advice needed

[brian sharpParticipant @briansharp62833]

I agree with the above points 100%.

I had 150a esc and it ran very cool, except for one area where I suspect that was the faulty, (broken) part and that area I could not touch!

The heatsink inside is dependant on touching all the hot parts, if these components are at different heights the heatsink might as well not be there and have air cooling instead ie a fan.

On this particular boat the water came out of the side by about 2 inches at speed and a good dribble at slow speed. I stand to be corrected; on brushless esc's the temperature rises on small openings of the throttle as that is when they are working the hardest, if so, we require more cool water at slow speed than high speed. But as I said I stand to be corrected.

So maybe just don't go down the watercooling path, just make the ESC waterproof.

Brian

[Paul TParticipant @pault84577]

Hi Dave

Thanks for the duffers guide to what should be a simple concept, the problem is that I just can't get my head around the basic principals of esc's, i.e. like how a bunch of electronics with no moving parts can change the speed of a boat.

I guess that I'm just an old fashioned petrol head.

I agree that a direct contact heat sink is the best way to solve my problems (as usual your drawings are superb and easy to understand)

Thanks

Paul

[Dave MilbournParticipant @davemilbourn48782]

Paul

Go and improve your education here **LINK** Note that ESCs for brushless motors don't work like this at all!

Dave M

[Paul TParticipant @pault84577]

Hi Dave

Its a good job that I dont understand brushless motors either

Paul

[brian sharpParticipant @briansharp62833]

Hi there, I did a test on my boat last night, static in water, setup as when the ESC packed up, I was drawing 28.5 amps – 458 watts on four cells lipo. I think the claimed ESC of 150amps must have been WAY OFF (which I don't think it could be over a 100amps out) or it was faulty.

I went to my local hobby boat shop today explained the situation to them and they sold me a Graupner 60a ESC, and said I could block the ends with silicon if I wanted to make it waterproof and it would still carry a guarantee!!. However I have choosen not too, but have placed it high up under the deck and tide the old watercooling jacket to it and it appears to work OK!!

Incidently the boat is perfectly dry inside when taken out of the water, so I'm quite confident in my building skills and also the boats designer who obviously thought over water getting in at speed.

I will let you know how it is still performing after a few more runs.

Brian

[Paul TParticipant @pault84577]

That is good news Brian

I'm glad that your esc problems seem to have been resolved and look forward to seeing your reports on future sailings.

Don't forget that if you have any more problems this forum does have access to some of the best model building brains who will be happy to provide answers.

Given your comments on designers I have to say that some model designers are very good at anticipating problem such as water ingress, for example I'm happy to praise the chap who designed the Huntsman as he seems to have got everything right, if you think about what is involved its just amazing what can be done with doodles on a beer mat

(isn't that right Dave )

 

Paul

 

 

Edited By The Fat Controller on 02/06/2012 07:20:50

[Dave MilbournParticipant @davemilbourn48782]

A fag packet, Paul – but those were carefree days then when cigarettes were actually good for you.

DM

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