Just an update regarding this mod and project It's been working flawlessly. I made 50 flights this past week, half of them were with the Canon 7D hovering to take pictures. My motor temps never went over 75 degrees even after hovering essentially in the same area for 5 minutes. Overall I have made over 120 flights since I installed the fan.
Over the past month I have been flying in weather ranging from 50 to 85 degrees with a corrected altitude anywhere between 1700 to 2100 feet above sea level (dependng on weather). This past week I have flown in early mornings when it was 55 degrees outside and as warm as 82 in the afternoon. Weather doesn't seem to have any affect on my motor temps now. In hovering conditions the motor temps seem to run right around 75-78 degrees no matter what the temp/humidity. When I hover I"m hovering for a good 3-4 minutes a shot when I'm taking stills. I could get to 100 degrees easy (often going as high as 109) without the fans in 78-85 degree weather.
I found that the sun plays a big part. I have flown when it was 90 degrees outside in the shade with no problems then 80 degrees with the sun radiating on the system same samera setup and the sun energy is enough to heat things up. In fact that was thesis with some predator systems on why they would get hot in the daytime with lower temps versus night and higher temps in different regions of similar altitude.
Interesting. In regards to my tests, I usually have flown only when its sunny and in direct sunlight.
I did a flight once by a commercial building demonstrating the technology to a film program for a magnet high School. I was flying their Sony FS-100 with an 18-200 glass. Low hover in the shade I got some ESC's in the 90's on the C scale. Then I climbed up to 150 feet then and started moving it to get wind over the ESC's. As soon stopped moving one BL hit 102. As I started give it about 15 mph of airspeed the BL's started to cool down with some airflow overt which makes me think that the fan is a great idea because it does not seem like it needs a lot of air to cool them down. This make me wonder how some companies can get away with heat shrink on the ESC's like Turnigy and even the Freefly ones. I suppose they are using higher power mosfets to transfer the energy more efficiently. It seems like those MK BL's just don't like current. I am surprised that MK hasn't developed a higher power system that can support 6S or higher batteries. It seems that the industry standard for serious professional work are systems using 6S batteries and 350 kV or lower motors.
I been wondering the same where is MK on developing the MK Bl Ctrl V3 so I wrote them an email and this is what I got Me: hi well it is probably a question you get very often Does Mikrokoter have any plans to upgrade in the near future the power distribution and the BL Ctrl to lift heavier payloads, I like many out there have reach the limits of the current Bl Ctrl and have to start the migration from MK Power and Bl,s to individual Esc's I dont like to use the I2C but have no choice, latter have to migrate to DJI FC etc I like MK but what can we do... thanks MK: Hello, many thanks for your Mail. So you have a very heavy copter and you need more power to fly with a high payload? We also plan a new BL-Ctrl but this takes a lot of time. So I can not tell you when this will be available. this email made me wonder even more
Hi I have successfully install a fan like Dave did to my CS8 copter and It does helps with keeping the temperatures bellow 79F degree range I flew with a total copter weight of 13.6 Lbs 6.15 Kg for 5 Minutes in about 75F degrees air temperature the fan keeps a constant airflow over the mosfets, the white non glamorous circle is a sun shade to keep the boards in the shade I think it helps too as soon as I get my GPX fille Il post my Bl temperatures in the meantime here is a pictures of my setup
Hi Jose - Is the battery plate above the white disc? What kind of adjustments did you need to make to get the fan attached to the battery plate? More so... where did you get those white spacers? I bought the fan myself, and just trying to figure out the easiest and least heavy way of connecting it to the plate, as it doesn't seem to properly line up. I'm also thinking of adding some sort of mesh on top of the fan.
Hi Cris ok first the green standoffs are 55mm + 25mm spacers = 80mm the one you see are temporary I have order longer ones made by Axial I needed 80mm total hight but can only find 70mm so I will add 10mm plastic spacers and longer screws to reach 80mm go to ebay and look for "axial 70mm post" the fan and the plastic white disc are under the battery plate and the fan is drop down using more of the white plastic spacers you can find the spacers in Home depot or Lowes hardware store buy several lenghs so you can play with the distance from the top of your electronics to the fan to the battery and white disk distance the spacers are cheap also get more 3mm longer screws metal washers and nuts too the fan, I like Dave connected it directly to the PSB board so as soon as you plug your main lipo the fan will work
Jose you will find that you don't need that sun shade anymore. I ran this in very hot and humid weather and it still didn't go above 78 degrees while hovering for 4-5 minutes. My total copter weight is also 15 pounds.
The other one thing I like about the shade is that if it starts to rain and the copter is in the air it gives me some time to land and run for cover but I will try with out it perhaps without it I can get more air to go trough the board have you try a smaller fan under thanks Dave
I have probably flown about 100 flights in the past month, mostly with the heavier 7D and most of the time hovering taking stills and the fan has been working awesome. I have probably have 200 flights since the fan has been installed and its definetely a very reliable mod that really works.