ESC

[60wattParticipant @60watt]

I didn’t have you in mind till I saw a post of yours in the afternoon.

I spent Wednesday afternoon in the company a dozen 80 year old men with model boats so I don’t actually look down on anyone with a natural fixation.

Of the more dangerous variety scratch Me,Jimbo,,Vinnie,Lee and Ashley from the list of possibles but Vinnie has already made the grade.

Does that help?

There’s a third category I didn’t mention,but I take strong meds which enables me to keep things in perspective.

Tom

[jimbo68Participant @jimbo68]

hello ev1, hello 60watt,

just got in – PMSL- I used to take strong meds too, but after 24 yrs I got off em, I found I was havin pops at people who didn’t know as much as me and they made me a bit cranky.

Anyway, thanks for  that explanation, I will study it when I have time, it’s very simplistic and I’m sure I wll have a better understanding, the way I am reading it at the moment, It wasn’t a reverse current probably due to it getting wet, like the bloke who used to make em from AsTec told me, that nacked it, It was a design fault because it should have it’s own heatsink, not be bolted to one ? Or how the set-up is, the bec should be cut out (single red wire on ESC) and the reciever should have it’s own power source via 4 pencell batteries ?

[Penny LeeParticipant @pennylee76979]

Jimbo,

Heres my blow by blow account for what its worth.

• Yesterday morning I had a hunch about what was causing your speed control to run hot and suggested you check it out with a finger test. That source of heat occurs at high voltage but it can be avoided and you could therefore stuff the speed control in a box with an extra battery.

• You asked "why" ,so I gave you why and how in 2 sentences after midnight,citing instructions.

• Tom said to do the same thing as me and gave you an additional reason to do so.

• I’m not 100% what your post was about this morning but Tom took it upon himself to explain in detail with heat calculations.

I understood those figures becuse I use those components and have to do heatsink calculations myself in electronic sub-assemblies.

I don’t know if you are operating the speed control in the way he suggests but if you are then the heatsink is definitely not big enough to run on 12 volts and a motor at more than a few amps.I’ve seen one of these Astec speed controllers.

  My friend once asked me to look at it and find why it suddenly worked in reverse in the middle of a sail.I found the neutral point had shifted or reset itself and also heard of other instances but that is not relevant here as that sorts itself when you remove and re apply the power.

I can see Tom’s figures cooking the speed control at moderate motor drain. If temperature cutout is absent from the drive then the design would be prone to failure due to overheating on 12 volt bec.The multi cell (12-20 NiCds) racing crowd all use speed controls with water cooling and thermal protection and the 20 cell class use miniature receiver batteries.

Regards

Lee Penny

[jimbo68Participant @jimbo68]

ok Lee, so am I to understand that running the boat as it is will eventually fry the FET again ? and If I want to avoid this I should disable the b.e.c ?

And was all the hot air  you mentioned the fact that it wasn’t water that did it but not having a large enough heatsink?

[jimbo68Participant @jimbo68]

One more thing plz Lee,

 is the heat problem the fact that the esc is also powering the receiver, and by disabling the bec the 5 volts that are needed to run the receiver are ‘eliminated’ from the amount going through the esc, causing it to run cooler and therefore protecting the FET. You can tell me if I’m not even in the same ball park. It won’t hurt.

[jimbo68Participant @jimbo68]

oh come on, the suspence is killing me, I’m nearly if not there aren’t I

[Penny LeeParticipant @pennylee76979]

jimbo68 wrote (see)

ok Lee, so am I to understand that running the boat as it is will eventually fry the FET again ? and If I want to avoid this I should disable the b.e.c ?

And was all the hot air  you mentioned the fact that it wasn’t water that did it but not having a large enough heatsink?

I still don’t know your actual arrangement,Jimbo. It has also been over two years since I laid eyes on one so I can’t even remember how to disable bec in that speed control.I suggest you seek out an instruction sheet or ask the person who did the repair.

All I know is that if you are presently running on 12 volts and Tom’s current figures are right then you will have 4 watts less.If you hold your fingers on a BEC which is giving off 2 watts it will give you a nasty burn.

Your possibly confusing on of Tom’s conclusions as coming from me.I thought you said you had water damage and I’m suggesting you can do a quick check and put in a box if the heatsink stays cool. If not disable bec and try again with a 4 pen cell battery.Tom’s suggestion of reducing drive voltage will have the same effect.

If the finger on the bec test showed the heat came from there and not the FET then the previous posts about astro-physics were proved no better than hot air.

Your second post was bang on but just how bec is disabled is guesswork without instructions.If the speed control works on 2-18 volt it would seem there must be a disable switch or link and you shouldn’t need to remove the red pin from the plug as other controllers require.

Do you have a meter in your car toolkit. If you find the subject other than dull then you can test for yourself

Regards

Lee Penny

[jimbo68Participant @jimbo68]

Dang it, the babies cryin, I have to go, I may have concluded one thing but that has lead to more I need answering, (or steering to the answer which you are so annoyingly good at)  just because I want to know. I have one of those minds.

Thanks Lee, 60watt,

It’s been fun.

[jimbo68Participant @jimbo68]

 So then, (after only managing to sleep for 3hrs thanks to my lovely newborn, and then getting the required amount of nicitotine and caffeine into meself)   

 If the bec can only dissipate 2w and supply 250ma without a heatsink, am I correct then in thinking that the purpose of the heatsink is to allow the bec to dissipate more watts so that it will supply more amps ? Because if things like this heat up the output goes down (maybe like what Mike was saying about). ??? And it has to supply 500ma

And is the job of a bec, say like on my boat which supplies 12v (from 2 6v batteries) to only allow 5v through it  ? (a bit like a fuse on a plug) and so the remaing 7v converts to heat, has to go somewhere to avoid the bec turning to fag ash – and thats where the heatsink comes in. ???

[jimbo68Participant @jimbo68]

woooaahhhhhh, scratch that !!!!

I am having a rethink

[jimbo68Participant @jimbo68]

You are saying the esc has been running at 12v and it should only be 5v, after re-reading your bit mike that would mean the heat from the extra voltage has caused the resistance to drop which will allow more current and in the end too much. (would it be like a snowball effect  or would it reach a peak which over time would fry it). Even at 5v at heatsink is necassary.

And so a heatsink isn’t to draw general heat away from the whole unit (which is what I thought it was).

THATS IT !! send me some meds 60watt. I could use em. Why without a heatsink can it only supply 1/4 amps – aaarrrghhhhhhhh !!!!! 

[jimbo68Participant @jimbo68]

And now I’ve started posting to myself

[jimbo68Participant @jimbo68]

[jimbo68Participant @jimbo68]

I’ve had another look at the HFR15 page on AsTec, I looked at it a week or so ago when all I knew about radio controll was that when you turn a vehicle on then turn the handset on, the sticks make the vehicle move.  And I can see that this esc needs the bec disconnecting if you are using receiver batteries or the supply is under 6 or over 14v. Which it is neither of these things. It is designed to take a 12v supply and should be fine.

So when I get it back (tomorrow hopefully) I dont think I will get my fingers burned and I do think I can put it in a box with some venting ( probably a rubbermaid box, now I know why you were thinking of Anne Summers you dirty dawg, vinnie ) and I do think this all started coz it got wet.

We shall see.

Granted, you have all had to go off my limited explanations but I was completely in the dark. And I have been fumbling around trying to give the best information I could so you all would have a reasonable chance of helping with this. And also deciphering all your jargon and technical twoddle so I could have some sort of knats arse chance of knowing what your’e all goin on about. It is all out of my curiousness and willingness to find out about these things. So that maybe I could be in your shoes one day helping some poor ignoramous who took his boat out in the rain and then it didn’t work. (for example  )

 60watts little lesson I was very grateful for and almost wish he had give it on day one, but if he had we wouldn’t be here now. And don’t get me wrong, I am not poopooing anyone,  none of you have had the thing in your hands and you have all been brilliant (and very funny too).

If anyone still would, would they point out and correct my mistakes in the posts I did at around 5 – 6 this morning.  And maybe you  would all be safer if you give me any more puzzles ? I don’ know.

Anyway, If anyone still even cares I will see when it gets here.

Phewwwwwwww

Jim

[Mike DavidsonParticipant @mikedavidson22772]

Just a quick look at basics Jimbo, With any speed controller, the principle can be seen in the so-called manual units where a wire wound resistor is inserted between the battery and the motor,  so, using your  digital thermal sensor described by Penny Lee, Run your motor at low speed for a short whileand note the temperature in the resistor, then repeat the test with high speed selected , my guess is that with slow speed selected, the resistor will be hottest because the resistor is "losing a lot of battery voltage because using the IVy Watts calculation of Ohms law, the motor supplied with a fraction of its design voltage is going to run slowly drawing a much lower amperageconsequently average power and heat generated will be low. When the speed control is at high, the series resistance will be such that the motor is fed almost all the battery voltage causing it to run hard drawing loads of current making shedloads of heat I think Paul had his finger on the button when he suggested importing some of that nice cool pondwater to help in this, so your ESC heatsinks need to be in contact with the water no matter how tentatively, and a good ally in this respect is the thermopath paste used on transistor heatsinks in audio circuitsThat or silicone grease both have a similar functionin transferring heat from one conductor to another and cooling the fevered brow of a device working too hard. I suggest a few  experiments where you run a test knowing all the facts, and testing the results clearly knowing what you are looking at and why. write down the results for further examination, and then you can tell us exactly what’s wrong

[ashley needhamParticipant @ashleyneedham69188]

Its good this, the original post was about gear getting wet, and we seem to writing a doctorate thesis on electronics for boats.  Its the fat controllers fault for mentioning that over heating MAY be a problem if the ESC is boxed in.  Overheating was never an issue as far as I can make out ???    Doh !

 Ashley

[Mike DavidsonParticipant @mikedavidson22772]

   Well JimboI have been trawling the memory banks for an occurrence in my past that I can draw on to help you, and reading all your posts again brought a glimmer of hope to my horizon. You said that you were running two lead acid batteries, and I guess that is for propulsion and not just ballast as you quippedIf you have them connected in series giving twelve volts, that could be the cause of your problem, try running the boat with just one battery in circuit and use penny Lee’s digital temperature sensor judiciously, it might be that the poor old ESC was washing off more volts than it could handle.Go on mate, give it a try, I’m dying to know what the answer is

YY

[jimbo68Participant @jimbo68]

lol, yes the batteries are also for propulsion Mike, I had to get them coz I couldn’t afford to feed the mouse anymore.  I don’t have temperature sensor, wish I did. Funny you should mention this Mike, I was wondering earlier, can it be possible for one battery to be running the motor and the other just powering the esc, receiver, servo. If it is, how would I know ? Yes, by the wiring, I know, but I don’t think I would know by looking.

Would you like to see Bessie, I could put a snapshot up, Inside an out ?

[jimbo68Participant @jimbo68]

You see, I cant help thinking that because I bought the boat in "perfect working order" and it was for 2 weeks, that it went wrong after it was out in a massive downpour and that nothing was overheating at all. Something shorted out because it got wet. And therefore there isn’t any problem really with the way the boat runs. The boat works as it should. I think I have said this before. But like I said I will know when it gets here and I run it for a while, see how hot it is actually getting.

Hang on in there Mike, not long now (Bloody thing)

Ashley’s right you know.

[Mike DavidsonParticipant @mikedavidson22772]

 Yes Jim it is possible to run seperate power supplies for the motor and radio, I do just that  as a matter of choice  keeping motor brush noise interference well away from the radio  p.s. keep your radio aerial well away from motor power wiring or you could find your precious boat doing unscheduled things, and find the park warden after you because your  boat chased some ducks   Mike   D

[Mike DavidsonParticipant @mikedavidson22772]

    Posting to yourself is not that bad, who is going to argue with you?  It is when you answer them the problem gets worse My recommendationn is read it all, inwardly digest, think about it and do the first thing that comes into your mind.Model boats are complicated,and wind you  up to the point where you think a bonfire is the only answer, just remember, that’s what girls are for.

[jimbo68Participant @jimbo68]

lol thanks Mike I know what you mean 

It got here this morning and It works like a dream   ( hurrah ). And at the moment thats all I care about lol. Can’t wait to terrorise the local duck population again. Think that’s what I’ll do tomorrow !! (joke – it’s impossible at 3 m/s, I have to try and outrun them lol)

Big Bessie’s back – she’s BAAACK lol

[jimbo68Participant @jimbo68]

oh yeah, I know girls are annoying but isn’t throwing them on a bonfire a bit extreme Mike ??? 

[jimbo68Participant @jimbo68]

Don’t tell me, not if it’s cold ?  

[Mike DavidsonParticipant @mikedavidson22772]

GOOD NEWS everybody, there is a new magazine out advertised on television today.The magazine is called Bait Boat, and comes with a free complete bait boatwith the first year’s issuesSo Ashley if you don’t know what a bait boat is, read and inwardly digestand Jimbo, now is your chance , the boat they are giving away looks a bit like a lancaster bomber with great big bomb bay doors that open to release the bait

Enjoy

           Mike    D

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