Hunka Hunka Burning Love Posted June 12, 2016 Share Posted June 12, 2016 Nice find on the flexible heat pipes. I've used up my 20 reps for the day or else I'd rep it up. Looking more closely at his photos it looks like there's limited space under the handle there so a muller vent won't fit. The mosfets look like they are lined up right at the one side there. I'm not sure how the KS heatsink plate is secured to the case, but maybe if one could raise it up slightly with offsets underneath, one could slip the flexible heat pipe underneath with some thermal grease and secure it with a little epoxy or friction fit it when screwing the KS plate down. I just don't know how sharp of a bend the flex heatsink pipe can withstand. It looks like in most photos you need a gradual curve of the material as a sharper bend may damage it and reduce its effectiveness. The control board looks like it's sitting right above the one battery pack and right at the edge of the cover so room is tight. Got any more photos @Cloud so we can take a closer look? Link to comment Share on other sites More sharing options...
Cloud Posted June 12, 2016 Author Share Posted June 12, 2016 29 minutes ago, lizardmech said: You can buy those flexible heatpipes on ebay. http://www.ebay.com/itm/HEAT-PIPE-ULTRA-FLAT-1TX100L-MM-Part-AMEC-THERMASOL-MHP-1220A-100A-/271932773766?hash=item3f5074d586:g:NEcAAOxyBjBTPxmi I would suggest bending it in a a U shape and epoxy it to the KS heatsink, then cover the opening so it's sealed with the other side of the U shape exposed. Finally mount a low profile server CPU cooler on the exposed part of the U shaped heat pipe, it won't have enough surface area by itself. Thank you. I will buy it and see what i can do. I may have to get a little fan but want to see if i can just use passive cooling first 3 minutes ago, HunkaHunkaBurningLove said: Nice find on the flexible heat pipes. I've used up my 20 reps for the day or else I'd rep it up. Looking more closely at his photos it looks like there's limited space under the handle there so a muller vent won't fit. The mosfets look like they are lined up right at the one side there. I'm not sure how the KS heatsink plate is secured to the case, but maybe if one could raise it up slightly with offsets underneath, one could slip the flexible heat pipe underneath with some thermal grease and secure it with a little epoxy or friction fit it when screwing the KS plate down. I just don't know how sharp of a bend the flex heatsink pipe can withstand. It looks like in most photos you need a gradual curve of the material as a sharper bend may damage it and reduce its effectiveness. The control board looks like it's sitting right above the one battery pack and right at the edge of the cover so room is tight. Got any more photos @Cloud so we can take a closer look? Yes i will take more pics. The space is super tight. Heat sink is screwed into the plastic underneath, these screws are small and not reliable, i dont really want to stick the heat pipe under the heat sink as it will compromise the already deficient attachment. Besides this will create a gap between the heat sink and the plastic underneath, which means the dirt and eater picked up by the wheel will start getting into the battery compartment from underneath. It already happened once before and shorted my battery. But i think i can find another way to attach the heat pipe to the heat sink. I can try to route it to the outside and connect to the outsude heat sink. Depends on how flexible it is. Link to comment Share on other sites More sharing options...
Hunka Hunka Burning Love Posted June 12, 2016 Share Posted June 12, 2016 Here's some info: http://www.amecthermasol.co.uk/product412.php?url=1&page=282&ty=4&gr=30&fg=148 It looks like the bending radius is R2 or 2mm. PDF: http://www.amecthermasol.co.uk/datasheets/MHP-1220A-100A.pdf I think it contains acetone as the heat transfer medium so be careful not to puncture it. A 2mm radius bend doesn't sound too bad actually. If you have a metal rod that is 4 mm in diameter I guess you could use that to carefully bend the pipe around. Just remember the bend bend bend break rule of some metals - they can only take so much back and forth bending before they crack and break unless they are really quite soft. Let us know how this all works out. I'm quite curious to see how things go! EDIT: Some different items as well from Thermasol http://www.ebay.com/sch/m.html?_odkw=&_ssn=top-quality-tools&hash=item3f5074d586%3Ag%3ANEcAAOxyBjBTPxmi&item=271932773766&_osacat=0&_from=R40&_trksid=p2046732.m570.l1313.TR12.TRC2.A0.H0.Xthermasol.TRS0&_nkw=thermasol&_sacat=0 One other idea is to unscrew the mosfets from the heatsink and bend them 90 degrees up. Find a narrow aluminum block/heatsink and Silpads or Kapton film / thermal silicon paste, double check the procedure to attach mosfets onto a heatsink without shorting them out, and then connect the flexible heat pipe onto the top or side. Link to comment Share on other sites More sharing options...
Cloud Posted June 17, 2016 Author Share Posted June 17, 2016 I havent had time to work on this but id like to report that the holes i made in the top of the casing work great. I've removed the plate on top and have the holes currently exposed. I havent had any overheating. Nothing at all, and didnt see the temperature rise over 60. one time there was a litght rain, and i just covered the holes with electrical tape which did the trick. Then removed the tape when the rain ended. Untill i have time to work out a more permanent solution, this will be my routine. Link to comment Share on other sites More sharing options...
OliverH Posted June 18, 2016 Share Posted June 18, 2016 7 hours ago, Cloud said: I havent had time to work on this but id like to report that the holes i made in the top of the casing work great. I've removed the plate on top and have the holes currently exposed. I havent had any overheating. Nothing at all, and didnt see the temperature rise over 60. one time there was a litght rain, and i just covered the holes with electrical tape which did the trick. Then removed the tape when the rain ended. Untill i have time to work out a more permanent solution, this will be my routine. Put a Sympathex or what ever foil/ membran to prevent water coming in. Link to comment Share on other sites More sharing options...
The Fat Unicyclist Posted June 18, 2016 Share Posted June 18, 2016 1 hour ago, OliverH said: Put a Sympathex or what ever foil/ membran to prevent water coming in. Or, save the cocktail umbrellas from some girlie drinks and attach them in strategic positions! Link to comment Share on other sites More sharing options...
Cloud Posted June 18, 2016 Author Share Posted June 18, 2016 12 hours ago, OliverH said: Put a Sympathex or what ever foil/ membran to prevent water coming in. I wouldnt trust these membranes to pully protect from water and at the same time circulate the air effectively, but i could experiment with them 10 hours ago, The Fat Unicyclist said: Or, save the cocktail umbrellas from some girlie drinks and attach them in strategic positions this essentially is what i wanted to do - a solid plate with an overhang, but the water that gets on the casing in other spots can roll down and get inside the hole too. I can use some silicone around the hole perimeter to create a little "wall" around it so that the water cannot easily roll in,. There is a lot of potential solutions, i will try to implement the simplest Link to comment Share on other sites More sharing options...
Cloud Posted July 8, 2016 Author Share Posted July 8, 2016 Ive purchased a few small fans which i am planning to install inside the casing to provide additional cooling. If this works, i will seal the holes i made in the top of the casing. Now, i may have asked in the past but i dont remember - does anyone know the location of the heat sensor in ks14? The fan is small, and may cool locally only. I am trying to avoid the situation where i will inadvertently cool the sensor but not cool the important electronics that need to be cooler. In other words, if the wheel stops showing the overheating issue but the control board will still get too hot, there will be a risk of failure without my knowing it. Thanks Link to comment Share on other sites More sharing options...
dmethvin Posted July 9, 2016 Share Posted July 9, 2016 16 hours ago, Cloud said: Now, i may have asked in the past but i dont remember - does anyone know the location of the heat sensor in ks14? The fan is small, and may cool locally only. I am trying to avoid the situation where i will inadvertently cool the sensor but not cool the important electronics that need to be cooler. In other words, if the wheel stops showing the overheating issue but the control board will still get too hot, there will be a risk of failure without my knowing it. Since the critical components are the mosfets, you'd think the sensor would be near them. How do you tap into the KS14 heat sensor information? Would it be easier to stick your own thermistor to the heat sink really close to the mosfets using thermal conductive epoxy and use that to modulate the fan speed? Link to comment Share on other sites More sharing options...
Cloud Posted July 9, 2016 Author Share Posted July 9, 2016 Well, i am planning to place the fan near the mosfets, i will try but the space is limited. also, besides the mosfets, i probably should try to cool some other electronics? Pretty much anything that fails will throw me off the wheel. but i guess , in any case, the best spot for the fan is near the mosfets. The app tells me the temperature, i wasnt planning to tap into it further. When the temp. per the app reaches 70, overheating alarm is triggered. I wasnt planning to modulate the fan speed - i would leave the fan on at all times when the wheel is on, because when i ride the tempersture is always above 50 and most of the time above 60. Ideally, if the heat sensor wasnt near the mosfets, if it was on the other side somewhere and i placed the fan near the mosfets, and the heat sensor showed that its cooler, i would know that it works across the whole thing pretty much. Will see, i will be receiving the fans soon, will experiment. Link to comment Share on other sites More sharing options...
Cloud Posted July 13, 2016 Author Share Posted July 13, 2016 So , ihad ordered a few minature 5v fans and received them today. Ive used 2 - one inch wide fans, connected them in parallel, place them under the side cover over the mosfets, ran the wiring thru one of the holes in the casing, that i had made earlier and connected to usb port. ( see atta hed pictures). Then i closed the opening in the casing i had made earlier and rode for 2 hours testing the set up. I picked a mile long route and rode aggressively on sidewalk without stopping. I first rode with fans off, and at the end of the mile run the temperature went up to 65. I then stopped and let it cool down to about 49 at which point i turned on the fans and rode back. When i came back to my origin the temperature was 60-61. I continued riding with fan on and on a small slope the temperature did go up to about 64. However with fans off, as i continued riding the temperature wpuld go up to about 68 and even overheated once. While the data is still insufficient i believe when the fans are on, the temperature is 4-5 degrees cooler. I believe a combination of the holes in the casing and the fans should cure the overheating issue all together. Will continue to experiment. Link to comment Share on other sites More sharing options...
Xima Lhotz Posted July 13, 2016 Share Posted July 13, 2016 A suggestion could be to place the fans directly under the holes you made in the plastic if they fit. They would then extract the air through the holes instead of blowing hot air around in the wheel and trusting that some of that air is vented through the holes. More like a PC casing. And to really try tha PC like solution use the metal plate you have made earlier and make custom holes that fit the fans properly. If you do that I think 1 fan would be enough for hot air extraction. Link to comment Share on other sites More sharing options...
US69 Posted July 13, 2016 Share Posted July 13, 2016 are their holes directly behind the fan? to blow air in directly from outside? perhaps with a little filter in front of The holes? i plan something similar if i ever get overheat on my Ks18...... your 14 gets really hot.....i never come near 60....most time stay under 45-48.....wow... Link to comment Share on other sites More sharing options...
Cloud Posted July 13, 2016 Author Share Posted July 13, 2016 I was thinking about placing the fan under the openin, but the opening is much smaller than the fan size and also the space under the openings is very tight. You are right, the fans are drawing the same hot air , it would be much better if they drew from the outside. Not sure how to best use the metal plate with the fans. Maybe i can make holes in the side cover right where the backs of the fans are, however there will be a risk of water getting in and thats where the battery is. Maybe i can come up wi a simpke hood solutikn for that or attach a tube pointed downward. 6 hours ago, KingSong69 said: are their holes directly behind the fan? to blow air in directly from outside? perhaps with a little filter in front of The holes? i plan something similar if i ever get overheat on my Ks18...... your 14 gets really hot.....i never come near 60....most time stay under 45-48.....wow... No, the holes are on top and the fan i had to place on the side. There is no hole behind the fan unfortunately, and also the fans are weak. Its bery tricky to place the fans under the holes i had made. Link to comment Share on other sites More sharing options...
Xima Lhotz Posted July 13, 2016 Share Posted July 13, 2016 Don't take air from the outside in, this will increase the temperature. Pushing air in to a space increase the temperature of the air as it compresses passing the fan and holes. Use the fans to extract air from inside the case to the outside so you get a vacuum inside the compartment where the battery and criqutboard is mounted. As a test you can place the fans on the outside of the case sucking air from the holes you made as there was little room inside of the case, just to see the effect. This is usally the best approach when getting rid of heat. As the case is not completely sealed there will be no vacuum, if the case was completely sealed then you would have to add an inlet for outside air to be sucked into the case. Link to comment Share on other sites More sharing options...
esaj Posted July 13, 2016 Share Posted July 13, 2016 5 minutes ago, Xima Lhotz said: Don't take air from the outside in, this will increase the temperature. Pushing air in to a space increase the temperature of the air as it compresses passing the fan and holes. Use the fans to extract air from inside the case to the outside so you get a vacuum inside the compartment where the battery and criqutboard is mounted. As a test you can place the fans on the outside of the case sucking air from the holes you made as there was little room inside of the case, just to see the effect. This is usally the best approach when getting rid of heat. As the case is not completely sealed there will be no vacuum, if the case was completely sealed then you would have to add an inlet for outside air to be sucked into the case. This is my understanding also, underpressure is better than overpressure in cooling. If you look at PC case and power supply designs, either there are only extracting fans, or if there are fans pulling air into the case (what's the opposite word for "extract"? ), they're less powerful than the extracting ones. Link to comment Share on other sites More sharing options...
Cloud Posted July 14, 2016 Author Share Posted July 14, 2016 In general i agree but not in this particular case. The fans i installed are very weak and hardly move the air. The pressure ( negative or possitive) will be too insignificant to make a difference in terms of temperature. When installed over the mosfets they provide a small air exchange inthe mosfet area which can make a bit of a difference. But they will not be strong enough to suck air from inside through a small hole and even if they did, it would be very local and not around the mosfets. The holes are so small, they would need to be enlarged and that would be a problem. Maybe if i get more powerful fans, maybe it would work. I still believe that even a weak fan can make a huge difference if it just exchanges the air and brings cooler air in. I think ideally if the fan is weak, there should be an opening right behind it as big as the fan itself. The outside air will be much cooler than the inside and this should do the trick. The fan on the putside is a great option because of lack of space inside, but the fan should then be virtually ducted to the inside, otherwise wont be effective. I will continue to looks for a better solution, but right now the fans seems to be able to reduce the temperature by a few degrees. Link to comment Share on other sites More sharing options...
Xima Lhotz Posted July 14, 2016 Share Posted July 14, 2016 I too think the fans will be strong enough for more improvement Because the natural flow of hot air is up, you are helping the natural flow and so they don't need to be to powerful. Just seal properly against the casing as you say and the fans will drag the hot air out, even through the small holes. And it wouldn't be local as hot air travels up so cool air stays down (with the mosfets). Example of extracting air through small holes, a big hole wold be preferable as you say, but not possible in this situation. IMG_3048.JPG And to top of gluing small aluminum heatsinks (if possible) on top of your mosfets should seal the deal. If you think that these fans are to weak to extract the air in the natural way hot air travels then going against this and pushing air into the case against the natural hot air flow might be even more difficult. Using the fans inside the case only moves the hot air around (with some escaping through the holes) so if you got a couple of degrees difference with this you should get a few more degrees extracting that hot air, and a combination of both is probably the most effective. A well, anyhow good luck with the project and keep us updated with the progress! And what is the opposite of extract.. Link to comment Share on other sites More sharing options...
Cloud Posted July 25, 2016 Author Share Posted July 25, 2016 Thanks. It hasnt overheated at all, since i installed the fans, even when the temperatures were around 92 last monday. The temperature came close to 79 but never reached it - or should i say my feet needed rest every time before the temperature could reach 70 . So in a sense i did resolve the problem in my own roundabout way. Well, however weird, this has worked. One day when i am more brave, i will make the whole in the casing bigger and install another fan that will suck the hot air out. Link to comment Share on other sites More sharing options...
checho Posted August 2, 2016 Share Posted August 2, 2016 On 6/5/2016 at 0:20 AM, Cloud said: Thanks. I just did another test. I rocked back and forth while holding on to something, this allowed me to go back and forth by a couple of feet only and fast. The temperature quickly went up to 67 at which pojnt i stopped rocking and just started riding. The temperature started slowly going down. The top plate and the plastic were hardly warm even though the temperature was reading 67. this is simply because the air above the control board had no time to heat up. The wheel would have overheated if i had continued rocking back and forth, and understandinly so - the holes can only become effective when the air above the control board has been fully heated. So i think this mod will be effective during long rides where the temperature goes up slowly and the top of the casing eventually gets very hot.. I will continue testing on a longer ride tomorrow. Becarefull anything above 60C can damage the control board, 70C will most likely ruin the control board. To have proper cooling a combination of heat sinks combined with air flow is needed. The hard part is getting the hot air out without getting the water in. I think your solution combined with heat sinks will be better. I did an experiment i drove with the top cover off the ks18 after adding a lot of heat sinks and there was a huge drop in temperature and the drop in temperature was quick. However that was an experiment since if it were to rain it would get the control board wet, but that could be acomplished in such a way that water stays out. Link to comment Share on other sites More sharing options...
Cloud Posted August 31, 2016 Author Share Posted August 31, 2016 As i was trying to get my other wheel up and running, i decided to make similar adjustments to the casing so as to prevent overheating. This time, instead of making 10 holes closer to the carrying handle i made in the other wheel, i decided to make just 3 holes on the top part of the side covers right over the mosfets. And Voilà! No verheating whatsoever, never rising over 60 degrees even in the warm new york weather. And seems like no fan needed! And easy to cover up in case of a light rain. Link to comment Share on other sites More sharing options...
Xima Lhotz Posted August 31, 2016 Share Posted August 31, 2016 @Cloud Nice solution that made me think of what's happening. How could 3 holes with no fan be better than 10 holes with 2 fans? So, that made me think of a bubble pool, when air gets sucked down into the waterjets to create bubbles. I think you created a type of Venturi effect. Moving your holes so the wind always blows across them at a 90 degree angle instead of having them protected under the handle you got exactly the effect you wanted. Moving air over your holes creates a low pressure above the holes so you then get a higher pressure inside your casing so the air is then blown (or sucked due to low pressure) out of your casing, a natural fan, cool! Picture is from a carburetor but it's the same principle, and as air has lower mass than fuel its more effective. Link to comment Share on other sites More sharing options...
Hunka Hunka Burning Love Posted August 31, 2016 Share Posted August 31, 2016 Now you just need to find three small corks to plug up those holes in case of rain! Plus a new charger cap. Link to comment Share on other sites More sharing options...
Cloud Posted September 1, 2016 Author Share Posted September 1, 2016 18 hours ago, Xima Lhotz said: @Cloud Nice solution that made me think of what's happening. How could 3 holes with no fan be better than 10 holes with 2 fans? So, that made me think of a bubble pool, when air gets sucked down into the waterjets to create bubbles. I think you created a type of Venturi effect. Moving your holes so the wind always blows across them at a 90 degree angle instead of having them protected under the handle you got exactly the effect you wanted. Moving air over your holes creates a low pressure above the holes so you then get a higher pressure inside your casing so the air is then blown (or sucked due to low pressure) out of your casing, a natural fan, cool! Picture is from a carburetor but it's the same principle, and as air has lower mass than fuel its more effective. Yep, this is exactly what must be happening on a small scale here. I continue riding and still no overheating. Yay 1 hour ago, HunkaHunkaBurningLove said: Now you just need to find three small corks to plug up those holes in case of rain! Plus a new charger cap. I just use electric tale because i am lazy. But yeah should get a more permanent solution Link to comment Share on other sites More sharing options...
who_the Posted September 1, 2016 Share Posted September 1, 2016 @Cloud Great mod. Can we drill right through the top or do we need to remove the case first to prevent damaging anything inside? Link to comment Share on other sites More sharing options...
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