Search found 13941 matches

by fechter
Oct 16 2019 9:46pm
Forum: E-Bike Technical
Topic: Help ID compounds on Strain Gauge in hub motor? - photo
Replies: 8
Views: 177

Re: Help ID compounds on Strain Gauge in hub motor? - photo

Both silly putty and dielectric grease are non conductive. And the strain gauge is a fairly low resistance resistor, so it would take something really conductive to mess it up. The most important thing is to get a good bond between the strain gauge and the metal. What goes over it shouldn't effect i...
by fechter
Oct 16 2019 8:33am
Forum: Motor Technology
Topic: Serious FOCer (84V VESC 6 based controller)
Replies: 174
Views: 9982

Re: Serious FOCer (84V VESC 6 based controller)

shaman wrote:
Oct 15 2019 6:13pm
Ok. This should do better for connectors in the beta units.
That looks pretty good to me. Much better than the separate end board.
by fechter
Oct 16 2019 8:28am
Forum: Large EV General Discussion
Topic: How to wire a key switch properly? (for main power)
Replies: 12
Views: 187

Re: How to wire a key switch properly? (for main power)

Most ebikes just have the battery always connected to the controller and only switch the low current "key" or "ignition" line. If you want to store the bike for a long time, unplug the controller.
by fechter
Oct 16 2019 8:13am
Forum: E-Bike Technical
Topic: BBSHD Controller not programmable
Replies: 2
Views: 80

Re: BBSHD Controller not programmable

I've had problems with some of the FTDI USB adapters. The Bafang controller needs the "low" signal to be really low, like less than 0.3v, but some of the adapters don't pull down low enough. In one case I was able to make one work by adding a 10k resistor from the TX line to ground to make it go a l...
by fechter
Oct 16 2019 8:06am
Forum: Large EV General Discussion
Topic: 3WD hybrid GO-4 project
Replies: 6
Views: 161

Re: 3WD hybrid GO-4 project

Any idea how much a GO4 weighs? They look pretty heavy. It's going to take a really big electric motor to make that thing move. If you get it dialed in right, you should be able to go full power on both gas and electric to get some impressive acceleration. Controlling the regen may be a bit challeng...
by fechter
Oct 16 2019 7:58am
Forum: Motor Technology
Topic: bbshd /Nucular controller or other ?
Replies: 2
Views: 95

Re: bbshd /Nucular controller or other ?

At least one person did a Phaserunner on a BBSHD. If you search around you should be able to find it. You may need the metal gear at higher power levels.
by fechter
Oct 16 2019 7:54am
Forum: Battery Technology
Topic: BMS problems
Replies: 14
Views: 236

Re: BMS problems

On one like that it would go from C- to B-. It's where the fat wires attach.
by fechter
Oct 15 2019 9:43pm
Forum: Battery Technology
Topic: BMS problems
Replies: 14
Views: 236

Re: BMS problems

Don't use the C- port. Mine has that too. Under normal conditions, the resistor can be pretty small like1/4W. If you have a shorted controller, the resistor will just smoke and be like a fuse. A larger wattage one won't hurt as long as it fits in the space. It doesn't matter much which way the resis...
by fechter
Oct 15 2019 9:37pm
Forum: General Discussion
Topic: la Nina rears her ugly head
Replies: 1426
Views: 73143

Re: la Nina rears her ugly head

My last rain was in May. Now forecast shows a chance Wednesday Night A 30 percent chance of showers, mainly after 11pm. Mostly cloudy, with a low around 51. West wind 6 to 10 mph. New precipitation amounts of less than a tenth of an inch possible. Then back to sunny and warm. Things are very dry now.
by fechter
Oct 15 2019 8:35am
Forum: Battery Technology
Topic: Safety of Charging Deeply Discharged Lithium Batteries.
Replies: 14
Views: 303

Re: Safety of Charging Deeply Discharged Lithium Batteries.

The copper plating issue seems to be the real problem with Li-ion cells that have been over discharged. Beside that, the internal resistance of most cells will drastically increase once you get close to zero SOC, so if you are running high charge or discharge rates, the cells could heat rapidly. Thi...
by fechter
Oct 15 2019 7:59am
Forum: Battery Technology
Topic: BMS problems
Replies: 14
Views: 236

Re: BMS problems

A regular switch would work, but a push button is best. If you forgot to turn the switch off, the resistor could burn up. You need the resistor to protect the switch when the controller is sitting at zero volts. Without the resistor, the switch would arc weld it's contacts as the pack tries to charg...
by fechter
Oct 14 2019 9:36pm
Forum: E-Bike Non-hub Motor Drives
Topic: Most quiet e-bike motor?
Replies: 20
Views: 629

Re: Most quiet e-bike motor?

watchdog_timer wrote:
Oct 14 2019 9:22pm
Do I have that correct?
Yep.

A dc-dc converter will have some losses though, so making it quieter will have a drawback. Pole count in the motor will make a difference too, but mainly you want to avoid any resonance in the parts.
by fechter
Oct 14 2019 12:13pm
Forum: E-Scooter and Motorcycle General Discussion
Topic: Quick but too quick!
Replies: 12
Views: 288

Re: Quick but too quick!

Here is a schematic of how to install the trimmer pot: You can use a higher value pot like 1k but the final value is usually around 150 ohms. It's best to use a 10-turn pot but you might get by with a single turn. Hall Throttle Zero Trimmer.jpg Here's a picture of an install. You can put tape or hea...
by fechter
Oct 13 2019 11:22pm
Forum: E-Scooter and Motorcycle General Discussion
Topic: Quick but too quick!
Replies: 12
Views: 288

Re: Quick but too quick!

It would probably be a lot better if you didn't have as much 'dead zone' in throttle. The very first part of the throttle is less sensitive but if the motor only starts when you are at 1/3 or so, it will be very sensitive and twitchy. Depending on the throttle style, you can place a trimmer resistor...
by fechter
Oct 13 2019 11:55am
Forum: Battery Technology
Topic: BMS problems
Replies: 14
Views: 236

Re: BMS problems

Sorry for the delay, busy around here. You need to open the pack enough to get access to the BMS board. The board will have markings where the wires attach. You want the button setup to go between the B- and P- connections. These are big, heavy wires so the spots on the board will be pretty easy to ...
by fechter
Oct 12 2019 8:06pm
Forum: Motor Technology
Topic: APL's DIY axial-flux motor
Replies: 717
Views: 32928

Re: APL's DIY axial-flux motor

Fiberglass would be ok.
by fechter
Oct 12 2019 7:17pm
Forum: Motor Technology
Topic: APL's DIY axial-flux motor
Replies: 717
Views: 32928

Re: APL's DIY axial-flux motor

You don’t want a sheet of lamination iron on the face of the core. This would have a major eddy current. Any laminations need to be parallel to the flux direction.
by fechter
Oct 12 2019 10:10am
Forum: Motor Technology
Topic: APL's DIY axial-flux motor
Replies: 717
Views: 32928

Re: APL's DIY axial-flux motor

The back iron for the cores needs to be laminated or powdered iron. Otherwise it will act like a shorted winding. If the backing for the cores was fiberglass or other non-conductive stuff, it would be better but you really don't want a big gap between the two core pieces. If the gap is fairly small ...
by fechter
Oct 12 2019 9:57am
Forum: Battery Technology
Topic: How Hot Do BMS Fets Get?
Replies: 9
Views: 209

Re: How Hot Do BMS Fets Get?

I never really noticed the fets getting even warm and was told that they don't really get hot since they only pass current and don't really "control" but I need someone to strengthen that theory. Your temperature test is a good way to know. Run it hard then stop and see how hot it gets. A FET that ...
by fechter
Oct 11 2019 2:39pm
Forum: E-Bike Build Threads / Photos & Video
Topic: Lowrider eBike project
Replies: 29
Views: 759

Re: Lowrider eBike project

Just looked into it, could I have one super bright led (3.2v) running on the front then a normal (1.8v) running on the rear in series? Probably not. In series they will be forced to run at the same current which would put too much on the rear. Most bike lights are made for a higher voltage though. ...
by fechter
Oct 11 2019 9:45am
Forum: Battery Technology
Topic: How Hot Do BMS Fets Get?
Replies: 9
Views: 209

Re: How Hot Do BMS Fets Get?

If you know the Rds specification on the FETs, how many are in parallel, and your current drain, you can calculate how much heat is going to be dissipated. But temperature will also depend on how much cooling the BMS gets.
by fechter
Oct 11 2019 9:40am
Forum: Battery Technology
Topic: Drawing Power From Battery Charging Port
Replies: 3
Views: 110

Re: Drawing Power From Battery Charging Port

Yes, you can draw power from the charge port. The only catch is if you forget to turn the load off, it could drain the pack beyond the low voltage cutoff point and damage the cells.
by fechter
Oct 11 2019 9:23am
Forum: E-Bike Non-hub Motor Drives
Topic: DIY Fix for BBS02/BBSHD Pedal/Throttle Issue
Replies: 106
Views: 16863

Re: DIY Fix for BBS02/BBSHD Pedal/Throttle Issue

That should work. Let us know how it works out.
by fechter
Oct 10 2019 10:07pm
Forum: Motor Technology
Topic: APL's DIY axial-flux motor
Replies: 717
Views: 32928

Re: APL's DIY axial-flux motor

I couldn't completely comprehend how their design works. Seems like it's a skewed winding that uses turns on the sides to add to the main winding face, sort of like a Halbach array. The picture of the "prototype" was easier to understand. I was thinking about the core shape more too. A circular cros...
by fechter
Oct 10 2019 7:26pm
Forum: E-Bike Non-hub Motor Drives
Topic: DIY Fix for BBS02/BBSHD Pedal/Throttle Issue
Replies: 106
Views: 16863

Re: DIY Fix for BBS02/BBSHD Pedal/Throttle Issue

eBlur wrote:
Oct 10 2019 11:26am
Just to double-check... in the original schematic posted by @fechter "BBS02/BBSHD Pas Correction" there appears two be two transistor symbols. I'm assuming this is just a single KSP13BU as it looks like just one in everyone's actual build photos ;)
Correct. That's the symbol for a Darlington.