The Duty Cycle AWD

the DN-10 works great. i have it on the lowest setting to avoid burning thru the cells and lettting the magic electrolyte out. yes, on this machine you use 2 hand-held electrodes and a foot pedal (i have my pack laid out in the plastic holders prior to welding so it's easier to do it this way).

cwah said:
j3tch1u said:
no, i don't think you'd be happy with that one either. i ordered this one (DN-10) based on some feedback i got from a friend. unfortunately, the website is in chinese. on my 2nd pack, i just soldered it--faster than using a cheap spot welder and more reliable connections.

http://trade.taobao.com/trade/detail/trade_snap.htm?spm=0.0.0.0.Vb2nir&trade_id=399086158140177
Click to expand...

Thanks for your answer. I've looked at the DN-10 but it seems that it doesn't have the 2 pin to weld cells? It needs to be done by hand?
Click to expand...
 
Have you got those welds repaired my friend?


j3tch1u said:
the 5A curve on that graph is quite impressive. matches my experience...short, sharp drop initially, then levels out and holds pretty strong. although, my connections are far from optimized. the cell-logs are showing excess drop on 3 p-groups (due to insufficient nickel and weak spot welds i think) so the bms is cutting out and i am not getting the most out of the pack. more work must to be done to tighten the spread.

cell-log discharge graph 7s (black line is pack V)


liveforphysics said:
The PD is the first EV developed 18650, and it's LiNiCoAlO2, and it's panasonic, and they all have Tesla's vent design, and there are photos of the PD used in the new Rav4 EV opened up battery pics (Rav4 battery supplied by Tesla).
http://www.dampfakkus.de/akkutest.php?id=99
Still doubt it's he model S cell?
Click to expand...
Click to expand...
 
liveforphysics said:
Have you got those welds repaired my friend?
Click to expand...

yup. no more cut-outs. i've got two duty cycles built in case you drop by luke ;)

i replaced the forks with a marzocchi dj1 that i modified for good strong axle connection. fork failure is not an option. basically just enlarged the slot and made a 20mm sleeve. the clamp is not enough to resist the torque so i added a set screw thru the top. wheel is still easy to remove wires and all.

IMG_1080 sml.jpg
IMG_1081 sml.jpg
IMG_1082 sml.jpg
IMG_1083 sml.jpg
 
Well as you suggest that it is quite a tease. 3000 watts, continuous without letting out the magic smoke? More importantly, how will it be mounted? All very interesting, especially in view of the quality of your builds.
Rich
 
hi rich, thank you. 3000w peak is theoretical at this point with aluminum heat bridge and air cooling. the unit bolts to a round bracket that is welded to the frame.

IMG_1236.JPG

richmpdx said:
Well as you suggest that it is quite a tease. 3000 watts, continuous without letting out the magic smoke? More importantly, how will it be mounted? All very interesting, especially in view of the quality of your builds.
Rich
Click to expand...
 
so much rain in Taiwan since i came back on 12/31/13. but during Chinese New years in early Feb. the weather was nice and I invited Ben to the country side for a day or two. He brought down both the black and white Duty Cycles and we had lot of fun riding them here. We also had awesome time riding it on the wet sandy beach. I think Ben has some photos and videos on his iphone... but here's the clip from go pro:

[youtube]kG31-hRSY5o[/youtube]
 
that is a MAC motor converted to crank drive. instead of having the axle or hub spin, i've connected the inner clutch to an output flange. a 2nd clutch modified to run in reverse is used as the outer freewheeling mechanism. a standard square taper crank spindle replaces the axle and rides on large diameter bearings. haven't had time to post details on this yet.

beache said:
That Crank drive Motor looks amazing. Was it made or purchased?
Click to expand...
 
" . . . for more speed i'd just run two 6T's at 72v /w sinewave controllers."

I have a 6T MAC running on a 16S LiFePO4 split pack with separate BMS's for each half. It's mounted on a 26" wheel and powering a Catrike Speed based velomobile. It cruises at 35+mph. One of my planned potential upgrades was to be adding a third "half" to the pack in series for 76.8V. Paul at EM3EV advised against it, even though I have a temp sensor and CA V3 set to roll off power as it heats up and have sealed it in preparation for oil cooling. You seem to think 72V wouldn't be a problem if there were two motors on a lighter vehicle. Do you agree with Paul about my plan? Would a steel planet gear make the difference?
 
ummm did i say that? can't remember. i'm no expert on these motors so can't really give u any advice. paul would know better.

kynoto said:
" . . . for more speed i'd just run two 6T's at 72v /w sinewave controllers."

I have a 6T MAC running on a 16S LiFePO4 split pack with separate BMS's for each half. It's mounted on a 26" wheel and powering a Catrike Speed based velomobile. It cruises at 35+mph. One of my planned potential upgrades was to be adding a third "half" to the pack in series for 76.8V. Paul at EM3EV advised against it, even though I have a temp sensor and CA V3 set to roll off power as it heats up and have sealed it in preparation for oil cooling. You seem to think 72V wouldn't be a problem if there were two motors on a lighter vehicle. Do you agree with Paul about my plan? Would a steel planet gear make the difference?
Click to expand...
 
One of my planned potential upgrades was to be adding a third "half" to the pack in series for 76.8V. Paul at EM3EV advised against it
Click to expand...

The newer "upgraded" MAC has thinner laminations, and that means it will not have excessive heat losses due to eddy-currents at higher RPM's. If you purchased a MAC that is not the new "upgraded" model (thicker phase wires, temp sensor factory installed, thinner lams), then you may find that at the higher RPMs from using 76V will cause a much higher increase in heat than you might have previously anticipated.

The more I have researched Pauls choices at em3ev.com, the more I realize he really has done his homework, and...I would take his advice. For a 35-MPH trike that you want to go faster (with a 26-inch driven wheel), I would advise a direct drive hub with either oil-cooling or air-cooling.
 
You can easily melt a single MAC 8T on 72v. A 6T will most definitely melt, given the correct amps to get it above the ~45mph that an 8T hits on that voltage.

Now if you distribute the load around two motors, the sky is the limit.

Thanks a bunch for the video; that acceleration is brutal and i love it; it looks similar to my magic pie in a 20" wheel.

[youtube]UD_K_TRGcs4[/youtube]

This is what 4kW looks like being dumped into a single 8T, with a 270lbs rider. After this run, the motor was very hot and the gears ( i had the original white ones - this isn't the 0.35mm lamination motor ) turned into mash the next day i rode it, lol.
 
spinningmagnets said:
The newer "upgraded" MAC has thinner laminations, and that means it will not have excessive heat losses due to eddy-currents at higher RPM's. If you purchased a MAC that is not the new "upgraded" model (thicker phase wires, temp sensor factory installed, thinner lams), then you may find that at the higher RPMs from using 76V will cause a much higher increase in heat than you might have previously anticipated.
Click to expand...

The MAC/BMC are very powerful motors for their weight, but as with all geared motor designs, they shed heat worse than a DD, so if you beat on them and overdrive those babies significantly past their 1000W rating, it's only going to tolerate it for so long.

I personally 'ride the line' and push my motor to 1,500W for 10 miles at a time in order to get to the store / post office / etc at 35-38mph. It gets warm-hot doing this, for sure. But i have seen mine get just as hot at 1,100W continuous over a 40 mile ride. It might have a power output squarely between what a 9C and Crystalyte HS35xx is capable of doing, but it has the heat shedding capability more like a 9C.

Mind you, when i'm giving you these figures, i'm talking about a well-abused motor with the old version stator. I've weakened the magnets significantly by running it at 2000W up an 8% grade hill when i was 55lbs heavier than i am now, and running 4kW into it.

I'd guess that Ben's setup could do 40-43mph continuous without the motors getting hot. Amirite?
 
Aha, so that's why he beat you ( for a while ).
2-3kw uphill continuous is spectacular.
 
Thx Ben for sharing this with us all. A great thread with lots of details, pics and smart ways to go about electric bikes.
Several times during this thread you talk about production bike, are you starting to sell electric bikes?

I am a heavy rider, 110 kilo. Looking for a 2WD setup. I think I will try to make a carbon copy of this bike, if you don't have one for sale?
Have you found the need to use oil cooling or liquid cooling for the motors? Or are the loads spread out so much by using 2 motors that cooling is no longer an issue? I've hold back cos I've seen people advise against using strong motors for front wheel. How did you stiffen the front fork?

May I ask what is the going rate for 100 Panasonic NCR18650PD? Is it cheaper to use these batteries over the standard packs widely available?
Or is it more power one going for Tesla batteries?

PM me if you got bikes for sale :)
 
thanks macribs. i'm currently building a few for friends but no plans on exporting them outside taiwan yet (too much legal stuff i don't wanna deal with).

u won't need oil or liquid cooling. i'm running a new pack 14s7p LG 18650-HE2 (30A discharge/cell). bottleneck are the controllers and bms. but even if you are running monster controllers, tire traction and the motor gears become an issue.

i have my controllers set to give max 60a rear / 40a front. seems like a good balance. i'm also experimenting now with torque vector controllers to smoothen out the ride.

you may want to add vents for the rear bag to cool the controllers (big issue). i have one on the side and rear.

2014-08-18 16.18.15 sml.jpg
2014-08-18 16.18.40 sml.jpg

the panasonics were around $4/cell when i bought them last year. they should be cheaper now.

best of luck with your build!

macribs said:
Thx Ben for sharing this with us all. A great thread with lots of details, pics and smart ways to go about electric bikes.
Several times during this thread you talk about production bike, are you starting to sell electric bikes?

I am a heavy rider, 110 kilo. Looking for a 2WD setup. I think I will try to make a carbon copy of this bike, if you don't have one for sale?
Have you found the need to use oil cooling or liquid cooling for the motors? Or are the loads spread out so much by using 2 motors that cooling is no longer an issue? I've hold back cos I've seen people advise against using strong motors for front wheel. How did you stiffen the front fork?

May I ask what is the going rate for 100 Panasonic NCR18650PD? Is it cheaper to use these batteries over the standard packs widely available?
Or is it more power one going for Tesla batteries?

PM me if you got bikes for sale :)
Click to expand...
 


updated specs of the current Duty Cycle:

Frame/fork: Montague Paratrooper
Battery: 14s7p LG ICR18650-HE2
Capacity: 17.5Ah
Front/rear motor: Twin MAC 6T (EM3EV)
Controllers: 12FET 4110 Infineon (EM3EV)
BMS: 14s Li-on (EM3EV)
Throttle: Thumb
Torque Sensor: TDCM
Brakes: Tektro Auriga E-Comp /w Shimano RT86 ice-tech rotors
Tyres: Schwalbe Big Ben 26 x 2.35"
Battery Bag: Salsa El Mariachi
Controller Bag: Revelate Pika
No Load Speed: 96kph
Real Speed: 78kph on flat road
 
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