Waterproofing a speed controller

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[gilesfordcrush]

Hello all,

I have an electric Catalina PBY. I'd like to protect the speed controller from water. Can I put it in a plastic bag, even loosely, without heating problems?

Giles

[alan c]

used to do fast electric boats,   we shoved them in a condom (unused,  money no object to us!!!)  and seal the end with a lacky band,     takeing it out to release any condensation,  we had no heat problems,   

[markg]

If it's one of the ones with a heatshrink covering then couldn't you just seal around the wires with some bathroom sealant?

[gilesfordcrush]

The speed controller is indeed covered with heatshrink - so I could give the silicone sealant a try. Good idea.

[Cactus]

most m-troniks speedos are watertight

[Ron van Sommeren]

Use acid-free sealant. If you smell vinegar the silicone sealant contains acid.

Vriendelijke groeten Ron

[half throttle]

Good tip Ron 

... and nice hat 

[2.4G Shaun]

Are the esc's in the motor nacells or in the fus?...
I've put the esc's in the nacells on my Cat so if I do decide to fly it off water, they should be well out of the way and benefit from additional forced cooling from the props..... I'm using 2.4g, so  interference that could be potentially induced in the long leads won't be a problem...It might be if you're using 35mHz though, a ground range test at full throttle would be well advised.

I believe, ( but may be wrong), the waterproof MTroniks esc's are for cars and have a reverse function....that would be interesting to use in flight 

Like Alan said, sticking them in blobbies works, the only caveat I would suggest is make sure they are amply rated...i.e. if you are pulling 25A use an esc rated a minimum of 50A so it will have a suficiently large heatsink on to dissipate any heat..A lower rated one would get a lot hotter at full tilt..... Oh and try to get unlubricated ones...lubed ones smell when they get hot...still for novelty value you could get ice cream or christmas pud flavoured ones   

Shaun

[Cactus]

no, most you can disable the reverse

[leccyflyer]

Are the esc's in the motor nacells or in the fus?...
I've put the esc's in the nacells on my Cat so if I do decide to fly it off water, they should be well out of the way and benefit from additional forced cooling from the props..... I'm using 2.4g, so  interference that could be potentially induced in the long leads won't be a problem...It might be if you're using 35mHz though, a ground range test at full throttle would be well advised.

Just a point of clarification here. The reason for maintaining short leads between ESC and battery isn't primarily due to risk of radio interference, it's due to inducing high voltage spikes in those long leads which may damage the ESC, especially if running this near it's limits.

So 2.4ghz vs 35mhz isn't really as important an issue as blowing up the ESC. It's generally better to extend the motor leads, rather than on the battery side.

[2.4G Shaun]

Leccy flier

Just a point of clarification here. The reason for maintaining short leads between ESC and battery isn't primarily due to risk of radio interference, it's due to inducing high voltage spikes in those long leads which may damage the ESC, especially if running this near it's limits.

In my post, I impressed, stressed the importance of having a suitably rated ESC...Running them on the edge ( as you intimated to be acceptable) is the reason most esc's get damaged.
If you're in any doubt speak to the guy at Giant Cod and ask him what the biggest single cause of esc failure is besides connecting them up the wrong way around...

Over the years the idea that long battery leads can cause damage, keeps rearing its head...In the very early days of electric flight ( over 20 years ago) this was a potential problem, mainly due to the fact that the semiconductor technolgy and circuit design available at the time was nowhere near as robust as modern day esc's, I know, I used to  build them.

I can only speak from experience of flying electric flight for over 25 years..it's never happened. Theory is fine but practical experience, to prove for, or against ,wins out every time....

Regarding 2.4 v 35mHz interference point,  again, I have flown multi engine, multi edf, high power ( 2Kw ) set ups and since converting to 2.4g , I have never had a single glitch ( the flight log on my Spektrum Rx's proves this), I used to get fed up trying to optimise RX, esc, extension lead positions etc to minimise interference  issues when on 35mHz ( even using multiplex IPD's, percieved to be the best for interference rejection).

Also the interference problem is more likely to be induced in the extended esc Rx lead ( hence the reason of optically coupled versions for higher power versions.
Also the migration from Brushed ( spark generating) motors to Brushless ( sparkless) motors has solved a large percentage of interference issues now.

Another issue for interference is also the use of  cheap linear becs in esc's not superior switch model devices which produce more electrical noise...( can of worms..... I know poorly designed, poorly screened, switched mode models can be problematic)

Also just to add to the discussion pot.... I have never had a problem in  multi's, using both esc's becs ,without disconnecting one  and also I have used a small capacity rx battery to top up the bec's current delivery, again with no issues ( 2nd can of worms).....

Theory may say no.. many , many years and hundreds of hours of use proves otherwise. ( New bigger can, bigger worms)

Shaun

[leccyflyer]

Leccy flier
In my post, I impressed, stressed the importance of having a suitably rated ESC...Running them on the edge ( as you intimated to be acceptable) is the reason most esc's get damaged.
If you're in any doubt speak to the guy at Giant Cod and ask him what the biggest single cause of esc failure is besides connecting them up the wrong way around...

Would it be grossly exaggerated manufacturer's ratings, such that they recommend using an 80Amp ESC for a 50 amp current draw? Or a 40 amp controller for a 25 amp current draw?

Over the years the idea that long battery leads can cause damage, keeps rearing its head...In the very early days of electric flight ( over 20 years ago) this was a potential problem, mainly due to the fact that the semiconductor technolgy and circuit design available at the time was nowhere near as robust as modern day esc's, I know, I used to  build them.

I can only speak from experience of flying electric flight for over 25 years..it's never happened. Theory is fine but practical experience, to prove for, or against ,wins out every time....

So, on that basis, any incidence where that has happened would be evidence that there can be an actual problem? There have been reports of such and a flying pal has had exactly that problem. The manufacturer's instructions refer to the problem and offer the appropriate advice.

It's a bit like those anti-Tiger tablets that people might take in deepest Surbiton. If you take the tablets and don't have a problem does it mean that the tigers were deterred, or were there never any Tigers there in the first place? I haven't had a problem either, but I do tend to follow the manufacturer's installation instructions with regards to lead length and so lack any contrary direct data.

I'm also happy to run my Jeti controllers a little below their rated limits,with a bit of headroom, whilst recognising that other manufacturer's kit simply couldn't handle that, having seen the results of Tornado 40 amp controllers letting out the blue smoke at just over 20 amps. The Jeti's have run for years at ca 40 amps for a 45 amp controller, with no problems, but I personally wouldn't dream of running an OEM or one of the cheapy 40 amp controllers at 35 amps.

[leccyflyer]

Regarding 2.4 v 35mHz interference point,  again, I have flown multi engine, multi edf, high power ( 2Kw ) set ups and since converting to 2.4g , I have never had a single glitch ( the flight log on my Spektrum Rx's proves this), I used to get fed up trying to optimise RX, esc, extension lead positions etc to minimise interference  issues when on 35mHz ( even using multiplex IPD's, percieved to be the best for interference rejection).

It's undoubtedly true that 2.4Ghz is the best thing since sliced bread for electric flyers in the elimination of much of the interference that plays around our electric flight systems.

Also the interference problem is more likely to be induced in the extended esc Rx lead ( hence the reason of optically coupled versions for higher power versions.

Agreed.

Also the migration from Brushed ( spark generating) motors to Brushless ( sparkless) motors has solved a large percentage of interference issues now.

Agreed, but it might also have produced new ones. I don't think that the switch away from motors with brushgear has been quite the panacea that we'd hoped for in reducing electrical noise. It's just a hunch, and something for which I wouldn't even say that I've got any particular hard data on, but there does seem to be quite a bit of interference reported from brushless controllers, possibly because of the reasons that you describe below

Another issue for interference is also the use of  cheap linear becs in esc's not superior switch model devices which produce more electrical noise...( can of worms..... I know poorly designed, poorly screened, switched mode models can be problematic)

Yep.

Also just to add to the discussion pot.... I have never had a problem in  multi's, using both esc's becs ,without disconnecting one  and also I have used a small capacity rx battery to top up the bec's current delivery, again with no issues ( 2nd can of worms)..... [

Theory may say no.. many , many years and hundreds of hours of use proves otherwise. ( New bigger can, bigger worms)

Shaun

Aaahh, since I've had very little exposure to twins, or multi-motor set-ups, I've no intention of going anywhere near those opened cans of worms, ta very much

Brian

[Alan]

Would it be grossly exaggerated manufacturer's ratings, such that they recommend using an 80Amp ESC for a 50 amp current draw? Or a 40 amp controller for a 25 amp current draw?

So, on that basis, any incidence where that has happened would be evidence that there can be an actual problem? There have been reports of such and a flying pal has had exactly that problem. The manufacturer's instructions refer to the problem and offer the appropriate advice.

It's a bit like those anti-Tiger tablets that people might take in deepest Surbiton. If you take the tablets and don't have a problem does it mean that the tigers were deterred, or were there never any Tigers there in the first place? I haven't had a problem either, but I do tend to follow the manufacturer's installation instructions with regards to lead length and so lack any contrary direct data.

I'm also happy to run my Jeti controllers a little below their rated limits,with a bit of headroom, whilst recognising that other manufacturer's kit simply couldn't handle that, having seen the results of Tornado 40 amp controllers letting out the blue smoke at just over 20 amps. The Jeti's have run for years at ca 40 amps for a 45 amp controller, with no problems, but I personally wouldn't dream of running an OEM or one of the cheapy 40 amp controllers at 35 amps.

Over-rating esc's? No

My Jeti 40A have been running fine for years at 44A peak, very well cooled, and the peak is for 5 secs or so only. Likewise Kontronic JAZZ esc's, happy to run at or just over rating. But they ain't cheap. Nowadays I buy 60A Emax/HWing etc, but run them at 40-45A and not had a problem. I might do at 60A though

Ref lead length, not yet smoked an esc due to extending battery-esc leads, but then I never extend more than 8" as per manufacturer recommendations.

[goony]

the guys that race 1/5th bikes waterproof the esc by dipping them in a tin of araldite suspend it above the pot over night to let the excess drip off then repeat and they have no overheating issues

  goony

[2.4G Shaun]

Hi Brian,

So, on that basis, any incidence where that has happened would be evidence that there can be an actual problem? There have been reports of such and a flying pal has had exactly that problem. The manufacturer's instructions refer to the problem and offer the appropriate advice.

There is always confusion over this issue...  The advice given ( as was the case for early Jeti Advance controllers, to not extend battery leads by more than 20cms ) was basically because the longer leads potentially could act as an aerial that could transmit interference to the esc Rx lead...That was the issue,( and the reason why it is always preferable and good practice to use twisted as opposed to ribbon type extension wiring), not, I believe that the  controller would be damaged by a  pulse flying down the  battery lead....

Your mate with the problem, was it interference or did the esc get damaged by using long leads ?..Had the esc been run at its max rated value or was there plenty of headroom?
Was it an esc of older design or a newer one and was it as you correctly mentioned , a cheap over egged chinese esc or a more expensive, but higher quality one. Was it adequately cooled...There are many, many reasons why esc's go west!!!

Again, I can only offer my actual experience of running long battery lead esc's. The info I posted was that, not, what I have been told  or heard or a personal theory or belief .

It's there as I said for people to agree with or not.....but over 25 years experience of flying electric models and I've never damaged one by using long leads....( I always used the multiplex extension leads with a ferrite ring on though and in many cases had a seperate Rx battery to the servo / esc supply pre 2.4g on the bigger set ups)

It's also interesting that many moden esc's  don't have that caveat re lead length in the instructions any more.....

I used to be an avid Jeti User, but have been using Turnigy ( hobbywing) ones now for the last 2 years from the minute 1g 3A single cell one up to 100A versions with no problems at all...If you've not tried one have a go...Easy programming , with lots of options, very well constructed and the quality is repeatable...i.e. a common problem with 2 same manufacture and spec esc's in twins is the start at different throttle stick positions, usually meaning a bit of clever programming using 2 Rx outputs to sync them.....The Turnigy ones are virtually identical in  performance, in my experience, to date, confirming a high level of quality control and design...At about half the price of a similar Jeti, there worth a look.

Not trying to be dictatorial here, just offering a view 

Shaun

[leccyflyer]

Hi Brian,
There is always confusion over this issue...  The advice given ( as was the case for early Jeti Advance controllers, to not extend battery leads by more than 20cms ) was basically because the longer leads potentially could act as an aerial that could transmit interference to the esc Rx lead...That was the issue,( and the reason why it is always preferable and good practice to use twisted as opposed to ribbon type extension wiring), not, I believe that the  controller would be damaged by a  pulse flying down the  battery lead....

Your mate with the problem, was it interference or did the esc get damaged by using long leads ?..Had the esc been run at its max rated value or was there plenty of headroom?


Was it an esc of older design or a newer one and was it as you correctly mentioned , a cheap over egged chinese esc or a more expensive, but higher quality one. Was it adequately cooled...There are many, many reasons why esc's go west!!!

IIRC the ESC was fried, but I'll ask him for the details, he's at Old Warden today though, so it might not be right away.

Again, I can only offer my actual experience of running long battery lead esc's. The info I posted was that, not, what I have been told  or heard or a personal theory or belief .

It's there as I said for people to agree with or not.....but over 25 years experience of flying electric models and I've never damaged one by using long leads....( I always used the multiplex extension leads with a ferrite ring on though and in many cases had a seperate Rx battery to the servo / esc supply pre 2.4g on the bigger set ups)

Hang on a mo, are we talking about the leads plugged into the receiver here? Only in my post I was referrring to the main battery to ESC leads, rather than the signal, positive+negative lead plugged in on extension leads.

It's also interesting that many moden esc's  don't have that caveat re lead length in the instructions any more.....

I used to be an avid Jeti User, but have been using Turnigy ( hobbywing) ones now for the last 2 years from the minute 1g 3A single cell one up to 100A versions with no problems at all...If you've not tried one have a go...Easy programming , with lots of options, very well constructed and the quality is repeatable...i.e. a common problem with 2 same manufacture and spec esc's in twins is the start at different throttle stick positions, usually meaning a bit of clever programming using 2 Rx outputs to sync them.....The Turnigy ones are virtually identical in  performance, in my experience, to date, confirming a high level of quality control and design...At about half the price of a similar Jeti, there worth a look.

I started using these (the Hobbywing Guard and Pentium versions) at the end of last year and I'm completely taken with them. Very impressed indeed. The programming card is great, they are a bit bigger physically than the Jeti's but you really can't argue with them at the price for everyday models. So far I've got one each of the 30 amp, 40 amp, 60 amp and 80 amp Hobbywing ESCs and they've been good as gold, provided one treats that number that they are rated by as being meaningless  .

Not trying to be dictatorial here, just offering a view 

Shaun

No problem, I didn't take it as dictatorial at all, just sharing the benefits of your experience

[leccyflyer]

Over-rating esc's? No

My Jeti 40A have been running fine for years at 44A peak, very well cooled, and the peak is for 5 secs or so only. Likewise Kontronic JAZZ esc's, happy to run at or just over rating. But they ain't cheap. Nowadays I buy 60A Emax/HWing etc, but run them at 40-45A and not had a problem. I might do at 60A though

Ref lead length, not yet smoked an esc due to extending battery-esc leads, but then I never extend more than 8" as per manufacturer recommendations.

Me too - my 80 amp Hobbywing is on a 6s1p setup, pulling 48 amps and the 60amp one is on a 4s1p setup pulling about 38 amps. The 40 amp one is on 3s1p pulling something around about 20 amps and the 30amp one will be pulling about 12 amps. The ratings don;t seem to mean a great deal, so I just follow the advice on the Giantcod website with regards to their actual comfort zone. It means using a physically larger controller than if it were a Jeti, but in these models that isn;t a problem.

[2.4G Shaun]

Hi Brian,

Hang on a mo, are we talking about the leads plugged into the receiver here? Only in my post I was referrring to the main battery to ESC leads, rather than the signal, positive+negative lead plugged in on extension leads.

When the battery - esc leads are extended, it's usually necessary to extend the esc - rx lead.
A high voltage pulse in the battery lead can induce a pulse in the long rx lead and can cause damage.. Similar principle to that of a transformer.

Thats why it's always good practice not to route any servo / esc leads parallel and in close proximity to the battery - esc cables.

I'll post some piccies  asap of my new 2.3mtr Catalina flying with the Jeti esc's in the nacells...I'll put my money where my mouth is...Just need to finish detailing the finish...

On that subject, is it me or has profilm / Spectra paints, undercoat, primoil shot up in price recently..Just spent £65.00  and I still need to get the stars and bars cut in Vinyl and buy some permament markers for the panel lines. 

Sorry Giles..we seem to have hijacked your post.....Have you any picks of your cat....Its probably may favourite wartime plane (with the exception of the DC3 and Stuka, JU 52 Trimotor and ME323 Gigant...Still need to decide on the Stuka but I've got  all the others waiting to be built...Still what it's just cost to finish the Cat, I may need to sell a kidney 

Shaun

[Ron van Sommeren]

... Over the years the idea that long battery leads can cause damage, keeps rearing its head ...

Shaun, all manufacturers say the same, don't extend battery wires. I compiled their statements. Also workarounds, rules of thumb, manuals, backgrounds in this post:
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long battery wires will kill ESC - RC Groups

You may not have run into trouble for two reasons:
* you fly WOT most of the time
* your ESC has ample input capacitor(s)

... make sure they are amply rated ...

About de-rating controllers, starting at 'for everyone else':
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Scorpion Motors:  Questions and Answers.... - Page 290 - RC Groups

(Why don't the manufacturers/sellers do the de-rating for us ? )

...  have a suficiently large heatsink on to dissipate any heat ...

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Welcome to Mgm-compro.com | MGM Compro - Electronics for Models

-> tech. info
-> controller cooling (Acrobat pdf file)

Prettig weekend Ron

[2.4G Shaun]

Hi Ron,

as I said previously , theory is great...
trouble is practical experience  wins out every time...10 years of doing it with no problems  and not flying WOT but...very big but as you said most reasonably modern and not cheap and nasty esc's have big capacitiors to stop sparking problems..Early esc's could suffer from this.

Have you actually run modern esc's in the way I have and had problems or have you only read about it and taken on board the manufacturers advice......

The beauty of forums is you can find out what other people have done and choose to try it yourself or ignore it.....

My experience to date has only been good....

Cheers,

Shaun

[Ron van Sommeren]

I don't fly, never flew electric, I just compile information

Prettig weekend Ron

[2.4G Shaun]

There you go Ron.....

I've got the 10 year old  T-Shirt....

To be fair the manufacturers try to limit potential problems..they have to offer advice based on the lowest common denominator of  user experience and worst possible scenario .

Using a soft start option wherever possible is always preferable...it's electronically kinder to the esc than slamming it wide open..

Modern Esc's  have large caps across the input terminals to stop this problem.

Long motor leads can also lead to potential problems with the motors getting out of phase, not revving properly or have trouble starting ..

There is a lot to be said for a petrol engine...I still hate cleaning the gunk off my models though, ( even though it's a lot  less on petrol then glow)

Shaun

[PDR]

Well as one who has actually measured the back-emf pulses in battery leads I would have to disagree. I was asked to perform precisely this experiment by an importer last year, because he was being sued by a customer for the cost of four £90 speed controllers (plus consequential damage) that he had fitted into a TN Lanc (the big one). He'd fitted the controllers adjacent to the motors and put the batteries in the bomb bay. 30 seconds into the first flight two of the controllers failed within a couple of seconds of eachother, and the remaining two failed (again within a couple of seconds of eachother) about 10 seonds later as he tried to bring it back. Unfortunately the model went into trees and was a complete write off, damaging several servos and the Rx as well - the customer was claiming a total of £1200.

The instructions supplied with the controllers stated "max battery to lead length 200mm", but the user had used lead lengths of between 800 and 1400mm.

The importer gave me four controllers - one of the original type (a "blue chip" brand, one of another "high cost" brand (Jeti) plus two "budget" ones. All were rated at over 60A, with the budget ones being 100A ratings in deference to their suppliers' advice that they be derated. The tests were conducted at 24v into the controllers using a lead-acid car battery (because I didn't want to wreck a perfectly good lipo should anything fail short-circuit), ramping up to 55A for the tests using an Axi 4120/18 driving a 14-8 prop as the load. Lead lengths from 2000mm to 200mm were used, in 200mm increments plus a few other lengths.

The initial tests were exploratory, setting a notional voltage limit of 100v and finding the shortest lead length at which this voltage was not exceeded at half throttle (starting with the longest lead, testing each controller and then cutting the leads down for the next group of tests - I went through a lot of solder that day!).

It is interesting to note that the observed back-emf pulses were essentially identical with all four controllers, indicating that they all had pretty similar input capacitance. This would suggest that their ability to withstand back-emf pulses was solely down to the characteristics of the MOSFETs used. Tests were observed by the importer and the customer.

From the initial tests we discovered that the longest length at which the back-emf pulses remained below 100v** was around 250-270mm. By inserting additional capacitors we found we could extend this to 500mm and 1000mm, but above that we started getting ringing in the cables so we stopped. We also found that with the additional capacitors fitted there was ringing in the cables if they were short - ie a specific level of capacitance only worked over a specific cable length.

Extended motor runs were then perfomed using each controller at 55Amps for five minutes, demonstrating that the controllers were able to drive the load on 200mm cables.

On the basis of these findings the importer then suggested we try a durability test "to destruction if necessary" with the cables at 800mm and no capacitors. An initial test found that at 55A in this configuration the 1msec pulsewidth was at 430volts. We proceeded to run the test and after 74 seconds (on the original blue-chip controller) the controller vented smoke and died. We then switched to 1400mm cables and repeated the test with the Jeti controller; the pulse voltage was over 700volts and the controller expired after 18 seconds. The tests were repeated with the two budget controllers (one at each cable length) giving numbers of 43 and 14 seconds respectively.

After witnessing the tests the customer withdrew his claim. As a gesture of goodwill the importer decided not to bill the customer for the cost of the controllers consumed, and I then felt that I had to waive my previously agreed fee for the four hours of work 

Now every installation is different, and the cable inductance may have bigger effects in some installations than others which is probably why many people have reported "getting away with it". But the 200mm figure is stated by the manufacturers for good reasons, and if you elect to ignore it you're on your own!

£0.02 supplied, YMMV,

PDR

**EMF pulses are not "square"; they are a sharp-edge followed by a decay. Based on advice from the EMH engineer at the office we set this threshold as "the point at which the pulse was above 100v for 1msec" because apparently a 1msec pulse was long enough to damage a MOSFET

[leccyflyer]

Nice analysis and testing programme Peter and very interesting results.

[PDR]

Nice analysis and testing programme Peter and very interesting results.

I would have reported it at the time but the importer asked for it to be kept private until the dust had settled (because the customer didn't exactly acquiesce gracefuly at the time).

PDR

[2.4G Shaun]

PDR...Interesting info / testing but whilst I  fully appreciate you managed to  destroy 4 esc's this is hardly a representative test ,that everybody should base their installs on. As you mentioned, the manner of the installation from model to model will have an effect on the results, If you twist the power leads and use a ferrite ring  this will effect the results, the quality of components used in the esc's will affect the results etc.etc ad infinitum. Your test didn't replicate a real life install / situation unless I have missunderstood in the testing carried out.

Even though it isn't recommended, a group of rebel lekky fliers have been pushing the envelope for a long time.

 I have never extended the leads by more than 500mm though,  I have never blown up an esc or have any of my flying mates who do exactly the same...so where does this leave us...Either I'm lying and haven't been doing this for the past 10 years , logged hundreds of hours flying and it's all the fault of the evil monkey in my head.



PS... as soon as I have chance I will post flying pictures of 4  x twin powered  models  of mine with the esc's in the nacelles flying  not frying and even worse...I didn't disconnect the bec's  they both work fine in parallel ..no problem, even though they say it can't be done.

Off to do some more buildiing now....

Shaun

[PDR]

If you feel it's agreesive Shaun then I suppose I appologise. But you are making some very strong assertions on the basis of which you are advising other people to risk their cash and their models by ignoring the guidence given by the suppliers and manufacturers of the products. I am merely reporting the results of controlled experiments in a manner that is equally ...err... "assertive". Yes, people have ignored this kind of advice and gotten away with it, just as people have ignored the advice and successfully dribven home after drinking 8 pints of Old Scroggett's Nectar. But that doesn't really mean that everyone would be well advised to do either.

The experiments in question were done to represent a specific installation on the basis that the results may have had to be used in a court, but the experiments showed the correleation between lead length (actually lead inductance) and stressing of the MOSFETs. If you run the results of the tests at (say) 350mm lead length through a Mil-217-based stress-screening analysis like PARTSTRESS you'll find the predicted MTBF of the MOSFETs drops by around 80-85%. Now whilst I place very little faith in the absolute values predicted by 217F methods, the trends are generally very representative.

Finally, on a point of order, configuring the *power* leads of a high-current setup won't reduce the threat to the MOSFETs - if anything it will increase it because it will marginally increase the mutual inductance of the cables. You are confusing two issues - inductive pickup causes interference, but the voltage levels of the induced currents are at the milli-volt level in low-impedance circuits like the power feeds (they are only significant in the high impedance circuits elsewhere in receivers and speed controllers) so they represent no threat to the MOSFETs at all. They can cause glitching, but they can't "damage" anything. The thing that does the damage is the inductance of the cables and the way it interacts with the high-current switching circuits.

This isn't a matter of not allowing anyone else to have an opinion; it's simply correcting errors of fact.

PDR

[2.4G Shaun]

OK.. accepting all you have said, how can you explain 10 years of problem free usage of esc's in this way by a number of flyers in our group...no vapourised esc's, no wrecked rx's

Theory and practice....the practice works...

On a point of order  all I stated was that my and the experience of others contradicts the theory you have posted.... that is the undeniable fact....Theory may say no  but....we have proved otherwise...Viewers of the post can make up their own minds as to whether or not, they choose to try this  .


Shaun

[leccyflyer]

The bottom line here is that PDR posted hard, real world data on a well thought out test, which essentially confirms, in a measureable and measured fashion, the phenomenon that the ESC manufacturers warn against. Others have posted comments and concers and indications and contra-indications around the issue, which has provided opinion and anectdotal evidence on the occurence of such problems in the real world, as well as the theory behind that.

The information is all there for the reader to make up their own mind and to weigh up the experimental evidence of an event that did occur and was measured, versus events that did not occur.