## Search found 1986 matches

May 05 2021 6:01pm
Forum: EScooters/EMotorcycles
Topic: Sur-Ron - New Mid drive Bike
Replies: 5473
Views: 627339

### Re: Sur-Ron - New Mid drive Bike

maybe there's a temp you could heat the esc in an oven and not damage the bits on the pcb so the potting material would get soft and be more easily removed. or maybe thats how you did it
May 04 2021 11:16pm
Forum: Battery Technology
Topic: 40T, neodymium magnets, plasti dip cycle test
Replies: 165
Views: 13640

### Re: 40T, neodymium magnets, plasti dip cycle test

How does potting effect the safety release valves on cells? I don’t know how but the A123 26650 cells will somehow disconnect when shorted for long enough and then magically come back. (Current will drop drastically but same voltage somehow, then later string current). It’s a pretty safe cell to beg...
Apr 28 2021 12:58pm
Forum: EBike Technical
Topic: Heat from amps, but what of watts?
Replies: 23
Views: 805

### Re: Heat from amps, but what of watts?

Wait.. I^2R reveals the wattage lost to heat and that formula is enough and no other math need be done right? I don’t need to figure the voltage drop as long as I already know the resistance. It’s the current alone that is causing the heat..voltage and resistance revealing that current Wattage lost ...
Apr 28 2021 12:48pm
Forum: EBike Technical
Topic: Heat from amps, but what of watts?
Replies: 23
Views: 805

### Re: Heat from amps, but what of watts?

.. I^2R to decide power lost. voltage isn’t in the equation. Yes, voltage is in the equation. U=R*I is the first part of the ri2 as (R*I)*I This voltage is the voltage drop at 100A due to the 1ohm resistance Yea I get it but voltage isn’t in the power lost equation directly and it’s just current x ...
Apr 28 2021 12:07pm
Forum: EBike Technical
Topic: Heat from amps, but what of watts?
Replies: 23
Views: 805

### Re: Heat from amps, but what of watts?

if amps kill you not volts but what happens if you get shot with 50,000 amps and 0.1volts? Assuming the voltage is high enough to pass that current you explode. Don’t think at .1v it will be anywhere near 50,000 amps even if electrodes under the skin How a taser can be a huge voltage but low curren...
Apr 28 2021 11:18am
Forum: EBike Technical
Topic: Heat from amps, but what of watts?
Replies: 23
Views: 805

### Re: Heat from amps, but what of watts?

goatman wrote:
Apr 28 2021 9:18am
you could try putting 100v 1 amp to your tongue
do you still have a tongue?
Think would either need be 100v and a whole lot of current based on my tongue resistance or some low voltage applied that would limit me to one amp due to the tongue resistance
Apr 28 2021 11:13am
Forum: EBike Technical
Topic: Heat from amps, but what of watts?
Replies: 23
Views: 805

### Re: Heat from amps, but what of watts?

With high voltage power lines I understood the voltage was increased so as to have less losses in the long wires. If I’m calculating the losses in a 10 mile wire and let’s say it’s one ohm total and 10,000 volts and let’s say 100 amp are passed through... how many watts are lost as heat? Ri2 for th...
Apr 28 2021 8:56am
Forum: EBike Technical
Topic: Heat from amps, but what of watts?
Replies: 23
Views: 805

### Re: Heat from amps, but what of watts?

With high voltage power lines I understood the voltage was increased so as to have less losses in the long wires. If I’m calculating the losses in a 10 mile wire and let’s say it’s one ohm total and 10,000 volts and let’s say 100 amp are passed through... how many watts are lost as heat?
Apr 26 2021 2:58pm
Forum: EBike Technical
Topic: Heat from amps, but what of watts?
Replies: 23
Views: 805

### Heat from amps, but what of watts?

If I pass 100 amps at 1 volt through a resistor it’s the same wattage as if 1amp through a much bigger resistor at 100 volts, and heat is measured in watts so should be the same temp produced no? But only amps create heat.
Apr 26 2021 11:07am
Forum: Battery Technology
Topic: 40T, neodymium magnets, plasti dip cycle test
Replies: 165
Views: 13640

### Re: 40T, neodymium magnets, plasti dip cycle test

Without a good resistance tester like one of those posted how good all these connection methods are is unknowable. Or could figure another way to do an accurate resistance test. I designed another method using 3D prints and rubber bands. Works fine but in use found the tight case it’s put in effecte...
Apr 25 2021 6:04pm
Forum: Battery Technology
Topic: 40T, neodymium magnets, plasti dip cycle test
Replies: 165
Views: 13640

### Re: 40T, neodymium magnets, plasti dip cycle test

ive got some of the tape with adhesive and its cheap and easily gotten and a nice shape but the adhesive always seems an obstacle and such thin copper. it sits unused. if only there was some way to get assured a clean contact I'd be sold. it may work as is and maybe would be no problem in any iterat...
Apr 25 2021 1:01pm
Forum: Battery Technology
Topic: 40T, neodymium magnets, plasti dip cycle test
Replies: 165
Views: 13640

### Re: 40T, neodymium magnets, plasti dip cycle test

Doesn’t the resin sneak between the copper and cell to some degree? The magnet maybe has a strong enough pressure to keep it out
Apr 22 2021 9:16am
Forum: Bike Mechanical & Structural
Topic: Working rear triangle to accommodate different hub widths. How much is too much
Replies: 11
Views: 477

### Re: Working rear triangle to accommodate different hub widths. How much is too much

Leaf sells a 110mm hub. I wish I’d gotten it and I don’t know what current others are doing but at 90 amps from a vesc I barely get this giant 135mm spaced 2000watt leaf motor warm no matter what mountain I climb( and the eBay clone)
Apr 21 2021 12:26pm
Forum: Bike Mechanical & Structural
Topic: Working rear triangle to accommodate different hub widths. How much is too much
Replies: 11
Views: 477

### Re: Working rear triangle to accommodate different hub widths. How much is too much

I’ve bent steel bmx frames that are 110mm to 140mm no problem using a fat threaded rod and a lot of nuts. Be careful and lock the rod to the dropout so it doesn’t get shot off the back while you’re doing and also stretch each side consistently doing maybe 4mm each side back and forth. Depending on h...
Apr 14 2021 9:52am
Forum: Battery Technology
Topic: kWeld - "Next level" DIY battery spot welder
Replies: 1337
Views: 206349

### Re: kWeld - "Next level" DIY battery spot welder

I think to get max power out of the welder requires getting a battery powerful enough, which isn’t hard, and cutting its wires so the resistance is just enough that you don’t get an “over current” and the wiring decides the current. Or you could trick the calibration process and go beyond its amp li...
Apr 10 2021 12:38pm
Forum: Battery Technology
Topic: Spot Welding Copper Strips to 18650 Battery Cells
Replies: 509
Views: 87210

### Re: Spot Welding Copper Strips to 18650 Battery Cells

Your criticism is appreciated. What I was hoping for. I play advocate looking for detractors who have a rationale. I learned about the ferrule.
Apr 10 2021 12:18am
Forum: Battery Technology
Topic: Spot Welding Copper Strips to 18650 Battery Cells
Replies: 509
Views: 87210

### Re: Spot Welding Copper Strips to 18650 Battery Cells

i was asking about how stacking .025mm copper would compare to multistrand for a bendable spot. https://imgur.com/a/zgOZjfx

but think has run it's course and the fantasy is over. i made pcbs with fat traces on them for a flexible battery already and was just wondering what people thought
Apr 09 2021 5:58pm
Forum: Battery Technology
Topic: Spot Welding Copper Strips to 18650 Battery Cells
Replies: 509
Views: 87210

### Re: Spot Welding Copper Strips to 18650 Battery Cells

With a crimp the wire is supported at the ends and bending limited so the flex occurs in the loop. 1. With one or more strips, the mechanical fixing is via a tiny spot weld with perhaps 1% of the cross section of the strip so most of the strain may occur there. i can glue the strip where it contact...
Apr 09 2021 10:36am
Forum: Battery Technology
Topic: Spot Welding Copper Strips to 18650 Battery Cells
Replies: 509
Views: 87210

### Re: Spot Welding Copper Strips to 18650 Battery Cells

Adding the multi strand with a soldered ferrule at the rigid side and then crimps to multistrand may be the proven standard for making a flexible connection and im sure would be good but i think there's alternatives that MAY be as reliable. at this point im thinking if using stacked thin strip and t...
Apr 09 2021 8:48am
Forum: Battery Technology
Topic: Spot Welding Copper Strips to 18650 Battery Cells
Replies: 509
Views: 87210

### Re: Spot Welding Copper Strips to 18650 Battery Cells

i have some crimp tool and tons of crimps i never use really and end up always soldering. While crimps n ferrules may be better than solder for a wire that is repeatedly bent but i see no way to crimp .1mm copper strip to a ferrule and dont think it will be possible. it may be the best technique..im...
Apr 08 2021 9:57pm
Forum: Battery Technology
Topic: Spot Welding Copper Strips to 18650 Battery Cells
Replies: 509
Views: 87210

### Re: Spot Welding Copper Strips to 18650 Battery Cells

How would you crimp spot-welded copper strip? Why wouldn’t you want to flex wire other than well into the wire? you mean if soldered? Maybe the bend radius need not be big depending on the amount of flex and more important it be consistent, but maybe as the metal is repeatedly bent it work hardens a...
Apr 08 2021 4:22pm
Forum: Battery Technology
Topic: Spot Welding Copper Strips to 18650 Battery Cells
Replies: 509
Views: 87210

### Re: Spot Welding Copper Strips to 18650 Battery Cells

as you say thinner the better for being strong. i was doing .05mm strip i happened to have and see .025mm strip out there. as you say with the strands in a wire i think it can take away any stress points. in my pics the sharp fold of the copper stip is no good in that regard and i did it in the inte...
Apr 08 2021 3:34pm
Forum: Battery Technology
Topic: kWeld - "Next level" DIY battery spot welder
Replies: 1337
Views: 206349

### Re: kWeld - "Next level" DIY battery spot welder

I’m getting repeated timeouts when calibrating and doing the “short” part. Luckily it still will weld just can’t calibrate again. Should I do Higher voltage? Pretty sure my battery isn’t to blame for a lack of power delivery, which I think is what the timeout means..not getting some amount of curren...
Apr 08 2021 3:32pm
Forum: Battery Technology
Topic: kWeld - "Next level" DIY battery spot welder
Replies: 1337
Views: 206349

### Re: kWeld - "Next level" DIY battery spot welder

Why people say not copper. I’ve done thousands of welds of .1mm copper and some even .2mm copper if w a slit in it and that’s on the a123 cells which have a very thick can. This is thinner .05mm copper folded for better flex without breaking. https://imgur.com/a/zgOZjfx All welds here are the 2x .05...
Apr 07 2021 11:31pm
Forum: Battery Technology
Topic: Spot Welding Copper Strips to 18650 Battery Cells
Replies: 509
Views: 87210

### Re: Spot Welding Copper Strips to 18650 Battery Cells

Tab strips are super easy to bend and break, probably takes about 3 or 4 complete folds to break Same goes for solid core wire Stranded wire is good for flexibility why would stranded copper be less likely to break than strip? they both in theory should have the same fatigue limit if the same thick...