advice needed

[brian sharpParticipant @briansharp62833]

Hi there i wonder if some of you could give me some feed back. I bought a watercooled esc which said it was for boats. When it arrived the circuit board was in a heatshrink wrap open at both ends. I sealed the ends with silicon to make it perfectly watertight as if a splash got in we all know the result!!

Well bless me it went wrong after five runs of about four to eight minutes each so total time less than an hour.

I contacted the supplier and surprise suprise no warranty as i put the silicon on it.

Well my attitude towards this is if it was a boat esc it should have been made waterproof completely in the first place.

Whilst I agree I altered it, was it sold under a false description ie boat esc which wasn't fully protected?

Look forward to your comments.

[brian sharpParticipant @briansharp62833]

esc

[Paul TParticipant @pault84577]

Can you tell us which esc you are talking about?

[brian sharpParticipant @briansharp62833]

hi there,thanks for your interest it is sold as ************ 150amp boat esc.

I don't wish to give the name at the moment as I am awaiting a reply from the supplier

[Paul TParticipant @pault84577]

Fair enough Brian but please understand that without knowing exactly what we are talking about you can't really expect us to provide the comments that you have asked for.

Paul

[neil hpParticipant @neilhp]

as far as I am aware…..none of the esc's that I have ever used, and those include robbe 200, mtronic's viper and best of all electronize, have ever been waterproof, and sadly if the esc has been "modified" the way that you have done, I can quite understand the supplier negating the warranty….sorry, but just like a TV, video or any electronic piece of equipmentyou start messing with it, even so much as taking a screw out the back of it…..that nulifies the warranty.

[brian sharpParticipant @briansharp62833]

hi NPH yes that is not in dispute that i sealed the end etc but surely a ESC that has been sold as a boat ESC should be fully protected from the adverse conditions it is expected to work in? Thanks for your interest.

[Colin BishopModerator @colinbishop34627]

Well radio gear, receivers and servos are not usually expected to be 100% waterproof in themselves so why should speed controllers differ? The usual assumption is that the builder will install the equipment in such a way as to preclude it from getting wet in normal sailing circumstances. Obviously if the boat should sink then all bets are off!

Colin

[DANIEL MORGANParticipant @danielmorgan23794]

i disagree brian

electronize which are sold as boat esc are not waterproof

microgyros esc also sold in heat shrink type sleeve open at both ends not waterproof

microgyros were on sale at waarwick boat show lots were sold

also ive been told that if you seal the ends they will pack up as heat needs to escape how true this is

i dont now ive used many many differant esc and dont think ive ever come across one thatss

100% waterproof even mtroniks are not 100% ie submersable as water gets in around the set button splash proof yes

hope this helps

[brian sharpParticipant @briansharp62833]

Thank you everyone for all your input, out of interest Perkins sell a similar item ie ESC in shrinkwrap sleeve with the ends sealed in white silicone so with water cooling I don't think heat is a problem, I have also noticed that some sealed ESC's have the ends of the circuit board exposed which could lead to problems, and I have also noticed that some are completely sealed in alloy cases and these say 'water proof' so all very interesting

[Paul TParticipant @pault84577]

Hello Brian

I have used an alloy clad waterproof esc with great effect by mounting the unit on the outside of the hull so I agree that the term 'waterproof' is very important, I have also done what you have done by sealing a plastic clad unit with silicon (and failed) I can't comment on your unit only to agree with what Neil has said about changes.

With this forum you have access to some of the best model boat builders and also the best advice available but without knowing which esc you are talking about we can only speculate on your problem.

Paul

[ashley needhamParticipant @ashleyneedham69188]

Are we getting ahead of ourselves here?? the first post said "watercooled" and not "waterproof", wot are different animals. Watercooled is just that, not waterrproof……was it sold as waterproof or simply watercooled?

This shrink wrap format is common for car and aircraft ESC`s and is simply to keep the bits together. .

Water should not be getting to the ESC in the first place, and a box or something to put it in may be better. I would not have that much (possible) water in my boats..and would not be worried that anything wasnt waterproof.

Ashley

[Paul TParticipant @pault84577]

Ashley

As usual you have injected a note of caution.

But the question still remains that without chucking it in the wet stuff how else would you water cool a esc?

Paul

[ashley needhamParticipant @ashleyneedham69188]

One side of these ESC`s are flat, and they hold a hollow plate to them (via the heat shrink wrap) this has a water inlet/outlet…..so the esc is in contact with cooled plate.

Graupner sell them., water cooled heatsink for esc`s. about 8 quid.

Ashley

[Dave MilbournParticipant @davemilbourn48782]

Brian

I think in all fairness that you are over-reacting a touch ref the water-proof requirements of model boat electronics. You are, after all, intending the model to float and to run with the water on the outside of the hull! If a speed controller has water-cooling pipes then make sure that the flexible pipes you use to connect them to the scoop and outlet are a good tight fit. Also ensure there is a decent coaming all round the radio access "hole" in the deck, and don't mount anything electrical directly onto the bottom of the hull. It's only common sense.

If you are really intent on having fully waterproofed ESCs, servos and receivers then you are going to have a hard time buying equipment. None of our ESCs are waterproof and yet I can't recall having to fix any with water-damage, save those which had been fully submerged when the model sank (and that's maybe half a dozen in five years). Trust me – if you really feel that you need that level of protection then you've clearly little confidence in your building ability.

As regards speed controllers sold with ridiculous claims for continuous current rating (e.g. 150Amps), my only comment would be that sometimes you don't get what you pay for. Buy cheap = buy twice. Silicone? If I had a speed controller sent back which was slathered in this crud then I wouldn’t be able to work on it – warranty or not – so please don't do it.

Dave M

Edited By Dave Milbourn on 29/05/2012 18:44:23

[ashley needhamParticipant @ashleyneedham69188]

I had not thought of it before, but at what sort of operating current would one need to water cool an ESC?? Mr T`s 50A ESC was definately hot to the touch running at about 20A, and would no doubt get even hotter if left to its own devices, so realising the 50A would be, in my view, impossible without it, or at least full fan cooling.

All my model are low-ish powered. Even the Fantome and Seahawk only take probably 12A max, and the ESC`s run warm to fairly warm, but no more. The Viper ESCs I have can be stuck on a spike and so be well ventilated, by virtue of being in free air.

Dave, at what sort of current do your excellent ESC`s run to and would they need more than "standard" ventilation to keep cool?

Ashley

[Colin BishopModerator @colinbishop34627]

I've always taken the line that unless you are going for ultimate speed regardless then the need for any sort of cooling is an indication of inefficiency in the setup. Heat is simply wasted battery power that would be better employed in driving the boat through the water.

Colin

[ashley needhamParticipant @ashleyneedham69188]

Colin, indeed, but it still remains that a, say, 20A ESC is not REALLY a 20A ESC as it would overheat at,say, 18A continuous in an enclosed hull with only minimal ventilation? would you say? or not.

None of mine run any where near their rated maximum, half or less mostly

I dont suppose, thinking about it, that many boats have ANY ventilation worth speaking of, and then the inside just gets warmer and warmer.

Ashley

[Paul TParticipant @pault84577]

One of the problems of running electric motors on my models is weight.

As most of you know my models tend to be on the large size and so need quite a bit of power to move them and even at moderate speeds the esc's do build up some heat, I have tried fans and ducting to move cooling air through the hulls with only moderate success so water cooling does have its attractions.

Paul

[Dave MilbournParticipant @davemilbourn48782]

Dave, at what sort of current do your excellent ESC`s run to and would they need more than "standard" ventilation to keep cool?

Ashley

They go from 1A (P68A) to 30A+(P98). The rating for each ESC is given on the website and price list, and we are quite conservative about these figures. For example, I know that a 20A Condor will run barely warm at 15A with normal ventillation inside a hull. There is provision for water-cooling on the big P98 (which I have run at 30A and 32V) but many users have found that the motor will need cooling before the speed controller fins get warm.

Dave M

[Paul TParticipant @pault84577]

Dave

A serious question from me (for once)

As you know my knowledge of electronics is stuck back in the 70s and my basic rule of speed control is having a fist full of throttle and enough water to avoid the bank so when it comes to esc's I tend to blow them up.

I don't understand how the esc shown below can be water cooled without chucking it in the drink.

It is listed as a water cooled 60amp Boat ESC

Paul

[Trevor HollowayParticipant @trevorholloway99134]

It looks to me that the two brass nipples on the two outer motor wires run through a water holding pad inside the heatshrink.

Thus giving the cooling effect.

[Paul TParticipant @pault84577]

Hi Trevor

Is it as easy as that?

Can such a small area keep the esc cool.

Paul

[ashley needhamParticipant @ashleyneedham69188]

As i said, I believe… Ashley

[Dave MilbournParticipant @davemilbourn48782]

Paul

It depends on several factors:

The difference in temperature between the water and the power FETs;
The rate at which the water flows through the tubes;
The area of contact between the FETs and the water tubes/pad.

Frankly I can't believe that such a minimal effort as this to provide cooling in a (supposedly) 60A ESC would equate to a decent-sized and adequately finned aluminium heat-sink, but I guess the proof of the pudding etc etc. The very best solution would be a physical heat-sink which itself is water-cooled. See Fig #8 here **LINK**

Dave M

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