Search found 13735 matches

by John in CR
Feb 21, 2018 10:20 pm
Forum: E-Bike Technical
Topic: switching power supply as DC/DC converter...issues???
Replies: 4
Views: 86

Re: switching power supply as DC/DC converter...issues???

Thanks AW. I got it working fine now. I had the neg battery wires of my controllers disconnected from the battery, and somehow there was voltage leaking back through the system, 0.3 milliamps, which was confusing the power supply. Once I connected the controllers' negative to the pack the bleed down...
by John in CR
Feb 20, 2018 11:41 pm
Forum: E-Bike Technical
Topic: switching power supply as DC/DC converter...issues???
Replies: 4
Views: 86

switching power supply as DC/DC converter...issues???

I'm wrapping up my current build with a 31s pack (115v nominal). Due to the high voltage I figured the cheap and easy route for my 12V for lights was to use one of the 12V power supplies I have around the house. It seemed like my best candidate, since I expect about a 2A load at night, was the Wii p...
by John in CR
Feb 17, 2018 8:45 pm
Forum: E-Scooter and Motorcycle General Discussion
Topic: Gilera Runner - Newbie tips
Replies: 5
Views: 240

Re: Gilera Runner - Newbie tips

Like I thought, not much room for batteries. The easiest would be to make a new swingarm for a hubmotor...pretty simple. The biggest advantage of a hubmotor is that it leaves all that space for batteries, a space is the biggest premium on our electrics. Others are: 1. Simpler and easier. 2. Less com...
by John in CR
Feb 16, 2018 10:47 pm
Forum: E-Bike General Discussion
Topic: E-14 Rohloff "The Ultimate Electric Bike Transmission"
Replies: 5
Views: 255

Re: E-14 Rohloff "The Ultimate Electric Bike Transmission"

The ultimate electric bike transmission is just a tire. ie the tire transmits the energy directly from the motor to the ground.
by John in CR
Feb 16, 2018 10:38 pm
Forum: E-Scooter and Motorcycle General Discussion
Topic: Gilera Runner - Newbie tips
Replies: 5
Views: 240

Re: Gilera Runner - Newbie tips

Do you have some pics of the frame without all the plastic. I ask because while it's a cool looking scoot, the shape doesn't appear to be very friendly to packing in a bunch of batteries down low where you want the bulk of them. Forget "gearing", you want a powerful hubmotor to mount on it. My littl...
by John in CR
Feb 14, 2018 12:11 am
Forum: E-Bike Technical
Topic: Definitive Tests on the Heating and Cooling of Hub Motors
Replies: 1982
Views: 255686

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

The motor vents need to be designed to pump air in on one side and pull air out on the other. Nothing a engineer couldn't figure out quickly. It would likely take me a day or two or more to figure so i'll leave it to those with the Computer programs and related skills :) Even optimized intake and e...
by John in CR
Feb 13, 2018 11:55 pm
Forum: E-Bike Technical
Topic: Definitive Tests on the Heating and Cooling of Hub Motors
Replies: 1982
Views: 255686

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

Why would running such a motor amp to battery amp ratio be beneficial? Just reduced? The typical high 2.5:1 Phase to Battery current limit ratio so commonly used is a main source of heat problems. The reason is because it too often creates high phase current when you don't want it, eg at lower spee...
by John in CR
Feb 12, 2018 8:15 am
Forum: E-Scooter and Motorcycle General Discussion
Topic: R Martin EVD Moped with HubMonster
Replies: 69
Views: 1962

Re: R Martin EVD Moped with HubMonster

I hope your luck doesn't run out. I'm glad I learned the lesson with nothing more than losing one pack and having to clean soot off of a table. Plenty of others haven't been so lucky, and it's quite likely we've lost at least one forum member to lipo and never known about it.
by John in CR
Feb 12, 2018 8:10 am
Forum: E-Bike Technical
Topic: Definitive Tests on the Heating and Cooling of Hub Motors
Replies: 1982
Views: 255686

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

Of course the easiest route to cooler temps (other than proper controller settings) remains the least used. That is directing more air flow toward the hubmotor shell. or a bigger motor which will have a lower electrical resistance Another easy way, though not as easy or cheap as air deflectors near...
by John in CR
Feb 11, 2018 7:12 pm
Forum: E-Scooter and Motorcycle General Discussion
Topic: R Martin EVD Moped with HubMonster
Replies: 69
Views: 1962

Re: R Martin EVD Moped with HubMonster

Yes, the little 4s RC lipo pack was just sitting there for at least a month on a table with each pack spaced apart about 5" after I checked a new shipment of 20 packs for balance. It was in our fan ventilated guest house that no one but me entered, so I know for a fact that they were undisturbed. I ...
by John in CR
Feb 11, 2018 2:48 pm
Forum: E-Scooter and Motorcycle General Discussion
Topic: R Martin EVD Moped with HubMonster
Replies: 69
Views: 1962

Re: R Martin EVD Moped with HubMonster

Partly into building the 30Ah pack, I thought it looked really close to the same size as a 50Ah SLA. Sure enough, they weigh almost the same amount too. Except that it's 30Ah at 66 volts as compared to 50Ah at 12 volts or 3.3X more capacity than the SLA at the same weight. More like 6X the real wor...
by John in CR
Feb 11, 2018 2:05 pm
Forum: E-Bike Technical
Topic: Hi. Need help to find controller..
Replies: 4
Views: 92

Re: Hi. Need help to find controller..

For a controller to make less than 30W of heat using 50V at 30A to meet your 98% efficiency requirement, you'll want a controller that is capable of far higher current and set it to your lower current requirements. You mention that size isn't important, so most any 18fet controller should fit the bi...
by John in CR
Feb 11, 2018 4:45 am
Forum: E-Bike Technical
Topic: Definitive Tests on the Heating and Cooling of Hub Motors
Replies: 1982
Views: 255686

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

Of course a hotter motor has less performance. Plus by then your battery voltage is lower and voltage is sagging even more. Regarding the earlier mention of adding more non-working weight to a motor by stuffing more aluminum on the stator isn't a good idea. That would actually slow heat transfer to ...
by John in CR
Feb 10, 2018 8:01 am
Forum: E-Vehicles General Discussion
Topic: The BEST connectors, period
Replies: 10
Views: 1421

Re: The BEST connectors, period

Well, I'm looking for some really high end connectors like you would find on a spacecraft or nuclear bomb. If you're building something that well, why do you need connectors? Just hard wire everything. In the amount of time it takes to install connectors you can hardwire 2 or 3 times. Connectors ar...
by John in CR
Feb 10, 2018 7:53 am
Forum: Motor Technology
Topic: Removable method of securing motor's axle nuts
Replies: 9
Views: 221

Re: Removable method of securing motor's axle nuts

Clamping torque arms for the win, though clamping dropouts are best. I don't even bother with axle nuts anymore except sometimes as decoration. Zero issues in 9 years.
by John in CR
Feb 09, 2018 10:45 pm
Forum: Motor Technology
Topic: Mid drive vs Hub Motor for 10000 watt project
Replies: 88
Views: 2467

Re: Mid drive vs Hub Motor for 10000 watt project

5) Obviously a tall gear (16 inch motorcycle wheel vs 20 inch bike wheel) is going to load the motor much more than a short gear, but I think this is minimized once the bike is moving... 16" moto wheels come in many sizes. Some of the narrowest result in an OD under 20". I have one of those, as wel...
by John in CR
Feb 02, 2018 9:55 pm
Forum: E-Scooter and Motorcycle General Discussion
Topic: R Martin EVD Moped with HubMonster
Replies: 69
Views: 1962

Re: R Martin EVD Moped with HubMonster

You diving down a rabbit hole. When you divide the slot and pole count by half (everything else the same), it will significantly increase Kv, maybe by more than 2x (I haven't chased that rabbit far enough to say exactly). For someone who can do their own controllers there's no benefit to going 6 pha...
by John in CR
Feb 01, 2018 11:10 pm
Forum: E-Scooter and Motorcycle General Discussion
Topic: R Martin EVD Moped with HubMonster
Replies: 69
Views: 1962

Re: R Martin EVD Moped with HubMonster

...This is the cheapest way to get the EV on the road without incurring massive SLA weight penalties or upgrading straight to 32S. Actually it's not, and you can have a far far safer much longer lived pack as well for cheaper. I bet I get zero sag too! LOL! Don't we all wish that was possible.
by John in CR
Feb 01, 2018 8:08 am
Forum: E-Scooter and Motorcycle Photos & Videos
Topic: electric trial bike
Replies: 263
Views: 67608

Re: electric trial bike

Once you forget about batteries, everything a gas motor can do an electric motor can do much better, because it's torque curve is so much wider with max torque from zero. Feel and precise control over torque delivery is where I'd like a clutch. Of course that's coming from someone yet to try an expe...
by John in CR
Jan 31, 2018 9:00 pm
Forum: E-Scooter and Motorcycle General Discussion
Topic: R Martin EVD Moped with HubMonster
Replies: 69
Views: 1962

Re: R Martin EVD Moped with HubMonster

FWIW, you wouldn't drive from the bolt flange for the rim. Just use the disc brake mount for the sprocket. That's how I'll use one for the off road moto I want. Of course there's a 2wd one planned too, but that will be with them in-wheel of course. I need to get EG's help on controller for that one ...
by John in CR
Jan 31, 2018 8:50 pm
Forum: E-Scooter and Motorcycle Photos & Videos
Topic: electric trial bike
Replies: 263
Views: 67608

Re: electric trial bike

I'd like to have a mechanical clutch, but I see no need for a flywheel. You guys are too accustomed to low power.
by John in CR
Jan 30, 2018 10:45 pm
Forum: E-Scooter and Motorcycle General Discussion
Topic: R Martin EVD Moped with HubMonster
Replies: 69
Views: 1962

Re: R Martin EVD Moped with HubMonster

The more I think about it, the more I think it was a 24 phase motor with 24 coils, ie essentially 1 tooth per phase. There's no efficiency gain by going 6 phase. I outlined the advantages above. The Monster family of hubmotors have high efficiency due to thin high quality laminations, great copper f...
by John in CR
Jan 27, 2018 7:22 am
Forum: Motor Technology
Topic: Mid drive vs Hub Motor for 10000 watt project
Replies: 88
Views: 2467

Re: Mid drive vs Hub Motor for 10000 watt project

You need to measure the phase-to-phase resistance of the windings. That's what will tell you the current handling of the motor. While the larger aluminum side covers and increased surface area of their sculpted shape increases the amount of heat that can be dissipated far beyond the 1kw or so that a...
by John in CR
Jan 27, 2018 6:45 am
Forum: E-Scooter and Motorcycle General Discussion
Topic: R Martin EVD Moped with HubMonster
Replies: 69
Views: 1962

Re: R Martin EVD Moped with HubMonster

The number of phases is no game changer, though I suspect as you add more controller MCUs hunting for the rotor position that the startup under load becomes smoother, maybe even enough so that sensorless operation becomes practical at useful power. In terms of the motor itself there is no difference...
by John in CR
Jan 26, 2018 9:53 pm
Forum: E-Scooter and Motorcycle General Discussion
Topic: R Martin EVD Moped with HubMonster
Replies: 69
Views: 1962

Re: R Martin EVD Moped with HubMonster

20 magnets of alternating polarity whizzing by 24 stator teeth is the same frequency regardless how it's wound. Pole count is based on magnets, not the stator. If your Alien motor has 20 magnets, then yes it will work fine wound with 6 sets of phases. If the magnetic pole count is different, then it...