Help rebalancing my bike collection

[atxmarmot]

In case anyone is curious about the radwagon with a BBSHD. Here is the current state of the bike. All of the functional bits and pieces are there, but I need to clean things up a bit in the handlebar and connect the some of the auxiliary bits and pieces like motor cutout, speed sensor, etc.




It is currently set up as a kid carrier and has no problem taking myself, a 2.5 and 4 year old up a >20% slope.

 

[Graham641]

The way I look at it, you have choices.
Very cheap chinese square wave. Cheap, will make noise, but will work without breaking for this application.
slightly more expensive sine wave. almost silent, not too expensive, will plug into your CA, but they all come in this clunky box.
phaserunner, silent, tiny, but you could buy 10 of the cheapest chinese square wave controllers for the price.

I think the 2nd one is your best option at the moment.

It is certainly looking that way. So no, onwards to find a reasonable sine wave controller and figure out how to hook it up!

On my radwagon front: I have mounted the BBSHD (very straightforward) and yesterday found a replacement wheel for the rear hub. I am keeping the 7 speed on the back so that I can reuse all the shifting hardware for the moment. I took it to a bike shop to do the change as I am not comfortable yet setting all the gear train. It will take them a few days, which is fine since I am waiting for an additional dolphin mount to be shipped. In the mean time, I am bike less, which is very sad

 

[Graham641]

I have always been under the impression that a fast switching square wave driver would dramatically kkeep the mosfet heating lower. The fets are either full on with very little voltage drop and high current or full off with high voltage but very little current through the fet. As I understand the fet market they are constantly trying to get faster switching fets. The stumbling block is that mosfets like to have a high gate capacitance which slows the switching speed. In an inverter design, where a sine wave is needed, the mosfets are pulse width modulated to approximate a sine wave. The problem with high speed switching is the RF noise that thet tend to generate. But for motor, you have a lot of RF noise anyway. A shielded cable is a good fix. Why do I read that some companies use sinewave output as an advertising point. They generate the peak power x .707.

 

[Graham641]

Again, the coolest drivers soild be close to a square wave, excluding rise and fall times.. The driver will be putting out all voltage or all curent so no wattage. Can't be done in a real world. I wasbnuncer the impession tha a sine unverter was best for house wiring.

 

[LewTwo]

... Why do I read that some companies use sinewave output as an advertising point...

They have the reputation of being quieter (less motor noise in the range of human hearing). Many people like quite.

 

[thepuzzlemaster]

In case anyone is curious about the radwagon with a BBSHD. Here is the current state of the bike. All of the functional bits and pieces are there, but I need to clean things up a bit in the handlebar and connect the some of the auxiliary bits and pieces like motor cutout, speed sensor, etc.

It is currently set up as a kid carrier and has no problem taking myself, a 2.5 and 4 year old up a >20% slope.

@atxmarmot, can you post any additional details about how you hooked up the radWagon battery to the BBSHD? I just bought a BBSHD kit to install on my radWagon and that's the only part I'm kind of unsure about. Would love to not have to cut any of the existing cables.

Thanks! I'm stoked to get this installed!