HV Hydro's ESC= Strong Enough?

[Takedown]

Im am debating on if I should get this esc for my 1/5 seeing that its meant for boats and that Ill be maxing out its voltage capabilities. Its meant for 32cells nimh/nicd which is a total voltage of 38.4v. I will be running three 12v 5000mah PB batts in series to make a 5000mah 36v setup. Also it says the esc does 90a continious. Is this enough or should I be looking for more capable esc's? This is the highest amp HV brushed esc I can find so... All help is appreciated.

[doo540]

I had the same questions for my upcoming 1/5 scale build. I emailed MGM, they emailed back saying the are working on a 250 amp and a 400 amp version esc for spring 2009. I will post that email tomorrow for you. I think the 400 amp monster was good for 15s. I really hope that they have them ready for early spring, until then I will be running a HV Hydro 240 from CC.

I have heard of some failures recently with the Castle HV Hydra ESCs over on the OSE forum

[doo540]

Below is the email reply I recieved from MGM.

Dear Tim,

I am sorry for delay.
I suppose for 10 or 12 Lipo and this motor and car you need controllers 200A, real 200A, no only "on the paper" as write, for example Novak (GTB brushless racing controller, 540A !!! ) or more. Very depend on the gear and mechanical load, however no available data for Neu motors - in this situation very problematic say you need 100A or 200A or 300A controller. We know Neu motors, however we don´t test this (2215 1y) type.

We have 10 Lipol controller only up to 125A and 15 Lipol controller up to 100A in this time.

We prepare new, real 200A and real 400A controllers up to 15 Lipol, however these new ESC will be available on the spring 2009.

Best regards,
Grisa
----- Original Message -----

To: mgm@mgm-compro.cz
Sent: Monday, November 17, 2008 3:28 PM
Subject: controller for 1/5 scale truck

Hello
I’m interested in what controller you would recommend for my project vehicle.

It’s a 1/5 scale 2 wheel drive truck. Running weight will be around 29 lbs. I will be running a Neu 2215 1y brushless motor. I plan on running between 10s and 12 s lipo batteries depending on how fast I want to go. I’m shooting for 45 mph min to 65 mph when I want to just drive fast. I’m starting with a HPI Baja 5T truck and converting that to brushless. This truck will be used for bashing, jumping, and fun stuff like that. Thank you for any info you can provide me.

Thanks Tim

[lutach]

A real 200A or 400A esc will be huge. Look at the Schulze 40.300, it's a monster and even makes my esc look small. If they come out with a ESC that looks the same as the ones they have available now, then we know they are becoming the Novak of Europe.

[BrianG]

15s @ 400A? That's over 22,000 watts, or almost 30HP! Yeah, that might just be enough...

Originally Posted by lutach

A real 200A or 400A esc will be huge. Look at the Schulze 40.300, it's a monster and even makes my esc look small. If they come out with a ESC that looks the same as the ones they have available now, then we know they are becoming the Novak of Europe.

I would imagine a Schulze 40-300 would be pushing a grand, the 40-160 goes for $725 if you can get your hands on one

[lutach]

Originally Posted by BrianG

15s @ 400A? That's over 22,000 watts, or almost 30HP! Yeah, that might just be enough...

BrianG,

You and I both know this, but please tell everyone one thing.

How big of a heat sink would we require to dissipate the amount of heat 63V @ 400A would create?

I've seen my share of electric 1:1 vehicles and have found many suppliers that offers anything from 8Kw to over 300Kw and even at 8Kw the ESC or Drive Module has a significant amount of cooling an some goes a far as liquid cooling.

[lutach]

Originally Posted by azjc

I would imagine a Schulze 40-300 would be pushing a grand, the 40-160 goes for $725 if you can get your hands on one

It will be up there and I'm sure Schulze will only build one when they get an order for one.

[BrianG]

Originally Posted by lutach

BrianG,

You and I both know this, but please tell everyone one thing.

How big of a heat sink would we require to dissipate the amount of heat 63V @ 400A would create?

I've seen my share of electric 1:1 vehicles and have found many suppliers that offers anything from 8Kw to over 300Kw and even at 8Kw the ESC or Drive Module has a significant amount of cooling an some goes a far as liquid cooling.

Well, just by playing with some rough figures; ESCs are about 85-95% efficient right? This of course depends greatly on FET slew rate, FET rdson values, PWM frequency, motor inductance, etc, but it should be fairly close. We'll use 95% just to be generous.

Now, let's say the ESC is drawing that 22,200w from the battery as opposed to assuming that power is what the ESC is sending to the motor.

At 95% efficiency, that is 1,110w being dissipated on the ESC (5% loss for the mathematically challenged ). Yeah, that'll take quite the large heatsink.

Of course, what reasonable R/C battery (or motor for that matter) can sustain 400A for any amount of time (and not drop to an unusable voltage)? Not many that I know of without running a 5p+ arrangment.

I would say the 400A rating is more of a sustained burst with a realistic continuous current rating of 200A. Either that, or since this ESC will most likely be used in boats(duh), the amount of time being run is measured in seconds anyway, so they can safely call it a 400A ESC. Either way, run time or duty cycle is short. But hey, it could be a true continuous all-day-long 400A, who knows? If so, could give CC's SHV 200A ESC a run for their money - although the CC will probably be substantially cheaper.

Ok, so I rambled a bit there; time to get back to the math stuff. So, let's say we are running this same 15s ESC at average running currents of 35A for 80% of the time, 150A bursts for 15% of the time (a little accel through bends) and 300A peaks for 5% of the time (heavy accel after corners). Pretty reasonable figures for a heavy vehicle running typical stop-n-go track usage, no? The total average current would be (35A*.8 + 150*.15 + 300*.05) = 65.5A (if I did the math correctly). Optimistically assuming (just to make math easier) we are still using 15s lipo, ESC is running at a constant 95% efficiency (which it won't because of the partial throttle), and the voltage is not dropping under loads (yeah, right), losses on the ESC would still be around 181w. That's still a LOT of power to shed as heat! Ever feel a 60w lightbulb? Now, triple that.

[lutach]

Originally Posted by BrianG

Well, just by playing with some rough figures; ESCs are about 85-95% efficient right? This of course depends greatly on FET slew rate, FET rdson values, PWM frequency, motor inductance, etc, but it should be fairly close. We'll use 95% just to be generous.

Now, let's say the ESC is drawing that 22,200w from the battery as opposed to assuming that power is what the ESC is sending to the motor.

At 95% efficiency, that is 1,110w being dissipated on the ESC (5% loss for the mathematically challenged ). Yeah, that'll take quite the large heatsink.

Of course, what reasonable R/C battery (or motor for that matter) can sustain 400A for any amount of time (and not drop to an unusable voltage)? Not many that I know of without running a 5p+ arrangment.

I would say the 400A rating is more of a sustained burst with a realistic continuous current rating of 200A. Either that, or since this ESC will most likely be used in boats(duh), the amount of time being run is measured in seconds anyway, so they can safely call it a 400A ESC. Either way, run time or duty cycle is short. But hey, it could be a true continuous all-day-long 400A, who knows? If so, could give CC's SHV 200A ESC a run for their money - although the CC will probably be substantially cheaper.

Ok, so I rambled a bit there; time to get back to the math stuff. So, let's say we are running this same 15s ESC at average running currents of 35A for 80% of the time, 150A bursts for 15% of the time (a little accel through bends) and 300A peaks for 5% of the time (heavy accel after corners). Pretty reasonable figures for a heavy vehicle running typical stop-n-go track usage, no? The total average current would be (35A*.8 + 150*.15 + 300*.05) = 65.5A (if I did the math correctly). Optimistically assuming (just to make math easier) we are still using 15s lipo, ESC is running at a constant 95% efficiency (which it won't because of the partial throttle), and the voltage is not dropping under loads (yeah, right), losses on the ESC would still be around 181w. That's still a LOT of power to shed as heat! Ever feel a 60w lightbulb? Now, triple that.

Thank you BrianG, you sir are my professor lol. Now let me explain why I asked that. I've been telling a few people, I like to treat what ever rating a ESC is built for as what it'll do for a spike (That hard acceleration on start ups and out of a corner). Let me use my 200A 1/10 scale ESC as an example. I use the 200A rating as a measure of the burst it'll handle. I got 178A burst out of it and snellemin has reached 182A. Now my 6S, 10S and any other ESC should be treated the same way so everyone won't get disappointed when their ESCs burned up because they were trying to get 100A+ continuous out of their ESC. I hope all the manufacturers who states a number that is out of this world would promote this to keep this hobby fun and safe. Thank you BrianG for your professional answer.

Regards.

[BrianG]

lol, not nearly a professor, just a bit of simple common sense and elementary math.

From what I've seen, many manufacturers tend to rate the current ratings on their ESCs according to the pure FET current rating. They don't take into account the temperature derating (our ESCs do NOT run at 25*C on a hot sunny day during track use!), the fact that there are a LOT of FETs packed into a TINY area with minimal cooling, and don't seem to figure in a little headroom for "overzealous" gearing.

Side note: Does anyone besides me appreciate the fact that companies are producing devices that control hundreds of amps in such a small space? I find it staggering personally. It's one thing to occasionally turn on/off devices that draw this current, but to do so thousands of times per second to precisely control a motor load? Man!

Anyway, the trouble with rating an ESC by the burst value is: what constitites a burst? Depending on how highly geared (effectively "stalled") a motor is, even 1/10 scale, a burst can get well into the high hundreds of amps during that initial microsecond. Eagletree does not catch that, or averages it out or something, since it seems to only catch sustained bursts. So, say you rate your ESC for 200A. People will inevitably push that ESC to 400A+ thinking it'll take it (think Trx noobs).

I would rather underrate an ESC to compensate for those people and have my product last longer - or at least design for huge bursts. But, it would be difficult to produce something at a decent price that matches other companies' overrated ESCs.

Personally, I think consumers should be required for IQ tests for any product like this. But that includes 1:1 vehicles, computers, TV's, etc. Basically, if your IQ is under that of my coffee cup, you shouldn't be using anything that you could hurt yourself with - which is why lawyers are so popular nowadays.

There I go again rambling on. I'll just blame this stupid head cold I have. Go figure. I take steroids to treat an insane poinon ivy outbreak and it weakens my defenses against everything else. Argg. Time for a smoke.

[lutach]

Originally Posted by BrianG

lol, not nearly a professor, just a bit of simple common sense and elementary math.

From what I've seen, many manufacturers tend to rate the current ratings on their ESCs according to the pure FET current rating. They don't take into account the temperature derating (our ESCs do NOT run at 25*C on a hot sunny day during track use!), the fact that there are a LOT of FETs packed into a TINY area with minimal cooling, and don't seem to figure in a little headroom for "overzealous" gearing.

Side note: Does anyone besides me appreciate the fact that companies are producing devices that control hundreds of amps in such a small space? I find it staggering personally. It's one thing to occasionally turn on/off devices that draw this current, but to do so thousands of times per second to precisely control a motor load? Man!

Anyway, the trouble with rating an ESC by the burst value is: what constitites a burst? Depending on how highly geared (effectively "stalled") a motor is, even 1/10 scale, a burst can get well into the high hundreds of amps during that initial microsecond. Eagletree does not catch that, or averages it out or something, since it seems to only catch sustained bursts. So, say you rate your ESC for 200A. People will inevitably push that ESC to 400A+ thinking it'll take it (think Trx noobs).

I would rather underrate an ESC to compensate for those people and have my product last longer - or at least design for huge bursts. But, it would be difficult to produce something at a decent price that matches other companies' overrated ESCs.

Personally, I think consumers should be required for IQ tests for any product like this. But that includes 1:1 vehicles, computers, TV's, etc. Basically, if your IQ is under that of my coffee cup, you shouldn't be using anything that you could hurt yourself with - which is why lawyers are so popular nowadays.

There I go again rambling on. I'll just blame this stupid head cold I have. Go figure. I take steroids to treat an insane poinon ivy outbreak and it weakens my defenses against everything else. Argg. Time for a smoke.

You are 100% right and it amazes me to see so many people without common sense (I hate to say it, but it's true). I actually tried to figure out how some big names (Castle and Tekin are not one of those as they don't claim such crazy out of this world numbers) claim such a high number and I must say it's not adding up even if I go with the MOSFET's burst rating. Are they using alien technology?

Get well soon Brian, sorry for all the questions.

[BrianG]

Originally Posted by lutach

I actually tried to figure out how some big names (Castle and Tekin are not one of those as they don't claim such crazy out of this world numbers) claim such a high number and I must say it's not adding up even if I go with the MOSFET's burst rating. Are they using alien technology?

Get well soon Brian, sorry for all the questions.

I don't know either. Look at the Quark 125B and the original MMM: both used the same FETs and the same number of them, yet the Quark was rated for 25% higher current. I would really like to see it even try to pass 125A on a contiuous basis! Actually, I'd like to see the MM try to do its 100A as well, even though it's more realistically rated. Don't get me wrong, I really like both those ESCs and recommend them to anyone, but I think the rating is a bit "aggressive". People will push them, simple as that.

The problem with rating might be how an engineer would rate it vs how their marketing department would rate it, vs how a consumer understands that rating. Or maybe it's about how an engineer thinks the consumer will hear it, or how the marketing department thinks the engineering department is rating it, because, as we all know, most engineers tend to err on the side of caution, and so marketing will re-inflate the rating. lol, we could go in circles with this all day.

Or maybe, as you said, it's alien technology after all. Heck, there could be tiny aliens actually inside the FETs doing the work and all that jargon about silicon and gates and source/drain and rdson, yadda yadda yadda is all just technobabble to confuse and distract us.

BTW: Takedown, sorry about the thread hijack.

[lutach]

I really hope that all the manufacturers can start teaching everyone how to use their electronics properly. I try my best to help people achieve a fun and safe set up. All I get sometimes there is an ignorant fool(s) who thinks he knows how this stuff works only because he has one. I've been messing with brushless since 1994 when I got my Aveox system and I'm still learning. I also think I was the first one to actually use a 12,000mAh lipo pack and guess what, I got so much crap and people telling me it's too much, but hold on when MA came out with their 12,000mAh everyone went nuts. One of the reasons why I never bothered getting my own lipos made and the other is the common sense factor that has burned houses, cars and many other things down .

I do apologize for hijacking this thread as well.