MR60

Worlds Best ESC - Making it Better

That's a bold statement ... Worlds Best. But it's even larger than that. Not just Worlds Best, but best for most all applications less than 30 Amps (limit of the tests). That means:

- duration ships that only pull 2 to 8 amps per rotor

- most all 6S and smaller ships (exception of nano-ships)

- any-size FPV racer

- any other ship in between

Why almost any size? Shouldn't a small FPV racer use a smaller and lighter ESC for response? Yes, if it does better on a net-lift response test. In other words, when you penalize the ESC for it's weight, is it still better and faster? What i continue to see is ESC manufacturers downsizing critical components of the ESC at a net loss. They weight savings is lost because of greater thrust loss and response. In other words, this heavier ESC will out accelerate, in the real world, a smaller and lighter ESC.

Why post this? To move technology forward, we need to report to industry what works and what doesn't. For some reason (i don't know why), this ESC works better than all others tested:

- for generating maximum thrust from the motor***

- for net-lift efficiency or the grams of weight it can lift (after it lifts the rotor) per watt

- for response (how fast it can generate targeted lift)

These tests were conducted on multiple days on multiple rotors of highly variant size, always being immediately compared back to another DYS 40A multicopter test to ensure that the baseline wasn't changing.

The ESC that dominated is a DYS 40A OPTO Multicopter using SimonK. The photo is included because there are two others that carry a similar or same name.

- Not the white cover DYS BLHeli 40A

- Not the one that is says "Programmable" versus "Multicopter" in the blue/purple band across the front

3691280727?profile=original

Have i tested all ESCs? No, but if you are convinced you know of one that would work better, let me know. I've tested most all of the following and one or more of their variants:

- DYS

- Multistar

- Turnigy

- T-Motor

- Afro

- Motortron

- Quattro

- 3DR

- Spider

- KDE

- ZLW

- Aris

- EMAX

- AutoQuad

- Exceed

- HobbyWing

- Lumenier

To do a test like this, a highly repeatable and finite test stand is needed. It took a while to develop one but what works is one that:

- measures (at a minimum) volts, amps, thrust, motor temp (shoots IR up the aft end of the motor)

- eliminates harmonics between the rotor and load sensor (this proved difficult but achievable)

- is calibrated and proves repeatable within 1.5%

- controlled by a system that can precisely repeat a rotor test (uses a Audurino Mega)

- directly feeds the data into Excel for analysis (uses DATAQ)

- uses a test script that produces repeatable results

- uses a test procedure that minimizes repeatability error (used average of multiple tests)

How much better is this ESC?  On average:

- 4.4% higher net lift (after it lifts itself)

- 2.3% more net-lift efficient (usually the larger the better)

- from more than twice the response or the same response as other ESCs (usually the larger the better)

                                                       So how to make it better?

Step 1: Strip it naked. See photo below.

           ... remove the cover

           ... remove the heat plate (better to locate the ESC under prop wash to run cooler, see below)

3691280569?profile=original

Step 2: Right-Size the bullet connectors or wires (see above where heavy wires are replaced by 2mm bullets)

           ... remove the large bullet connectors or wires

           ... replace them with ones that are the most net-lift efficient (where heat loss = weight loss)

Step 3: Seal the ESC. Seal it with Electrical Sealant to protect from moisture and conductive dust

           ... tape or plug connectors and wires

           ... repeatedly spray each side from different angles

           ... a mistake i made was not sealing the bullet connectors and solder

               - don't tape them off like i did

               - insert a male connector into the end of bullets so sealant doesn't get inside them

3691280655?profile=original

Step 4: Locate ESCs under Prop Wash. See photos below. The turbulence generated by the prop does not adversely affect lift when the ESC is placed on edge to the prop wash.

           ... Use something non-conductive like hot glue to bond the ESCs to the motor mast or spar

           ... Face the FETS (the little square warehouses or Fire Emitting Transistors) to open air

           ... Protect the ESCs from below from ground contact (not needed here because of clearance)

back-side with hot glue

3691280584?profile=original

front-side with FETs completely exposed to open prop wash

3691280749?profile=original

Step 5: Tie up wiring. Use dental floss to secure wiring away from the prop.

***Note: The T-motor Air 40 in high-timing mode (an option) generated higher thrust, but at the sacrifice of efficiency and motor temp. Also, the T-Motor Air 40 was 2nd best and close in performance. If you are using an Air40, it probably isn't worth switching.

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Replies

      • Yes

    • Matt: You made me spew beer on my keyboard!  My son is gonna copy your 'baby seal' line on some of his friends.

      The 'wet noodler'?

      Dare he?  Us?  Jack off?

      Read that fast 3 times.

      Sorry.

  • MR60

    Why ESC aluminum heat sinks do not work and should be replaced with something that does (let's ignore for now the fact that these little Aluminum slabs weigh about 16 grams on a quad and thus require more amps to lift them creating more heat).

    1) The heat sink is not large enough to be an infinite sink for even a short flight. The slab heats up quickly to FET temp, doing no good what so ever, unless it can transfer that heat to the surrounding air (in a computer this is done by putting a slab on the back of the main chip and the slab spreads that heat quickly though a much larger surface area of runners and fins that is fan cooled). Thus the ESC heat sink is actually a heat transfer slab.

    2) Whether an ESC is naked (no slab) or uses a slab, both cases are limited by the thermal conductivity of air, the final layer. So no matter how "fast" the heat sink is, it doesn't do any good if it is interfacing to the same amount of air as the original element. Aluminum does nothing to make air absorb heat faster. Air is air. The only way to increase the performance of air is to increase its contact area or lower its temperature.  The slab doesn't do either.

    3) The heat transfer-sinks on ESCs are sized to cover the FETS and because of that have nearly the same surface area as the FETS (sides + tops). Thus these slabs do not add significantly to the ability of the system to transfer heat into the air (there is some benefit to the slabs as the total surface area of the Al slab is maybe 5% larger than the total summed surface area of all of the FETs).

    4) Heat transfer-sinks only work when their surface area is larger than the original element. Aluminum is especially effective at cooling because it can spread heat quickly throughout itself to tiny fins that create a much larger surface area that can then be cooled by air (just like your mini-finned radiator on your car).

    Note: There is an adhesive gel/cloth between the FET and Al slab. It too is approximately the same surface area of the FETs and serves the purpose of minimizing air gaps between the FET and Al slab.

    5) There is a 2 mil or thicker plastic layer between the Al slab and air. This plastic layer nearly nullifies the Aluminum layer. So now all that the Al layer is doing is acting to spread the heat from one very hot FET to another maybe only hot FET and adding weight (more amps and heat). 

    7) For the heat to dissipate, it needs to go through 5 layers (the plastic of the FET, the cloth, the slab, the shrink-wrap, the air, all without significantly increasing surface area. A naked ESC goes directly from the FET plastic to the air.

    Now add to that the reality of the 16+ grams of added weight that requires more amps to lift begetting more amps begetting more heat.

    Sometimes a picture is better than words.

    3702202081?profile=original

    • MR60

      @ ESC manufacturers - Option 2 does not cost much more than option 1. Shrink wrap can then be applied as before and then in an additional but low cost process, stamp-cut away to expose the finned aluminum. At least consider stamp-cutting an opening on the Al slab that you currently use. 

      • @Forrest,

        I have already provided you with weblink to manufacturer of Option 2 ESC.

        plastic wrapped, unwrapped, bare,  radiator mounted, finned Al stab,

        every option, design already manufactured and open market offered.

        What you call:

        "

        Note: There is an adhesive gel/cloth between the FET and Al slab. It too is approximately the same surface area of the FETs and serves the purpose of minimizing air gaps between the FET and Al slab."

        What you call "gel" is in fact high thermal conductivity paste, gel, glue.

        Why 3M sealant is not ok ?

        3M sealant has not been certified or advised by Fairchild Semi for painting Mosfets made by Fairchild Semi.

        Low power dissipation modern Mosfets by Fairchild Semi don't require large radiator, finned Al stab at all.

        Mosfet's thermal energy distribution has been tested and verified with the use of thermal cameras at labs.

        So I can assure you, manufacturers of ESC are accountable for flaws in design, manufacture, if any, and can be contacted , reached immediately in case of ESC failure resulting in drone crash.

        Anyway, my Open Technology Park is ready to fully support your efforts in design and manufacture of better ESC for drones.

        Every project can be pretested at the OpenFabLab with thermal camera 

        and any lab equipment you find required or necessary to succeed.

        Wish you all the best and prosperity in private and business life.

        Open Technology Park

    • Composition Edit

      Thermal grease consists of a polymerizable liquid matrix and large volume fractions of @Forrest,

      could you stop your pseudo science theories ?

      Manufactuers of ESC PCB hire best university, technology institute graduates (faculty of physics, mechanics, electronics, mechanical engineering)

      so what you write sounds like a joke for kids.

      you said:

      "

      Note: There is an adhesive gel/cloth between the FET and Al slab. It too is approximately the same surface area of the FETs and serves the purpose of minimizing air gaps between the FET and Al slab.

      "

      What you call adhesive gel/cloth is exactly thermal paste , thermal grease or high-thermal conductivity glue.

      read first before you start your pseudo-science theories again

      https://en.m.wikipedia.org/wiki/Thermal_grease

      "

      Composition Edit

      Thermal grease consists of a polymerizable liquid matrix and large volume fractions of electrically insulating, but thermally conductive filler. Typical matrix materials are epoxies, silicones, urethanes, and acrylates, solvent-based systems, hot-melt adhesives, and pressure-sensitive adhesive tapes are also available. Aluminum oxide, boron nitride, zinc oxide, and increasingly aluminum nitride are used as fillers for these types of adhesives. The filler loading can be as high as 70–80 wt %, and the fillers raise the thermal conductivity of the base matrix from 0.17–0.3 watts per meter Kelvin or W/(mK), up to about 2 W/(mK).[1]

      "

      Remember:

      High thermal conductivity glue !!!!!!!!!!!!!!!!!!!!!!!

      but you said:

      "

      Note: There is an adhesive gel/cloth between the FET and Al slab. It too is approximately the same surface area of the FETs and serves the purpose of minimizing air gaps between the FET and Al slab.

      "

      Pls stop your nonsense.

      Pls

      Visit local university, faculty of physics, engineering, electronics

      to get basics of PCB design, basics of PCB cooling with heatsink,

      basics of heat pipe cooling

      basics of science

      pls

      Thermal grease
      Thermal grease (also called CPU grease, heat paste, heat sink compound, heat sink paste, thermal compound, thermal gel, thermal interface material, o…
      • T3

        Ugh, Darius please stop.  What a waste of a post.  Anyone worth their salt in this thread knows what a thermal pad is, and no one is saying that the thermal pad is impeding the flow of heat here.  Please read: literally every other point Forrest made in that post.

        • @Stephen,

          say so to @Forrest to stop fooling us with his crazy stories and pseudo science ideas

          @Forrest said:

          "

          4) Heat transfer-sinks only work when their surface area is larger than the original element. "

          wrong

          heat transfer sinks always, irrespective of the surface area

          surface areas should match as in case of PC computer's CPU and radiator

          affixed to it (surface areas exactly match, size to size)

          @Forrest said:

          "Note: There is an adhesive gel/cloth between the FET and Al slab. It too is approximately the same surface area of the FETs and serves the purpose of minimizing air gaps between the FET and Al slab.

          "

          wrong

          This is thermal paste , thermal grease or high-thermal conductivity glue.

          Thermal conductivity of MOSFET to air vs. MOSFET to Al thermal sink

          is exactly like thermal conductivity of air vs. thermal conductivity of Al thermal sink, is like 10 **(-2) vs. 10**2 = 1/100 vs. 100,

          so Al thermal sink has 10,000 times higher thermal conductivity than air,

          so we always affix Al thermal sink to Mosfet and build thermal sink to feature radiator on top.

          Cooling can be ambient air cooling or fan forced air cooling or heat pipe cooling

          But Mosfet Al thermal sink cooling should not be replaced by 

          bare Mosfet forced air fan cooling, due to a risk of dust buildup sticked to PCB

          and electronic elements, Mosfet itself.

          So plastic pillow wrapping is done to keep ESC PCB board clean and free from dust, which can exactly reduce thermal conductivity.

          There is no such standard in electronical engineering to operate open PCB in outdoor, unprotected, unboxed, not plastic pillow wrapped.

          Other risk involved are dust particles in the air, attacking PCB and electronic elements at high speed directly, since Al heat sink has been removed.

          But pls close this thread and contact Fairchild directly for Mosfet specification on

          thermal conductivity and required cooling via Al radiator or Al heat-sink.

          Fairchild provides highly professional data specification and solution to all your problems and ideas.

          Pls don't ruin individual DIY modellers and don't crash their invaluable DIY drones with your pseudo science ideas put into practice.

          Contact local electronics repair shop to learn basics of Mosfet and  heat sinks.

          • Usually i don't like Darius comments...but this much BS and pseudo science ideas from MR.Forrest is unbelievable...and he is doing that for years trying to get attention with bombastic headlines...world best esc,world lightest multi with worlds best materials known to mankind,worlds longest flight,mr.60 what a joke....Mr.Forrest,did you ever try to visit some institution for people like you?

            • @Emin

              Good point! At least Darius has some backing-up from leading experts in the field (Fairchild of course is one of them!). I have the same problem with Mr. Forrest. Please, Forrest do not use such bombastic titles! And no matter how much I love one man's ingenuity, try to stick with what is already discovered to be good and scientifically proven. Don't invent a hot water, and don't use  a kitchen knife for puling carrots out of dirt. There are other tools to do so :-)

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