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by dogman dan
Feb 10 2020 7:18am
Forum: E-Bike General Discussion
Topic: Fat Bike vs (Hardtail)-MTB
Replies: 7
Views: 597

Re: Fat Bike vs (Hardtail)-MTB

Yeah,,,, you want it. And it does exist. In a gas motorcycle. I mean fast on road, pretty nimble suspension for off road. Perfect, except in many places riding that motorcycle on a bike trail is very illegal. The only real solution is to throw money at the problem, which is a real problem when there...
by dogman dan
Feb 10 2020 6:59am
Forum: General Discussion
Topic: What powerful rear geared hub motor?
Replies: 10
Views: 1531

Re: What powerful rear geared hub motor?

That should work, particularly since in a 12t winding, the motor will reach middle rpm where the motor stops running so inefficient a few seconds sooner than a fast winding would have. As the motor winds up to speed, it will stop trying to pull the full amps, effectively limiting excess motor heatin...
by dogman dan
Feb 07 2020 9:09am
Forum: E-Bike General Discussion
Topic: questions about mini-hub for a child
Replies: 6
Views: 463

Re: questions about mini-hub for a child

For a child, I'd do two things after choosing a low power mid drive. 1 remove all but the smallest front chainring. This will protect the motor, by insuring it will not be run in the wrong, very high, gear on a steep hill. Even a 350 watt will not overheat if its simply in the correct lower gears fo...
by dogman dan
Feb 05 2020 7:49am
Forum: E-Bike Technical
Topic: Battery pack made from several small modem packs.
Replies: 32
Views: 1311

Re: Battery pack made from several small modem packs.

Pretty much what I keep saying,, they will work fine in a 50 ah pack. But 50 ah is a lot of battery to carry on a normal bike. Maybe you are doing something else? but this is the bike section, sooo… I did build a custom frame that could easily carry 80 ah, but that does not mean it was going to ride...
by dogman dan
Feb 05 2020 7:39am
Forum: E-Bike General Discussion
Topic: Power cuts off because of cold weather?
Replies: 11
Views: 527

Re: Power cuts off because of cold weather?

Cold enough can do that. If the battery actually freezes, its also very harmful to try to use it. So you gotta do something, to keep it warmer while you work. You must keep it above freezing. If its cold, but still not froze, it will still perform very poorly, till it uses up enough of its power in ...
by dogman dan
Feb 05 2020 7:35am
Forum: General Discussion
Topic: Northern Lights Visible
Replies: 12
Views: 1471

Re: Northern Lights Visible

I used to see it in Idaho, when we spent summers there as a kid. They are very beautiful. Stars were great there too, we were way out in the sticks, off grid, so very low light pollution there. No seeing it here on the Mexican border last night. it was snowing. Last gasp of winter for us last night.
by dogman dan
Feb 02 2020 9:41am
Forum: E-Bike Technical
Topic: Battery pack made from several small modem packs.
Replies: 32
Views: 1311

Re: Battery pack made from several small modem packs.

What I was trying to say as well. they are the wrong cells when new, and now they are at least aged, if not used, if not used up. Go for it if you want, but be expecting spectacularly poor results, after a lot of hard work. Throttle can limit amps,, don't be surprised when the system shuts itself do...
by dogman dan
Feb 02 2020 9:35am
Forum: E-Bike Technical
Topic: New E Fat bike build help!
Replies: 6
Views: 652

Re: New E Fat bike build help!

Yeah, doable for that budget, but maybe no so much, if you want a really good riding bike. Trying to say, just the bike alone for that quality ride pushes 3 thou these days. But in between, there is a tolerable ride there in the used MTB's, that are now maybe 5 or more years old, but were not ridden...
by dogman dan
Feb 02 2020 9:17am
Forum: E-Bike Technical
Topic: Ebikes are they AC, DC or?
Replies: 56
Views: 2228

Re: Ebikes are they AC, DC or?

Interesting. I had been thinking all these years it was just DC,, with each phase simply turning on and off in sequence to make the motor want to turn towards the next magnet. Or is that true, but just of square wave controller? So still a Tesla type motor? Or is it that even Edison motor is ac? Ign...
by dogman dan
Feb 02 2020 9:05am
Forum: E-Bike General Discussion
Topic: Chinese moped motor
Replies: 7
Views: 421

Re: Chinese moped motor

Well,,, first get a third one,, then volt it up till it melts quickly. Back down another 12 or 24v, and there you are. Assuming they are direct drive type motors,, then whatever they say on the side, you can surely triple it. So typical 500w rated bike motors easily handle 1500w. 48v 30 amps. And th...
by dogman dan
Feb 02 2020 8:59am
Forum: E-Bike General Discussion
Topic: Holding your pants and your battery...
Replies: 21
Views: 898

Re: Holding your pants and your battery...

https://www.bing.com/videos/search?q=truckers+hitch&view=detail&mid=4413B24AF7C6C53A61E84413B24AF7C6C53A61E8&FORM=VIRE I never heard of truckers hitch. Then when I googled it, it turns out to be what I learned to use to tie canoes to the roof when I was in an explorers troop that raced canoes. That ...
by dogman dan
Feb 02 2020 8:50am
Forum: E-Bike General Discussion
Topic: Powerd wheelchair build
Replies: 23
Views: 1087

Re: Powerd wheelchair build

Yeah, just like that AW. No doubt, I'd seen one somewhere, most likely in a picture you posted years ago. And I vaguely recall somebody else here was designing something like that for his kid, but I cant recall if it was a trike or a quadricycle type thing. I seem to remember two small rear drive wh...
by dogman dan
Feb 01 2020 8:51am
Forum: E-Bike Technical
Topic: Hub motor high frequency noise
Replies: 12
Views: 1075

Re: Hub motor high frequency noise

FWIW, every time I ran a motor with enough power to melt it quickly, it howled like a jet engine. These were the smaller 500w rated " 9 continent" type DD hubmotors. Feed em 4000w, and they scream. ZZZZZZTTT.
by dogman dan
Feb 01 2020 8:44am
Forum: E-Bike Technical
Topic: help testing controller
Replies: 9
Views: 223

Re: After Learning Mode how do i know if Hall correct

Growling noise under the most load, but not too much is normal. It may have learned right, but still have a poor contact on one of the (usually) 8 wires to the motor, causing stutter. So what I mean is, if it just growls but runs fairly smooth, normal. if it bucks and makes a ton of noise, you are r...
by dogman dan
Feb 01 2020 8:40am
Forum: E-Bike Technical
Topic: Battery pack made from several small modem packs.
Replies: 32
Views: 1311

Re: Battery pack made from several small modem packs.

These really are the wrong cells. But parallel enough of them and you can do something with them. Really suggest you break them up into individual cells, with some tab attached if at all possible. Once you have the suitcase size thing built, use voltage sag under load to tell you what your real worl...
by dogman dan
Feb 01 2020 8:31am
Forum: E-Bike General Discussion
Topic: Powerd wheelchair build
Replies: 23
Views: 1087

Re: Powerd wheelchair build

Might get medical insurance to pay for the wheelchair attachments too. That's what I was leading into when I asked if you were in a chair, or a person who can walk some with difficulty, but needs different type mobility solutions. We've seen some really cool bikes and trikes for those that are just ...
by dogman dan
Feb 01 2020 8:21am
Forum: E-Bike General Discussion
Topic: Holding your pants and your battery...
Replies: 21
Views: 898

Re: Holding your pants and your battery...

if its just a back up, it really doesn't need the ratchet. I found the ones that just grip it at H freight. That's what I have as my back up strap. Cut to size. It just needs to be snug enough to keep it on the bike if the screws on my mount fail. Once, I had a ping battery fly off the back of my bi...
by dogman dan
Feb 01 2020 8:12am
Forum: Battery Technology
Topic: Paralleling uneven voltage cells?
Replies: 49
Views: 2146

Re: Paralleling uneven voltage cells?

Short version. Don't do it.

Damage to the cell itself is the real reason, although it could also get the strip hot enough to cause it to become a resistor.

If you can't charge them to closer to the same voltage, then for sure you don't want that piece of dog shit cell in your string.
by dogman dan
Jan 31 2020 8:06am
Forum: E-Bike General Discussion
Topic: Holding your pants and your battery...
Replies: 21
Views: 898

Re: Holding your pants and your battery...

Always a good idea to back up a good mount with something.

I really have learned to trust the magnet mount on my luna pack. Incredibly strong. But I still put a stout strap on it, more for just in case the screws on the thing break, than to improve the magnetic connection.
by dogman dan
Jan 30 2020 7:31am
Forum: Battery Technology
Topic: Help pls - New battery Unbalanced after 3 cycles
Replies: 7
Views: 651

Re: Help pls - New battery Unbalanced after 3 cycles

What I would do. Since I have RC chargers around, I would disconnect the bms first. Then I would connect one way or another, to charge each parallel section to full, or full as the RC charger will take them. ( might not be all the way to 4.2v). Record the voltage of each P section after charging ful...
by dogman dan
Jan 29 2020 8:00am
Forum: E-Bike Technical
Topic: How to check the condition of a battery?
Replies: 6
Views: 637

Re: How to check the condition of a battery?

FWIW, she did real good getting two years from lead. So replacing them with similar lead will work fine for her. Look at the code on the side of the battery, and try to source the same type. EV type lead weighs more, and costs more, so beware of a bargain cell that looks the same, but is too light a...
by dogman dan
Jan 29 2020 7:57am
Forum: E-Bike Technical
Topic: Budget Battery suggestions 72v?
Replies: 18
Views: 973

Re: Budget Battery suggestions 72v?

Lead for a slow, 24 or 36v bike, intended for use for under 6 miles. Forget it for 72v. The only thing affordable for 72v are lipos, which most get at hobby king. but they are known to be dangerous, and you have a lot to learn to use those safely. 72v speed on bikes is tricky, cheap bikes break down...
by dogman dan
Jan 29 2020 7:46am
Forum: E-Bike Technical
Topic: Battery pack made from several small modem packs.
Replies: 32
Views: 1311

Re: Battery pack made from several small modem packs.

Best approach would be to strip down to individual cells, leaving tabs attached. Test cells, then build 4 or 5 p sections which would then use a conventional bms. The testing will tell what quality cells you have, but often the c rate is much less than the top quality cells used to make packs able t...
by dogman dan
Jan 29 2020 7:40am
Forum: E-Bike General Discussion
Topic: Troubleshooting
Replies: 18
Views: 1012

Re: Ebike Hub 3 phase wire melting issue

Usually that's just a battery too weak to run the motor well. It sags under load so much it can't stay turned on.

Same problem can be similar to this thread, really poor connections or plugs causing the same thing.
by dogman dan
Jan 27 2020 8:24am
Forum: E-Bike Technical
Topic: Dapu hub motor compatible controller.
Replies: 3
Views: 476

Re: Dapu hub motor compatible controller.

That is an odd wiring setup. A generic sensorless controller that can run without halls connected will run it, connected to only the three fat wires.

Not sure what is with the other 3, usually its 5 wires for halls.