Search found 11753 matches

by fechter
Feb 23, 2018 9:34 pm
Forum: E-Bike General Discussion
Topic: Zip Tie Failure
Replies: 16
Views: 315

Re: Zip Tie Failure

I use 1" webbing strap with a quick release buckle on my A2B. I can cinch the strap pretty tight and it has worked well for a couple of years.
by fechter
Feb 23, 2018 7:06 pm
Forum: Battery Technology
Topic: Would you charge a 4s LiFePo with a "15V" wall wart (intended for charging a 12V SLA)?
Replies: 19
Views: 240

Re: Would you charge a 4s LiFePo with a "15V" wall wart (intended for charging a 12V SLA)?

In reading more carefully, it seems the circuit board might do the limiting and the wall wart is just a raw supply. It will need some kind of current limiting to avoid overloading the transformer.
by fechter
Feb 23, 2018 3:11 pm
Forum: Battery Technology
Topic: Would you charge a 4s LiFePo with a "15V" wall wart (intended for charging a 12V SLA)?
Replies: 19
Views: 240

Re: Would you charge a 4s LiFePo with a "15V" wall wart (intended for charging a 12V SLA)?

If the wall wart was made for charging lead-acid, then it should have some kind of current limiting and should work with LiFePO4.

I would worry a little about balancing though. Some LiFePO4 are prone to getting out of balance. Check individual voltages after charging.
by fechter
Feb 23, 2018 3:05 pm
Forum: E-Bike Technical
Topic: DD Hub motors: Why only 23 pole pairs?
Replies: 2
Views: 118

Re: DD Hub motors: Why only 23 pole pairs?

I don't think the number of pole pairs is going to have a dramatic effect on the performance, though obviously there must be some optimum number. Using a smaller wheel is effectively gearing the motor lower and allowing it to spend less time in the inefficient range. If you played with the number of...
by fechter
Feb 23, 2018 10:04 am
Forum: Motor Technology
Topic: Voltage drop
Replies: 2
Views: 46

Re: Voltage drop

There has to be a break in the wire someplace to get that kind of drop. Could be right at the connector.
by fechter
Feb 23, 2018 9:50 am
Forum: E-Bike Photos & Video
Topic: First Mid Drive build, cyclone 3kw, custom mounts, Full suspension Bike.
Replies: 25
Views: 228

Re: First Mid Drive build, cyclone 3kw, custom mounts, Full suspension Bike.

The controller might overheat being insulated inside the bag. I'd keep an eye on temps during testing.

One possible solution would be to glue one side of the controller to the inside of the bag. This would eliminate the air gap and allow for better cooling through the bag material.
by fechter
Feb 23, 2018 9:07 am
Forum: E-Bike Non-hub Motor Drives
Topic: Sur-Ron - New Mid drive Bike from China
Replies: 508
Views: 27381

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

I don't think the pedals were ever meant to actually pedal the bike. They are just there to meet regulatory requirements. It does seem possible to make a more functional pedal system though. Something that drives the jack shaft and has the right gearing could be done, but it would likely be expensiv...
by fechter
Feb 22, 2018 5:08 pm
Forum: Battery Technology
Topic: 12V 90Ah Lithium Ion Battery Construction - Newbie
Replies: 8
Views: 182

Re: 12V 90Ah Lithium Ion Battery Construction - Newbie

Peltier devices can operate over a wide voltage range. The heat flow will be roughly proportional to the voltage. 3 series would range from about 12.6v hot off the charger, down to about 9.9v at fully discharged. Average during discharge will be around 10.8v. 4 series would range from about 16.8v to...
by fechter
Feb 22, 2018 3:20 pm
Forum: Battery Technology
Topic: 12V 90Ah Lithium Ion Battery Construction - Newbie
Replies: 8
Views: 182

Re: 12V 90Ah Lithium Ion Battery Construction - Newbie

If the battery is 12V 90Ah, then it will be able to support a 30A draw for 1.5 hours, correct? Or am I completely off base? Correct. It could go for 3 hours in theory, but the battery will live longer if you use less of the capacity on each cycle. The main problem is no combination of Li-ion cells ...
by fechter
Feb 22, 2018 3:08 pm
Forum: Battery Technology
Topic: kWeld - "Next level" DIY battery spot welder
Replies: 299
Views: 25370

Re: kWeld - "Next level" DIY battery spot welder

I tested a 10Ahr, 6s Lithium Titanate pack but it was pretty weak.

The 20Ahr A123 prismatic cells might be something to try.
by fechter
Feb 22, 2018 3:00 pm
Forum: E-Bike Technical
Topic: Speed control with a potentiometer
Replies: 22
Views: 368

Re: Speed control with a potentiometer

It's hard to see in the pictures. If you trace the green throttle wire to the board, there should be some kind of letter marking on the spot where it attaches. Can you read the marking? Also, check the bottom of the board. Sometimes they get sloppy with the soldering and accidentally bridge across t...
by fechter
Feb 21, 2018 9:13 am
Forum: E-Bike Technical
Topic: Speed control with a potentiometer
Replies: 22
Views: 368

Re: Speed control with a potentiometer

Something is wrong there. It should be zero. Either something is shorted inside the controller or the wires are mixed up. At this point, I would want to take a look inside the controller and see where that green wire is attached. If you remove the end panel, you might be able to see it without takin...
by fechter
Feb 20, 2018 10:32 pm
Forum: E-Bike Technical
Topic: Any good and simple "cop button" solutions?
Replies: 39
Views: 1211

Re: Any good and simple "cop button" solutions?

Something like that might work on a Bafang BBSxx as well. The display would power up and defaults to setting 1. When you hit the button to change levels, it would go up on the display, but not on the motor. I might have to try this to see if it works. Motor might not run at all if it gets nothing fr...
by fechter
Feb 20, 2018 11:46 am
Forum: E-Bike Technical
Topic: Speed control with a potentiometer
Replies: 22
Views: 368

Re: Speed control with a potentiometer

Hmm... seems like maybe you have a defective controller. You might try opening the case and do an inspection of the wires inside. sometimes you can see something obvious. One more test; if you leave the green throttle wire disconnected, try measuring the voltage on it against battery negative. Norma...
by fechter
Feb 19, 2018 4:50 pm
Forum: E-Bike Non-hub Motor Drives
Topic: Sur-Ron - New Mid drive Bike from China
Replies: 508
Views: 27381

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

Seems like it wouldn't be too hard to make a cover to enclose the primary belt to keep dirt from getting on it.
by fechter
Feb 19, 2018 3:50 pm
Forum: Battery Technology
Topic: Motorcycle starter battery
Replies: 5
Views: 134

Re: Motorcycle starter battery

Are you using the 20Ahr A123 pouch cells? I don't think you can solder to those.
by fechter
Feb 19, 2018 3:33 pm
Forum: Motor Technology
Topic: Ferrofluid for hub cooling? BS or real?
Replies: 30
Views: 700

Re: Ferrofluid for hub cooling? BS or real?

howz bout iff either's good then do both must be better. FTW squared n'est-ce pas? what happens if you mix the two? concerned lemmings gotz 2no. touch o' da spring fever Probably a bad idea. The oil bases may not be compatible and the surfactant in the FF might not like it and cause all the iron pa...
by fechter
Feb 19, 2018 3:14 pm
Forum: E-Bike Photos & Video
Topic: BBSHD Takes on the Luiz Fire Road
Replies: 7
Views: 324

Re: BBSHD Takes on the Luiz Fire Road

richmpdx wrote:
Feb 16, 2018 11:51 am
Nice video, great ride location. Thanks for sharing. Interesting that the BBSHD handles the sustained climb with no problem. Obviously that is not your A2B, what's the ride?
Yes, the A2B wouldn't make it very far up that kind of grade. It's my fat bike:
Img_0654A.jpg
Img_0654A.jpg (131.83 KiB) Viewed 98 times
by fechter
Feb 19, 2018 2:59 pm
Forum: E-Bike Technical
Topic: Speed control with a potentiometer
Replies: 22
Views: 368

Re: Speed control with a potentiometer

If you disconnect the throttle green wire, does it stop running?
by fechter
Feb 19, 2018 1:56 pm
Forum: General Discussion
Topic: la Nina rears her ugly head
Replies: 664
Views: 23179

Re: la Nina rears her ugly head

Freeze warning for here tonight. Down to 30 predicted. While balmy by Midwest standards, a lot of vegetation around here isn't built to survive freezing.
by fechter
Feb 19, 2018 1:52 pm
Forum: E-Bike Technical
Topic: Speed control with a potentiometer
Replies: 22
Views: 368

Re: Speed control with a potentiometer

Hard to see exactly in the picture. The potentiometer is wired reversed, so that clockwise will decrease speed. This won't matter except the way you turn it is reversed. Swap the two outer legs to make clockwise increase speed. I don't see the red wire going to the throttle. Do the measurement I sug...
by fechter
Feb 18, 2018 1:31 pm
Forum: E-Bike Technical
Topic: Speed control with a potentiometer
Replies: 22
Views: 368

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: 22
Views: 368

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: 22
Views: 368

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: 10758

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...