ESC Options with extreme HL Motors, IC2 MK

[BorisS]

Hi guys,

my goal is to get some extreme heavy-lift motors on my Hexa, like the Axis 2820/14, 2826/12 or 4120/14 or even the plettenbergs. As far a I understand with my given basic knowledge the MK distribution board and the standard BL-Ctrl are not an option anymore if it comes to such monsters peaking over 40A. So what are the options using a IC2 serializer and getting some ESCs that can take the load. Would the Hercules II from Andreas Baier http://www.andreasbaier.de/ be an option. I am little confused which way to go more or less aware of certain disadvantages and advantages there are moving away from the standard MK setup. Also considering that more voltage than 4s would be desirable.

One of you following the same goals and has some more insights on this which way to go ?

Thanks

Boris

 

[ovdt]

I'm also in the process of building heavy quad. I think I'll go with Hercules II since it eleminates the wiring needed.

I don't like the ESCs hanging around the arms or the center plates.

I also own IC2 to PWM converter and HobbyKing 60A ESCs. I'm going to build a setup with these parts to see how it works. But it'll take some time for me to build (around a month ).


Another thing is, I don't trust cheap ESCs. Hercules II quality is much better than people expected. The caps are low quality on the pictures represented on Andreas web site, but it's up to you which caps to use..

 

[BorisS]

HI Ovdt,

andreas answers some questions in the text below. The question/answer about the possibilities to use the 4120 axis puzzles me. I think he is stating that for such motors the current Hercules wont work ?

Guys,
Quote
1) Do you talked with MK staff to try a total integration with MK parameters in the mk tool, for example ?
I talking about temperature, lipos voltage, motors rpm. Doe we already have this ?

Not yet, honestly i am not sure if MK wants to cooperate with me or if i am only one bad guy with cracy ideas...

About features: When you read my moto below, it is "less is more". Means the less functions you have the less problems you will get. The Herkules II design concentrated mainly on his main job: Driving BLDC motors, and this as good as s possible. But anyway, currently i thought already about some usefull features:

1) Voltage measurement: already build in, readback possible by I2C, so if 7V5 is going to FC, no additional VBAT is needed. Only some one has to update the MK-SW if he wants to read out more from Herkules.
2) Motor rpm: in Firmware available, but not yet available in I2C. But can be easily brought in if needed
3) Temperature: As it makes no sense to have on one board 4 temp-sensors (they will read the same pcb-temperature) i am thinking of implementing one stand-alone I2C-temp-sensor on pcb which can be read out indepentely of the controllers.
4) Molex Connector. Don't know yet if i should implement this. Has some benefit, no soldering in FC needed anymore.

Quote
2) Can we expect a octo and hexa single board?

Currently a octo-board makes no sense for me because of
1) Connection of 2 Herkules can be easily done by Micromatch-connector and is not limited(i know from a guy who uses 4 x Herkules II to drive a 16-motor Kopter).
2) Main reason: Have no time for this right now. This will cause a lot of effort and the benefit is not so high.
3) But i can think of assembling only 3 of the 4 ESCs for an Hexacopter or so. This will bring down the price also a little bit. But main costs are currently the price of the PCB + assembling costs because volume is too low right now.

Quote
3) Can we expect a "Heavy Duty" board, with capacity for 4120/20 series Axi motors (quads / hexas and octos) ?
Large capacitors, thick force lines and what more you need.
All the community is waiting for a more secure system to lift $ 2.000 - .000,00 camera gear.
We have to many problems with I2C.
I do not care about some buck$ more for this

Yes you can. But when? I am working for a longer time on the concept of a big ESC with "industrial standard". Higher power, improved diagnosis and protection (current measurement in each motor phase), 8-14S capability, Error correction of communication, redundantacy and and and... but:
Who will pay for the development time? For this i would have to quit my job or my wife quits me ;-)

Quote
4) Can you provide a star I2C distribuition config in the future OCTO/HEXA boards (prevention of a general I2C failure if a isolated BL went bad)?
Do we already have "STAR" lines for I2c in your boards ?

Within this board i see not the need for this. Main reason for I2C-errors are ground offsets caused by high currents an voltage drop across long distance I2C. With this concept, having all ESCs close together and very close to the FC, we have no ground bouncing issues any more. All my I2C errors are gone since im using this quad-controllers.
And as i wrote: I did not design the ESCs to be destroyed. I expect that they will stay alive because a most of destroying root causes are gone.

Quote
5)Do you know how comercial potential do you have in your hands ?
Try to improve your logistics, you are going to start a bussines.
Do a site with a PayPal paying option.

I appreciate if you see also the benefit of this Design. Even if manufacturing cost is a bit higher than stand-alone ESCs, the safety advantage and build-up simplification is much more worth then a few bucks of money.

Honestly, the story currently consumes too much of private time. If i don't find a possibility to finance this hobby, it will die.

I will see if some one will be interested in this design (and currently it seems so ;-)... I do not know if i really want to comercialize this story. It will have a lot of consequences...;-)
_______________

 

[ovdt]

The peak current that Herkules II can provide is around 100A. I don't know where I read but the provided continious current is around 60A.

So, if you look at the specs of Pulso 4120 series, which are identical with AXi in terms of specs, max current needed for the motor is around 55Amps. This means, Herkules II will be enough or very close to the limit for this kind of motor.

And if you ask me, a motor like AXi 2826/12 of which thrust capacity is around 3kg, will be quite enough for a very heavy lift Hexa setup.

 

[BorisS]

By the way got some numbers on the axis and thrust from Kopterworx, might be interesting to some.

View attachment 751

 

[ichwillnix]

The peak current that Herkules II can provide is around 100A. I don't know where I read but the provided continious current is around 60A.
So, if you look at the specs of Pulso 4120 series, which are identical with AXi in terms of specs, max current needed for the motor is around 55Amps. This means, Herkules II will be enough or very close to the limit for this kind of motor.
And if you ask me, a motor like AXi 2826/12 of which thrust capacity is around 3kg, will be quite enough for a very heavy lift Hexa setup.

Hi ovdt,

sorry, i read this thread quite late. I don't know where you read the 100A. Herkules II does not provide current up to 100A !
The max continous current is 20A per Motor and peak up to 40A per motor.
100A is the abs. max. rating of the Power MOSFETs mounted on! This is the peak motor phase current but NOT average motor current !!!

Example: A typical copter system hovers at about 50% dutycycle, depending on the ratio of battery voltage and motor KV (RPM/V). A Motor average current of 20A causes here an motor phase current of 40A (this is what the MOSFETs see).
If you now push throttle stick to 100%, the motor phase current can go much higher than 100A during accelleration. Herkules II does not limit this current and might be destroyed!

For such applications, the new Herkules III was designed. Here there is current limitation and overcurrent protection which protects the MOSFETs from overcurrent. Additionally, the double amount of MOSFETs is mounted so double of average current.

Short: Max average currents per motor:
Herkules II (20A) - with good cooling
Herkules III (40A) - with good cooling.

regards,
Andreas