Best bang for the buck DD Rear Hub Kit

[Bullfrog]

The two motors are really close, and the RH212 might have an edge on efficiency with how I ride my bike, but I used the Grin simulator comparing the two using the ranges, speeds, and hill grades that I mostly ride. I don't really care about top speed, but I care a lot about acceleration and torque in the mid range, specifically between 25 mph and 35 mph for safety, when/if I need to ride among cars. With my controller and battery, the Leaf had a very slight edge on roll on acceleration at those speeds, and pulls decently up to 40 mph before the torque curve drops, but you can still feel some throttle response at 45.

Here's a video from my voltage sag testing, trying to limit sag to improve my 25-35 and 30-40 roll on. I need a better methodology, since it's hard to hold steady at 25 or 30 before hitting the throttle, but the CA recorded the sag, so good enough.

Thank You....a few more questions please:

A. What winding/turn count is your Leaf motor?

B. What controller are you using and what is the peak amperage both battery and phase is it set for...if you don't have all the answers, that is perfectly OK, just let us know the answers you do have.

C. Based on the voltage on the CA display, I assume you are running a 72v/20s battery...is that correct?

D. What rear tire are you running...brand, diameter, and width? Just wanted this info so I can calculate the outside diameter of the rear tire.

E. What is your top speed on level ground?

Just FYI, I added a lot of extra explanation to my comments below so anyone not familiar with ebikes can understand better...I seriously doubt you need it .

I like the methodology you used and the speeds you are running so I may basically copy what you have done. The only change I might make is a winding that has a little bit slower top speed and/or mount the motor in a smaller diameter wheel. The smaller wheel would slow the speed down a little bit as well as make it a little more capable of higher acceleration since the diameter of the driven wheel determines the final gearing.

Background if anybody is interested...when I started this thread, I intended to go with either the cheapest DD conversion kit I could find just to try a DD motor for the first time or something on the opposite end of the spectrum like the Cromotor/QS205 so I could get acceleration similar to my MAC. After considering how I plan to use this particular bike, the weight of a bigger motor and how it would have a significant rear weight bias that could affect the way the bike handles, and the battery required to feed a big motor if I really wanted to use it to the fullest extent it was capable of, I have come to the conclusion that a DD motor with about a 35mm stator and Statorade or ATF will be the best compromise...all things considered. I tried the AW 1,000 watt kit via Amazon and I would recomend it if anybody had a very limited budget and/or didn't need/want a lot of power. With the Z910 connector between the controller and the motor, it was really simple and easy to remove the rear wheel should I need to change a tire but the Z910 connector can not handle a lot of amperage without melting and the controller that came with the AW 1,000 watt kit was capable of 30A (battery current) and although I didn't have any issues with it, I would not want to go over 30A with a Z910 connector.

 

[E-HP]

Thank You....a few more questions please:

A. What winding/turn count is your Leaf motor?

B. What controller are you using and what is the peak amperage both battery and phase is it set for...if you don't have all the answers, that is perfectly OK, just let us know the answers you do have.

C. Based on the voltage on the CA display, I assume you are running a 72v/20s battery...is that correct?

D. What rear tire are you running...brand, diameter, and width? Just wanted this info so I can calculate the outside diameter of the rear tire.

E. What is your top speed on level ground?

A. I recall it's the 5T winding (and performance matches very closely with the 5T on the simulator).
B. Sabvoton ML7280 clone (they are sold by a lot of different vendors listing varying specs). Claim is 80A battery, 240A phase, but seems these clones come delivered with some random current limits and need a shunt mod to get them to the rated current. (I shunt modded to 90A, but I normally limit to 70A, for a safe margin).
https://www.amazon.com/gp/product/B0B8CRXGTW/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1
I bought two of these for $70 each, but see the price has gone up to $90 now. APL is using a clone like this on his bike, but modded to higher current.
C. Yes, but a Frankenstein configuration using lipos and lithium ion, but works for me and allows me to charge fast.
D. 24x2.8 Specialized Big Roller. They recently discontinued this tire, so I just ordered 3 last week, since mine are currently bald.
E. Not sure. At close to a full charge, I've seen over 50 mph with field weakening before shutting it down (that's too dangerous with a bicycle helmet). At the moment, I accidentally installed an undersized breaker, that trips if I'm over 50A for 10 seconds, which happens when accelerating past 47 mph. when the field weakening kicks and starts pulling more current. I never get tripping with peak currents up to 90A, so I've been lazy and living with it for a year.

The Leaf is an efficient motor, but my choice wasn't made to maximize efficiency at the speeds I normally ride, but to have the performance I want in the speed range is use for my normal riding. I don't care what the top speed is, as long as it pulls hard in that speed range. That range has to be covered by the blue torque curve, before the drop off (happening at 40 mph in the graph below).

 

[Bullfrog]

A. I recall it's the 5T winding (and performance matches very closely with the 5T on the simulator).
B. Sabvoton ML7280 clone (they are sold by a lot of different vendors listing varying specs). Claim is 80A battery, 240A phase, but seems these clones come delivered with some random current limits and need a shunt mod to get them to the rated current. (I shunt modded to 90A, but I normally limit to 70A, for a safe margin).
https://www.amazon.com/gp/product/B0B8CRXGTW/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1
I bought two of these for $70 each, but see the price has gone up to $90 now. APL is using a clone like this on his bike, but modded to higher current.
C. Yes, but a Frankenstein configuration using lipos and lithium ion, but works for me and allows me to charge fast.
D. 24x2.8 Specialized Big Roller. They recently discontinued this tire, so I just ordered 3 last week, since mine are currently bald.
E. Not sure. At close to a full charge, I've seen over 50 mph with field weakening before shutting it down (that's too dangerous with a bicycle helmet). At the moment, I accidentally installed an undersized breaker, that trips if I'm over 50A for 10 seconds, which happens when accelerating past 47 mph. when the field weakening kicks and starts pulling more current. I never get tripping with peak currents up to 90A, so I've been lazy and living with it for a year.

The Leaf is an efficient motor, but my choice wasn't made to maximize efficiency at the speeds I normally ride, but to have the performance I want in the speed range is use for my normal riding. I don't care what the top speed is, as long as it pulls hard in that speed range. That range has to be covered by the blue torque curve, before the drop off (happening at 40 mph in the graph below).

View attachment 335108

Great info...Thank You Very Much .

 

[calab]

Your best bang for the buck is to buy a used dd hub motor. I'd only buy it if it could be opened up, see the color of the windings and do the sniff test. Think about the casual fella, studied up on es or bought someones ride. Rode it hard for a month and put in the shed, then life got busy. Yr(s) later, now comes cleaning time, and the ole electron fitness equipment is only in the way of the new lawn mower. Battery is worthless but you could pick buddies ride up on the cheap.

 

[Bullfrog]

Update....I am currently putting together a Schwinn Axum with a 4T Leaf Motor. My plan is to try the Leaf on 52v and then on 72v and depending on how i like it, I may eventually go to the Crystalyte H55100 motor.

The Leaf weighs 16.2 lbs and the Crystalyte weighs 19.8 lbs. The Cromotor and the QS205 are considerably heavier. The H55 motor from Crystalyte has a 55mm stator and is 135mm wide so it should fit most traditional donor bike frames.