Having some questions during building a bike-generator

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Hello,I am building a bike-generator. Well I have found a few articles about that on the internet, but I have put together a list of questions and I would be really appreciated if someone could answer them (see below)

The goal: To have a bike, and by pedalling on it generate electricity, which will charge a battery. The battery will be then used to power multiple USB outputs (smartphone charging)

My setup: I have connected a dynamo from old car (14V, 42 amps) to a bike. Then I have a battery(http://www.kynix.com/Parts/5570/A23C.html)(12V). My setup will look like this:

Image

And I have a few questions about this:

1.Is this form of "charging" suitable? How do I limit the current, so when pedalling faster (-> more current), I won't destroy the battery?
2.Is it possible to use the voltmeter VM1 to monitor the charge level of the battery? Or how to do it?
3.Can I plug smartphone into the USB ports? Is it safe? Can I use PolySwitch fuses?
4.Will this even work? :) Or any other comments/suggestions/etc. appreciated

Notes:
Sorry for any mistakes in my English
My level of understanding electronics is somewhere near medium-low, I learned it all by myself, so I hope this isn't a total nonsense :)
Thanks in advance!
Hello ,

Yes , this form of charging is suitable , but it needs some optimisation.

If your battery is lead-acid type , you must charge it with constant voltage , if it is nickel-cadmium type then you must charge it with constant current.

The voltage or current requirements printed on the battery.

For a 12 volt lead-acid type battery , you must fix the voltage around 14.4 volts so you need a voltage regulator. Some car dynamos have a regulator inside and give constant voltage , simply check the output with a voltmeter.

Others give voltage proportional to revolution and needs a voltage regulator. You may find such regulators on auto parts store.

You may connect a voltmeter parallel to battery in order to check the voltage levels.

As far as I know , USB ports have 5 volts output , so you need to reduce the battery voltage to 5 volts to connect the USB ports.
You may use LM7805 regulator ( 5 volts / 1 amp ) to get 5 volts output.
To prevent overheating , use a cooling fin for LM7805.

Good luck !
For further optimization, you may need the LM7805, which can be found here https://www.allicdata.com/list.html?search_type=Products&keyword=LM7805
uzman wrote:
Hello ,

Yes , this form of charging is suitable , but it needs some optimisation.

If your battery is lead-acid type , you must charge it with constant voltage , if it is nickel-cadmium type then you must charge it with constant current.

The voltage or current requirements printed on the battery.

For a 12 volt lead-acid type battery , you must fix the voltage around 14.4 volts so you need a voltage regulator. Some car dynamos have a regulator inside and give constant voltage , simply check the output with a voltmeter.

Others give voltage proportional to revolution and needs a voltage regulator. You may find such regulators on auto parts store.

You may connect a voltmeter parallel to battery in order to check the voltage levels.

As far as I know , USB ports have 5 volts output , so you need to reduce the battery voltage to 5 volts to connect the USB ports.
You may use LM7805 regulator ( 5 volts / 1 amp ) to get 5 volts output.
To prevent overheating , use a cooling fin for LM7805.

Good luck !


General Motors style Alternators normally have the internal voltage regulators. You can probably find one at an automotive salvage yard. They are not only used in GM vehicles, you just need to check what types of vehicles use them.
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