eLofty Direct Drive Discussions-read before buying

mishrasubhransu · June 2, 2019, 3:46am

This thread is is to discuss the eLofty/Lofty direct drives. This includes the features, latest news, your reviews, upgrades, issues, failures etc. To avoid derailing the thread please back your opinion, both good and bad, with data. I’ll try to keep this first post updated with all pertinent information. Please let me know if you would like to have something useful added up here.

It all started with @BillGordon’s review of the direct drives. Followed by positive comments from @esk8jpn, @topcloud, @mishrasubhransu(me). Later @topcloud and @Winfly negotiated group buy prices for the drives and the relevant thread is here.

As far as I know these are the people who bought the drives: @esk8jpn, @BillGordon , @DAddYE, @hiboute(other forum), @Goldrabe, @Njull69(other forum), @landonkun, @river and @ryansinatra; and maybe able to help you with additional questions that I may have. Please let me know privately if you rather not have your names tagged here.

You can find the rest of the information from the builders forum here.

Specification

Number of Magnets/Poles: 20(this is what you use in VESC)
Number of stator poles: 18
KV: 58KV(even though it is advertised at 75KV(however @Goldrabe seems to have gotten 75KV motor ))
Vesc Detection:

To get the KV of your motor use the following formula:
KV = 26672erpm / (10pole_pair*38.5Volts*0.95duty_cycle) = 72.92.
Where you get the erpm, battery_in_voltage, duty_cycle from the vesc_tool realtime info by taking a screenshot while at max throttle( then duty cycle would be 95% i.e. 0.95).

Known Issues

Issue: Braking is very soft at low speeds. This is an issue shared by other direct drives/hub motors too.
Solution: Use current mode with a low reverse speed limit(I chose 4km/hr ). This uses active braking as opposed to locking the brakes at very low speed. With this I can come to a stop even on a decline slope. I used the vesc_tool mobile app to set the speed under the profiles tab. If you use metr pro, it can be done through modes.

Issue: Motor getting hot when climbing hills. If you look at the motor detection results, you can see that the internal resistance(IR) is 85mOhm. My flipsky 6374 motors have IR of 13mOhm. Heat produced is i²R so that tells us that the heat produced by 50Amp in 13mOhm motor will be same as 20Amps in 87mOhm motor. I wonder what other direct drives compare here.
Solution: Use lower limits on current than what you would use on geared drives. VESC automatic current settings are good, but you can push them a bit more(5-10Amps more, but be careful). To truly solve it, the IR should be reduced(open ended problem). I use +50/-60 for motor current in VESC and very happy with it.

How to buy

The best way is to talk to Kenna( with username kenna on the other forum, but rarely active) over email or whatsapp( + eight6 13four 1186 842three).

Price

Following was group-buy price so please use that in reference when asking for single qty price with Kenna.

Sensor wires

The white temperature wire may or may not present in your model

Pics

TKP setup

I paid a total of $22 for all the things needed for TKP setup.

1 X pack of pivot cups, bushing and nuts

2 X base_plate

Pneumatic setup

3D printed hubs:

Files are here.
After falling 3 times, in a month, because of stupid rocks, street plates bad roads, I refuse to ride thane anymore. I have already nearly 900km on 6" pneumatics and haven’t had a single problem since. So the only way I would these DD would be with pneumatics. Due to lack of available versions I made 3D printed hubs that directly works with these drives. I printed them in PETG . It’s been working great so far(50kms or so). Ideal material would be nylon, if you can access it. “Taulman Alloy 910” would be my recommendation.

Print Settings:

Material: Nylon(Recommended), PETG or ABS. PLA+ might also work.
Layer Cooling: off(To increase layer adhesion)
Infill: 100% and concentric(prints like walls)
Walls: 6 Walls

3D printed hub adapter:

Currently only the Bergmeister 150mm wheels are supported. It was designed by @landonkun and tested by @DAddYE . The files are here:

Aluminum hubs:

CNCed

@Janux-esk8 or @marcmt88(other forum), manufactured a sample for @topcloud and might be able to do it for you too. Edit: they are now available at janux-esk8.com
(Following 2 images are from @topcloud’s post on other forum)

Casted and CNCed

I modified the 3D printed parts to be more suitable for production using casting and followed by CNC. This is still in development. I made a poll here to guage the interest in such a hub here.

These wheels can also be used with a pulley, if you have a change of heart.

mishrasubhransu · June 2, 2019, 3:47am

No exactly a review, but here are some images, videos and metr pro plots

First Ride

Ride Video + metr pro

Consumption

The max consumption is really high because I use brakes to stop myself on inclines. Since watts are being consumed while I am not moving hence consumption shoots up. For some reason the average ride statistics report average consumption as 17wh/km whereas the plot above reports it as 25wh/km. Will have to get more data on that and figure out why. I have a feeling that using current mode is messing with the regen values(As processed by metr pro or in actuality). Take a look at the regen numbers.

Braking

Braking is fantastic by using current mode and limiting the reverse speed.

ryansinatra · June 2, 2019, 3:59am

Thanks for posting this here. Was waiting for someone to start an elofty thread on this forum. Still waiting on mine will update

Thama · June 2, 2019, 4:15am

I got a pair

ryansinatra · June 2, 2019, 4:17am

And? How are they? :d

Thama · June 2, 2019, 4:49am

Not test them yet, because it always rains when I want to go outside,

Goldrabe · June 2, 2019, 5:25am

Thanks for putting the thread up and organizing it neatly!

Sadly I pulled the battery from the board running these drives, so can´t check for myself. Are the 85mOhm confirmed by other people too?
I noticed that the drives are getting warm/hot after quite some distance but nothing too crazy, after a 20km ride I still can touch them for an extended period of time, I know it´s not really scientific, but for comparison Maytech hubs and R-Spec hubs are too hot to touch after the same distance.
I noticed your ESC got quite hot too, but 17Wh/km isn´t too bad for pneumatic wheels. I get an average of 19Wh/km with 100mm Urethane.
Here is the most recent Metr. record.

BillGordon · June 2, 2019, 5:41am

This was very much needed here. Nicely done, sir.

Winfly · June 2, 2019, 5:46am

Thanks for doing this.

mishrasubhransu · June 2, 2019, 7:48am

.Exactly the same for me. They were about 55C. I was comparing them to my belt drives which are warm(35C or so) for a similar trip.

That’s probably because they are 4.12 ones without heat sink. What ESC are you using?

Goldrabe · June 2, 2019, 8:05am

That makes it clear, I am on Escapes with Heatsink.
My cans got banged up quite a bit, do you know when the sleeves will be available? Maybe we could get enough interest that @RipTideSports could make us heatsink Urethane sleeves. At the moment I am building a 11S battery for those drives, looking forward how they will perform with less Amps and more Volts.

McErono · June 2, 2019, 11:55am

65 on my TBDD 75kv

ryansinatra · June 2, 2019, 4:53pm

I know that feeling

mishrasubhransu · June 2, 2019, 9:24pm

Then, that seems like the right number when compared to 85mOhm for 58kv eLofty.

@Goldrabe, do you have a screenshot of your VESC detection results? You said that your motors are probably 75KV?

mishrasubhransu · June 2, 2019, 10:34pm

That sadly won’t make any difference to the motor heat, because your ESC works like a step down regulator and applies the required voltage to the motor windings. It will reduce both the 10S voltage and the 11S voltage to the same voltage if given same command from your throttle. Only difference would be the current drawn from battery(it will go down), battery life and the top speed.

Goldrabe · June 2, 2019, 11:23pm

Sadly I pulled the battery from the board running these drives. I can’t check at the moment. They are probably between 60 to 70kv. I reached 40km/h on flat terrain with a little throttle left. According to the calculators I should only be able to reach 38km/h @ 60kv.

mishrasubhransu · June 2, 2019, 11:38pm

Maybe you were going down the slope? Since these don’t have belt drag, it does actually speed up down slope even with my Pneumatics very easily. My belt does that too but on steep down slope.

Goldrabe · June 3, 2019, 12:06am

In my perception it was totally flat, I will provide a screenshot of the detection ASAP. Isn’t it possible to get the kv by typing kv in the Vesctool console?

mishrasubhransu · June 3, 2019, 12:20am

For KV, you have to open the realtime plot and take a screenshot of

erpm or rpm
battery voltage
duty cycle

Winfly · June 3, 2019, 12:24am

These wheels feel great. Definitely best 90mm available on the market atm. I hard carved them on dkp. Tons of grip but not too soft. Still getting that road feel.