Search found 11732 matches

by fechter
Feb 18, 2018 1:31 pm
Forum: E-Bike Technical
Topic: Speed control with a potentiometer
Replies: 10
Views: 199

Re: Speed control with a potentiometer

It sounds like you don't have a connection to the ground wire.
The black wire should be ground. Measure all three legs on the pot against battery negative.
by fechter
Feb 17, 2018 12:05 pm
Forum: E-Bike Technical
Topic: Speed control with a potentiometer
Replies: 10
Views: 199

Re: Speed control with a potentiometer

blue wire says speedometer, so don't use that one.
The green throttle wire goes to the middle leg on the pot.

The orange wire needs to be connected to the red wire to turn the controller on.
by fechter
Feb 16, 2018 1:13 pm
Forum: E-Bike Technical
Topic: Speed control with a potentiometer
Replies: 10
Views: 199

Re: Speed control with a potentiometer

You can use a regular potentiometer if you place fixed resistors in series with the 5v and ground wires. I would use a 5k pot, but the value is not critical. The fixed resistors for a 5k pot would be about 1.2k each. You want the signal to go from about 1v to 4v with a 5v source.
by fechter
Feb 15, 2018 9:27 am
Forum: E-Bike General Discussion
Topic: How To, 50A BBSHD Controller Mod
Replies: 142
Views: 10630

Re: How To, 50A BBSHD Controller Mod

If I am going to be replacing mosfets with better quality and higher voltage ratings, would this be a suitable candidate for this kind of modification? https://em3ev.com/shop/bafang-bbs02-48v-750w-controller/ It will be potted, so difficult to replace the FETs. If it has the 3077 FETs installed, th...
by fechter
Feb 14, 2018 8:09 pm
Forum: Alternative Energy
Topic: Need help with a transformer
Replies: 22
Views: 450

Re: Need help with a transformer

It will look like drawing 3. What you have is single phase, split phase.

A good description of it is here:
https://en.wikipedia.org/wiki/Split-pha ... tric_power
by fechter
Feb 14, 2018 9:16 am
Forum: E-Bike Non-hub Motor Drives
Topic: Sur-Ron - New Mid drive Bike from China
Replies: 462
Views: 25825

Re: Sur-Ron - New Mid drive Bike from China

Interesting.

Here's a cut sheet for the BMS chip:

http://www.lapis-semi.com/en/data/leafl ... 238_en.pdf
Lapis BMS.JPG
Lapis BMS.JPG (125.9 KiB) Viewed 395 times
by fechter
Feb 14, 2018 12:22 am
Forum: E-Bike General Discussion
Topic: How To, 50A BBSHD Controller Mod
Replies: 142
Views: 10630

Re: How To, 50A BBSHD Controller Mod

I know the BBSHD I'm running has the shitty 75NF75 FETs, but it still does amazingly well. I don't run 30A for long periods either, but the motor heating is more of an issue than the controller heating for me. Someone measured one with a FLIR and the temps around the controller are higher than the r...
by fechter
Feb 13, 2018 8:07 pm
Forum: E-Bike General Discussion
Topic: How To, 50A BBSHD Controller Mod
Replies: 142
Views: 10630

Re: How To, 50A BBSHD Controller Mod

I don't know how to tell without taking it apart and looking at the markings on the FETs.

I have seen an enhanced housing with extra cooling fins that Luna makes. Not sure if they are sold separately or not.
by fechter
Feb 13, 2018 8:03 pm
Forum: E-Bike Non-hub Motor Drives
Topic: Sur-Ron - New Mid drive Bike from China
Replies: 462
Views: 25825

Re: Sur-Ron - New Mid drive Bike from China

Wow, thanks for posting the teardown on the pack. Can you read the numbers on the BMS chips? It looks better than the typical cheap Chinese variety.
by fechter
Feb 13, 2018 3:03 pm
Forum: E-Bike General Discussion
Topic: More E-bikes found in NON-ebike media
Replies: 4778
Views: 198054

Re: More E-bikes found in NON-ebike media

NYC e-Bike Ban is Disaster for Immigrant Delivery Workers : https://www.voanews.com/a/new-york-city-e-bike-ban-immigrant-delivery-workers/4251812.html Some large ebike company with lots of money should help the delivery workers go on strike. Maybe selectively refuse deliveries to NYC lawmakers. Bik...
by fechter
Feb 13, 2018 2:58 pm
Forum: E-Bike Technical
Topic: Parallel throttle?
Replies: 6
Views: 175

Re: Parallel throttle?

Some throttles can sink as well as source. It depends on the hall sensor used.
by fechter
Feb 13, 2018 2:57 pm
Forum: E-Bike General Discussion
Topic: Active pre-charge/inrush control
Replies: 679
Views: 53213

Re: Active pre-charge/inrush control

I built a variation of the V3 inrush limiter design to use with my 12s 20Ah ebike pack. I'm using a normally open keyswitch to control it. I usually estimate about 20A per FET for minimal heat sinking. You should have no problems with heat as long as the board gets some air flow or against somethin...
by fechter
Feb 13, 2018 9:48 am
Forum: E-Bike Technical
Topic: Parallel throttle?
Replies: 6
Views: 175

Re: Parallel throttle?

I don't think you can just parallel the two as one could be fighting the other and possibly fry something. If each signal wire passed through a diode before being combined, then there would be no chance of backfeeding either one. The diode would result in a slightly lower signal voltage though, and ...
by fechter
Feb 13, 2018 9:42 am
Forum: E-Bike Technical
Topic: RCA 10.5 Connector for Battery Charger
Replies: 8
Views: 142

Re: RCA 10.5 Connector for Battery Charger

Just curious:
Was the fire caused by the bike?
by fechter
Feb 13, 2018 9:36 am
Forum: Battery Technology
Topic: Common pack design mistakes, how to avoid?
Replies: 234
Views: 18447

Re: Common pack design mistakes, how to avoid?

I've seen some packs that are completely potted, even over the vents (Grin LiGo, for example). I guess if the cell gets to the point where it wants to vent, you have bigger problems anyway. The foam stuff won't hold back a venting cell much anyway. If you could find some foam that doesn't expand muc...
by fechter
Feb 13, 2018 9:21 am
Forum: E-Bike General Discussion
Topic: Active pre-charge/inrush control
Replies: 679
Views: 53213

Re: Active pre-charge/inrush control

Interesting what they say about using zener diodes. I think they were talking mainly about their behavior at high speed. For the case of just limiting a slowly rising voltage, I don't think there would be any issue. The ringing part is hard to model or predict. I would guess the gate drive impedance...
by fechter
Feb 13, 2018 12:26 am
Forum: E-Bike General Discussion
Topic: Active pre-charge/inrush control
Replies: 679
Views: 53213

Re: Active pre-charge/inrush control

Bummer. That should earn you the Fried Guinea Pig award. An award I used to bestow to people who tried something untested and had the result of smoke release. Interesting about the ringing. I guess that's why they always use some kind of gate resistor. What was the FET and how many did you have in p...
by fechter
Feb 12, 2018 3:35 pm
Forum: E-Bike Technical
Topic: portable air compressors for tires
Replies: 49
Views: 1121

Re: portable air compressors for tires

tomjasz wrote:
Feb 12, 2018 2:42 pm
Thanks, how much case did you remove? Any chance of a picture? Always up for one of your project photos! THANKS!
It's the one shown about 12 posts up.
Another angle:
Tire pump final top.jpg
Tire pump final top.jpg (52.07 KiB) Viewed 285 times
by fechter
Feb 12, 2018 3:24 pm
Forum: Motor Technology
Topic: 2 controllers in paralell for one hub motor, is it possible?
Replies: 31
Views: 540

Re: 2 controllers in paralell for one hub motor, is it possible?

In a buck converter topology, when the switch is off and the magnetic field is collapsing, the current is circulated by a diode. Buck Converter Basics.JPG In a motor controller, this diode is really the body diode in the low side FET. When this diode is conducting, there will be a voltage drop acros...
by fechter
Feb 12, 2018 9:33 am
Forum: E-Bike Technical
Topic: portable air compressors for tires
Replies: 49
Views: 1121

Re: portable air compressors for tires

Here's what mine looked like inside before I cut down the case:
Tire Pump insides.jpg
Tire Pump insides.jpg (47.92 KiB) Viewed 181 times
by fechter
Feb 12, 2018 9:28 am
Forum: E-Bike Photos & Video
Topic: BBSHD Takes on the Luiz Fire Road
Replies: 5
Views: 223

Re: BBSHD Takes on the Luiz Fire Road

All the south-facing slopes are pretty bald and more trees on the north-facing sides. I'm sure it has to do with the dry climate. I've never seen anyone hang gliding around there. I suspect it's not allowed. That and there aren't many good landing spots at the bottom. There is a place about 20mi sou...
by fechter
Feb 12, 2018 9:16 am
Forum: E-Bike Technical
Topic: Kelly controller programming
Replies: 13
Views: 290

Re: Kelly controller programming

scrachdat wrote:
Feb 12, 2018 7:55 am

With adapter connected
1)V+, 1.79V
2)TX, 3.35V
3)RX, 1.62
Something doesn't look right there. the V+ should be closer to 5v.
by fechter
Feb 12, 2018 12:40 am
Forum: E-Bike Technical
Topic: portable air compressors for tires
Replies: 49
Views: 1121

Re: portable air compressors for tires

if anyone is interested there's a 48 - 60V portable compressor at banggood - 8.44 UK pounds delivered so that must be under $12. There's only a few left so if you're interested move fast. (I've looked at banggood a few times but not previously bought from them). That looks pretty similar to the one...
by fechter
Feb 11, 2018 1:45 pm
Forum: Motor Technology
Topic: 2 controllers in paralell for one hub motor, is it possible?
Replies: 31
Views: 540

Re: 2 controllers in paralell for one hub motor, is it possible?

The controller is using the motor windings as the inductor in a buck converter topology. If the PWM isn't synchronized, sometimes they would be in phase and sometimes they would be out of phase. If the controllers aren't using synchronous rectification, then they shouldn't blow up from this but you ...
by fechter
Feb 10, 2018 8:41 pm
Forum: E-Bike Technical
Topic: Help needed Motor does not run
Replies: 5
Views: 97

Re: Help needed Motor does not run

There are several things that can make it not run. Brake switch activated Hall sensors signal invalid Battery voltage too low Throttle signal bad And probably a few more, but you can eliminate these one by one with testing. I would try unplugging the brake switch wires too, as these are not needed t...