Cooling brain fart

**Jeff Wohlt** · 10-09-2009, 04:35 PM

Yes, when I look at my coleman electric cooler I have... most of it is heatsink...but that is for long-term use. If I can get cooling for the first 6 minutes on a board then I would be happy but until I actually hook one up to 12v and feel it I will not know. The bottom side of the ESC board is fine if it warms up but my desire is to keep fets cool from the top.

It may not work and I may be back to my ice water idea. I do know what comes out pretty warm but I also agree that more flow is better and cooler, Ken.

**hyrulejedi86** · 10-09-2009, 10:22 PM

OK, I may be missing something but why not use conventional water cooling, it's constantly being refreshed and the heat won't build in the tank?

**bwells** · 10-09-2009, 10:36 PM

I would assume they are trying to get away from the drag the conventional cooling system causes. I'm seeing added weight so far but I will continue to monitor. Innovation is what founded America!

**Rumdog** · 10-09-2009, 10:42 PM

A pinhole in a rudder is hardly drag. A lot of these guys run in hot climates where the pond water is consistantly 80 degrees or more. That may make it a little harder to keep things cool for sure!

**hyrulejedi86** · 10-09-2009, 10:42 PM

makes sense

**Ken Haines** · 10-09-2009, 11:13 PM

hyrulejedi86,
I do not necessarily need to replace the conventional cooling system, but rather enhance it.
Certainly there are some huge advantages of using the lake as the coolant. My problem in some set-ups is that it is still not keeping things cool enough. Sort of like the combustion engine can operate wth air cooling, but is even better with a radiator typr water cooling system. As some of our hobby is a test bed for other uses of electric power, could we actually dream up something to enhance the cooling on extreme set-ups ? That why this thread to me is so unique. I'm sure we all realize there are a lot of bright minds in FE and on this forum, who knows what we may come up with.
Good question,
Ken

**hyrulejedi86** · 10-09-2009, 11:31 PM

That makes perfect, sense. I guess having kept my personal experiances thus far fairly small I didn't think about it from that point of view.

Well, I certainly wish you the best of luck with it! Ice sounds good though.

**domwilson** · 10-09-2009, 11:39 PM

Originally Posted by pescador

There are also these thermoelectric Peltier coolers they use in aquariums and computers maybe somebody could figure out an application for them.
Keep your water tank cold electrically?

http://shop.ebay.com/i.html?_nkw=pel...1&_from=&_ipg=

The thing about the peltier coolers is that one side will always be hot and the other side will be cold. You reverse the polarity so that you physically don't have to flip the element. Also, how cold they get also depends on the temp of the heated side. Keep that cooler and the cool side will get colder. The way these work is by moving heat from one side of the element to the other. Because of this, my biggest concern would be how to waterproof these so that water would not enter in between the grids. Thought about silicon but not sure how well it would handle the temperature differential.

**Steven Vaccaro** · 10-10-2009, 08:14 AM

Originally Posted by Ken Haines

Hi Steve,
Certainly you are correct on using larger than required motors, ESC, Batteries etc. to lower all the temps, but I'm challenged by the LSO & LSH restrictions. Especially in LSO when a 4 minute run is required. Since we have a spec power system your current options all sacrifice speed. I'm not much for that so I blow up a lot of motors.
I do beleive that we are looking at a chemical coolant ie; freon or ice packs or an efficient electrical cooling system. Maybe someone will have an even better idea. I'm still concerned about the coolant loop volume. Even the water pickup sytems turn the water pretty hot, just feel thewater outlet water on most of your boats when you pull them out of the water. Sometimes than little trickle of water is even hot enogh to sting you. Cooling takes time and if the flow cycle duration is too short the heat transfer will not have time enough to occur. I do not think however that slower flow is the answer either, although some would challenge this physics would not agree with them.
Pardon me everyone I work at a nuclear plant, some of the same cooling theories apply, maybe thats why I'm so interested in this topic. Sorry to geek out !!!
This is good stuff from everyone lets keep this going.
Thanks, Ken

Ken thats the problem with spec classes. Some people have deep enough pockets to continually abuse their equipment. I witnessed a person in n1 mono kill a motor in each heat. if you are going to spec a motor, the prop should also be spec'd. Its the restrictor plate of rc fe boating.

**crabstick** · 10-11-2009, 04:35 PM

Yesterday at racing, one of the guys picked up his whiplash and in the side of the boat where the esc was, there was some heat, which you could feel through the hull I suggested ( as a joke at first ) cutting a hole in the bottom of the boat and putting a piece of alloy plate in the bottom of the hull to act as a closed loop heatsink, It actually doesn't sound like that bad of an idea now.

I have a petrol offshore cat that I run in the sea and I really don't like running salt through the motor that said, I live 300m from the beach and wash the boat down with the hose including flushing the water jackets after each run.After reading Jeffs post about a small tank and pump, if you combine that with a heat exchanger (such as an alloy plate in a ride pad) you have closed loop cooling! and you can even add corrosion inhibitor to the cooling system.

Some SeaDoo 4 stroke jetski's run this system and use the ride plate as the heat exchanger.

I think it would be worthwhile in a boat you run in the sea. Only issue I can see is if the pump fails, you have no tell tale letting you know your cooling is working

**questtek** · 10-11-2009, 06:57 PM

I owned a 50 foot twin Diesel motor yacht years ago that used this technology.....it was called "Keel Cooling". On the bottom of the hull was a finned radiator fabricated from Naval brass, (for lack of a better description) The fresh water and coolant from the engine was a closed loop cycle but was routed through this "Keel Cooler" This way the boat diesel engines, which were GM 671's, never saw salt water. It worked great and I never had a temp or corrosion problem. The Naval brass had a high copper content thus minimized marine fouling. However, the max speed of this boat was about 12 knots or about 14 mph.......a far cry from the current FE speeds!

If you do this as an experiment I would consider using copper plate since the thermal coef. is much higher than aluminum. Drag may be a problem however unless it is faired into the bottom of the hull correctly.

As an alternate, I am currently using a cooling system for my "modestly" fast electrics that involves a "Chill" unit. I took a 35 mm film cnaster and wound inside lots of copper pipe with the inlet and outlet coming thru the top via sealed gromets. I fill the film canaster with water and put it in the freezer. The lake in front of my home is 76 degree sF freh water. I run the water inlet through the pre-frozen copper tubing in the canister and the outlet temp is 20 degrees cooler than the inlet temp. from the lake water.

To verify this, use an Eagle Tree Data logger that has 3 temp thermisters. I have one in the intake line, one in the exhaust line and one after canister cooling. This indeed does verify the temp drop from the "Film Can cooling" Naturally this is only good for several minutes...........but this is the duration of my rund anyway. Consider....there are MUCH better fluids to add to the film canister than water!

Hopefully this will stir some brain cells and the FE wizzards will improve on this concept much more!

**Ken Haines** · 10-12-2009, 12:22 PM

Questtek & Crabstick,
Both of you have great workable ideas these could be used in conjunction with open or closed loop systems. I'm starting work on a new LSO boat. This would be the perfect opportunity to incorporate both ideas. The Heat exchanger and the ice canisters. I will install velcro pads to mount an airplane fuel pump. I'm also going to use a motor mount with the cooling housing and a good cooling motor jacket.
This project could be a month away, but I will give it a try and post my results.
Maybe with all this cooling I can get the extra performance I'm hoping for out of these spec. motors even for a 4 minute offshore race.
I knew we have some brilliant minds here.

Thanks, Ken

**questtek** · 10-12-2009, 12:38 PM

You can count on me for help.....I have all the Eagle Tree monitoring equipment needed. I am working on an option that will solve the heating problems of ESC's that does not involve a pump, fan, Peltier cooler, keel cooler, dry ice or ice canister. I purchased 4 large 200 amp Mystery controllers to test the concept. Will keep the forum posted.......when the ESC's arrive.

**Jeff Wohlt** · 10-12-2009, 01:00 PM

Running cold water thru a coil with fluid around it is a good idea.

If only one layer of fets then the other side of the peltier is warm but water iff we water cooled that side of the unit? :) They do get cold pretty fast but only 40 degrees below ambient temps. Fine with me..plenty cold.

The pump and water may be a much less amp draw though and keep water flowing. I do not worry about water flow stopping with a pump.

How about a small tupperware box sealed and then cooling coils inside. You freeze the tupperware full of water and then just hook up the silicone tubes to it. You can take almost 3 feet and make a cooling coil and then flattend it out. I do think the cold water would be cooler running thru the line and faster. Easy to add a few cubes of ice...I have ice in the cooler when running all the time.

**Rex R** · 10-12-2009, 01:42 PM

if you need more cooling (colder fluid) consider dry ice and alcohol

**domwilson** · 10-12-2009, 02:03 PM

Another alternative... http://en.wikipedia.org/wiki/Heat_pipe

**Ken Haines** · 10-12-2009, 02:24 PM

Any type of tank container with the pre-installed cooling coils surrounded by water.
Keep this cooler velcro mounted so that you can take it right from the freezer to the boat, install it before each run. Have several all made up and frozen and just plug in the newly frozen cooler in for the next run. Even open loop would provide extra cooling.
Ken

**crabstick** · 10-12-2009, 03:44 PM

how about this,

The copper coils mounted to a copper plate that is through the hull

a. flush with a ride pad on a cat
b. flush with the surfaces on a vee.

I guess the main thing is getting the heat exchange plate in contact with water 80% of the time.

I have just sketched up a design of a through hull cooling plate, will transfer it to the pc and upload a bit later

**Jeff Wohlt** · 10-12-2009, 03:47 PM

Good idea, Ken. As long as enough pressure is coming from the rudder water it should work well. Simple and easy and use alum tubing KS. The more tubing the better and I know these are almost 3 feet of alum that I have made for motors.

Better than water>>>>>> break apart or cut the crap in the cooling things from what they sell for coolers (bags or the plastic hard kind and I have both in the freezer now) and put that in the box...it is slimey thick and stays frozen longer that ice.

Need to go to walmart anyway....I will buzz by the tupperware department and there are many other little boxes that can work. Sealing them up forever should be easy.

**sailr** · 10-12-2009, 04:20 PM

Wow! We must dub thee "Keeper of the Smoke" if you get that to work! Can't wait to see more!!

Originally Posted by questtek

You can count on me for help.....I have all the Eagle Tree monitoring equipment needed. I am working on an option that will solve the heating problems of ESC's that does not involve a pump, fan, Peltier cooler, keel cooler, dry ice or ice canister. I purchased 4 large 200 amp Mystery controllers to test the concept. Will keep the forum posted.......when the ESC's arrive.

**questtek** · 10-12-2009, 08:10 PM

Originally Posted by Jeff Wohlt

Good idea, Ken. As long as enough pressure is coming from the rudder water it should work well. Simple and easy and use alum tubing KS. The more tubing the better and I know these are almost 3 feet of alum that I have made for motors.

Better than water>>>>>> break apart or cut the crap in the cooling things from what they sell for coolers (bags or the plastic hard kind and I have both in the freezer now) and put that in the box...it is slimey thick and stays frozen longer that ice.

Need to go to walmart anyway....I will buzz by the tupperware department and there are many other little boxes that can work. Sealing them up forever should be easy.

I am just posting a new thread on ESC cooling...the moderator is reviewing it now. It should help answer all your questions and possibly even provide some helpful suggestions. It is only a start........there lots of improvements that can be made. Proper ESC cooling is a project worth a bit of thought time!

**Jeff Wohlt** · 10-13-2009, 09:15 PM

Well, her eis what I did.

Mini Cooler pack 4 x 2x 1" .97 at walmart

5/32 brass pipe. left over stuff

Silcone tubing...left over stuff

Drilled a bit smaller hole for the pipes and they seem to be sealed without glue at this point...remember, this stuff is thick and not water.

3 pieces of 6" brass.

Will it work....hell if I know but it looks cool!

After frozen I will run it thru the pipes at a maintained water temp and see what it comes out at. Also, we are not looking for fast flow...just a small trickle coming from the exit.

**NorthernBoater** · 10-13-2009, 11:59 PM

I was thinking maybe we could use pass the water tube through a heat sink that has a peltier cooler attached to it. Cool the water before it hits the motor or ESC. An some either put a big heat sink inside the boat or mount the heat sink on the deck of the boat so air can cool it.

**domwilson** · 10-14-2009, 12:06 AM

When funds become available, I plan on purchasing another Himodel 200a ESC. I plan on running a peltier on top of the OSE cooling plate and on that the stock heat sink from a Himodel 200A ESC. I bet that will be cool running ESC.

**Steven Vaccaro** · 10-14-2009, 07:23 AM

Originally Posted by Jeff Wohlt

Well, her eis what I did.

Mini Cooler pack 4 x 2x 1" .97 at walmart

5/32 brass pipe. left over stuff

Silcone tubing...left over stuff

Drilled a bit smaller hole for the pipes and they seem to be sealed without glue at this point...remember, this stuff is thick and not water.

3 pieces of 6" brass.

Will it work....hell if I know but it looks cool!

After frozen I will run it thru the pipes at a maintained water temp and see what it comes out at. Also, we are not looking for fast flow...just a small trickle coming from the exit.

Jeff thats pretty large.

Did you ever see these?

**Jeff Wohlt** · 10-14-2009, 10:01 AM

This was my first attemp and a very easy one, I might add. Took all of 10 minutes to make. I was going to cut it open and slip the coil in and then seal it. It is less than palm size. I will also get a real size...I guessed at that when loooking at it.

It was a concept only but I might put it in my MM today and go run it. I may just take some readings from it as water passes thru and see if it even cools the water....if it can take 80 degree water to 60 I would be happy.

I still think the ice water with small pump is the key. You can turn it on prior to running and continue it even after the run. Ice water can stay cold for some time.

THe peltier is a great option. But you need 12v. The small fuel pump for rc runs on 6 or 12 volt.

Weight is not an issue at this point. It may weight 8 oz...or about the same as a gps I use. This is for bigger setups and boats.

**crabstick** · 10-14-2009, 04:50 PM

I would avoid the Peltier.

I will scan my sketch and upload soon, Ive redesigned my plate...

**norbique** · 10-14-2009, 05:25 PM

Finally, I read through this thread. I must say the first thing that came on my mine when I reached the part where some of you mention using small electric pump was the same what Crabstick advised later in the thread. A closed loop cooling system. My addition to Crabstick's idea is: what if you make the heat exchanger part so that it has small fins running lengthwise (not a flat piece of copper) on the bottom of the hull, so not adding too much drag, yet adding more water contact/heat transfer area?!

The peltier isn't good in my opinion for more reasons:
1. cost
2. it consumes a lot of electric energy from your batts.
3. since 99.9% of the fast electric boats have closed hulls, heat produced by the peltier will heat up the closed space of the hull. If you say this is good for the lipos, I can accept that, but you're still heating the air inside the boat = heating motors, ESC and everything inside.

**domwilson** · 10-14-2009, 05:44 PM

The cost is not that prohibitive.. http://cgi.ebay.com/1pc-12706-Thermo...item3a53b6f9c9

This is just one example. Current draw is around 6 amps. I don't think heat inside the hull would be a problem if you water-cool the "hot" side with a cooling plate. Thus making the "cold" side even cooler.

**6S HYDRO** · 10-14-2009, 06:39 PM

Are you sure you dont have to make the hot side hotter to make the cool side colder?

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