Test1 RedCat Earthquake 8e
 

Another First good testing day.....
Today I tested out my RedCat Earthquake 8e
and the Motor gets Warm Fast the way i was usen it in this video.
The batteries get warm
The ESC gets luke warm
...Over all the truck has WAY more power than it needs!
!!!!!!! NEVER run it Without a Wheelie bar !!!!!!
Over all the truck is a Good truck for $299.

Nothing big just a testing video
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This truck KiCkS Butt
WAY more power than it needs!

That's not a good sign - what motor is it? A good brushless motor should be able to handle that type of driving without any problems.

oh yes its 100% WaterPROOF

i used Epoxi to waterproof it.

http://a5.sphotos.ak.fbcdn.net/hphot..._2003281_n.jpg

ESC before waterproofing

http://a4.sphotos.ak.fbcdn.net/hphot..._8073435_n.jpg

http://a7.sphotos.ak.fbcdn.net/hphot..._1945239_n.jpg

After Waterproofing

http://a1.sphotos.ak.fbcdn.net/hphot..._5949096_n.jpg

http://a3.sphotos.ak.fbcdn.net/hphot..._6349143_n.jpg

melt water was flooding the esc here

http://a6.sphotos.ak.fbcdn.net/hphot..._6789018_n.jpg

it does handle it.
just after 20 minutes of full throttle puntch and full brake to full puntch.
the motor is about 130 with NO fan on it. >>> to ME <<< 130 is hot
the esc was 91
tested with ir .
the motor is a 2230Kv 540 .

I have to say that using that epoxy to waterproof your esc may cause you problems down the road. Specifically I fear that you may not be able to dissipate any excess "EPE" that will built up in your esc, leading to premature failure. For more information, be sure to read this post carefully:

http://www.rc-monster.com/forum/show...0&postcount=22

I hope this helps.

I vote that the above linked post should be stickied. All in favor??:yipi:

thanks
but i have had NO problems with any esc's i have done in the past for others or myself ....
others i have done have been working for over 3 years sofar with no problems .
i do know what needs Proper heat dissipation and some other factors.
other things have been added to the esc for reasons of safety and longevity.
i have been doing electronics for far to many years to go about things blindly.

But thanks for your concern.

the above link was a Fun read
but only applies to a device that is used in a way that it was NOT intended to be used OR was of a Bad Desing to start with
or used out of specification....
like "More brake load /force" than the fet's can shunt to gorund and with that type of electron power energy flow or "EPE" as was put ..
look at it like this ..................JUST an EXAMPLE >> if a FET can handle 5000 electrons per ms shunt to ground and you force 20000 to it just what do you think will happen?????? you will end up with a electron saturation within the device ...and in a short way to say you will get your Magic smoke.
99.5% of the time this is the cause of the ESC letting out the Magic smoke people usen a motor that draws more current and Or present more shunt load than the ESC can TRUELY handle over a period of time leading to a catastrophic failure of the FET's in the ESC.

i think its funny when i see people saying ....
when you apply brake the power goes back to the battery on a rc.......
NOT!!!!!
the motor can otuput WAY OVER 10amps on brake
so basicly thay are saying thay are putting OVER 10amps of power back into the battery...OMG.. "BOOM"!!!
the brake load is shunted to ground not put back to the battery......
we are not talking like a hybrid car here a rc esc is very simple in its Desing.

you've got it wrong radioman.

R/C esc's are quite sophisticated and do indeed have regenerative braking.

"Energy is neither created or destroyed" You can't just "shunt to ground" the multi kilowatt output of motor braking. THAT would blow the esc.

And that many watts of motor braking cannot be simply dissipated as heat.

The energy does indeed go back into the batteries. That is why a battery with a low internal resistance is so critical.

You seem to be making a lot of assumptions based on your prior electrical knowledge. I feel you should learn about the new technology before you claim to understand it.

i think someone is drinking bongwater and huffing krylon fusion paint

:slap:

if you "say"
Thats cool
it looks like i will see if Or when it dies.
or any of the others do.

HMMmmmm.

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As was said

"That is why a battery with a low internal resistance is so critical."

low internal resistance. Measured in milliohms, the internal resistance is the gatekeeper that, to a large extent, determines the runtime. The lower the resistance, the less restriction the battery encounters in delivering the needed power spikes. A high mW reading can trigger an early 'low battery' indication on a seemingly good battery because the available energy cannot be delivered in the required manner and remains in the battery.


These might help you.

http://www.popularrc.com/?p=382

http://batteryuniversity.com/partone-22.htm


i was wrong to a point on how the brake works on a brushles esc............
BASICLY
not going into pulse timing or other detailed information that is not needed.

when you brake 2 coils get a voltage 1 on eatch side of the armature
the harder you brake the higher the voltage..... in turn slows the armature and or holds it in place.
the esc can detect the rotation and will very the voltage to said coils as is needed as you increase or decrease your brake force
upto the esc's Brake amperage .
but still does not offload voltage to the battery.

Sorry bu I do think I'm going to have to go with Patrick and my Eagletree in that ESCs do have regernerative breaking and that some (not all) of the energy is passed back into the battery.

The only other option would be for the ESC to convert the energy into heat - now a 30lb baja at 52mph.

Kinetic Energy = m x v x v
KE = 13.6kg x 23.3 m/s x 23.3 m/s = 7.3 KJ

Braking in 3 seconds

KW = 7.3/3 = 2.9KW of energy to disipate

Yes this assumes no mechanical drag / surface friction etc but you get the idea.

I've been meaning to add some kind of brake calculator thingie to my site. Thanks for posting the formulas Chris; saved me from getting them myself. :smile:

Ok, now back to your regularly scheduled thread topic...

all i can say

Is do testing and you will see the esc has 0 output under breaking.
and look at how the voltage is sent to the motor under breaking.

Under realworld bench testing.
just test a few esc/motor combos on the bench.

I need not say more on this as the proof is easy to find
and dont Overthink and make it harder than it is.

and remember this just because a motor runs on just say 6v @ 3 amps
thats not saying that it will OUTPUT 6v @ 3a as a Generator cause it wont.
so this blows away the number tossing game out the window.

there just might be Some or a few Rc Brushless esc's that do utilise regernerative breaking but i myself have not found one.

just do some Simple testing that others and i can do to see .......
And if i am found Wrong i will drop off ALL Rc forums completely never to post again .

Here is some info:

If Patrick said it you can pretty much take it as gospel.

http://www.rc-monster.com/forum/show...=regen+braking

i want to see a way to reproduce these "facts" in a way that Everyone can try and see.
as i took the motor and esc out of the truck and mounted it on the bench and powered it up and did some more testing with it.

and with the motor at 75% brake force and with breake on i drove the brushless motor with another Brushed motor runing on 12v @ 15amp .
and the brushless esc did get Very warm But did NOT show a positive output on the battery connector all i got was a constant dip or drop in voltage as the esc applied more voltage to the Brushless motor to try to hold the motor still .

you cant make the test more Simple than this setup and its one EVERYONE can do.

Note when testing
when you brake ......2 coils get a voltage 1 on eatch side of the armature
the harder you brake the higher the voltage..... in turn slows the armature and or holds it or in place.

its just a way to test this that ALL or everybody can do and only takes 10 to 15 minutes to setup.
Videos are welcome as it is easy to "say" but better to prove.

I don't think it's that simple. If you are running at 75% brake force, you are just resisting the motor turning. Therefore, any induced (regenerated) voltage will not exceed the supply (battery) voltage and no charging current will flow. Remember, these motors are ~35% efficient (according to patrick IIRC) when braking vs ~90% when running. So it makes sense you'd have to have a motor with decent amount of kinetic energy behind it (vehicle weight at speed) and stop quickly to generate a visible amount of regen current.

Patrick does explain, in depth, how regen braking works: http://www.rc-monster.com/forum/show...0&postcount=57

All my logs show Voltage spikes during braking and some brake current. This is a good read why the voltage increase during braking by MGM Compro.

http://mgm-compro.com/pdf/en-motor-braking-050409-g.pdf

All you need to be able see the voltage spike and some reverse current during braking, is a Datalogger like the one I use by Eagletree. As simple as plugging it in series between your battery and ESC.

I don't see why one's knowledge gaps should cause total forum abandonment but on this I really think that science (Brian and Patrick) is on the side of regen braking.

Best of luck - Please let a mod know if you want your account locked ;)

Can we even do that?

No need to drop of the face of the earth for being wrong. I have been wrong several times. I don’t have a license to be an Electronic Tech, but I do have a degree (as do several others here). Here is a simple test. I am sure you must have a meter that has a peak hold function on it. Strap that on your RC car, turn on the peak hold feature connect to the battery and take it out. Do some hard braking and see what happens.

Jeff

Radioman..
Try this,
put a AC volt meter on one of the motor cables and see what it reads.. just for sh*ts and giggles...
lets say you're cruising down the streets @ 40MPH with the RC car.. and the motor is spinning while coming to a stop, that energy must go somewhere.. Because if you connect 2 brushless motors together and give one of them a spin, the other one will spin also.. I'm assuming that some RC ESCs do not allow that energy to be sent back to the ESC or battery or whatever.. but the energy just doesn't disappear. Maybe the proper term is not regenerative braking? Maybe regenerative slowing down.. LOL.. but give her a test..

Anyways, it's cool to be wrong.. I'm wrong all the time.. but once and a while I am correct... have a good one guys..

I have to add that some ESCs, such as the MMM, do have a TVS device which limits the amount of peak voltage generated during hard braking. IIRC, it's rated somewhere between 26 and 28v, which means that any voltage peaks above its rating are essentially shunted to ground. This means that you might not truly measure the full voltage peak potential. But really, any value above the battery voltage should indicate regen braking, because any voltage above the battery voltage will cause current to flow from the higher to lower potential, which is from the motor to the battery.

Looks like he is only running 4S so it shouldn't be a problem, but thanks for pointing that out.

Jeff

This is all I have to say:

http://i128.photobucket.com/albums/p...sonpopcorn.gif

lol...

:mdr:

radioman, i think you are thinking of brushed motors. brushless motors do not have the same style brakes and instead, send the energy back to the battery. i have seen enough eagletree graphs to know this.

also, patrick del castillo, the owner of castle creations even stated himself that most, if not, all brushless escs use regenerative braking.

btw, we don't want you off the forums, we just want you to not take it personally when you are wrong and know that we all make mistakes. i used to argue that my 8-cell ni-mh batteries could put out more power than 2s lipo. now i know better.

Ok so I figured I would give it a try. My setup doesn't lend itself to this type of testing, but it at least shows that it does work.

I used my Rustler running a MMM and a Fine Design 6 turn slotless 2 pole motor, 2S2P A123 battery. Braking isn't very good, and the added weight of the DMM didn't help. The meter I use is a Fluke 112 DMM. The battery pack was not fully charged it was as I pulled it from the drawer.

to add to what scarletboa said^^^^

i've been all over the net, and Rc-Monster was not only there at the beginning of the brushless movement, but continues to be at the cutting edge of technology.

People don't assume things here. We either state fact or say "IMO" (in my opinion)

Nobody wants you to leave, but you were wrong. You owe us a video of your earthquake puddle skipping.:yes:

Im almost certain that brushed esc's use regenerative braking as well. Not sure how the old mechanical speed controls had brakes, but i remember they did....or at least the ones i had had brakes

ok cool
but even on my scope i MYSELF show no positive voltage peaks or spike even under full 100% breaking force.
but Even going by all the chatter on this EVEN if it does the voltage is VERY little back to the battery and if a lipo can only take a 14v @ 5c Max charge rate or 2.2 amps ......
and the Motor under breaking puts out lets say 31v @ 10amps for that time just were do you think that is all going?????
that Aint dumping into the battery over 97% is shunted to ground otherwise the battery life would be very short and would mess up the ballance up quite badly.
so in going just by this alone would make the regernerative breaking conversation Moot for rc cars as the regernerative breaking power Back to the batteries would not charge them Enough to even consider being a regernerative system........

and yes i only run 4s on the Xerun 80A
and a 2230Kv motor

and yes paralyzed if we get more rain here as we did yesterday you will have your "puddle skipping" video but you wont see smoke like your hoping for. as the esc has been tested under water a few times now :mdr:

we're arguing semantics now. The bottom line is that power goes back to the batteries, which you assumed didn't happen.

We've given you several links with factual data showing that power does indeed go back to the batteries. The MGM one in particular describes why insufficient batteries can kill an esc during braking.

We even informed you that Patrick Del Castillo (Castle Creations namesake and chief engineer) is a forum member here and has written us a technical explanation of how castle esc's use regenerative braking.

If you won't read and learn from the links, and refuse to believe what the person who makes esc's says, then there is no point discussing anything with you.

Can you at least admit you are making assumptions based on your prior knowledge, and that you really aren't sure what you're talking about? Because I am sure, if I'm not I preface my statements with, "I think" or "IMO".

"we're arguing semantics now. The bottom line is that power goes back to the batteries, which you assumed didn't happen."

and I DONT off this esc and full 100% breake force as i said.

and as
brianG has said

"I have to add that some ESCs, such as the MMM, do have a TVS device which limits the amount of peak voltage generated during hard braking. IIRC, it's rated somewhere between 26 and 28v, which means that any voltage peaks above its rating are essentially shunted to ground. This means that you might not truly measure the full voltage peak potential."

and on testing THIS esc and motor from Full throttle to Full 100% breake forced by a 12v window motor here on the bench and on a scpoe there is 0 peaks 0 voltage spikes back from the esc to the batteries i even tryed at one time a 20a diode inline the hot of the esc so power will ONLY flow ONE Way and still got 0 on Breakeing testing eather side of the diode i did get all kinds of voltage drops on breakeing with or without the diode.
im not saying thay are wrong im just saying in the case of THIS esc it Don't.
i will test the vxl3s tomarrow and see what i find on that one.
I in no way have said thay are full of crap or that thay dont know what thay are talking about.
just think it just might not apply to ALL esc's or configurations and cause one manufacture has one or some that do one thing does not mean its in stone that ALL other manufactures build or design theres the same way ......
alot of things just might apply to this
Eg
input voltage
cell count
motor kv
esc design
and alot more Im just saying i dont see it here on My bench all i can go by is wht i see happen when i force the motor to spin at 500 rpm under 100% force all that happens is o return voltage and a Hot esc..... oh and a Very HOT window motor that is driving the brushless motor that is trying to stop turning.
the ONLY spike or Peak voltage i have found is the voltage that is there in between throttle and breake the "deadzone" and that is only the battery recovering from the voltage sag from throttle and when you hit the breake it sags again as voltage is applyed to the motor for breaking ..... and in that SHORT short period in between the two "throttle and breake" might LOOK like a return voltage but is not its just that 2ns of time the esc has no load on the battery.


as i Have said before
Im not saying nobody is Wrong or full of crap
but i AM saying that i cant produce the facts that i am wrong and have tryed for over 15 hours of on and off testing of this
and 5 sets of lipos in need of charging badly LOL

and with a little luck and some more rain i will have some wet rc videos to post up tomarrow

Good nite and God bless .

fair enough. Castle esc's and mgm esc's have regenerative braking per the manufacturer.

this is in opposition to your blanket statement that esc's were simple unlike hybrid cars.

Just understand that people know what they are talking about here on RCM. We don't suppose or assume things. That's why I come here. If you open your mind you can learn a lot from the members here, and nobody will lead you astray.

Looks like I am going to have to set up my own test about this and get some pics (or maybe a video) of it. I know it happens, I've seen it. I guess part of it is understanding how it works so you can reproduce it. Although, it obviously won't be in a running vehicle, so results won't be completely realistic.