JBWeld to seal up an ESC?

[785boats]

I've been using the HiModel GX 200A ESCs for years. Also the 4-8s version & I always use the internal BEC. Never blown one yet. Had the brains board fail on one & won't accept programing , but that's all.
Mind you mainly on 4s & with an Amp draw around the 80-130 Amps, but in all sorts of boats. But they are the only ESC I use.
I think you will need to remove the cooling plate & you will see that the tape is probably only touching 2 0r 3 fets.
the fets need to be filed flush & a proper heat transfer paste used. I also make my cooling plates but I put 3 cross holes in them for extra cooling.

Have a read through this & it might explain things a bit better.

http://www.rcgroups.com/forums/showthread.php?t=1274741

cheers.
Paul.

[FighterCat57]

Thanks for the link!

Hmm.. I actually went with the opto because it didn't have a BEC and would hopefully produce less heat...

I did add the paste (CPU heat sink grease) and made sure to get good contact with all the fets..

I also sprayed them with conformal coating and checked the coating under UV light. (neat stuff)


I'm running 6s and likely to pull 100 amps or more.

[785boats]

BECs creating high heat is an old fear left over from when a BEC was a voltage 'regulator'. Now a days the BEC is a voltage 'switching unit' in most ESCs.
They don't create anywhere near the heat that the old 'regulator' circuit did.
But beware. Some modern ESCs still use the old regulator circuits. Thankfully the HiModel (Suppo) range is not one of them. I've run them on 6s with no problem.

If you sprayed conformal coating over the FETs you have basically insulated them from the cooling plate.
You NEED to file that stuff off the FETS before adding the grease & plate.
Cheers.
Paul.

[FighterCat57]

BECs creating high heat is an old fear left over from when a BEC was a voltage 'regulator'. Now a days the BEC is a voltage 'switching unit' in most ESCs.
They don't create anywhere near the heat that the old 'regulator' circuit did.
But beware. Some modern ESCs still use the old regulator circuits. Thankfully the HiModel (Suppo) range is not one of them. I've run them on 6s with no problem.

If you sprayed conformal coating over the FETs you have basically insulated them from the cooling plate.
You NEED to file that stuff off the FETS before adding the grease & plate.
Cheers.
Paul.

Aw dammit. I totally over looked the thermal properties of the conformal coating.

OK, I'm going to start by filing down the fets so they are even, then thermal grease the Cooling Plate to the FETS...

[domwilson]

I wouldn't file. It may chip an FET. Block sand with 400 grit or higher.

[FighterCat57]

What do those esc's cost?

They are like $40.

But with all this messing around required... and one already dead on the bench...

I just wanted to give them a try first hand.

[FighterCat57]

I wouldn't file. It may chip an FET. Block sand with 400 grit or higher.

Well, I used 250, but it worked quite well.

BECs creating high heat is an old fear left over from when a BEC was a voltage 'regulator'. Now a days the BEC is a voltage 'switching unit' in most ESCs.
They don't create anywhere near the heat that the old 'regulator' circuit did.
But beware. Some modern ESCs still use the old regulator circuits. Thankfully the HiModel (Suppo) range is not one of them. I've run them on 6s with no problem.

If you sprayed conformal coating over the FETs you have basically insulated them from the cooling plate.
You NEED to file that stuff off the FETS before adding the grease & plate.
Cheers.
Paul.

Filed off, smooth and greased up. Made sure the block was sitting flat on the fets and each one left a square mark in the cooling block. Thanks!

Caution, JB weld is slightly conductive so it is not advised to seal electronics.

Sounds like you need thermal grease to conduct the heat away from the fets. The main problem I see with this controller is that you can only cool one level of fets. All the others an inaccessible. These tightly packaged controllers are really only good for short bursts like SAW's or plylon planes.

Use cautiously for sustained use.

TG

That's the biggest concern. The cooling block has been low temp, but the bottom of the ESC has been getting hot. Doesn't look like there's a way to cool off the middle.

I was thinking JB Weld had some thermal conductive properties to exploit, but if it has residual conductivity, probably a bad idea. Thermal epoxy might help dissipate heat, but at $12 an ounce...

Think I'm going to put this ESC on light duty and go back to either the Hydra 240 or the Seaking 180.

Thanks for all the input/help guys!

[NativePaul]

i beleive the suppo and the himodel 200a 4-8s bec are the exact same

All the ESCs I listed above are either made by Suppo or made from kits made by Suppo the skywing, mystery and HiModel are exactly the same apart from the heatsinks and heatshrink,the ETTIs are of a slightly different mainboard design to accommodate the caps that they wanted, are conformally coated and have the etti watercooled heatsink but as chances have it the ETTI cooler fits the other suppo ESCs perfectly if you dont fancy making your own cooler and if your Suppo didn't come with instructions as my mystery and skywing didn't you can use the ETTI instructions to program them. The Himodels have instructions which are essentially the same but ETTI have a better translation and make are a little easier to follow.

[785boats]

FighterCat 57
I would say the reason the ESC was feeling hot on the brainsboard side is that the cooling block wasn't taking any (or at least very little) heat away from the fets because of the insulating effects of the conformal coating on them. It's the heat radiating through the ESC you are feeling.

It should feel cooler now that you've fixed that.
But the two extra cross holes in the plate (shown in that link), make a world of difference too. Brought the temps down from roughly 50C to around 40-42C on the same setup in the same boat doing the same number of laps. But on second thoughts a large proportion of that could have been the leveling of the FETS too.
Anyhow, it all helps keep things cool.
All the best.
Paul

[FighterCat57]

FighterCat 57
I would say the reason the ESC was feeling hot on the brainsboard side is that the cooling block wasn't taking any (or at least very little) heat away from the fets because of the insulating effects of the conformal coating on them. It's the heat radiating through the ESC you are feeling.

It should feel cooler now that you've fixed that.
But the two extra cross holes in the plate (shown in that link), make a world of difference too. Brought the temps down from roughly 50C to around 40-42C on the same setup in the same boat doing the same number of laps. But on second thoughts a large proportion of that could have been the leveling of the FETS too.
Anyhow, it all helps keep things cool.
All the best.
Paul

Thanks Paul, I'm really hoping so. Just put it all back together and back in the boat. Going to give it a shot tomorrow.

Benjamin

[FighterCat57]

While we're on this subject, I'll bring this up...


I was thinking about cutting out a rectangle in the belly of the hull and mounting the ESC cooling plate in that hole. That way it would get air, splash and direct water at a stand still. If I made an aluminum plate with a channel around it, I could countersink it flush. Similar to mounting the bottom of the hull water pickups.

Anyone ever try this? It seems very logical.

[m4a1usr]

FighterCat 57
I would say the reason the ESC was feeling hot on the brainsboard side is that the cooling block wasn't taking any (or at least very little) heat away from the fets because of the insulating effects of the conformal coating on them.

Thats true for an epoxy or 2 part mix encapsulation. Where you cannot control its film coverage. Spray coatings, such as the MG Chemicals or similar, are so thin in application (less then 1/10th thickness of a human hair!) seal appropriately and have literaly no insulation value. Yeah,.......you can goto the makers web site and find the data but for all intent and purpose, most sprays do not have such thermal insulating effects on the FET's. Thats why you see manufacturers using it to water proof their speedos. They dont bother to cover their FET's when applying.

John

[FighterCat57]

Add a huge cap to the esc, radio shack sells a 4700 or 5700uf 35v caps for about 5 bucks each, it greatly reduces the heat in the controller

4700uF, I have some on the way. I'm also adding a 470ohm resistor for anti-spark.

Going to experiment with the extra cap and anti-spark on this ESC.

[LarrysDrifter]

While we're on this subject, I'll bring this up...


I was thinking about cutting out a rectangle in the belly of the hull and mounting the ESC cooling plate in that hole. That way it would get air, splash and direct water at a stand still. If I made an aluminum plate with a channel around it, I could countersink it flush. Similar to mounting the bottom of the hull water pickups.

Anyone ever try this? It seems very logical.

Never tried or thought about it.I think it would work good in a cat near the rear of the hull.Maybe this would work a little easier:
Mount your flat aluminum cooling plate on top of the esc then put a heat sink with somewhere near 1/2" fins on the bottom.Let the fins be the only part "hanging" down from the hull.Face it so the fins are parallel with the sponsons.It may cause a little drag,but not enough to cause concern with speed loss.That way,you ll get air and water always passing though the fins.I mite have to fashion my broke EKOS hull together to try this one.

[FighterCat57]

Never tried or thought about it.I think it would work good in a cat near the rear of the hull.Maybe this would work a little easier:
Mount your flat aluminum cooling plate on top of the esc then put a heat sink with somewhere near 1/2" fins on the bottom.Let the fins be the only part "hanging" down from the hull.Face it so the fins are parallel with the sponsons.It may cause a little drag,but not enough to cause concern with speed loss.That way,you ll get air and water always passing though the fins.I mite have to fashion my broke EKOS hull together to try this one.

I have a flat plate off of a PC HDD cooler I was thinking about using. I was also thinking about mounting the ESC air cooling block in the hatch cover. It just seems too good to pass up all that air and water when the boat is stationary. That way it would actually get a cool down when you stop, rather than build up heat due to lack of water flow.