Search found 13072 matches

by fechter
Mar 22 2019 6:50pm
Forum: Items for Sale - New
Topic: JP spot welder
Replies: 1198
Views: 150840

Re: JP spot welder

Good luck with your new work. I sure got my money's worth out of my welder so far. Still working perfect.
Img_1098A.jpg
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by fechter
Mar 22 2019 6:46pm
Forum: General Discussion
Topic: la Nina rears her ugly head
Replies: 1220
Views: 53740

Re: la Nina rears her ugly head

Coming down here again, but light so far. About 1/3" since this morning. I'm starting to feel pretty soggy.
by fechter
Mar 22 2019 1:03pm
Forum: Battery Technology
Topic: Ryobi Sale - hack together a 72V, 9Ah, Sony VTC6 battery for ~$300
Replies: 14
Views: 296

Re: Ryobi Sale - hack together a 72V, 9Ah, Sony VTC6 battery for ~$300

Right. You can probably get by with a lower current rating as your controller should trip on LVC if any packs go out. If one pack drops out and you keep running the motor, the diode will get very hot. It's hard to miss a sudden 18v drop in battery voltage, so you need to stop right away if you feel ...
by fechter
Mar 22 2019 11:14am
Forum: Battery Technology
Topic: Ryobi Sale - hack together a 72V, 9Ah, Sony VTC6 battery for ~$300
Replies: 14
Views: 296

Re: Ryobi Sale - hack together a 72V, 9Ah, Sony VTC6 battery for ~$300

But I'M not following. Why would the individual BMS see 72 volts? I'm planning to keep the whole pack intact and wire them in series. Each BMS should only see 18v, right? But if one of the three decides to trip, the load (controller) drops to zero and puts the full 72v across the tripped one, which...
by fechter
Mar 22 2019 8:16am
Forum: Motor Technology
Topic: Revolt RV-series motor review and comparisons
Replies: 164
Views: 7077

Re: Revolt RV-series motor review and comparisons

Do you think that size of the drive sprockets or pulleys would have an influence on the shock loads (the feather key sees)? If we take for example a drive train with 1:5 reduction. one with 10/50T and the other one 20/100T. Same type of chain or belt. I'm sure that has some effect. With smaller spr...
by fechter
Mar 22 2019 7:49am
Forum: Battery Technology
Topic: 3rd ebike battery. This time, doing it right
Replies: 80
Views: 3381

Re: 3rd ebike battery. This time, doing it right

I have a 48v input inverter that runs straight off the pack. I've used it to power my TV and DVD player during a power failure. I missed it a while back, but on your BMS, the unused balance wires should be all tied to the highest cell. If not, you may get false triggers and shutdown as soon as you t...
by fechter
Mar 21 2019 8:03pm
Forum: Battery Technology
Topic: 26s BMS for 600A max?
Replies: 11
Views: 203

Re: 26s BMS for 600A max?

A typical small BMS won’t have a shunt rated for 600A. Otherwise you are correct.
by fechter
Mar 21 2019 3:20pm
Forum: E-Bike General Discussion
Topic: Opinions requested by ambitious greenhorn
Replies: 16
Views: 259

Re: Opinions requested by ambitious greenhorn

A direct drive hub motor can generally handle much more than the rated power for short durations. My A2B motor is officially rated for 500W but I run it up to 2500W. For pavement use, a hub motor is hard to beat. For really steep off road trails, they overheat quickly. MP ride 7 solar farm.jpg The b...
by fechter
Mar 21 2019 2:59pm
Forum: Motor Technology
Topic: Revolt RV-series motor review and comparisons
Replies: 164
Views: 7077

Re: Revolt RV-series motor review and comparisons

larsb wrote:
Mar 21 2019 2:57pm
I've used the loctite retaining compounds:
https://www.henkel-adhesives.com/us/en/ ... ounds.html
worked well to fit loose shaft to bearing in that application
Which one? There are many.
by fechter
Mar 21 2019 2:57pm
Forum: Battery Technology
Topic: 20s 10p battery build, help with nickel strip needed
Replies: 11
Views: 248

Re: 20s 10p battery build, help with nickel strip needed

Those are some sweet looking packs. 😎 How would you go about fixing the rather large copper busbars to the ends of the pack? Solder? Am I right in thinking you can’t spot weld copper? On mine, the pack has to be split into two halves to mount on the bike. Img_1023.jpg Correct, spot welding to coppe...
by fechter
Mar 21 2019 2:49pm
Forum: Motor Technology
Topic: Revolt RV-series motor review and comparisons
Replies: 164
Views: 7077

Re: Revolt RV-series motor review and comparisons

Super Loctite was sort of joke. They do make many different flavors though. I used some green "wicking grade" stuff that was almost like welding the parts together. I don't remember the number. It was more like super glue. Yes, any kind of anaerobic locking fluid doesn't work well if there is much c...
by fechter
Mar 21 2019 2:37pm
Forum: Battery Technology
Topic: LiFePo4 starter battery BMS with only 2 leads?
Replies: 17
Views: 278

Re: LiFePo4 starter battery BMS with only 2 leads?

miro13car wrote:
Mar 21 2019 11:08am

LVC off is all that I need
That what it SAVED my battery, many, many times!!!!
No cheap shoddy BMS.
Imagine current on car V6 engine start up battery, what BMS can handle it
How did you do that?
by fechter
Mar 21 2019 9:04am
Forum: Motor Technology
Topic: Revolt RV-series motor review and comparisons
Replies: 164
Views: 7077

Re: Revolt RV-series motor review and comparisons

Any pictures of failed keyways? One thing that would help is to glue the connection together with super Loctite or something that will prevent any movement between parts. Its when you get a little free play things start to hammer and you get deformation. Just high power isn't the real problem but sh...
by fechter
Mar 21 2019 8:55am
Forum: E-Bike General Discussion
Topic: Any tips to power a bicycle with a hub motor from a scooter?
Replies: 9
Views: 157

Re: Any tips to power a bicycle with a hub motor from a scooter?

You could drill the flange for spokes and mount a bicycle wheel, but the diameter of even a 20" wheel is way larger than the little 8" scooter tire so the motor will be bogging down all the time and either overheat or just be too weak. A hub motor made for a bicycle size wheel is very inexpensive th...
by fechter
Mar 21 2019 8:33am
Forum: E-Bike Technical
Topic: Overheating middrive motor?
Replies: 22
Views: 293

Re: Overheating middrive motor?

I would try to keep the temp under 60C. Around 125C, you might lose the hall sensors or demagnetize the magnets.
It sounds like you have it geared too fast. Use lower gearing if possible. Another big factor is air speed over the motor. Anything to get more air over it will help a lot.
by fechter
Mar 21 2019 8:13am
Forum: Battery Technology
Topic: LiFePo4 starter battery BMS with only 2 leads?
Replies: 17
Views: 278

Re: LiFePo4 starter battery BMS with only 2 leads?

[ I did a car starter battery with 2 of this in parallel https://www.ebay.com/itm/4S-12-8V-14-4V-100A-LiFePO4-18650-Battery-Packs-BMS-Protection-PCB-Board-3-2V-x4-/322613685070?hash=item4b1d462b4e They are good to start 1.6l motor sometimes, but half of the times over current shuts it down. I may a...
by fechter
Mar 21 2019 8:05am
Forum: Battery Technology
Topic: 26s BMS for 600A max?
Replies: 11
Views: 203

Re: 26s BMS for 600A max?

If the BMS has overcurrent sensing, it doesn't even lose that, becuase it would still trip the contactor off. If your are bypassing the BMS with the contactor, the circuit will only be sensing the current in the contactor coil. It may be possible to use a humongous shunt in the main line and wire i...
by fechter
Mar 21 2019 8:00am
Forum: Items for Sale - New
Topic: JP spot welder
Replies: 1198
Views: 150840

Re: JP spot welder

Cowardlyduck wrote:
Mar 21 2019 2:28am
For those not following the Stealth Futr thread, here is how I recently made a HUGE battery using my JP.

The tip sharpening and booster subpack I added to my JP certainly made this a much easier build than it otherwise would have been. :D 8)

Cheers
Awesome! I wish I worked that fast.
by fechter
Mar 20 2019 11:16pm
Forum: Battery Technology
Topic: 26s BMS for 600A max?
Replies: 11
Views: 203

Re: 26s BMS for 600A max?

john61ct wrote:
Mar 20 2019 2:56pm
Would that approach still allow using the BMS for "live balancing" ?
Yes. The only thing you would lose is over current protection. Use a really big fuse.
by fechter
Mar 20 2019 11:14pm
Forum: General Discussion
Topic: la Nina rears her ugly head
Replies: 1220
Views: 53740

Re: la Nina rears her ugly head

Another 1/2" today. Should be nice tomorrow, but back to rain again on Friday. We don't need the rain at this point, but as long as the amounts are small, it doesn't cause any problems other than interfering with my riding time.
by fechter
Mar 20 2019 1:48pm
Forum: General Discussion
Topic: Boeing 737 Max 8 failures..an explanation ?
Replies: 35
Views: 578

Re: Boeing 737 Max 8 failures..an explanation ?

Graphics for those of us too lazy to read:
Boeing-737-max.jpg
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737-max-mcas.jpg (195.31 KiB) Viewed 98 times
by fechter
Mar 20 2019 10:22am
Forum: E-Bike General Discussion
Topic: BBS02 possible seal failure?
Replies: 4
Views: 92

Re: BBS02 possible seal failure?

My BBSHD does the same thing. I have to wipe it off every few rides. It even comes out of the non-moving joints.

Just don't blast it with a high pressure water hose. That will push dirt inside the motor.
by fechter
Mar 20 2019 9:47am
Forum: Battery Technology
Topic: 26s BMS for 600A max?
Replies: 11
Views: 203

Re: 26s BMS for 600A max?

One approach is to find a 26s BMS with a much lower current ranting and use the output of that to power the coil on a big contactor. If the BMS trips due to voltage being out of range, the contactor will open. The contactor would bypass the BMS and go straight to the cells.
by fechter
Mar 20 2019 9:40am
Forum: E-Bike Technical
Topic: Hub motor cracking noise
Replies: 10
Views: 169

Re: Hub motor cracking noise

I had one that did something like that. It turned out the spoke tension was uneven, causing the hub to get out of round and allowed the magnets to rub in one spot. You might also have a piece of debris stuck to a magnet. If you take apart the motor, you can usually see marks where anything is rubbing.
by fechter
Mar 20 2019 9:36am
Forum: Battery Technology
Topic: LiFePo4 starter battery BMS with only 2 leads?
Replies: 17
Views: 278

Re: LiFePo4 starter battery BMS with only 2 leads?

They do make BMS boards with a single port. Here's an example: https://www.ebay.com/itm/Waterproof-BMS-4S-12V-25A-35A-45A-60A-lifepo4-Battery-Charger-Proection-Balanced/153178686210?hash=item23aa294302:m:mspFssOoAy_6X3tjxu-U3NA But 4s of A123 cells is probably almost the same cost. You could skip th...