Recent content by cerewa

Seems like a lot of the folks on this forum know how to accomplish some pretty awesome stuff with electronics, so I wanted to offer a challenge. I know a number of Haitians who use laptop computers off-the-grid in Haiti. Small solar panels are not particularly expensive, but the cost barrier...

In order to use your existing shifter, you'd need a 9 speed freewheel. Search google for 9 speed freewheel. Note that your crystalyte wheel with a 9 speed freewheel may be too wide to fit in your frame. With a steel frame, you can just bend to fit if you want; non steel frames (any metal or...

Just one of those 48V20Ah packs is some serious range. Two packs and you'll be able to go a long, long way.

At anything near 100% of the no-load speed, pulse width modulation is normally not what limits the current to the motor, it's just I=V/R (current equals voltage divided by resistance) because the effective voltage is small (back EMF voltage being nearly as high as battery [forward] voltage)...

I suspect car wiper motors are something like 50 watts at the most. The motor and controller are both designed for that kind of low power use. If you want something that even matches a low power ebike, neither the DC controller nor the motor will be suitable, I suspect.

This is for the commute I used to do. The motor's controller broke and I switched jobs, and these days I commute without a motor. 1. Efficiency (Watt-hours/mile): 6 - 7 watt hours per mile 2. Speed (mph | kph): 16mph (65 minutes each way, 17 miles each way) 3. Gradient (%): lots of hills, 10%...

If it breaks we will know why. It apparently has capacitors (and other components, maybe) that are designed for 50 volts (actual volts) max. The ping battery is rated at "48V" but its actual voltage during use starts at about 56 volts and only drops to 48 volts when the battery is nearly 100%...

Each cell may be folded over on itself several times. A 48V12Ah pack that's made of 3V4Ah cells must be set up as 16-series x 3-parallel for a total of 48 cells. (note, most packs do not have the same number of cells as their voltage.. just a coincidence)

to the best of my knowlege, your pack consists of cells that are 4Ah, nominal voltage 3V. (actual operating voltage closer to 3.1V to 3.4V) If that's true, you could set it up as 72V 8Ah provided you had an appropriate BMS or some other way to avoid over-discharging individual cells. The...

On an e-bike that you pedal, yeah, 5 speeds should be enough. E-bikes can keep much more consistent speeds with up-hills, compared to regular bikes. So there's generally no need for ultra-low gears.

If it seems like the long wire is eating more energy than you want it to, all you need is a wire that is fatter than necessary... Like fechter says, the wire will drop the voltage some, (under load only) but not the current. If the total voltage of the pack is dropped too much across the wire...

What component is used to switch the capacitors?

Besides high amperage and high voltage, another factor that could influence whether or not your gears will strip is rider+vehicle weight. If you put a lot of power into the motor and there isn't much resistance then why would the gears get damaged... but if there is a lot of weight to keep the...

Peak power of 1,400 watts is a lot! Yes, crystalyte 4xx motors can do well over 1400 watts but, assuming you are not looking for an e-motorcycle, 1400 watts should do.

The 20mph is part of what can get you within the definition of "bicycle" and out of the definition of "motor vehicle". If you're riding a "motor bicycle" (moped) you may need a vehicle registration and liability insurance. Once you have a registered mo-ped, it's probably not legal on bike paths...