I've seen quite a few posts the past few days with people listing proposed parts lists and the multistar ESC's keep coming up. I can see why, they say "multi" right in the name and the marketing talk from HK sure makes them sound like they're designed for multirotor use.
But I'm going to pull up an OLD meme and try to warn people away from them.
When I built my quad I picked the 10A multistars because they were cheap and claimed to be designed for multirotor use. It also looked like they were on at least one of the quads in the FT knuckle video so I figured they must work fairly well on a multirotor and were worth giving a try. I also saw reports that they probably could be flashed with SimonK so I figured even if they didn't work well I could always reflash them and be good.
Don't make my mistake!
The stock firmware is not great at all. It has a slower PWM rate than the stock Blue series, it has no ability to program throttle end points, and even changing the other settings the instructions provided with them don't seem to actually work as intended. But worst of all is they can stall. If the motor encounters any resistance at all it will stall and you won't be able to restart until throttling all the way down.
I run MultiWii on my quad so when I arm it starts the props spinning at a slow idle speed. At this low speed any contact with the props, motor bell or spinner will likely stall the motor. Lightly tapping the spinner is enough. And if I set my quad in tallish grass - the impact of the props against the blades of grass is enough to stall them. I then have to disarm and rearm to get the ESC's to respond again. Thankfully this never happened to me in the air...but I have heard anecdotal reports from other people who tried the multistars that it has happened to them in the air when doing extreme maneuvers.
But they're cheap, and you can flash them! Well....The 10a's are all but impossible to flash. I tried. Theoretically its possible. But they use an ultra tiny leadless MLF package chip which is too small to use a "socket tool" on and they don't have pads for programming. Maybe with a stereo microscope and ultra fine point soldering iron and the hands of a surgeon it's possible...but with my meager magnification and merely fine pointed soldering iron (which I do most SMT parts with no complaints) it was impossible. The lead free solder they use is just ridiculously hard to remelt and attach a tiny tiny wire too. (If you do try I found that 80 pin IDE cables have just about the perfect size wire to use.)
The 20a's are flashable with a socket tool, and the 30a's and up do have programming pads. So they can be flashed with SimonK - BUT. They're still a poor choice because:
1) They use the kda.hex version of simonk - because of the way the hardware is designed on these even if you flash them with the simonk bootloader you can't reflash them over the servo wire.
2) They don't work well at high refresh rates and the reports I've seen of people who have successfully flashed them have had to lower the refresh rate to get them to work - minimizing one of the big benefits of simonk.
3) Other than the 45a version they're all P/N FET designs which are inherently less efficient than all N FET designs.
Considering all that there are other options such as the HK Blue's and the cheap F20/F30 ESC's which are can be reflashed through the servo wire, are all N FET designs, work great at high refresh rates and in some cases are actually cheaper than the Multistars.
Or if you're not into flashing ESC's yourself there's the outstanding AFRO's and a number of other sources for pre-flashed simonK ESC's.
Don't make the mistake I did and fall for the multistar marketing hype. The difference simonk makes is astounding and there's just no comparison between it and the multistars. If you already have them - flashing is an option. If not put your money towards better ESC's than the multistars.
But I'm going to pull up an OLD meme and try to warn people away from them.
When I built my quad I picked the 10A multistars because they were cheap and claimed to be designed for multirotor use. It also looked like they were on at least one of the quads in the FT knuckle video so I figured they must work fairly well on a multirotor and were worth giving a try. I also saw reports that they probably could be flashed with SimonK so I figured even if they didn't work well I could always reflash them and be good.
Don't make my mistake!
The stock firmware is not great at all. It has a slower PWM rate than the stock Blue series, it has no ability to program throttle end points, and even changing the other settings the instructions provided with them don't seem to actually work as intended. But worst of all is they can stall. If the motor encounters any resistance at all it will stall and you won't be able to restart until throttling all the way down.
I run MultiWii on my quad so when I arm it starts the props spinning at a slow idle speed. At this low speed any contact with the props, motor bell or spinner will likely stall the motor. Lightly tapping the spinner is enough. And if I set my quad in tallish grass - the impact of the props against the blades of grass is enough to stall them. I then have to disarm and rearm to get the ESC's to respond again. Thankfully this never happened to me in the air...but I have heard anecdotal reports from other people who tried the multistars that it has happened to them in the air when doing extreme maneuvers.
But they're cheap, and you can flash them! Well....The 10a's are all but impossible to flash. I tried. Theoretically its possible. But they use an ultra tiny leadless MLF package chip which is too small to use a "socket tool" on and they don't have pads for programming. Maybe with a stereo microscope and ultra fine point soldering iron and the hands of a surgeon it's possible...but with my meager magnification and merely fine pointed soldering iron (which I do most SMT parts with no complaints) it was impossible. The lead free solder they use is just ridiculously hard to remelt and attach a tiny tiny wire too. (If you do try I found that 80 pin IDE cables have just about the perfect size wire to use.)
The 20a's are flashable with a socket tool, and the 30a's and up do have programming pads. So they can be flashed with SimonK - BUT. They're still a poor choice because:
1) They use the kda.hex version of simonk - because of the way the hardware is designed on these even if you flash them with the simonk bootloader you can't reflash them over the servo wire.
2) They don't work well at high refresh rates and the reports I've seen of people who have successfully flashed them have had to lower the refresh rate to get them to work - minimizing one of the big benefits of simonk.
3) Other than the 45a version they're all P/N FET designs which are inherently less efficient than all N FET designs.
Considering all that there are other options such as the HK Blue's and the cheap F20/F30 ESC's which are can be reflashed through the servo wire, are all N FET designs, work great at high refresh rates and in some cases are actually cheaper than the Multistars.
Or if you're not into flashing ESC's yourself there's the outstanding AFRO's and a number of other sources for pre-flashed simonK ESC's.
Don't make the mistake I did and fall for the multistar marketing hype. The difference simonk makes is astounding and there's just no comparison between it and the multistars. If you already have them - flashing is an option. If not put your money towards better ESC's than the multistars.
