contemplating rewinded 80100 build

[1KW]

Hello,

Putting together some info on a possible DH mid drive build using a 80100 motor.

I am not a fan of lots of reduction, to me its more metal that will/and can possibly brake.

I have sourced a 80100 store that can add hall sensors, japanese bearings, keyway for sprocket, and rewind the motor to a low 80KV. I believe they can go lower than that but im not sure whats recommended?

At 80kv, I will just need a 1 stage directly to the freewheel cranks, then off the rear wheel. I would use a heavy duty chain and freewheel, and a heavy duty freewheeling crank setup(cyclone 140 dollar ISIS set).

Other option is to do a lower KV, 40? Then run it to other side as direct drive, it just wouldn't be efficient or as powerful.

Pricing everything out, I can do this cheaper than buying a STOCK gng kit that will need lots of money into it to upgrade, and I will have to buy those cranks listed above anyway....

Hardest part honestly seems like the mounting of the motor, and programming a sensored controller to the motor.

When rewound, is a different voltage okay? Or is 12s still the maximum?

 

[AussieJester]

I would say the hardest part is keeping the smoke from coming out the controller unless you spend large on a big Kelly controller or similar...
I would go gng if your going for off-road, less head aches imho

Best of luck

KiM

 

[gwhy!1]

I must be a exception as regards using the cheaper e-bike controllers.. just for info I have run a 8085 rewound ( in WYE) for 120kv and use external hall sensors, I use a modded 12fet 48v controller on a bike that is geared for 40-45mph and peaking at 7.5kw ( average of 5-6kw running ) and have not popped a controller yet, the motor gets warm/hot but not scary hot. Its all about tuning the controller to the gearing :wink:

Edit:
The problem with lower kv ( this is what I have found ) is that the motor will run much hotter if still trying to push the motor to its limits. I have not had a 80100 to play with but I think that these longer motors will run hotter than the 8085 for the same battery current. I would like to get hold of a 80100 to test this out but at the mo I am happy with 8085's

 

[turbo1889]

I think others would greatly appreciate you posting the source you have found for buying these kind of motors custom modified as you state including custom rewinding.

I know I would for sure. Do they only do that size or will they do other sizes as well?

 

[gwhy!1]

I now get all my motors from http://www.giantshark.co.uk/ and custom wind them myself.

 

[turbo1889]

That's cool but some of us don't like to do our own winding or install our own hall sensors and would gladly pay a fair sum to someone else who knows what they are doing to do that for us.

I've installed my own hall sensors on a 6354 following an online instructional text, photo, and video posted by a guy who installs hall sensors on 6374 motors for building those little folding kick-board scooters and making them go crazy fast on electric power and that was a chore I would rather have not have had to do myself and I've rewound a couple brush-less automobile radiator motors myself to get them into the RPM zone I wanted and would rather have not have had do myself.

For some of us the reason we do our own builds is to get what we want without having to resort to off the shelf e-bike kits (that usually suck) not for the love of building and rather we have a love of riding and would rather have custom quality services available that allow us to still get what we want and save us build time and hassle and give us more riding time.

Not nocking your "DIY" suggestion, for many that is the fun part. But for others custom services like the OP is describing would be highly desirable especially for those of us who have to figure out how to install hall sensors or re-wind for the first time and we probably don't do as good of a job as someone who has been doing it for quite a while. Skipping at least portions of the learning curve can be beneficial and advisable in some situations.

 

[gwhy!1]

That's cool but some of us don't like to do our own winding or install our own hall sensors and would gladly pay a fair sum to someone else who knows what they are doing to do that for us.

I've installed my own hall sensors on a 6354 following an online instructional text, photo, and video posted by a guy who installs hall sensors on 6374 motors for building those little folding kick-board scooters and making them go crazy fast on electric power and that was a chore I would rather have not have had to do myself and I've rewound a couple brush-less automobile radiator motors myself to get them into the RPM zone I wanted and would rather have not have had do myself.

For some of us the reason we do our own builds is to get what we want without having to resort to off the shelf e-bike kits (that usually suck) not for the love of building and rather we have a love of riding and would rather have custom quality services available that allow us to still get what we want and save us build time and hassle and give us more riding time.

Not nocking your "DIY" suggestion, for many that is the fun part. But for others custom services like the OP is describing would be highly desirable especially for those of us who have to figure out how to install hall sensors or re-wind for the first time and we probably don't do as good of a job as someone who has been doing it for quite a while. Skipping at least portions of the learning curve can be beneficial and advisable in some situations.

There is someone on here ( bruno ) that do custom wind motors , not sure if he does the 8085 but he does the 80100's , and as regards hall sensors there are a couple of off the shelf external hall sensors setup options, the controllers can also be bought pre modded. I would prob custom wind motors,mod controllers and supply hall sensors if someone wanted to make it worth my while and pay my hourly rate for doing it, But at this moment I just dont have any additional spare time even if I wanted to.

 

[Danny Mayes]

I think you will struggle with only one stage of reduction.

Or let me rephrase that, you will not get full power out of that motor with one stage of reduction. You got to have that 80100 spinning around 8/9000rpm for full power (if thats what you want).

What you are proposing might be ok for 1-2kw but not 5. Like Gwhy! said,it is all about the gearing.

Btw, what is the total reduction on the set up you were referring to Gwhy!? Out of interest.

I think AJs suggestion of GNG is a smart one. If you must go 80100, then start dealing with how you are going to implement at least 2 stages of reduction, that is something in the order of >10:1 (as an absolute minimum!) to the cranks and your 80100 no less than about 80kv...

With a 12fett you can go over 100v if needed. The voltage you need depends on your gearing and motor kV.

What top speed do you want?

D

 

[1KW]

thanks everyone for the help. My main ultimate goal is awesome torque with a limited top speed. I have good sized rolling hills here, and want to whop any car off the line. I really want to keep the voltage lower and carry the minimum needed for a 11 mile commute, less batteries to charge/connect/monitor the better. Thats why i was looking at BB drive reduction/gears. I have a 50lbs DH MTB that it will be going on. What i am requesting seems possible with a low wind 9c hub motor on 18s lipo...but im looking for a cheap route. Otherwise i have a hub motor I can snatch up for 200 USD.

-Is it possible to mount all this up without messing up my bikes frame? i used to have one of those 2 stroke motors on a cruiser frame, and the torque of the uBolts holding the motor on actually cracked the steel.

-one stage reduction is SIMPLE, imo. It would also remove 1-2 reductions that would/could have issues of their own. A simple one stage going to a larger sprocket then letting the cranks do the gear swap. This will allow shifting to keep motor in a better range for efficiency. However, for the torque i need I think a single sprocket to rear wheel is what i need?

Lets be honest, is there really a difference between 35mph and 40mph on a commute? We all usually hit the same red lights., right?

Entrance to my place...what percent grade is this?

 

[Danny Mayes]

1KW, You are not going to get the acceleration you are looking for with a 80100 at 80kv with a single stage reduction geared for 35mph. Just not going to happen.

I have a bike geared for 35mph with an 80100 rewound at 80kv and i have an 11:1 reduction to the rear wheel. It gets to 35 impressively quick.

Your proposal will only have about 2:1 reduction to the rear wheel. You will blow shit up and be unhappy. It is not going to work like you hope.

A gear cluster will handle an 80100 OK, there are people doing that, you will not necessarily need one gear. I however have no experience with this other than what I have observed from other here.

D

PS, where you live looks wonderful.

 

[turbo1889]

Estimating grade from pictures is very hard to impossible due to the loss of depth perception in a 2D image and grades often look shallower or steeper then the really are in pictures.

Most mid-drives that are geared correctly are capable of climbing most common road grades just by downshifting.

One thing you should consider is doing a mid-point jack-shaft build which will allow you to get more reduction with only one reduction stage. The problem with gearing down to the pedal crank is that the pedal crank is geared up to the rear wheel so you often loose most if not all of your reduction. Where on the other hand if you mount a jack-shaft in-between the crank and rear wheel and run a decently small size rigid output sprocket (16t for example) on the jack-shaft back to the rear wheel gear cluster and then run your motor reduction stage down to that jack-shaft (usually on the left side) you can have maximize your possible reduction with only one stage and then to tie the pedals in you just run a chain back from the cranks to a single speed freewheel on the jack-shaft which also means you don't have to use a freewheeling crank assembly and can use a standard bicycle crank assembly. The down-sides is that you end up having one more chain loop in the assembly, plus you have the added complexity and mounting location issues of the jack-shaft and you also loose your front derailer gears and only have the rear spool.



I'm running a somewhat more complicated set-up like that using a 6354 with sensors added with its original factory winding of 200-Kv running a 12.8V 40Ah 4s2p pack made from 20Ah prismatic screw top terminal LiFePO4 cells. That build is on a custom frame using 20" wheels with a slightly reclined crank forward flat footed riding position that also makes room for the jack-shaft and motor to just barely fit with all the clearances working out a little above and behind the crank. It uses a 10t-80t #25 chain reduction on the motor on the left side to the jack-shaft and the jack-shaft has three rigid mounted output sprockets (no derailer, manually lift and move chain by hand when stopped to change) of 14t, 18t, & 22t with an 8-speed rear freehub with a 13t-34t range and then the pedal drive has a 52t chain-wheel on the crank going back to a 16t single speed freewheel on the jackshaft to tie in the pedal drive.

In the top gear ratio (22t front manual change, 13t rear wheel derailer high gear) with the motor running near the top of its RPM range and me pedaling like a gorilla or on a down hill or with a stiff tail wind it tops out at just barely under 30-mph but at the same time in the lowest gear ratio (14t front manual change, 34t rear wheel derailer low gear) it will climb a 5% grade into a 10-mph head wind hauling 120 pounds of cargo load at about 6-mph without me doing any pedaling and the motor doing all the work and actually still running at more then 50% of its free load RPM so its still in a fairly efficient zone.

And that is all with a single reduction stage and I'm only running 500 watts of power (12.8v with a 40A limit on the programmable controller) and my motor is factory 200-Kv wound. It is true I'm running a lot less voltage then most people but on a 36V system one would only need to re-wind down to 67-Kv to use the exact same gearing I am using.

Long story short with either low enough Kv and/or low enough voltage and/or a big enough reduction ratio it is possible to get away with only one reduction step so long as your reducing down to a jack-shaft that is in-between the crank and the wheel rather then reducing down to the crank where it just gets geared right back up again going back to the rear wheel.