll be using for the real deal.

Karen

Working on a Piaggio Boxer (mo-ped) EV conversion: http://gpsy.com/ev

Submitted by leopardpm on Wed, 07/30/2008 - 07:41.

OK, wasn't thinking about cooling the ESC - I will do so as per your advice! I really want to make the lower cost ESC work for our purposes(EV Vehicles) - just having a hard time wrapping my little mind around getting a possible 7-8hp motor/controller for under $250!! I really like the USB programability of the ESC, apparently I can program in a 'slow start' as well as a multitude of other variables - I figure these options will help the motors deal with all the load put on them.

I noticed that about the BESC'S BEC, I will figure in another $20 or whatever for a separate UBEC.

Getting into all this R/C stuff makes for some really interesting options - if the drive unit works as hoped, then I will upgrade the entire vehicle to full R/C control which would be a whole other way to enjoy driving it around (for instance, remote driving the multitude of small children which seem to always be underfoot!) - I like the way all R/C components seem to easily talk to each other and are made 'plug-n-play'... simplifies things for my linear lego building block mind.

I keep reading about 'water cooling' the ESC in R/C boats - seems like an excellent way to go but are they really waterproof? Can't figure out how do setup such a contraption on a motor vehicle without the entire project getting a bit out-of-hand.

I will be holding my breath for your new ESC to arrive so that I can live vicariously through your discovery process!

Thanks again!

nasukaren's picture

Submitted by nasukaren on Wed, 07/30/2008 - 19:01.

Water-cooling's actually pretty easy. I was thinking about doing it if air-cooling wasn't sufficient. In fact, you can do it all with plug-n-play over the counter equipment from your local computer shop. Just look for CPU coolers that are water-cooled. They come with their own built-in pumps and radiators. Very cool.

There was a clearance sale at my local Rat Shack for CPU fans, so I bought a *ton* of them, about 8 for less than $12 including one with a built-in thermostat that controls the fan speed depending on the CPU.... err..... the ESC's temperature. That should do the trick. They are all 12V modules but they also had 5V ones too.

Looks like my new ESC won't arrive until next Monday! Very very aggravating to watch it slowly cross the USA on UPS's website.

Karen

Working on a Piaggio Boxer (mo-ped) EV conversion: http://gpsy.com/ev

Submitted by leopardpm on Thu, 07/31/2008 - 07:12.

Exellent! watercooled CPRU units - great idea!

nasukaren's picture

Submitted by nasukaren on Sat, 08/02/2008 - 03:13.

After doing my test run with the Phoenix, I had some thoughts on the BESC that you were planning to use. It's only rated to 25V which sort of limits your RPM to 25V * 130 kV = 3250 rpm. If you get that one, you may want to get the 180 kV motor, which would give you 4500 rpm. I am intuiting that these RC motors prefer to be run at higher speeds with less torque.

I'm also beginning to think that what blew out my first ESC (the Elf) wasn't armature locked current (since I was at a relatively low throttle) but instead back EMF from the rear wheel when I was decelerating. The ESC blew and shorted the leads, that's what caused the rear wheel to lock. I noticed that the back EMF from the motor is actually high enough to boot my Phoenix ESC even when the main power is off (I was pedaling home in bicycle mode). I might think of a way that the motor leads are actually turned off via a relay when the main power is off or the brakes are being applied.

K

Working on a Piaggio Boxer (mo-ped) EV conversion: http://gpsy.com/ev

Submitted by leopardpm on Sat, 08/02/2008 - 09:43.

I was going over my figures and discovered the whole 25v thing about that ESC (hate how they measure things in 'c' and stuff, not straight volts/amps but rather cells of LiPo) - don't like that. I really like the ESC though, with its programmability and all its features. The only other ESC I found was pretty simple with no programming or anything, but it could drive 48v. I will keep searching - I want cheap, programmability, 48v, and hopefully heavy duty.

Your idea about back EMF is spot on: a relay when throttle is off and/or brake applied (when brake is applied, throttle should also automatically be cut off like the scooter controllers are set up). I don't figure that these controllers have a way to do regenerative braking, huh?! Perhaps some heavy-duty diodes between the ESC and motor as a safety as well?

When is your new ESC due?

nasukaren's picture

Submitted by nasukaren on Sat, 08/02/2008 - 17:47.

Leopard-san

My new Phoenix ESC arrived and I've been putting it through the ropes! I've posted pix and notes on my blog!

Karen

Working on a Piaggio Boxer (mo-ped) EV conversion: http://gpsy.com/ev


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