Search found 12718 matches

by fechter
Dec 15 2018 6:46pm
Forum: General Discussion
Topic: la Nina rears her ugly head
Replies: 1039
Views: 45611

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: 1044

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: 2308

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 157 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 157 times
by fechter
Dec 15 2018 2:33pm
Forum: E-Bike Non-hub Motor Drives
Topic: Sur-Ron - New Mid drive Bike
Replies: 2774
Views: 161995

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: 316

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: 46
Views: 1046

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: 1044

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: 582

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: 2774
Views: 161995

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: 141626

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...
by fechter
Dec 13 2018 3:25pm
Forum: Battery Technology
Topic: Generic-Chinese-Bluetooth-BMS-communication-protocol
Replies: 21
Views: 1491

Re: Generic-Chinese-Bluetooth-BMS-communication-protocol

I don't know of any way you can get the Atmel processor that runs the BMS boards to send 'raw' commands to the TI chip. You could remove or disable the Atmel chip and talk directly to the TI chips via I2C bus if you wanted to. Simon I see, there is an intermediary Atmel that talking to the outside....
by fechter
Dec 13 2018 3:20pm
Forum: Battery Technology
Topic: Any advantage of one layout over the other?
Replies: 21
Views: 1044

Re: Any advantage of one layout over the other?

MJSfoto1956 wrote:
Dec 13 2018 12:57pm
I'm aiming for a 20s20p 72V 68Ah pack (the diagram shown is just 1/4 of the whole battery)

M
How many amps?
by fechter
Dec 13 2018 3:14pm
Forum: E-Bike Non-hub Motor Drives
Topic: Sur-Ron - New Mid drive Bike
Replies: 2774
Views: 161995

Re: Sur-Ron - New Mid drive Bike

Most of those style dc-dc converters have some kind of current limiting so should be hard to blow up. I'm not sure how much the headlight takes but that could be measured. I think 5A for grips should be OK, but no guarantee. If it did blow up, here is a similar unit for about $20usd. Rated for 72v m...
by fechter
Dec 13 2018 10:44am
Forum: Large EV General Discussion
Topic: Toro Workman MDE conversion
Replies: 21
Views: 789

Re: Toro Workman MDE conversion

The batteries do seem pretty expensive. A DIY pack made from EV car batteries would be a great option if they were available. Seems like the supply of those is pretty limited in your area. Bummer. Personally, I would never go back to lead-acid. In the long run, the lithium batteries should be more c...
by fechter
Dec 13 2018 10:38am
Forum: Battery Technology
Topic: Replace Cells?
Replies: 33
Views: 582

Re: Replace Cells?

I could see the pictures OK. Removing and replacing the nickel strips doesn't look too bad, but there is no way to remove cells without cutting away part of the cell holders or completely un-welding the entire pack. To replace a cell group, I would pull the nickel strips off both sides of the bad ce...
by fechter
Dec 13 2018 10:23am
Forum: Stand-up E-scooters and E-skateboards
Topic: 5200W stand-up scooter with air suspension
Replies: 46
Views: 1046

Re: Stand-up scooter "VOSTOK 1"

CNC porn. :bigthumb:

I like the huge pile of swarf on the floor. That's going to be one really nice looking scooter.
by fechter
Dec 13 2018 10:17am
Forum: E-Bike Non-hub Motor Drives
Topic: Sur-Ron - New Mid drive Bike
Replies: 2774
Views: 161995

Re: Sur-Ron - New Mid drive Bike

A Domino throttle should work fine but will need a couple of resistors to make the output in the same range as a hall. The microswitch is not really needed. Over a long time, these had a track record of wearing out. There may be some decent quality hall effect twist throttles out there that would be...
by fechter
Dec 13 2018 12:17am
Forum: E-Bike Non-hub Motor Drives
Topic: Sur-Ron - New Mid drive Bike
Replies: 2774
Views: 161995

Re: Sur-Ron - New Mid drive Bike

Would anyone happen to know what that silver device I circled in the picture is? It has 3 wires going to it, Black/Green/Red wire. Is that the DC/DC converter? If it is, does anyone know how many amps it is rated for? Yes, that's the dc-dc converter. I couldn't find any marking on mine, but didn't ...
by fechter
Dec 12 2018 2:18pm
Forum: Stand-up E-scooters and E-skateboards
Topic: 5200W stand-up scooter with air suspension
Replies: 46
Views: 1046

Re: Stand-up scooter "VOSTOK 1"

The suspension looks like it's really doing its job. Also looks like you really need it around there. I thought the roads here were bad...
by fechter
Dec 12 2018 11:06am
Forum: Battery Technology
Topic: Generic-Chinese-Bluetooth-BMS-communication-protocol
Replies: 21
Views: 1491

Re: Generic-Chinese-Bluetooth-BMS-communication-protocol

That's great work. Thanks for posting.

If they use TI chips, would the datasheet for the chip tell us about the available commands?
by fechter
Dec 12 2018 10:57am
Forum: Stand-up E-scooters and E-skateboards
Topic: 5200W stand-up scooter with air suspension
Replies: 46
Views: 1046

Re: Stand-up scooter "VOSTOK 1"

Looks great so far...

What motor are you going to use? You may want to use two motors to get that much power.
by fechter
Dec 12 2018 10:51am
Forum: Battery Technology
Topic: Help with BMS
Replies: 6
Views: 134

Re: Help with BMS

It's possible the charger discharged the pack when not plugged in.
by fechter
Dec 12 2018 10:49am
Forum: Items for Sale - New
Topic: JP spot welder
Replies: 1131
Views: 141626

Re: JP spot welder

hello friend. Could I replace the battery with a modified microwave transformer? The welder circuit won't work with AC. If you had a rectifier on the output of the transformer, it could possibly work but the rectifier would need to handle over 1000 amps. I don't think a transformer would be able to...
by fechter
Dec 12 2018 10:45am
Forum: Battery Technology
Topic: Replace Cells?
Replies: 33
Views: 582

Re: Replace Cells?

Post a picture of your pack. Replacing a cell group may be challenging to impossible depending on pack construction and your skill level. I have a couple packs with bad cell groups but the welding and gluing was very strong and hard to take apart without destroying the good parts. Never fixed them. ...
by fechter
Dec 12 2018 10:30am
Forum: Motor Technology
Topic: Sensorless at standstill, development updates and status
Replies: 54
Views: 3038

Re: Sensorless at standstill, development updates and status

Great news on the design. I know what you're talking about with commerciallizing an invention. The business aspect is not something most engineers are good at. It's even worse in the medical device business to get things implemented and turned into an actual product that people can buy. At this stag...