Thinking about water cooling...

[electric]

I was wondering about the impact of our nice warm (87deg - 92 deg) pond water and the ambient temp of about 97 deg and its effect on cooling the esc, motor. Anybody have any thoughts on this?

I think a lot of the temps on esc and motors come from folks running in much cooler water and air temps. I have seen some people say I ran such and such and the esc was 90 when I got done. I am thinking to myself my temps start at 90's before I even plug the thing in! Seriously, my Lipo's start the run at 97degrees if I have them outside long enough before the run! That is in the shade!

Does the swing in temps have that great of an effect on the end temps on the esc and motor? I have seen the threads on a closed loop(with ice) system and I am beginning to think that might not be a bad idea, particuarly when you are running in a "hot" pond. I have had what I think are two incidents with two different esc's thermaling(sp?) when I am well below the max amperage.

[Jeff Wohlt]

The closed loop is a great system for warm water and weather. Worth doing if you want to keep her cool. Turn it on 2-3 minutes before putting her in and then leave run while you change lipos.

I am planning on getting some pumps I found and a couple nitro tanks to be able to make a unit that all I have to do is use velcro and switch to any boat. Take a cooler with some ice...need that anyway for the beverages and then drop a few cubes in the nitro tank to begin cooling the water.

[Jesse J]

Wouldn't the drinks do enough cooling? oh wait just the biologic side...

How much would these pumps and reservoirs add? sounds like a lot... but might be worth it to be able to run in those temps.

[Fluid]

I was wondering about the impact of our nice warm (87deg - 92 deg) pond water and the ambient temp of about 97 deg and its effect on cooling the esc, motor. Anybody have any thoughts on this?

Setups which run 100 in February generally run around 120 in July here in Houston - these are motor and ESC temps. Don't believe every temperature quote you read online - you don't know where the readings were taken. I've seen boaters measure motor heat on the water jacket and on the ESC logic board....

Seriously, my Lipo's start the run at 97degrees if I have them outside long enough before the run! That is in the shade!

Your LiPos should be at least 100F before starting, even in the winter. Internal resistance is much much lower when cell temps are above 100F. While it seems counter-intuitive, the temperatures of my cells after a race heat is usually lower when I start them at 100F then when I start them at 75F. We use LiPo heaters when running below 80F ambient.




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[electric]

The closed loop is a great system for warm water and weather. Worth doing if you want to keep her cool. Turn it on 2-3 minutes before putting her in and then leave run while you change lipos.

I am planning on getting some pumps I found and a couple nitro tanks to be able to make a unit that all I have to do is use velcro and switch to any boat. Take a cooler with some ice...need that anyway for the beverages and then drop a few cubes in the nitro tank to begin cooling the water.

Jeff, I scanned through some of the "research" that was done on this topic and oh my gosh, it was crazy. Could you just give me a short shopping list to put together a basic closed loop cooling system that works and is not to difficult to set up.
1. Container needed (how big in oz's and type)
2. Motor, where to get a good cheap pump motor
3. Ice Water or the blue gell stuff?

I want to try and throw one together to just cool my esc at minimal cost/effort to try out. My thinking is to just build a little unit that uses a simple receiver pack with a switch, tank and pump. Something I can drop in and connect to my Turnigy 180 to cool it down. I will just leave the motor on the traditional cooling loop since it is a Neu and is having no issues.

[electric]

Setups which run 100 in February generally run around 120 in July here in Houston - these are motor and ESC temps. Don't believe every temperature quote you read online - you don't know where the readings were taken. I've seen boaters measure motor heat on the water jacket and on the ESC logic board....


Your LiPos should be at least 100F before starting, even in the winter. Internal resistance is much much lower when cell temps are above 100F. While it seems counter-intuitive, the temperatures of my cells after a race heat is usually lower when I start them at 100F then when I start them at 75F. We use LiPo heaters when running below 80F ambient.




.

Good information. Thanks. Hey, my family is about to head to the West Coast (next Tuesday) to escape from the Texas heat. Which, leaves my weekends more or less free. I just got my Triton running and would like to come out and run next time you guys get together. Any plans to meet and run over the next month or so? You are part of the bunch that runs over in the Katy area correct?

[electric]

Went by the LHS during lunch and got two different size tanks to try this out. Will order the motor I found on one of the other threads. Looking forward to testing this out.

[Jeff Wohlt]

I will look thru my links. I would use a 6v pump and then run a small 800 mah 2S lipo. That would keep it pumping a long time. Graupner makes a sweet small pump for cheap. Let me look around.

I will be doing the same....if a person really want to invest they do make micro submergible pumps to fit in the tanks then just need and outlet. The inlet just is a connector on top of the tank...any exhaust pressure nipple will work...just seal it.

Weight is not an issue unless running something small. Pump, tank and pack should not be over about 7-8 oz then add water. Might be a great CG balancer!

I was just going to use heavy velcro and stick it on the floor. Unkook two lies and move it if you want. Mount the pump and cell pack on the tank so it is portable!

More to come as I will be building one. Rought tests made it the best tested so far.

[questtek]

Cooling Pump system ideas and testing for FE boats

The attached pictures the first of two different water cooling systems I am using for several of my FE boats. If you search the forums there has been a considerable amount written on various cooling techniques. The system that Jeff referred to consists of an inexpensive nitro fuel tank (ice and water tank), 2-3S Lipo pump and a small, hand build 3S LiPo pac. Note that the tank, to seal the opening hole, has a black rubber cork with three small holes. Two are for the water inlet/outlet and one is for the micro temperature sensor for the Eagle Tree Data Logger. The small stainless screw on the top of this cap permits tightening by expansion of the rubber stopper in the water tank to prevent leakage.
The weights of the units in oz, with and without the additional LiPo pac are shown. Note the LiPo pac has two output plugs, one for the pump and the other for the BEC or UBEC. In some cases I add a third power output plug for an additional cooling fan.
My test results on performance are based on Eagle Tree temp monitoring. I use three micro temp sensors; water cooling bath, ESC and brushless motor. My tests, as I have reported to Jeff, is that I see an approximate 15-20 F rise in temp in the ESC and motor AFTER I stop my FE and pull it out of the water with ONLY conventional cooling. The additional pump cooling never permits this rise since water and/or the fan continues cooling water/air circulation.
I obtained several different types of miniature pumps years ago at surplus. I do not know where they can be purchased today but I will do some investigation and report back on this forum.
It is important that ice (crushed or chips) and water be put into the tank. Water alone is not sufficient, even at 32 degrees. You must rely on the “Latent Heat of Melting” to really cool the temps down. Hope this gives you some ideas.

[questtek]

I have included pictures of a second system I am using on my Mean Machine. Rather than a nitro fuel tank i use a small Tupperware container (4 for 99 cents and the dollar store) and a different type of 2-3s LiPo pump. In this case the pump mounts thru a punched hole in the plastic lid. Power can be by a separate LiPo pac or just jumper off the charge plug of your LiPo pac since the current draw on these pumps is very low and fairly negligible if you are using 5000 mAhr pacs like I am. Anyway, more ideas for you to think about............

[Jeff Wohlt]

I like the second set up! That is what I was thinking but maybe a diffeent tank...but for the money what the heck! I want one portable to just use velcro and stick it down...all built on one tank...lipo and all attached.

Does that pump pull from the opening or do you put a tube on it to hit the bottom. Ice floats is what I wondered...a clunker filter on the bottom seems it would do well.

[questtek]

I like the second set up! That is what I was thinking but maybe a diffeent tank...but for the money what the heck! I want one portable to just use velcro and stick it down...all built on one tank...lipo and all attached.

Does that pump pull from the opening or do you put a tube on it to hit the bottom. Ice floats is what I wondered...a clunker filter on the bottom seems it would do well.

Would be easy to do as an all-in-one unit with LiPo pac. I keep it separate due to it powering the fan and BEC/UBEC in many cases. I did not show the micro temp sensor for the Eagle Tree and bottom connection to the pump with screen that pulls up water from the bottom of the Tupperware container. You are really observant!

PS, the volume of both the nitro tank in system 1 and the Tupperware container in system 2 are BOTH 6 cubic inches.

[Jeff Wohlt]

Can you show where to buy that pump? I think I need a couple. My other option is the graupner pump which is 6v and looks pretty good.

[GeoVW72]

good old ebay:
ebay pump one

ebay pump two

[m4a1usr]

Wow. Out of curiousity I did a rough order calculation and .216 lb (6 cu/in) of ice has the ability to remove approx 211 watts over a 3 minute run time. Thats more then I would have guessed.

Of course the systems you guys have designed and run cannot carry 6 cubic inches of ice. I just used that number as it was much easier to use a known volume. The real numbers would probably be less then half as no gradient or material coefficients were included and those all would reduce the cooling capacity.

John

http://www.mhi-inc.com/Converter/watt_calculator.htm