I am making a generator that is a very small geared DC motor. I need to put it inline to charge 4 Lithium or NiCad 1.5V batteries. I need some guidance on what would be the proper linear voltage regulator to use. The problem I see is that at times the generator may only put out 2-3 V based on its speed with a maximum output of maybe 20V. I need a VR that will handle both of these variables with it keeping the max output at 6VDC. Will I need any other components inline besides the VR?

Thank you

 

A current limiter and full charge detector.

 

A current limiter and full charge detector.

I guess I didn't put my question properly, what would be the proper voltage regulator to use

Thanks again

 

What is the maximum current the motor will produce?

 

What is the maximum current the motor will produce?

This is the motor being used: https://www.amazon.com/gp/product/B006W2HLSY/ref=od_aui_detailpages00?ie=UTF8&psc=1

Thank you

 

The best way to regulate a DC generator is obtain a motor with a wound field if you can find one now, it is very easy to implement, you may find an older automotive based one.
Max.

 

Do you want to charge the cells in parallel or in series? If in series, will you be using a charge equaliser? There are ICs available for controlling that.

 

One other piece of info I failed to mention; the generator will be the input to a USB charger so I think all the necessary current limiter and full charge detector would already be in place.

 

The generator is to be a mobile means to supply power to a preexisting charger that is normally powered via a USB.

 

The problem I see is that at times the generator may only put out 2-3 V based on its speed with a maximum output of maybe 20V.

Sounds like you need a buck-boost DC-DC converter rather than a simple regulator.

 

Sounds like you need a buck-boost DC-DC converter rather than a simple regulator.

I am involved in this as a mentor to a student doing a STEM/STEAM project. My expertise is as a machinist and am helping him create his idea. My knowledge of electronics is fair but not at this level. If at all possible, I would really appreciate being directed to the proper unit to purchase for this application. Additionally, I intend to use a bridge rectifier to keep the DC polarity the same no matter which way the generator spins. Any assistance would be greatly appreciated.

Thank you

 

The advantage of the field regulator is that the rpm can be held at a high rpm with a constant regulated output, the bridge should work as a polarity steering bridge.
Max.

 

Search for a dc-dc converter .A buck boost one .It keeps the output constant regardless of input as long as the input is between limits.Also i recommand to use an electrolytic cap after the bridge rectifier in order to smooth the input voltage to the regulator.Also parallel it with a 100nf cap for high frequency transients from the generator or any other input noise.

 

DC/DC converters take voltage from a Direct Current (DC) source and then converts it from a certain DC voltage level to another. They are used to raise or reduce the voltage level of supply voltage. They are often used in automobiles and household electronics.
Source : blog.enrgtech.co.uk/dual-dcdc-converter-power-driver-modules/