Pedal generator from a friction drive?

[fechter]

You might be able to use a cheap generic boost converter. About $20 on eBay

 

[amberwolf]

Seems I was wrong in thinking that a MPPT took any old lower voltage and turned it into pulses at the optimal charging voltage of the battery, using 'charge caps in parallel - discharge in series' tech..?
So what does that? Some sort of special Boost converter - MPPT combo?

An MPPT is just another form of SMPS, like your chargers, power supplies, etc.

Simplistically, "any" SMPS *could* be a boost or a buck, or both, if it was designed that way. Many are only designed to be one or the toher and have limiting circuitry that prevents them from doing the other job (because that would cause damage to the device being powered by it under intended usage).

Realistically, just look for buck/boost as a spec on anything you want to do both, and ensure that the input voltage range on the side of the function you want matches your supply, and the output voltage range on the the other side of that function matches your destination.

 

[yabert]

You might be able to use a cheap generic boost converter

Quite an affordable solution for sure.
I think I will manage to spin the motor at higher RPM first.
Then look at what I need to reach my goal of charging at 52+V.

 

[Logic11]

Quite an affordable solution for sure.
I think I will manage to spin the motor at higher RPM first.
Then look at what I need to reach my goal of charging at 52+V.

I would say, for this to be practical/desirable being able to pedal at any cadence and effort level is important.


IMHO optimal charging voltage out, in pulses (how else?) has to be part of the project..?

I dont know much about electronics, but did a quick search for:
electronics circuit boost charge controller that outputs optimal charging voltage from lower input voltage amperage

https://www.analog.com/en/products/lt8491.html
...The LT8491 is a buck-boost switching regulator battery charger that implements a constant-current constant-voltage (CCCV) charging profile...

https://www.digikey.com/en/blog/buck-boost-battery-charge-controller

 

[MxusMick]

Have you attempted to connect a 3 phase bridge rectifier directly to the 3 phase motor and measure the voltage output at different pedal speeds? Hoverboard motors are cheap, take that treadmill motor and mount it next to the back wheel of a trike for a belt/ pully, it will get 18 mpg on 36v