Buck and Boost Converter -Charging

Thread Starter

aliso

Joined Aug 3, 2022
4
I want to make an energy control system on a stationary bike. The main input comes from the generator and the secondary input comes from the 6V battery. The voltage from the generator ranges from 1-10V, so I need to make a buck converter to 5V as load power supply. before pedaling, the power supply comes from the battery, and after pedaling, the power supply comes from the buck converter. There is a time when the output of the buck converter is used as input to the boost converter to 6.8V to charge the battery.

With the circuit in the figure, is the system working?

Please help, thank you.
 

Attachments

LowQCab

Joined Nov 6, 2012
3,939
What You are proposing is very common for newbies.
There are losses everywhere, in every component, that can not be avoided.
There's no "Free-Lunch".
What You want to do is not very practical, hence, few responses.
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Dodgydave

Joined Jun 22, 2012
11,243
So you have a stationary bike with a generator on it, and you're going to be pedaling to charge the battery and a buck converter for a 5V output for items, it will work but all the effort is in pedaling, .
 

Thread Starter

aliso

Joined Aug 3, 2022
4
I cannot understand your wiring diagram. Can you provide a block diagram and an explanation of how it is supposed to work?
Hi,

I want to make my own power supply system. when i exercise i want to know the heart rate and etc. so i need a power supply. I want to use my pedaling energy to generate electricity. therefore I want to make this system.

from the generator then through a DC-DC to 5V converter. at the same time, the energy is also used to charge the battery.
 

Attachments

DickCappels

Joined Aug 21, 2008
10,123
Wow! That's much better!

Can you list the required inputs and outputs as far as you know. You may find that linear regulators are a little easier to use than buck converters.

Why is the relay in the circuit? That would probably help all of us.
 

ronsimpson

Joined Oct 7, 2019
2,894
The voltage from the generator ranges from 1-10V............
6.8V to charge the battery....................
From the battery to your "computer" we could use a LDO linear regulator or a PWM power supply.
From the generator, why not directly drive the battery? When you pedal slow, and the voltage is low, there is no current to charge. Then you pedal fast the current charges the battery. The voltage will never get to 7 volts because the battery will take all the power.
What is the maximum current form the generator? As long as the battery can handle that current it should work. If you are worried about over charge we could build a circuit that lights a power LED to eat up the extra current if the battery voltage gets too high.
 

Thread Starter

aliso

Joined Aug 3, 2022
4
Wow! That's much better!

Can you list the required inputs and outputs as far as you know. You may find that linear regulators are a little easier to use than buck converters.

Why is the relay in the circuit? That would probably help all of us.
Hi,
My consideration regarding the linear regulator, there is a minimum voltage so that the output is in accordance with the linear regulator specifications.

The purpose of installing the relay is to perform the switch. At first, the power source comes from the battery (relay: NO), when the buck converter has issued 5V, the power source will change to the output of the buck converter (relay: NC).
 

Thread Starter

aliso

Joined Aug 3, 2022
4
From the battery to your "computer" we could use a LDO linear regulator or a PWM power supply.
From the generator, why not directly drive the battery? When you pedal slow, and the voltage is low, there is no current to charge. Then you pedal fast the current charges the battery. The voltage will never get to 7 volts because the battery will take all the power.
What is the maximum current form the generator? As long as the battery can handle that current it should work. If you are worried about over charge we could build a circuit that lights a power LED to eat up the extra current if the battery voltage gets too high.
Hi,
Interesting. By block diagram, do you mean like this?
1662649365091.png
 
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