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
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)
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
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
front-side with FETs completely exposed to open prop wash
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.
Replies
Wow! thank's, I noticed that some Esc are much lighter and looks that they haven't have that alum slab or is very tiny perhaps that explain weight difference http://www.hobbyking.com/hobbyking/store/__98568__DYS_XM20A_20A_3_4...
- sometimes mfg weight data isn't accurate
The primary weight factors on as-shipped ESCs are:
- Al slab as you mentioned
- Wire length and diameter
- Bullet size
The lightest ESC I've come across is around 2 grams naked as compared to the DYS that is 13 grams naked (so a small difference once stripped to bare bones. The key is the testing process that takes ESC weight into account. Before the DYS even starts to perform, first it has to lift 13 grams whereas a little guy maybe 3 grams before the fun starts.
Sorry the ignorance: all this products to protect esc, discussed above, can I use them to protect all electronics that come naked instead to protect them with other plastic covers? Eg, the pixracer, it's power board, the minim, etc.? It's safe?
Yes. Don't make my mistake though. Tape over or insert fake plugs into all connectors whether male or female, USB ports, etc. before you seal. Electrical sealant, like the 3M product, will give you the maximum protection from moisture in the air. The 3M product is a really tough covering, similar to what is around motor winding wire. The dip product is a rubber coating that is more pliable and also good.
Second best is shrink wrap, but because the ends are open, not as good in high humidity or fog or a dust storm and weighs more.
A product's MSDS covers transportation of materials in their pre-use form (thus what's in the aerosol can), not what the product is after it cures. Do take the directions on the can seriously. We like you Cala and want you to stay around.
I only seal what is directly exposed to me and grass (thus the ESCs). Humidity here is only about 60% and i don't fly on foggy days. But that will change, so I might seal more.
Painting over the pixracer will destroy the barometer, ruining the flight controller.
Yes, taking in consideration to protect it and the connectors as Forrest advertise, but baro have it's oun sponge protection so is no problem; but thank's for advertise, in case,
Thank's, I learned in the worse manner that shrink wrap isn't the best because the ends are open :( I was connecting a mini APM perhipeals for a Bixler and, at the end, all working, I did the last test and the P module become smoked when I connect the batt, I, confused, visit an electronic thechnic to make an authopsy and said that, probably, when I was soldering, a little tin ball went inside the shrink wrap and burn a component GRRR!!! new PM to the basket. I'm going to see what product I can find here, looks very usefull.
The 3M sealant is certainly tough. I did a sloppy plug tape up job on a Pixhawk some time ago and some of the sealant got onto the DF13 pins. It was a job and a half scraping it off.
That's amazing! How do you think it would stack up against a very light board like say, this 4 in 1? I'm interested in making a bare bones sub 2kg quad carrying a pair of GEB8043125.
This battery is 6000mah, or 6Amps max discharge rate (1C). Even for a light quad this is too low. If you get two in parallel, you'll get to 12A which is also too low. To give you an idea, for a light quad flying more than an hour (voltage will go down, amps consumption will go up), you 'll start at about 10ish amps consumption and will end up at 15ish amps. So that means you'd need three in parallel, but then you are getting sub-optimized for the weight of the battery (3x525g = more than 1500gr for a battery capable of outputting 18 amps which is oversized by 3 amps)
You'd have a better performance with a self made 4S5P assembly of individual Panasonic 18650 Li-Ion cells (at 48gr per cell), so total weight for the battery of 960gr. (4S is lighter than 6S, obviously)
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