Search found 12733 matches

by fechter
Dec 19 2018 12:21am
Forum: Stand-up E-scooters and E-skateboards
Topic: 5200W stand-up scooter with air suspension
Replies: 62
Views: 1844

Re: 5200W stand-up scooter with air suspension

In the future, I thought about anodized. I tried to do using what is, the result is not pleased... If do, do it accurately. And for this need to buy special equipment. For details of my size, suitable equipment will cost $4,500 The raw aluminum has an appeal to it but might get corroded over time. ...
by fechter
Dec 19 2018 12:18am
Forum: Motor Technology
Topic: Ferrite as a stator material?
Replies: 13
Views: 1067

Re: Ferrite as a stator material?

I'm a materials engineer who develops soft magnetic materials for a living so feel free to pick my brain on the topic :thumb: Thanks. Magnetism is still sort of a black art. I didn't consider the magnetostriction of Metglas. It might be good as an ultrasonic driver then. Can you think of a better m...
by fechter
Dec 18 2018 3:41pm
Forum: E-Bike Non-hub Motor Drives
Topic: Calling all Belt Drive Experts
Replies: 44
Views: 1278

Re: Calling all Belt Drive Experts

The belt has arrived! Looks cool as H^ll! :D Length looks good. Do these belts "break in", ie become less stiff? It took a lot of tension just to make it look straight... Not much. They stay pretty consistent over their life. That ratio looks pretty close to what I had on my old Vego. Proper belt t...
by fechter
Dec 18 2018 3:34pm
Forum: E-Bike Reviews & Testing
Topic: Epic 7kw+ 12 fet controller...or there abouts :)
Replies: 58
Views: 1817

Re: Epic 7kw+ 12 fet controller...or there abouts :)

OK...ignore the guy that has been repairing electronics since the 70's. What could I possibly know. You can learn a lot from other peoples' design mistakes. When you see the same kind of failure over and over and over, you eventually get it. I agree you shouldn't totally redesign the PV layout, but...
by fechter
Dec 18 2018 1:10pm
Forum: E-Bike Reviews & Testing
Topic: Epic 7kw+ 12 fet controller...or there abouts :)
Replies: 58
Views: 1817

Re: Epic 7kw+ 12 fet controller...or there abouts :)

I haven't seen CSD19536 before. It has great specs. Significantly better than the trusty old IRFB4110. You could always use the tab for the drain connection instead of the leg to at least eliminate that as a weak spot. The high side drains will be fed by the V+ rail, which could be a big aluminum or...
by fechter
Dec 18 2018 9:39am
Forum: E-Bike General Discussion
Topic: Worksman utility trike build
Replies: 16
Views: 685

Re: Worksman utility trike build

Just curious; does that thing have a differential in the rear or how do they accommodate going around corners?
by fechter
Dec 18 2018 9:28am
Forum: General Discussion
Topic: la Nina rears her ugly head
Replies: 1043
Views: 45789

Re: la Nina rears her ugly head

1.3" since Friday, so pretty close to the predicted.
Season total so far: 9.6". This time last year: 3.15". We're running close to normal so far this year.
by fechter
Dec 18 2018 9:26am
Forum: Motor Technology
Topic: Brushless motor efficiency
Replies: 16
Views: 657

Re: Brushless motor efficiency

I don't know, you might be right about that. There will always be an AC component to the current (ripple). The magnitude of the ripple will be less at a higher frequency. But the transition takes place more often, so might sort of cancel that out. For motors with lower inductance, the optimum freque...
by fechter
Dec 18 2018 8:58am
Forum: E-Bike Non-hub Motor Drives
Topic: Sur-Ron - New Mid drive Bike
Replies: 2794
Views: 163093

Re: Sur-Ron - New Mid drive Bike

As long as the bash guard doesn't bend with light impacts it will be acceptable. Right now the stock guard will bend up with like bike weight alone. Another possibility is to make something out of metal tubes like a cage that can support some weight. An intentional weak link might help protect the ...
by fechter
Dec 18 2018 8:46am
Forum: Stand-up E-scooters and E-skateboards
Topic: 5200W stand-up scooter with air suspension
Replies: 62
Views: 1844

Re: 5200W stand-up scooter with air suspension

New batteries for sure. Trick will be to find some that fit nicely (and are affordable).

Just wondering, how many hours of work did it take to build that? At the speed I do things, it would take about 20 years.
Are the parts coated or anodized? Anodizing would really take it to the next level.
by fechter
Dec 18 2018 12:18am
Forum: E-Bike Non-hub Motor Drives
Topic: Calling all Belt Drive Experts
Replies: 44
Views: 1278

Re: Calling all Belt Drive Experts

Minimum pulley size is another issue. Bigger pulleys have more teeth so can handle more load without slipping. The minimum recommended size is specified for a given belt type, but that is based on bending radius and not damaging the cords. You may need to use more teeth to get satisfactory results. ...
by fechter
Dec 17 2018 4:42pm
Forum: E-Bike Non-hub Motor Drives
Topic: Calling all Belt Drive Experts
Replies: 44
Views: 1278

Re: Calling all Belt Drive Experts

My experience comes from my old Zappy scooter. No pedals involved, but during regen the larger sprocket drives the smaller one.
I'm just pointing out that anytime a larger sprocket is driving a smaller one, skipping is more of a problem.
by fechter
Dec 17 2018 3:12pm
Forum: E-Bike Non-hub Motor Drives
Topic: Calling all Belt Drive Experts
Replies: 44
Views: 1278

Re: Calling all Belt Drive Experts

Yikes! You know they didn't make the thing thicker and heavier than they thought was necessary, right? Who actually pedals around here? One issue you are likely to run into is belt skipping. From experience I know that a small pulley driving a large one works well up to very high power levels. But ...
by fechter
Dec 17 2018 10:27am
Forum: E-Bike Technical
Topic: list of potting brands and conformal coatings for electronics
Replies: 3
Views: 93

Re: list of potting brands and conformal coatings for electronics

One I've used is Dow RTV734. This is like regular silicone glue except it's low viscosity and flowable. Good for small areas. It can be brushed over larger areas. It gives off acetic acid during cure so fumes must be vented during cure or can corrode copper. RTV3140 is similar only "electronic grade...
by fechter
Dec 17 2018 10:10am
Forum: E-Bike General Discussion
Topic: How To, 50A BBSHD Controller Mod
Replies: 204
Views: 23294

Re: How To, 50A BBSHD Controller Mod

I checked one I have here. It's 5200 ohms.
by fechter
Dec 15 2018 6:46pm
Forum: General Discussion
Topic: la Nina rears her ugly head
Replies: 1043
Views: 45789

Re: la Nina rears her ugly head

About 0.2" here since yesterday. Predicting over 1" for tomorrow and Monday. We'll see.
by fechter
Dec 15 2018 6:44pm
Forum: Battery Technology
Topic: Any advantage of one layout over the other?
Replies: 21
Views: 1058

Re: Any advantage of one layout over the other?

That looks good. I'd go for 100A. The controller is supposed to limit to below that. The breaker should only trip if something shorts out.
by fechter
Dec 15 2018 2:48pm
Forum: General Discussion
Topic: Reid Welch Returns (was Re: E.S. Quotable Quotes !)
Replies: 33
Views: 2331

Re: Reid Welch Returns (was Re: E.S. Quotable Quotes !)

Reid_Welch wrote:
Dec 15 2018 11:03am
Hello fechter. It's now the end of the year.

How do you like to light up?

Reid
cheech and chong1.jpg
cheech and chong1.jpg (7.93 KiB) Viewed 167 times
Oh, I think you were talking about the LEDs. Something more like this:
Burning Man Bikes.jpg
Burning Man Bikes.jpg (35.85 KiB) Viewed 167 times
by fechter
Dec 15 2018 2:33pm
Forum: E-Bike Non-hub Motor Drives
Topic: Sur-Ron - New Mid drive Bike
Replies: 2794
Views: 163093

Re: Sur-Ron - New Mid drive Bike

It might even work to take the stock plate and reinforce it with another aluminum plate that goes back to that frame member. Ideally done before it gets bent up. The stock skid plate is more of a splash guard and can't take much of a hit from an obstacle.
by fechter
Dec 14 2018 4:25pm
Forum: Large EV General Discussion
Topic: Porsche sets charging record of 400kw
Replies: 14
Views: 350

Re: Porsche sets charging record of 400kw

https://www.cnn.com/2018/12/13/business/electric-cars-charge-bmw-porsche/index.html Keith Pullen, a professor of energy systems at City, University of London, said that super-fast charging comes with other drawbacks. "If you charge a battery very quickly, it's less efficient [and] it actually damag...
by fechter
Dec 14 2018 1:35pm
Forum: Stand-up E-scooters and E-skateboards
Topic: 5200W stand-up scooter with air suspension
Replies: 62
Views: 1844

Re: Stand-up scooter "VOSTOK 1"

Looks great.

A sine wave controller will make it almost silent. If you get one with field weakening, you can get a higher top speed depending on load.

Any estimate on the total weight?

Are you compressing the cells?
by fechter
Dec 14 2018 1:30pm
Forum: Battery Technology
Topic: Any advantage of one layout over the other?
Replies: 21
Views: 1058

Re: Any advantage of one layout over the other?

That should work well. Depending on your cells, you might be able to run 10kW without overheating. A 80A fuse or breaker is supposed to handle 80A all day and will only trip or blow when it gets somewhat above that. I like the solar circuit breakers but they are large. Yes, you can program the batte...
by fechter
Dec 14 2018 12:14am
Forum: Battery Technology
Topic: Replace Cells?
Replies: 33
Views: 596

Re: Replace Cells?

I agree with your assessment. Sucks to have an expensive battery damaged.

Your options are DIY repair with no guarantee of success or replace the pack. Cells that get damaged in that manner may be more prone to catching on fire later. Always charge in a fire safe location.
by fechter
Dec 14 2018 12:11am
Forum: E-Bike Non-hub Motor Drives
Topic: Sur-Ron - New Mid drive Bike
Replies: 2794
Views: 163093

Re: Sur-Ron - New Mid drive Bike

I didn't know they existed. Sounds like a good option. There are advantages to having the hall sensor in a pot box where it can't get smashed or wet so easily.

Can you post a link?
by fechter
Dec 13 2018 3:30pm
Forum: Items for Sale - New
Topic: JP spot welder
Replies: 1131
Views: 141953

Re: JP spot welder

I was thinking about use some server Power supply in parallel. Do you think they can handle? If not, what about use 48v as a DC source? I can get a lot of power supplys for free they are 48v 50A, 2400w... I can parallel them, bit not sure if 48v is too much. 48v is too much. 12v is about the maximu...