I'm trying to power a PC from a bike pedal generator, and have some parts at my disposal, but I wanted to figure out the most efficient setup possible.
The PC uses a "Pico power supply", so it is powered from 12 volts DC. It consumes between 40-160 watts depending on if I am gaming with the GPU or not. The idea is I want to hook it up to a 12v nominal lithium ion battery pack and charge that pack with pedaling. If I don't exercise at my PC it'll shut off. Sounds motivating! But it needs to be efficient enough that I'm not drenched in sweat all night either; I'm shooting for cardio heart rates here
Stuff I have:
- Bike frame to sit on and pedal
- 32v 500w ebike hub motor
- 32v 350w "hoverboard" self-balancing scooter wheel (brushless DC motor like the ebike)
- Cogs of varying tooth count that I can weld to any of the motors above
- tons of 18650 cells... like 1kwh worth of them
Stuff I could buy:
- I scoured the internet for an MPPT, buck-boost wind turbine charge controller. I found exactly one that can take an AC (i.e. PMDC) motor, and supports custom charging profiles for Li-Ion: https://www.amazon.com/dp/B01IX6OYEA/
- If it would be more efficient than the bike or hoverboard motor, I could buy a Turnigy RC motor, since those are powerful and cheap, but I think the bike hub wheel or hoverboard wheel might be a better match for the volts/RPM range that would be practical with gearing
Challenges:
- Rectifiers top out at 81% efficiency from what I read which seems pretty poor, but MPPT charge controllers claim up to 98% (I assume when input/output are within a few volts of each other), so I'm thinking I'm going to need to go straight from motor to MPPT to squeeze the most energy into the batteries
- I need to keep the thing as simple as possible, since all conversions sap more power. Same with hooking up the chain drive... preferably it would be one chain from the crank to the motor I'm turning, with weight added to the crank to act as a flywheel
- I think the output to the PC power supply should ideally be as close to 12v as possible; I'm wondering if that would require a voltage regulator between the batteries and the power supply, or if a large enough pool of batteries, (for example 3 18650 cells at 4.0v nominal in series, 30 in parallel) would be able to stay within +/- half a volt from 12vdc if I'm keeping up with pedaling.
The PC uses a "Pico power supply", so it is powered from 12 volts DC. It consumes between 40-160 watts depending on if I am gaming with the GPU or not. The idea is I want to hook it up to a 12v nominal lithium ion battery pack and charge that pack with pedaling. If I don't exercise at my PC it'll shut off. Sounds motivating! But it needs to be efficient enough that I'm not drenched in sweat all night either; I'm shooting for cardio heart rates here
Stuff I have:
- Bike frame to sit on and pedal
- 32v 500w ebike hub motor
- 32v 350w "hoverboard" self-balancing scooter wheel (brushless DC motor like the ebike)
- Cogs of varying tooth count that I can weld to any of the motors above
- tons of 18650 cells... like 1kwh worth of them
Stuff I could buy:
- I scoured the internet for an MPPT, buck-boost wind turbine charge controller. I found exactly one that can take an AC (i.e. PMDC) motor, and supports custom charging profiles for Li-Ion: https://www.amazon.com/dp/B01IX6OYEA/
- If it would be more efficient than the bike or hoverboard motor, I could buy a Turnigy RC motor, since those are powerful and cheap, but I think the bike hub wheel or hoverboard wheel might be a better match for the volts/RPM range that would be practical with gearing
Challenges:
- Rectifiers top out at 81% efficiency from what I read which seems pretty poor, but MPPT charge controllers claim up to 98% (I assume when input/output are within a few volts of each other), so I'm thinking I'm going to need to go straight from motor to MPPT to squeeze the most energy into the batteries
- I need to keep the thing as simple as possible, since all conversions sap more power. Same with hooking up the chain drive... preferably it would be one chain from the crank to the motor I'm turning, with weight added to the crank to act as a flywheel
- I think the output to the PC power supply should ideally be as close to 12v as possible; I'm wondering if that would require a voltage regulator between the batteries and the power supply, or if a large enough pool of batteries, (for example 3 18650 cells at 4.0v nominal in series, 30 in parallel) would be able to stay within +/- half a volt from 12vdc if I'm keeping up with pedaling.