Efficient ESC for Lehner TorqStar 1 7025/40 @86v

[jimcroisdale]

Hi all,


First post here.


Me and a team (we're in the UK) are building a single seat electric endurance car. Not RC I know, but it will share a lot of the technology. We started looking at motors several weeks ago, with efficiency being the primary goal. We started with Astro, then Neu, and finally landed on Lehner. After comparing the datasheets (of which Lehner's is by far the most useful) we're pretty set on the Lehner TorqStar 1 7025 in the 40 wind configuration.


I asked Andreas Lehner which ESC would go well with this motor and he has pointed me to a German consultant that deals with the VESC controllers. He charges for his time (no issue with that) but before we stump up the cash I wanted to ask around on a few forums and see what other people think.


Our battery pack uses LiFePO4 cells. It'll be 93.6v right off the charger, and will fall quickly to 86v under load. The cells will be ready for recharge when they get to around 80v approx. We'll be averaging around 630w, with peaks of maybe 1000w (I know this is child's play wattage for you guys).


However, looking at what's available, it's our voltage that narrows things down a bit - most ESC's not going high enough.


There are a couple of models that are rated to 100v, but that includes peaks. I don't know how or when our pack may introduce peaks into the power line, so I don't know if 100v models will be right for us. Anyway, assuming they are (and we can fix any voltage spike issues), here's what I've got shortlisted:


APD UHV 120v/300a - $2500
https://neumotors.com/apd-electronic...ushless-esc-2/



APD HVPRO 100v/200a - $1900
https://neumotors.com/apd-electronic...brushless-esc/


MGM HBCI 110120-3 120v/110a - $1250
https://www.mgm-compro.com/brushless...r-controllers/


VESC STR-500 100v/500a - ?895/$1120
https://trampaboards.com/vesc-str500...--p-35876.html


VESC 100/250 100v/250a - ?375/$470
https://trampaboards.com/1x-vesc-100...h-p-28115.html


Our main goals here are:


- Works well with the Lehner motor
- Efficient
- Reliable
- Forward and reverse
- CANbus data transmission


What are your opinions on these speed controllers in conjunction with the lehner? are there other ESC's out there that are better for the job?


I welcome any questions, and thankyou for your time in advance!


Jim

[photohoward1]

https://forums.offshoreelectrics.com...3-RaceMechaniX

Tyler may be able to help you. Link above. He actually does this tech on a larger scale for a living.

[vvviivvv]

As previously mentioned, Tyler is your best bet.

In RC we are fairly limited to around 60V so not too many escs are capable of handling much more.

MGM are probably the closest any of us would have experience with going over 14 / 15s Lipo I do know some people have issues with the complexity of MGM's

[jimcroisdale]

I have PM'd the gentleman in question! :-)

[koen]

you can also look at fliermodel.com they have esc's from 6s to 22s

[jimcroisdale]

That's some generic looking Chinese stuff if EVER I saw it! :-D Im not saying it's all rubbish, just that I wouldnt trust it for a once in a lifetime 24 hour race.

[fweasel]

That's some generic looking Chinese stuff if EVER I saw it! :-D Im not saying it's all rubbish, just that I wouldnt trust it for a once in a lifetime 24 hour race.

I wouldn't trust a flier product any further than I could throw it.

[koen]

i didn't know they were that bad, it's good to know now

[RaceMechaniX]

Hello Jim,

Sounds like an interesting project. I do have a fair bit of experience with the HV ESC's and have a number of the 41xx and 70xx Torquestar motors from Lehner although not always paired together.

The ESC's I would trust in no particular order are APD, MGM and SLS.

The need for CAN likely also rules out many of the other potential hobby brands. The three companies above all have industrial/automotive/aerospace projects which include higher reliability and better engineering practices.
MGM have a lot of experience with innovation projects and their ESC's tend to be very flexible, however they must be used within the nameplate ratings. That is to say, you cannot expect 200A continuously from a 110A rated ESC. MGM have very good thermal and electrical protection systems in place. They also have great support, but you should expect to pay some reasonable NRE fee for support.

APD likely have the best software and hardware as well as familiarity of driving outrunner motors to high speeds. They have some pretty wild X class quadcopter projects which demonstrate good control of high fundamental frequency motors and HV applications. I have one of the MGM 120110's and 400400's but have never tested these specifically with the outrunner motors. If you are interested in either I would likely be willing to sell these to you.

SLS in Germany is another good supplier with nice hardware. I have used their products are work driving 48V motors with very good success.

Other companies to reach out to include YGE and Kontronik. Both have a lot of experience with outrunner motors although I am not sure either have 100V ESC's. If they do, they might not be listed on the website but an inquiry to them could tell more.

Besides the hardware, the key for your success is support from the ESC's engineering department. You will have questions on regenerative braking, CAN, softstart and other control logic where good support is critical.

Kind Regards,

-Tyler

[photohoward1]

I wouldn't trust a flier product any further than I could throw it.

I disagree. Have had great luck with them.


Sent from my iPhone using Tapatalk

[jimcroisdale]

Ah, cheers for the info Tyler!

Some good links there, but as you say, most don't go up close to 100v. It's still looking like a shootout between APD, MGM or VESC.

I've got my hands on the datasheet for the MGM120110 and it's certainly "feature rich" :D I've also inquired about their BMS/Charging systems, and I think if they can tailor an ESC/BMS/Charging system to suit, we may well go with them.

if they can't, and we're back to getting bits from different places, I will look back at the APD and VESC stuff.

At the end of the day, what we really want is efficiency and I did state this to Andreas Lehner, and he said go with VESC.

I'll see what MGM say next....

[RaceMechaniX]

Best of luck Jim,
Is this a university project or professional?

-Tyler

[jimcroisdale]

Neither really. You could say we're a bunch of amateurs, although we do have a decent team - https://darkstarracing.co.uk/

[RaceMechaniX]

Got it, was not sure if you had a shoestring budget as a Uni team or slightly deeper pockets to afford good hardware.
I spent some time looking at the VESC, looks like a great option in addition to the MGM.

[jimcroisdale]

Well, with the VESC we have the consultant guy who can help us. I'm sure for the hourly rate he's after, he'll at least be responsive (MGM are taking ages to answer questions via email). See what they come back with anyway - if their charging solution doesn't do what we want, then there'd be no possibility of an integrated MGM controller / BMS / charger system, so no real reason to use the motor controller over anything else, particularly.

Budget is definitely shoestring, but we believe we can still compete... :-)