RC-Monster Forums - Argument thread: Low specc batteries don't kill ESC's. Or do they?

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- - Argument thread: Low specc batteries don't kill ESC's. Or do they? (https://www.rc-monster.com/forum/showthread.php?t=28164)

all this arguing needs to stop. If you know facts state them. (thank you Linc, Arct1k, slim) If you are making an assumption keep it to yourself or preface your statment with, "in my understanding", or, "I think it works this way". But don't state assumptions as fact, and then argue to support your assumptions. That is pure ignorance.

Quite simply- We are at the leading edge of technology in our r/c world. What we see on a small scale will be seen in the future in full size cars. We have the best ESC's and best motors and we need the BEST batteries.

Using sub-par batteries is like putting wooden wheels on an f-1 car.

Let's stop the childish bickering and get back to sharing knowledge to help RCM and the R/C industry to grow, mmmkay?:yes:

Quote:

Originally Posted by BrianG (Post 381627)

Slim: Actually, if you think about it. Water would "jump" from a cup if enough pressure is present. It would either blast a hole in the bottom (signifying breakdown of the "insulator" which is what happens with HV), or splash out. :wink:

first time i have smiled reading this thread:rofl: gotta get me one of those cups, could make my drinking that much easier if it eould just jump into my mouth:lol: was hoping the sine wave wouldn't come up but you caught me brian. interesting though how simmilar the two motors behave.

and yes i will play nice from now on guys:whistle:

Quote:

Originally Posted by T-birdJunkie (Post 381598)

If you don't understand the analogy because you don't understand fluid dynamics, that's fine. Don't pretend electricity is more complex than fluid flow, though.

This annoys me, firstly I do have specialised knowledge of fluid dynamics. My knowledge isn't in hydraulic's as such but in airflow, aerofoil, hullforms etc

Secondly while I was using an small (hydraulic) excavator today I realised my dismissal of the analogy was hasty & wrong, it is actually a reasonable analogy...especially when considering 'ripple current' and 'fluid hammer' for example

I thought of an excellent analogy between supercavitation & C ratings in cells if you want to keep playing with analogies :lol:

Quote:

Originally Posted by lincpimp (Post 381608)

The battery has to be able to output a stable voltage at high current levels while also having low internal resistance to keep from getting hot, and also accepting a charge back from the regen brakes. The esc has the task of controlling the motor and ducting the electrons to and from the battery.

I am by no means in full understanding of how this stuff really works, but I do know that the battery is the single most important part of these brushless systems. I have experiemented with alot of different batteries and there is a difference.

Quote:

Originally Posted by slimthelineman (Post 381623)

enough with this water crap. it is not the same, nice try though. you might be an expert in that area, congrats. when have you ever worked with REAL electricity?

Quote:

show me water that will seek a path to ground at all costs.

You are aware that electricity only seeks a ground simply because it's charged, and it's going to something that's charged oppositely, right?
We are constantly surrounded by electricity whether we are near electrical devices or not. Is ThunderbirdJunkie going to get zapped to death just sitting here, typing this out? In theory, it could happen, should the power supply on his computer go kaput, but that's another conversation for another time.
Water under pressure will go to wherever the pressure isn't. That is all there is to it. Go turn on your hose; it's going to come out the end, right? Not flow backwards. The unpressurized end of the hose is the ground.

Quote:

is it going to jump out of your cup? no.

Absolutely, if it's charged (pressurized) properly

Quote:

if you stand too close to a full pool will the water arc out and hit you because you are dry no.

Funny thing about this. If everything around you is a high pressure water system, and you yourself are unpressurized, absolutely it will.

Quote:

show me a pipe which water will flow through that has a resistance value.

It's called mechanical resistance. Also known as friction.

Quote:

show me a capacitor for water that will correct power factor(voltage lagging behind current)

Just another word for "pressure regulator".

Quote:

water in no way behaves like electricity other than the fact that it flows.

Prove it.

Quote:

sure electrons do the same but they dont flow through a pipe or hydrant or any of that.

Ah, metaphors are lost on you. If you don't understand anything about hydraulic systems why don't you spend your time learning about how they work rather than telling everybody how they don't work.

Quote:

electrons flow due to a difference in potential.

And fluids flow for the same reason. If there wasn't more pressure behind the fluid pushing it to where it was going, it wouldn't be going that way.

Anyway, done dissecting your post. It's fruitless and it will solve nothing. Your mind is made up, and you're choosing to, rather than explain what's going on, chide somebody for asking questions in an effort to understand this mystical "ripple current" that spikes and stuff, and more to the point, have somebody explain why it kills ESCs.

Quote:

Originally Posted by BrianG (Post 381627)

Sheesh guys! lol.

The water analogy works for a very basic understanding of electricity. It works ok for the most part when dealing with DC, but falls apart very quickly with AC. And our ESCs running pulsed DC is effectively AC (no one said AC has to be a sine wave). So, it is very difficult to use the whole water example effectively.

In short, water pressure=voltage, restriction in a hose=resistance, water flow=current. That's about all you can do.

Slim: Actually, if you think about it. Water would "jump" from a cup if enough pressure is present. It would either blast a hole in the bottom (signifying breakdown of the "insulator" which is what happens with HV), or splash out. :wink:

Thank God somebody understands the analogy. A very basic understanding of DC is all ThunderbirdJunkie is after, and why voltage spikes would come from being drawn, and why this
This isn't an alternator in a car, where (since it generates alternating current electricity) voltage must be regulated, the voltage is (for the sake of argument) constant under load from the battery (yes, everybody is aware of voltage drop, etc etc, no need to nitpick...), why would it spike from the battery?
What would cause two 7 cell batteries on a Flux to spike to the point that it would surpass the MMM's 6S 24ish voltage max? Two 8.4v batteries, 9vish fully charged, shouldn't jump past 24v?

Everybody seems to be hung up on the fact that electricity isn't water and ignoring the fact that there are legitimate questions being asked.

Remember...input voltage is DC. Doesn't matter what the output is, unless what's frying is the switching mechanism, which the more ThunderbirdJunkie reads on the issue, it seems to be the caps and the fets smoking themselves from not being able to switch fast enough to deal with the ripple current, which again, points to more of a hardware issue with the speed control rather than a battery issue.

Thought I would throw this in the mix. Power is not only from the battery.

Quote:

Originally Posted by Pdelcast (Post 318010)

Sorry to resurrect a really old thread... but I saw that people were asking me to jump in and "pay my respects" so to speak... (And I'm having trouble getting to sleep tonight!!)

Regenerative braking does occur in all Castle ESCs. And yes, the actual braking action is achieved by just shorting the windings together through the FETs.

What happens is this -- the ESC shorts the windings of the motor, and forces the motor to start acting like a generator. Remember that a turning motor generates a specific voltage -- back EMF. This voltage is actually the voltage induced in the windings by the moving magnets.

Because the motor windings are shorted, the voltage drops to a very low level (usually less than .1V) and current rises very high, very quickly (often hundreds of amps.) As energy is generated (by the drag created by the voltage difference) current rises, and energy is circulated through the windings and the FETs - -- And a large magnetic field (with a LOT of energy) is stored in the winding.

After a short time, the FETs turn off -- and this is when the regeneration occurs. The current that was flowing through the windings suddenly has nowhere to go. Inductors (like a motor winding) abhor a change in current, so the stored energy (in the motor winding magnetic field) forces the voltage to rise until the winding current can continue to flow. The current flows from the battery negative, up through the body diodes of the low side FETs, through the motor winding, back through the body diodes of the high side FETs, and into the capacitors (and battery...)

This is similar to how a boost converter works:

http://en.wikipedia.org/wiki/Boost_converter

(stolen from the Wiki:) The key principle that drives the boost converter is the tendency of an inductor to resist changes in current. When being charged it acts as a load and absorbs energy (somewhat like a resistor), when being discharged, it acts as an energy source (somewhat like a battery). The voltage it produces during the discharge phase is related to the rate of change of current, and not to the original charging voltage, thus allowing different input and output voltages.

But instead of a supply, there is a magnet passing the coil that creates the current source.

Hope that clears it up for you all!

you guys know freezebytch is probably watching this thread and laughing his ass off knowing that he started a huge fight. If you notice he hasnt replied once to this. He started it, and hasnt said anything since then lol

Quote:

Originally Posted by T-birdJunkie (Post 381637)

Never. 480 is as high as ThunderbirdJunkie has worked with. We are talking sub-30 volts here, though, so none of that has any bearing on this conversation. We are simply talking SIMPLE DC systems, such as what deliver power to the ESC.

You are aware that electricity only seeks a ground simply because it's charged, and it's going to something that's charged oppositely, right?
We are constantly surrounded by electricity whether we are near electrical devices or not. Is ThunderbirdJunkie going to get zapped to death just sitting here, typing this out? In theory, it could happen, should the power supply on his computer go kaput, but that's another conversation for another time.
Water under pressure will go to wherever the pressure isn't. That is all there is to it. Go turn on your hose; it's going to come out the end, right? Not flow backwards. The unpressurized end of the hose is the ground.

Absolutely, if it's charged (pressurized) properly

Funny thing about this. If everything around you is a high pressure water system, and you yourself are unpressurized, absolutely it will.

It's called mechanical resistance. Also known as friction.

Just another word for "pressure regulator".

Prove it.

Ah, metaphors are lost on you. If you don't understand anything about hydraulic systems why don't you spend your time learning about how they work rather than telling everybody how they don't work.

And fluids flow for the same reason. If there wasn't more pressure behind the fluid pushing it to where it was going, it wouldn't be going that way.

Anyway, done dissecting your post. It's fruitless and it will solve nothing. Your mind is made up, and you're choosing to, rather than explain what's going on, chide somebody for asking questions in an effort to understand this mystical "ripple current" that spikes and stuff, and more to the point, have somebody explain why it kills ESCs.

Thank God somebody understands the analogy. A very basic understanding of DC is all ThunderbirdJunkie is after, and why voltage spikes would come from being drawn, and why this
This isn't an alternator in a car, where (since it generates alternating current electricity) voltage must be regulated, the voltage is (for the sake of argument) constant under load from the battery (yes, everybody is aware of voltage drop, etc etc, no need to nitpick...), why would it spike from the battery?
What would cause two 7 cell batteries on a Flux to spike to the point that it would surpass the MMM's 6S 24ish voltage max? Two 8.4v batteries, 9vish fully charged, shouldn't jump past 24v?

Everybody seems to be hung up on the fact that electricity isn't water and ignoring the fact that there are legitimate questions being asked.

Remember...input voltage is DC. Doesn't matter what the output is, unless what's frying is the switching mechanism, which the more ThunderbirdJunkie reads on the issue, it seems to be the caps and the fets smoking themselves from not being able to switch fast enough to deal with the ripple current, which again, points to more of a hardware issue with the speed control rather than a battery issue.

never in his life did SuicideNeil come across such a know it all who beleived he had all the answers, yet actually had so few. WE ARE NOT DISCUSSING WATER, IT HAS NOTHING TO DO WITH ESCS. You show me one, just one BL MT weighing 10lbs+ that can run on duracell AAAs @ 50mph+ and I'll eat my hat. Sub standard batteries suck, that is all you need to know. Whether CastleCreations need to look at different FETS is very doubtful- that use items that arent even available to other manufacturers, at the cutting edge of design and capability for their esc's operating spec- aint using cheap components to save a few bucks here and there. Escs are also far from simple, otherwise every man & his dog would be designing and selling them to enthusiasts- ever built a BL esc yourself chap?

If they say to use good lipos capable of suppling enough current to meet the demands of the system, then thats what you should do, not argue about fluid dynamics and how it applies to battery selection; it really doesnt...:sarcastic:

ThunderbirdJunkie never once claimed he knows it all.
He is ONLY in this thread to LEARN.
DC voltage...IN...is causing these issues, no?

Neil, rather than blasting somebody trying to grasp a concept that doesn't make sense to him, why don't you try, instead, answering the questions as to why?

:rofl: ignorance is bliss! and just to be a jerk alternators on cars do not produce alternating (ac) current. its dc, otherwise how the hell would you charge the dc battery. have to agree with linc on this, get over yourself t-bird. obviuosly the function and behaviours of electricity have eluded you. this is fine, could care less. but at the same time all slimthelineman was trying to do was put some info out there to help people why its a bad idea to use low amperage batteries with high aperage motors. i think its interesting how some people will try to rationalize anything anyway they can to prove their veiws are correct. two words to end all this water hubub, mutual induction.

all that aside why does nobody have the good stuff in their quotes? only the stuff that they feel like they can prove wrong somehow with all their infinate knowledge of electricity. its like i said, 120amp rated motor, 120amp rated esc, why the hell would you use anything less than a 120amp capable battery? it would be like using a fire hydrant that only gives 100psi and trying to use a pump truck to pull 1000psi through the hydrant.:whip:

its official slim is now a fluid dynamics expert cause i used a water analogy.

as far as not seeing freeze anymore probably just has to do with people being easier to argue with on other forums, or is lost as far as what some are saying. could be he just got bored, i know i am aproaching that point. the manufacture puts a recomendation on minimum amperage for your batteries. without knowing anything elese it would probably be best to do what they say. they know more about their product than anyone. like i said your electrical system is only as strong as its weakest componet.

so lest be nice to our dc input ac output controllers and give them what they want. i think the question at this point should have been why use crappy low amperage batteries on a super powerful brushless setup?:neutral:

88gtanotchback is confused....

_paralyzed_ thinks 88 gta notchbacks are a sick one run car. 350 tpi ftw:yes:

Quote:

Originally Posted by slimthelineman (Post 381661)

:rofl: ignorance is bliss! and just to be a jerk alternators on cars do not produce alternating (ac) current. its dc, otherwise how the hell would you charge the dc battery...

Not to argue, but car alternators DO produce AC. Actually, three phase AC. Then it's just rectified to DC...

'pinkpanda3310' thinks 'sneezebutt' had little intension of arguing about water in this thread.... but that's what 'sneezebutt' got.

Quote:

Originally Posted by BrianG (Post 381667)

Not to argue, but car alternators DO produce AC. Actually, three phase AC. Then it's just rectified to DC...

Linc 'rectifies my..... oh wait, forum ettiquette:neutral:

Quote:

Originally Posted by BrianG (Post 381667)

Not to argue, but car alternators DO produce AC. Actually, three phase AC. Then it's just rectified to DC...

well there you go, can always stand to learn something new if you are willing. just so happens that Brian G is the one opening my eyes a little wider most of the time:lol: its funny i just finished replacing the altenator in my wifes civic cause the regulator went bad. never would have guessed it rectified the current to dc, even though its called an altenator:rules:

slimthelineman is glad there are forums with people way smartet than me and willing to share those smarts, especially them street smarts:lol:

Quote:

Originally Posted by _paralyzed_ (Post 381666)

_paralyzed_ thinks 88 gta notchbacks are a sick one run car. 350 tpi ftw:yes:

88gtanotchback thanks ya, even tho most consider it a mullet mobile. And since 88gtanotchback is not contributing to the thread consider him outsky.:mdr:

So nobody can explain what ripple current is?

In a switching power supply, the voltage coming out of the O/P rectifier and into the O/P inductor is a positive-polarity square wave. The O/P inductor and O/P capacitor(s) filter that into a DC voltage. The current through the inductor is a DC level (which goes to the load) with triangle-shaped AC current riding on the DC level. The AC current is due to the charging of the inductor (during the switch "On" time) and discharging of the inductor (during the switch "Off" time). If things are designed properly and operating normally, the inductor never "fully" charges (saturation), nor discharges fully. Almost all of the AC current, several amps rms, goes through the O/P capacitors rather than to the load (if it did, the ripple voltage would be fairly high). While a capacitor's DC resistance is very high, its impedance to AC depends on the frequency of the AC. In the 100KHz range, that impedance is milliohms (thousandths of an ohm). By way of contrast, the effective resistance on the load in the computer is much higher (e.g., if the O/P voltage is 2V and the load current is 20A, the DC "resistance" is 100 milliohms). So it is entirely normal for the capacitors to be conducting several amps of ripple current, as this is due to the capacitors' smoothing action.

What is impedance? In a capacitor, it has 3 basic components in series with each other: an ideal capacitor; the ESL, equivalent series inductance, of the leads; the equivalent series resistance of the leads, the foils, and the electrolyte. Impedance is the vector sum of the capacitive reactance [1/(6.28xFxC)] X(C), the inductive reactance (6.28xFxL) X(L), and the ESR. At relatively low frequencies, X(C) is basically the impedance. As frequency increases, the impedance falls until the ESR is greater than the X(C), and the ESR is basically the impedance. As frequency continues to rise, the X(L) becomes greater than the ESR, and the impedance is basically the X(L). P/Ss and VRMs operate in the frequency range where the impedance and ESR are approximately the same.

If the capacitor is conducting ripple current, it is dissipating power (I^2)(ESR), which is heat. The higher the ripple current, the more the heat. If you exceed the ripple current rating, the cap will overheat, unless the ripple current is so high that hydrogen gas is being generated. So the failure mechanisms with excessive ripple current are electrolyte evaporation and evaporation- or gas-related venting.

To me, post #34 explains it. Combine that with post #45 and that is how esc's can die from ripple.

I have heard the water analogy before and didn't particularly like it as it was explained to me by someone with less knowledge of electricity than myself. With pressure you have explained it better. I guess it wasn't recieved well on rcm as some people here like the more technical answers.

The above mentioned posts are quotes from Pdelcast and his company.

Quote:

Originally Posted by T-birdJunkie (Post 381657)

ThunderbirdJunkie never once claimed he knows it all.

You act like it enough...

Quote:

He is ONLY in this thread to spam/troll.

Fixed.

Quote:

DC voltage...IN...is causing these issues, no?

Which has what to do with water exactly? Analogies are lovely, but offer zero help when seeking to find the cause of esc failure. Insufficicent batts, and components that cant compensate for said crappy batts quickly enough. If you use decent batts, its not a problem; only failures you have to worry about then are ones caused by physical damage & user error ( DOA is DOA, different issue entirely.. ).

Quote:

Neil, rather than blasting somebody trying to grasp a concept that doesn't make sense to him, why don't you try, instead, answering the questions as to why?

Im not blasting you, we all are :lol:
Analogies dont help when you look past the surface of the problem- analogies are for helping kids understand basic principles, not for diagnosing complicated technical issues. You only followed freezepop over here because of his little paddy he threw at RCU. If you wanna learn, ask relevent questions or make helpful sugestions, not keep on talking about fluid dynamics because it doesnt solve any questions.

Wow, my basic question/concern thread has been turned into this:

http://i100.photobucket.com/albums/m...rgumentmx6.gif

:lol:welcome to RCM !
Its like a new movie.......

http://www.beatyourtruck.com/forum/i...lt-popcorn.gif
"The Clash of the Egos"

Cant argue with Monty Python..

<object width="480" height="385"><param name="movie" value="http://www.youtube.com/v/kQFKtI6gn9Y?fs=1&hl=en_GB"></param><param name="allowFullScreen" value="true"></param><param name="allowscriptaccess" value="always"></param><embed src="http://www.youtube.com/v/kQFKtI6gn9Y?fs=1&hl=en_GB" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="480" height="385"></embed></object>

Its Fee on here....:mdr:

Quote:

Originally Posted by radioman193 (Post 381833)

Its Fee on here....:mdr:

No it isn't

ok you got me on that...........
i admit i was wrong

I did have to pay my isp
and electric bill.:intello:

but its Still Cheap entertainment.:rofl:

Quote:

Originally Posted by slimthelineman (Post 381843)

And what was the point of your last post freeze? Thanks for contributing. Maybee we should all take note of radiomans ability to be a woman and admit he was wrong, not like it even mattered in any way.

Peas and Carrots
:rofl::rofl::rofl:

Quote:

Originally Posted by slimthelineman (Post 381843)

And what was the point of your last post freeze? Thanks for contributing. Maybee we should all take note of radiomans ability to be a man and admit he was wrong, not like it even mattered in any way.

i don't feel the need to.

if im wrong then im wrong.
if im not then im not .
it does not bother me in either way
therefore the subject is moot.

No one person has the correct answer.
and
No one person is Wrong.

there is to many ways for electronics to fail.
there are to many reasons for a electronic device to fail.

its not the end of the world as we know it .

when you boil this "NOISE" down it comes down to poor design
to prevent these types of things from happening.

Enjoy .............

Why don't you come up here and make me freeze. You are the one that started the "argument thread". Yes I missed the joke sorry all for being too serios for your liking. As for being judgemental, damn right I can be whatever I want. But then again I didn't come to this forum with a beef from another forum asking members here to judge your adversaries.