Search found 38 matches

by kevbo
Mar 16 2017 1:13pm
Forum: E-Bike General Discussion
Topic: perfect gear ratio and components.
Replies: 14
Views: 1756

Re: perfect gear ratio and components.

People, terrain, riding style, etc. vary so much that there is no formula that will yield an exact, or even necessarily close gearing. And that is just for pedal bikes. Throw in variable motor size, battery, range goals, etc. with an eBike, and it is totally an impossible question to answer. There i...
by kevbo
Mar 16 2017 12:12pm
Forum: E-Bike General Discussion
Topic: Warning to Yuba Owners - don't use large rotors
Replies: 176
Views: 19668

Re: Warning to Yuba Owners - don't use large rotors

Thanks for posting this warning to mundo owners. I have replaced my fork in response to this thread. Besides the new design Yuba fork, Surly sells the Big Dummy fork as a spare part, and that is what I elected you use. Mainly because the steerer was a bit longer, and I am tall. The Surly fork is als...
by kevbo
Mar 16 2017 11:29am
Forum: E-Bike General Discussion
Topic: Black Paint, & Heat Spunge..
Replies: 4
Views: 642

Re: Black Paint, & Heat Spunge..

I know of a few ham radio operators have used black shoe polish inside high powered amplifiers with radiation cooled tubes (3-500Z s). The liquid kind with the sponge applicator built into the bottle. I think this is mainly because it is fairly easy to apply without masking or disassembling the ampl...
by kevbo
Mar 15 2017 5:58pm
Forum: E-Bike General Discussion
Topic: Lots of punctures - replace with solid or puncture resistant
Replies: 35
Views: 2733

Re: Lots of punctures - replace with solid or puncture resis

And carry a C02 Cartridge pump. Small pumps are a pain when servicing a tire out on the road. I agree, the bulk of frame mounted pumps are not fun. But then I discovered this style, and have put them on most of my bikes: https://www.amazon.com/Schwinn-Mini-Frame-Floor-Pump/dp/B00F2DG3KQ That Schwin...
by kevbo
Mar 13 2017 9:38pm
Forum: E-Bike Non-hub Motor Drives
Topic: A Newb and his Yuba/Stokemonkey
Replies: 11
Views: 1846

Re: A Newb and his Yuba/Stokemonkey

Here are some photos of how I set up the eBrake switch: The bent spoke in the foreground pivots at the elbow end where it is zip-tied to the frame. https://photos.smugmug.com/Other/SmugShots/i-phRnSfx/0/L/smugshot_3546703-L.jpg It is linked (another zip-tie) to one side of the straddle cable for the...
by kevbo
Mar 13 2017 8:02pm
Forum: Battery Technology
Topic: Enlighten me please: why focus on P connections, not S?
Replies: 12
Views: 1925

Re: Enlighten me please: why focus on P connections, not S?

Hillhater wrote:What you have missed is numerous other threads discussing this same topic.
Like this one..
https://endless-sphere.com/forums/viewt ... 14&t=84412
and lots of similar ones if you use the search function.
Thanks. Not knowing the name for a thing makes it hard to search for.
by kevbo
Mar 13 2017 4:43pm
Forum: Battery Technology
Topic: Enlighten me please: why focus on P connections, not S?
Replies: 12
Views: 1925

Enlighten me please: why focus on P connections, not S?

The images below are lifted from other posts, which I am not linking to because I don't mean to pick on anyone in particular. I just want to show examples of what I am talking about, as this construction seems pretty typical. I'm sure the batteries in the photo work just fine as is...but maybe they ...
by kevbo
Mar 13 2017 3:55pm
Forum: E-Bike General Discussion
Topic: Lots of punctures - replace with solid or puncture resistant
Replies: 35
Views: 2733

Re: Lots of punctures - replace with solid or puncture resis

If you use a Presta valve tube, you may need to find one with the removable valve core, and the tool to remove it. Not every Presta valve has a removable core, unlike Schrader tubes, which are all removable. You have to remove the core to get the slime in the tube, but it's worth it. There is a too...
by kevbo
Mar 13 2017 12:01pm
Forum: E-Bike Non-hub Motor Drives
Topic: A Newb and his Yuba/Stokemonkey
Replies: 11
Views: 1846

Re: A Newb and his Yuba/Stokemonkey

In addition to getting the gearsensor working, I fitted a Grin 6V output DC-DC converter, so have ditched the dynamo. I also rigged the reed switch from a cheap cateye computer as an ebrake switch. With just the cable travel moving the magnet, it was very fussy getting it to make and brake reliably....
by kevbo
Mar 13 2017 11:43am
Forum: E-Bike General Discussion
Topic: Lots of punctures - replace with solid or puncture resistant
Replies: 35
Views: 2733

Re: Lots of punctures - replace with solid or puncture resis

Schwalbe Marathon Plus have excellent flat resistance. I second this. Albuquerque is lousy with goatheads. When I was commuting every day ( just 10 mi. RT) I was averaging around 1.5 punctures per week...most weeks I'd have one, some weeks 2-3. The Marathon Plus tires got this down to one puncture ...
by kevbo
Mar 11 2017 3:54pm
Forum: E-Bike Non-hub Motor Drives
Topic: A Newb and his Yuba/Stokemonkey
Replies: 11
Views: 1846

Re: A Newb and his Yuba/Stokemonkey

This may not be an original idea, but here is how to make a single cable gear sensor work for both F and R derallieurs. https://photos.smugmug.com/Ebikes/i-FnqwhHr/0/L/IMG_3219-L.jpg The photo shows the gear sensor located under the top tube where both shift cables make parallel open runs. This shou...
by kevbo
Mar 09 2017 1:44pm
Forum: E-Bike Technical
Topic: CA3.01 temperature sensor setup problem: "Disbld"
Replies: 2
Views: 496

Re: CA3.01 temperature sensor setup problem: "Disbld"

Well I finally got a comm cable, and that was the needful item. The temp sensor setup screen had all values disabled. I think I could change the settings from the CA onboard menu now...but so much easier using the setup utility. I also did some research, and it seems like people really like the Engi...
by kevbo
Mar 06 2017 12:43pm
Forum: Battery Technology
Topic: Arduino based charge balancer
Replies: 127
Views: 12213

Re: Arduino based charge balancer

I am likewise replying to follow, though perhaps I can add some things of value. Point one...general note on these little telecom style relays: I noted mention in an early post in the thread that these are sealed relays, and that is a good thing. Long ago I used a bunch of similar relays on a work r...
by kevbo
Mar 03 2017 11:53am
Forum: E-Bike Technical
Topic: An economical Hi Amp DIY BLDC controller
Replies: 65
Views: 7727

Re: An economical Hi Amp DIY BLDC controller

I think you should be fine using a copper section as a shunt, with an appropriate amplifier circuit. You'd need to be careful with the op-amp design since it's a noisy environment. You'd also probably need to make it possible to calibrate the shunt. I don't think it'd be very accurate with the shun...
by kevbo
Mar 02 2017 5:41pm
Forum: E-Bike Non-hub Motor Drives
Topic: A Newb and his Yuba/Stokemonkey
Replies: 11
Views: 1846

Re: A Newb and his Yuba/Stokemonkey

Yes on the dual pull brake levers. The dual brakes idea came from hating to Look at the canti-stud "warts". I've had the bike about five years now, the bottle dynamo has worked well, but yes, a Buck converter is obviously the way to go. Maybe I'll make one, and give it a couple USB chargin...
by kevbo
Mar 02 2017 11:52am
Forum: Battery Technology
Topic: Parallel Charging Lipo question
Replies: 14
Views: 1613

Re: Parallel Charging Lipo question

Balance leads serve two functions: The balance leads are used both to sense balance and to discharge/bypass the higher voltage cells. If the balance leads to each tap (in each series string of cells) had a small series resistor...perhaps .1 ohm or so, then the max current that could flow through the...
by kevbo
Feb 28 2017 11:45am
Forum: E-Bike Non-hub Motor Drives
Topic: A Newb and his Yuba/Stokemonkey
Replies: 11
Views: 1846

Re: A Newb and his Yuba/Stokemonkey

Well, I got the new fork on, and a few other odds and ends...far enough along that I rode it to work today. Prior to this, I had only done a few 3 mile uphill runs to take the pooch to the off-leash park. There was hella headwind, (~15 mph) which was no problem with stoke monkey helping. I was using...
by kevbo
Feb 24 2017 12:08pm
Forum: E-Bike General Discussion
Topic: MY1018 final gear?
Replies: 14
Views: 1312

Re: MY1018 final gear?

6t sounds ridiculous and probably doesn't exist, but why not have one or 2 made up? The reason low tooth count sprockets are not sold is because they work very poorly. If lower tooth-count sprockets were viable, every vendor would sell them. People are always needing higher reduction or step-up rat...
by kevbo
Feb 22 2017 6:41pm
Forum: E-Bike Technical
Topic: A switch for shortening throttle
Replies: 2
Views: 465

Re: A switch for shortening throttle

Best to make it a self energizing relay*, and set it up so it drops out when Ebrake active. *relay with multiple poles. One pole switches throttle signal to new pot. Second pole supplies current to relay coil via NO contacts. On button momentarly NO contacts, relay energizes and keeps itself on. Off...
by kevbo
Feb 20 2017 11:46am
Forum: E-Bike General Discussion
Topic: MY1018 final gear?
Replies: 14
Views: 1312

Re: MY1018 final gear?

I'm surprised you found a 9T, but looking online, I see that a few vendors offer down to 8T...that is only going to drop your speed about 1 mph. Gear tooth geometry gets rather funky below 12T. I'm less familiar with roller chain sprockets than normal (tooth-tooth) gearing, but if you look at how th...
by kevbo
Feb 15 2017 4:00pm
Forum: E-Bike Technical
Topic: 6fet or 9fet for system under 1200 Watts
Replies: 10
Views: 1198

Re: 6fet or 9fet for system under 1200 Watts

I got curious about 9 FET controllers after reading this thread, and did some looking. It seems that most controllers switch the lower FETs of each half-bridge at the commutation rate. The upper FETs, by contrast, are pulse width modulated (PWM) at a fairly high frequency to control the current/torq...
by kevbo
Feb 15 2017 11:26am
Forum: E-Vehicles General Discussion
Topic: Linear Technology’s LT8315 monolithic flyback regulator
Replies: 3
Views: 622

Re: Linear Technology’s LT8315 monolithic flyback regulator

The voltage on the various windings will be related by their turns ratio. If the forward drop in the output diode is assumed constant (and it should be within 0.1V or so) then sampling the voltage on a different winding while the diode is turned on gives a reliable indication of the output voltage. ...
by kevbo
Feb 14 2017 2:12pm
Forum: E-Bike Non-hub Motor Drives
Topic: Rewinding a car alternator for ebike use
Replies: 15
Views: 10306

Re: Rewinding a car alternator for ebike use

A 3 phase induction motor with a proper drive circuit need not have zero stall torque. Essentially you want to have the slip frequency be the same at all speeds. A 50/60 Hz induction motor will typically be rated at around 5% slip at design speed, so the slip frequency is 2.5-3Hz. So at standstill y...
by kevbo
Feb 14 2017 12:20pm
Forum: Battery Technology
Topic: Brass for spot-welding 18650 parallel cell groups?
Replies: 69
Views: 11207

Re: Brass for spot-welding 18650 parallel cell groups?

Just a thought: Instead of slotting a single strap, it might be easier to use two straps in parallel, welded at the same time, one electrode on each strap, forcing the cell to complete the circuit. You would need some means to maintain a small gap between them until they are welded down. Tape might ...