Search found 3784 matches

by johnrobholmes
Jan 25 2016 1:51pm
Forum: E-Bike Technical
Topic: Definitive Tests on the Heating and Cooling of Hub Motors
Replies: 2101
Views: 383038

Re: Definitive Tests on the Heating and Cooling of Hub Motor

it wipes out easy with a paper towel, no big deal.
by johnrobholmes
Jan 25 2016 1:00pm
Forum: E-Bike Technical
Topic: Definitive Tests on the Heating and Cooling of Hub Motors
Replies: 2101
Views: 383038

Re: Definitive Tests on the Heating and Cooling of Hub Motor

The problem with running a no load test is that the power consumption is very low. 100-200w at most depending on the voltage. Even if you run the motor for extended periods of time to let the motor's heat saturate you still don't get a good idea of real world usage where power is 10-20x if not more...
by johnrobholmes
Jan 10 2016 9:01am
Forum: Items for Sale - New
Topic: Moped Rims and Wheels, 36 hole, 16" 17" 18" 19"
Replies: 175
Views: 41614

Re: Moped Rims and Wheels, 36 hole, 16" 17" 18" 19"

The factory didn't even make 3/4 of what I ordered too, so I don't see these lasting the length it takes them to make. Searching for new factories right now. Price was increased before stock was updated.
by johnrobholmes
Jan 09 2016 12:34pm
Forum: Items for Sale - New
Topic: Moped Rims and Wheels, 36 hole, 16" 17" 18" 19"
Replies: 175
Views: 41614

Re: Moped Rims and Wheels, 36 hole, 16" 17" 18" 19"

Hubmotor specific 17" rims just arrived and are back in stock.
by johnrobholmes
Dec 24 2015 12:14pm
Forum: Items for Sale - New
Topic: Moped Rims and Wheels, 36 hole, 16" 17" 18" 19"
Replies: 175
Views: 41614

Re: Moped Rims and Wheels, 36 hole, 16" 17" 18" 19"

One of my workers, Jonathan, will be leaving us in about 6 weeks and he runs the spoke machine. I no longer have time for it and the machine is tedious to operate, so we are considering just keeping certain lengths in stock for common hub motors. If you can please list the motors you want to lace in...
by johnrobholmes
Dec 24 2015 12:45am
Forum: Items for Sale - New
Topic: Moped Rims and Wheels, 36 hole, 16" 17" 18" 19"
Replies: 175
Views: 41614

Re: Moped Rims and Wheels, 36 hole, 16" 17" 18" 19"

Will do. They are due about any time now.
by johnrobholmes
Nov 12 2015 10:54pm
Forum: E-Bike Non-hub Motor Drives
Topic: What are you guys building over the winter?
Replies: 40
Views: 6570

Re: What are you guys building over the winter?

solid axle gokart on a mini chassis powered by a hub motor, underneath a power wheels jeep body. Radio controlled so I can ride on top or use it as a golf caddy. Tow trailers, kids, adults, whatever. I used it with the stock driveline until it burned up the motors and I got sick of the gearbox whine...
by johnrobholmes
Nov 08 2015 2:41pm
Forum: E-Bike Technical
Topic: Definitive Tests on the Heating and Cooling of Hub Motors
Replies: 2101
Views: 383038

Re: Definitive Tests on the Heating and Cooling of Hub Motor

Upon further consideration, the fully potted motor does give some advantage over just "dipped" if we consider long term reliability as the main goal. With the delicate parts sealed , an open sidecover is much more feasible too. With the core having some improved thermal coupling to the copper it can...
by johnrobholmes
Nov 08 2015 11:29am
Forum: E-Bike Technical
Topic: Definitive Tests on the Heating and Cooling of Hub Motors
Replies: 2101
Views: 383038

Re: Definitive Tests on the Heating and Cooling of Hub Motor

Great test. Not too surprising that the potting doesn't make much difference since the copper is in direct contact with the iron. A thin coat of epoxy or varnish may be all that is needed to keep the windings from moving around and help a little with heat transfer between wire strands. Based on my ...
by johnrobholmes
Nov 06 2015 11:42am
Forum: Battery Technology
Topic: The Cycle Satiator, universal charger for the enthusiasts
Replies: 743
Views: 128824

Re: The Cycle Satiator, universal charger for the enthusiast

As long as you don't charge them cold and then bring them into a warm place, it's not a big deal to charge cold if you aren't at fast rates.
by johnrobholmes
Nov 05 2015 11:25am
Forum: Battery Technology
Topic: The Cycle Satiator, universal charger for the enthusiasts
Replies: 743
Views: 128824

Re: The Cycle Satiator, universal charger for the enthusiast

Update for me, charger is still the most excellent part of kit I have. Accidentally left it out in a light rain, no problems.


The only downside is that I need a lot more of them so I can hard mount them on all my rigs!
by johnrobholmes
Nov 05 2015 9:04am
Forum: E-Bike Technical
Topic: Definitive Tests on the Heating and Cooling of Hub Motors
Replies: 2101
Views: 383038

Re: Definitive Tests on the Heating and Cooling of Hub Motor

Why dump heat into the sidecovers? Because they are aluminum and have the largest surface area! Might as well use what is already there to sink heat. I shape the back iron on our UAV outrunner motors the same way, for the same reason of trying to get lowest weight. I'll gladly take a few of your fir...
by johnrobholmes
Nov 04 2015 10:17pm
Forum: Motor Technology
Topic: Asynchronous motors - is induction the new future?
Replies: 76
Views: 18199

Re: Asynchronous motors - is induction the new future?

I talked with an engineer at thingap many years ago, about using them in "traction" vehicles. His suggestion was that I look elsewhere, because of the low torque density and low thermal mass of their motors. They can go from good to smoked too fast. Fine platform for positioning and robotics use, bu...
by johnrobholmes
Oct 15 2015 10:14pm
Forum: Motor Technology
Topic: Asynchronous motors - is induction the new future?
Replies: 76
Views: 18199

Re: Asynchronous motors - is induction the new future?

Yeah, I stuffed my subspindle not too long after getting it and it wasn't cheap to swap out. Got a good core swap value on my old one at least. I'm thinking a swiss lathe might have been smarter to learn production on, less mass when it crashes :lol:
by johnrobholmes
Oct 15 2015 9:58pm
Forum: Motor Technology
Topic: Asynchronous motors - is induction the new future?
Replies: 76
Views: 18199

Re: Asynchronous motors - is induction the new future?

My Mazak has an integrated DD spindle motor, and I bet it is also embedded magnet SR. No detent torque in rotation, and high torque density. I had asked a bunch of questions about it and none of the reps or repair men really know the nitty gritty of the drive design.
by johnrobholmes
Oct 12 2015 11:14pm
Forum: EV Business World
Topic: Tesla Model X
Replies: 23
Views: 4683

Re: Tesla Model X intro.

The model S I drove had the glass roof. Tesla is doing it right with the windows, even if it looks a little strange from the outside. From the inside it is really nice to have so much view. Plenty of power and storage, looks like a great mix of features. Wish I had them wing doors for my kid, I hate...
by johnrobholmes
Oct 11 2015 10:27pm
Forum: Motor Technology
Topic: Asynchronous motors - is induction the new future?
Replies: 76
Views: 18199

Re: Asynchronous motors - is induction the new future?

We theoretically discussed SRM hub motors on our forum, but came to conclusion that this type of electric motors will provide way smaller specific power (watts per kg). That's because the rotor in SRMs is not magnetic, it's just a piece of iron, so it does not produce any force per se. That's in co...
by johnrobholmes
Oct 03 2015 12:14am
Forum: Motor Technology
Topic: Asynchronous motors - is induction the new future?
Replies: 76
Views: 18199

Re: Asynchronous motors - is induction the new future?

I would be more inclined to say that switched reluctance topology will be favored in the long run, when controllers are more mature. Torque density of PMDC but without magnets, seems like a winner.


Good to see an induction motor used on an ebike, can only be positive for the future.
by johnrobholmes
Aug 14 2015 7:14am
Forum: Battery Technology
Topic: The Cycle Satiator, universal charger for the enthusiasts
Replies: 743
Views: 128824

Re: The Cycle Satiator, universal charger for the enthusiast

I certainly need one capable of 24s life!
by johnrobholmes
Aug 13 2015 8:05am
Forum: Battery Technology
Topic: The Cycle Satiator, universal charger for the enthusiasts
Replies: 743
Views: 128824

Re: The Cycle Satiator, universal charger for the enthusiast

Been rocking the crap out of my charger with nothing but great results, from a few cycles per week to a few per day. I'll update firmwares and see how it does.
by johnrobholmes
Aug 13 2015 7:50am
Forum: E-Bike Technical
Topic: A DIY Shop Tool for Making Torque Plates
Replies: 19
Views: 3889

Re: A DIY Shop Tool for Making Torque Plates

Very sweet little tool holder! I've certainly cut my fair share of torque plates by hand, and this would be far easier. Now I have a band saw, but it doesn't offer the ability to get square corners unless the slot is wider than the blade depth. A similar option is to adapt a regular grinder to hold ...
by johnrobholmes
Aug 13 2015 7:42am
Forum: Large EV General Discussion
Topic: Tesla Model "S" more details !!
Replies: 43
Views: 9668

Re: Tesla Model "S" more details !!

I get emails too, they do have marketing and news releases which is often signed by Elon himself. It's refreshing to have a face to the company. I don't know of any other consumer volume car company with a "face" that isn't merely a paid actor in TV commercials. Good point about production levels vs...
by johnrobholmes
Aug 12 2015 11:30am
Forum: Large EV General Discussion
Topic: Tesla Model "S" more details !!
Replies: 43
Views: 9668

Re: Tesla Model "S" more details !!

http://inhabitat.com/no-tesla-doesnt-lose-4000-every-time-they-sell-a-model-s/ Phew. I guess. A quick back of the envelope math (by dummies on the internet) makes it seem like they are loosing X amount of dollars per car sold. What they are actually doing is investing in the battery factory and R&D...
by johnrobholmes
Jul 27 2015 1:03pm
Forum: E-Bike Technical
Topic: Activate reverse on Infineon
Replies: 5
Views: 467

Re: Activate reverse on Infineon

Typically you will pull dx3 to ground, which enables reverse. Some models are not labeled the same, you might find it labeled as X3- .
by johnrobholmes
Jul 25 2015 11:15am
Forum: Battery Technology
Topic: AllCell vs Ping
Replies: 39
Views: 3361

Re: AllCell vs Ping

I've had more problem cells show up in ping packs than from em3ev or allcell, counting both customer and personal packs. If you are getting a ping pack, I would suggest cycling it at least 10 times to check for runts. One pack from em3ev got a bad string of cells after 5 years and multiple low volta...