# How do you reduce voltage and make a current last longer?

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Well the explosion is what I wan to avoid, but I'm having trouble figuring out what a charge regulator does differently because doesn't a charge regulator have to do SOMETHING with all that extra energy? ...

If there is no electrical load then there is no flow of electricity; it's an open circuit. The energy used to drive the generator when there is no electrical load is lost as heat. Edited by Acme

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So if there's no flow, why would a charge regulator need a water heater or resistors to get rid of extra energy from the flow of electricity that surpassed he limit of what would otherwise overcharge a battery?

Edited by MWresearch
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So if there's no flow, why would a charge regulator need a water heater or resistors to get rid of extra energy from the flow of electricity that surpassed he limit of what would otherwise overcharge a battery?

? What are you talking about with a water heater? Where did you get that?

All-in-all you have laid out nothing but whacky misconceptions while ignoring several direct requests for the specifics of your setup. Good luck.

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Well the explosion is what I wan to avoid, but I'm having trouble figuring out what a charge regulator does differently because doesn't a charge regulator have to do SOMETHING with all that extra energy?

What extra energy? A charge controller will deliver a constant voltage and a controlled current to charge the battery. The current required depends on the type of battery - some require a constant current, some need the current to reduce as the battery approaches full charge. When the battery is fully charged, the controller will detect that and stop the charging current.

Unless you can give some details of what your initial power source is, why you need to charge a battery, how much energy you need to store, what the load is (lights?), and what voltage and current the load requires, etc. no one can tell you anything very helpful.

Unknown energy source: it may need to be converted from AC to DC, the voltage may need to be stepped up or down.

Energy storage: how much, what voltage and whether it will be used occasionally at high current or continuously at low current, whether it will be trickle charged or needs to be charged quickly when power is available.

Load: voltage, current, AC or DC, power factor, ...

I guess a DC-DC converter would do the trick from what you describe, but it would have to be a variable converter, like DCX-DC, no matter what input it had for voltage, the output voltage would be the same

Switch mode power supplies can do this. If you have a laptop, look at the power supply: it will probably cope with any input voltage between 110 and 240V, but provide a steady 12V (or whatever) output.

Edit:

An important factor here might be noise rejection: the amount (dynamic) change in the input that can be coped with and still provide (nearly) constant output.

Of course, as you won't tell us what the characteristics of your power source is, I have no idea if that is relevant or not...

A charge controller redirects extra energy to some kind of water heater ...

Wha! You think electric cars have water heaters in them?

Edited by Strange
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!

Moderator Note

This thread looks like it's dying for lack of clarity. I suggest the OP get this under control, and provide at least some answers to previous questions. Without it, you'll get more and more frustrated replies.

Let's stay civil, and if the clarity doesn't improve, we'll have to close this.

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? What are you talking about with a water heater? Where did you get that?

All-in-all you have laid out nothing but whacky misconceptions while ignoring several direct requests for the specifics of your setup. Good luck.

"All in all" I've given you a basic scenario that I would expect anyone with experience in electrical engineering to understand. A generator with a stator and rotator generates electricity into batteries which power lights over a duration of time greater than the duration of time that it took to charge the betteries. That idea is a very simple setup, don't over think it and insert detail where there is none. What's hard is when you and everyone else keeps arguing over what the "best" solution is to not over-charging the batteries and making sure the battery output has the proper voltage.

The water heater is what I got from looking up a model of a charge regulator. It doesn't have to be a water heater but it has to direct the energy into some auxiliary load which is exactly what I was talking about before, that excess energy still has to go somewhere. And since water has a high specific heat I'm guessing that's why they thought a small water heater wouldn't be a bad idea.

Edited by MWresearch
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"All in all" I've given you a basic scenario that I would expect anyone with experience in electrical engineering to understand. A generator with a stator and rotator feeds current into batteries which power lights. It's a very simple setup, don't over think something and insert detail where there is none.

The trouble is, it is impossible to say what a realistic solution is without details.

For example, why does your "simple" setup have batteries? Why not just drive the lights directly from the generator (via a DC-DC converter if necessary)?

What's hard is when you and everyone else keeps arguing over what the "best" solution is to not over-charging the batteries and making sure the battery output has the proper voltage.

Because this depends on the characteristics of the power source, the type of batteries and the type of load.

The water heater is what I got from looking up a model of a charge regulator.

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"All in all" I've given you a basic scenario that I would expect anyone with experience in electrical engineering to understand. A generator with a stator and rotator feeds current into batteries which power lights. It's a very simple setup, don't over think something and insert detail where there is none. What's hard is when you and everyone else keeps arguing over what the "best" solution is to not over-charging the batteries and making sure the battery output has the proper voltage.

The water heater is what I got from looking up a model of a charge regulator.

Let's see that model please. Give a link or cite a specific source.

Given that there are different kinds of batteries, the details are required for any solution let alone a 'best' solution. So far your information is insufficient and poorly expressed.

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The trouble is, it is impossible to say what a realistic solution is without details.

For example, why does your "simple" setup have batteries? Why not just drive the lights directly from the generator (via a DC-DC converter if necessary)?

Because who knows how fast the rotor will turn, who would want electricity in a circuit with a current that changes unpredictably by the second?

Because this depends on the characteristics of the power source, the type of batteries and the type of load.

The power source as I said is a generator with a stator and a rotor, like a turbine. Lights and a way to get rid of electricity with resistors automatically imply a resistive load and the use of capacitors or batteries to resist variability in the current from the generator throughout the circuit would imply a capacitive load to form a multiple load circuit.

https://en.wikipedia.org/wiki/Charge_controller

Let's see that model please. Give a link or cite a specific source.

Given that there are different kinds of batteries, the details are required for any solution let alone a 'best' solution. So far your information is insufficient and poorly expressed.

Google "turbine" and you'll get the gist of what I'm trying to do. I have a generator with a stator and rotor, ok? Now, that generator can and will have a rotor rotating at an infinite number of different possible angular velocities, ok? But, I want to turn that varying current from the different possible inputs of power into a constant current to feed lights that are powered consistently for a duration of time.

Edited by MWresearch
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Given that there are different kinds of batteries, the details are required for any solution let alone a 'best' solution. So far your information is insufficient and poorly expressed.

Because who knows how fast the generator will turn, who would want electricity in a circuit with a current that changes unpredictably by the second?

OK, that's something. Now, does the generator produce AC or DC and at what voltage. What is powering the generator?

The power source as I said is a generator with a stator and a rotor, like a turbine. Lights and a way to get rid of electricity with resistors automatically imply a resistive load and the use of capacitors or batteries to resist variability in the current from the generator throughout the circuit would imply a capacitive load to form a multiple load circuit.

Google "turbine" and you'll get the gist of what I'm trying to do. I have a generator with a stator and rotor, ok? Now, that generator can and will have a rotor rotating at an infinite number of different possible angular velocities, ok? But, I want to turn that varying current from the different possible inputs of power into a constant current to feed lights that are powered consistently for a duration of time.

The 'get rid of electricity' part is meaningless. If the charge controller shuts off the battery in the circuit then the generator circuit is open and there is no electricity. You take power from the battery to run whatever at a constant level and when the battery runs low below the set-point the charge controller closes the charging circuit and electricity flows again.

Again, if there is no load on the generator it isn't making electricity.

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Because who knows how fast the generator will turn

I assumed you would, as you know what this generator is. Why wouldn't it turn at steady rate? And depending on how much variation there is, then it might be enough to have a capacitor. If the generator is very intermittent then you may need batteries (but you need to work out how much energy needs to be stored - i.e. how long is the generator off for, versus the power used by the lights).

who would want electricity in a circuit with a current that changes unpredictably by the second?

The current is going to be determined by the load (the lights).

The power source as I said is a generator with a stator and a rotor, like a turbine.

Is this a wind turbine? Steam? Hydroelectric?

Lights and a way to get rid of electricity automatically imply a resistive load and the use of capacitors or batteries to resist variability in the current from the generator throughout the circuit would imply a capacitive load to form a multiple load circuit.

If you use a charge controller to charge the batteries from the generator, and the battery voltage is the same as that required by your lights, then there is nothing else required.

Thanks. I have never come across such a shunt regulator. I don't know when or why they would be used. (The referenced document is no longer available.)

Google "turbine" and you'll get the gist of what I'm trying to do. I have a generator, ok? Now, that generator can and will have a rotor at an infinite number of different possible velocities, ok? But, I want to turn that varying current into a constant current to feed lights that are powered consistently for a duration of time.

I would imagine you could buy a charge controller for whatever type of batteries you decide to use. It should charge the batteries whenever the [wind] turbine provides enough power. Then just run the lights off the battery.

Edited by Strange
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OK, that's something. Now, does the generator produce AC or DC and at what voltage. What is powering the generator?

I see nothing that would cause the current to alternate and I already said I want the lights to be powered consistently, I would assume DC. Doesn't matter what's powering the generator. Doesn't matter if its wind, doesn't matter if its water, all that matters is that the generator turns and it can turn at different rates.

OK, that's something. Now, does the generator produce AC or DC and at what voltage. What is powering the generator?

The 'get rid of electricity' part is meaningless. If the charge controller shuts off the battery in the circuit then the generator circuit is open and there is no electricity. You take power from the battery to run whatever at a constant level and when the battery runs low below the set-point the charge controller closes the charging circuit and electricity flows again.

Then that would be a reason why a charge controller is the best option.

I assumed you would, as you know what this generator is. Why wouldn't it turn at steady rate?

Because nature is chaotic? Because wind picks up and dies down? Because water splashes into itself and forms eddies? Because most kinetic motion changes? because friction exists and causes energy loss over time?

The current is going to be determined by the load (the lights).

No, current is also determined by the voltage applied to the lights, not just their resistance.

Is this a wind turbine? Steam? Hydroelectric?

Assume its a spaghetti monster, doesn't matter, all that matters is there's something turning it. But if you must know, it would work best for a renewable source of energy like wind or water but it isn't limited to those types of circumstances. It's a device I'm constructing for the simple direct measurement of energy based on rotor frequency or angular velocity using lights to quantize and categorize the energy into different bins based on which light flashes at which time so I can use the data on excel without doing a bunch of programming to have it directly hook up to the computer and record the data.

If you use a charge controller to charge the batteries from the generator, and the battery voltage is the same as that required by your lights, then there is nothing else required.

If it's sophisticated enough yeah, but I still want to control how it deals with excess energy because its completely possible that there will be a huge spontaneous burst of energy that makes the rotor rotate at huge speeds, and I don't want anything to overheat either.

Edited by MWresearch
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For a simple home-built system whether powered by wind, water or internal combustion engine you can use an automotive alternator, an automotive charge controller [called a regulator in cars] and a 12 volt deep-cell battery. You can get the alternator and regulator at a junk yard. I'd look for equipment made before digital electronics were introduced for the sake of simplicity.

A typical automotive alternator is designed to operate between 2000 and 10000 rpm. Gear it appropriate to your power source to stay in this range It produces AC which is changed to DC using a diode array that's in the alternator case. Back in the day autos had DC generators but they didn't produce enough juice at low rpm so when you stopped at night the heater would slow, the lights would dim and the battery would drain.

If you need AC house-current @120volts you get an inverter which attaches to the 12 volt battery. These come in varying wattages, e.g. mine is 800watts. Note these need to have a wattage that exceeds the regular operating wattage of some devices as there is a surge when starting those devices. Again for example, my 800 watt inverter will not run a 750watt hot-plate or heater.

The battery capacity, measured in amp hours determines how long you can run specific stuff. My deep-cell battery is rated at 100amp/hours, though in practice you can only get about 80% of these batteries' capacity.

Note alternators also have different ratings. These examples should make it clear why we need specifics on equipment rather than generalized descriptions.

PS Use this formula to figure out the load in suitable units. Watts = Volts * Amps

So if you have a 20 watt 12 volt light bulb you find the amperage 20watts / 12 volts = 1.6 amps. So that bulb would stay lit by my battery for 80 [amp/hours] / 1.6 amps = 50 hours.

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I see nothing that would cause the current to alternate

It depends on the type of generator you are using.

No, current is also determined by the voltage applied to the lights, not just their resistance.

But one of the benefits of running the lights from the battery is that most types of batteries will give a fairly constant voltage. If they don't you use a DC-DC convert to get a constant voltage out.

It's a device I'm constructing for the simple direct measurement of energy based on rotor frequency or angular velocity using lights to quantize and categorize the energy into different bins based on which light flashes at which time so I can use the data on excel without doing a bunch of programming to have it directly hook up to the computer and record the data.

This sounds like an incredibly complicated way of achieving that.

If it's sophisticated enough yeah, but I still want to control how it deals with excess energy

I'm not sure what "excess energy" means in this context.

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...It's a device I'm constructing for the simple direct measurement of energy based on rotor frequency or angular velocity using lights to quantize and categorize the energy into different bins based on which light flashes at which time so I can use the data on excel without doing a bunch of programming to have it directly hook up to the computer and record the data. ...

Get a pocket multimeter at the hardware store for about 20$and you can read exact voltages and amperages for your spreadsheet. They measure DC & AC usually from tenths of a volt up to 1000. Note: Ammeters must be connected in series or you'll blow them out. Edited by Acme ##### Link to comment ##### Share on other sites For a simple home-built system whether powered by wind, water or internal combustion engine you can use an automotive alternator, an automotive charge controller [called a regulator in cars] and a 12 volt deep-cell battery. You can get the alternator and regulator at a junk yard. I'd look for equipment made before digital electronics were introduced for the sake of simplicity. A typical automotive alternator is designed to operate between 2000 and 10000 rpm. Gear it appropriate to your power source to stay in this range It produces AC which is changed to DC using a diode array that's in the alternator case. Back in the day autos had DC generators but they didn't produce enough juice at low rpm so when you stopped at night the heater would slow, the lights would dim and the battery would drain. If you need AC house-current @120volts you get an inverter which attaches to the 12 volt battery. These come in varying wattages, e.g. mine is 800watts. Note these need to have a wattage that exceeds the regular operating wattage of some devices as there is a surge when starting those devices. Again for example, my 800 watt inverter will not run a 750watt hot-plate or heater. The battery capacity, measured in amp hours determines how long you can run specific stuff. My deep-cell battery is rated at 100amp/hours, though in practice you can only get about 80% of these batteries' capacity. Note alternators also have different ratings. These examples should make it clear why we need specifics on equipment rather than generalized descriptions. PS Use this formula to figure out the load in suitable units. Watts = Volts * Amps So if you have a 20 watt 12 volt light bulb you find the amperage 20watts / 12 volts = 1.6 amps. So that bulb would stay lit by my battery for 80 [amp/hours] / 1.6 amps = 50 hours. That's a lot of good information, thanks for that. But, is there any particular reason why the magnetic field should rotate relative to the structure of the device instead of the coiled armature? It seems like the design would be simpler if I didn't need a diode array. Can an alternator charge a dead battery too? The input isn't going to be constant, at times it will be 0 which means the lights are going to drain power from the batteries until there's none left. Get a pocket multimeter at the hardware store for about 20$ and you can read exact voltages and amperages for your spreadsheet. They measure DC & AC usually from tenths of a volt up to 1000.

Note: Ammeters must be connected in series or you'll blow them out.

I want to construct something myself to also just get general experience with electrical engineering. I don't know why, but for some reason mechanical engineering doesn't go very far with circuitry and I always thought it was important to know electrical engineering for understanding modern technology, not to mention that physics like wave mechanics and electromagnetics could be used to develop new circuitry components.

But, is there any particular reason why the magnetic field should rotate relative to the structure of the device instead of the coiled armature? It seems like the design would be simpler if I didn't need a diode array. Can an alternator charge a dead battery too?

Edited by MWresearch
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That's a lot of good information, thanks for that. But, is there any particular reason why the magnetic field should rotate relative to the structure of the device instead of the coiled armature?

There are different alternator/generator designs for different applications. Wiki has a good general article that describes them. >> Alternator @Wiki

It seems like the design would be simpler if I didn't need a diode array. Can an alternator charge a dead battery too?

You cannot charge a battery with AC if that's what you are asking.

The input isn't going to be constant, at times it will be 0 which means the lights are going to drain power from the batteries until there's none left.

Correct. If you expect such a drain you add more batteries [in parallel] to increase the amp hours.

I want to construct something myself to also just get general experience with electrical engineering. I don't know why, but for some reason mechanical engineering doesn't go very far with circuitry and I always thought it was important to know electrical engineering for understanding modern technology, not to mention that physics like wave mechanics and electromagnetics could be used to develop new circuitry components.

If you want to experiment then it's still a good idea to get the components I mentioned. Take them apart to see how they are constructed and seek out technical manuals specific to the parts you get. Do some web searches along the line of 'introduction to electronics'.

PS Here is an excellent resource for all things battery. >> Battery University

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You cannot charge a battery with AC if that's what you are asking.

So that's why I need the diodes is what you're saying. But why not just have a generator then instead of an alternator if I have batteries?

Edited by MWresearch
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So that's why I need the diodes is what you're saying. But why not just have a generator then instead of an alternator if I have batteries?

Because a DC generator won't deliver a constant voltage/current with the differing rpms. This is why autos use alternators as I earlier related. A straight DC generator will also act as a motor, so if it isn't putting out enough juice to charge the battery it will draw juice from the battery and run.

As an aside, if you get an alternator and regulator from a junkyard, take them out of the same vehicle so they will be properly matched.

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Because a DC generator won't deliver a constant voltage/current with the differing rpms.

But I though that's why I had a charge regulator. Are you saying a diode can both rectify and regulate a current at the same time? I also can't figure out why a generator draws energy if all it does is complete a circuit when it's sitting stationary. Do ferromagnetic materials somehow use up energy to create a static magnetic field?

Edited by MWresearch
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But I though that's why I had a charge regulator. Are you saying a diode can both rectify and regulate a current at the same time? I also can't figure out why a generator draws energy if all it does is complete a circuit when it's sitting stationary. Do ferromagnetic materials somehow use up energy to create a static magnetic field?

The old auto generators also used regulators to keep from overcharging the battery.

Get a little DC motor, hook it to a small light, and spin it with a drill. [spin the motor, not the light. ] The light glows. Obviously if you hook a battery to the motor the motor runs. It's just the nature of the device. The magnets don't use energy; it's the coils using energy when there's a current flowing in them.

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Exactly, ferromagnetic materials don't need electricity to be magnets, so what exactly is drawing current in the generator? The coils simply existing don't draw current from anything...unless the magnetic field acts as a cathode on one end and an anode on another end, while the magnet itself acts as an electrolyte?

Edited by MWresearch
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Exactly, ferromagnetic materials don't need electricity to be magnets, so what exactly is drawing current in the generator? The coils simply existing don't draw current from anything...unless the magnetic field acts as a cathode on one end and an anode on another end, while the magnet itself acts as an electrolyte?

Electrolysis is an entirely different animal than motors and generators. In simplest terms, a current moving in a conductor creates a magnetic field around that conductor and a conductor moving in a magnetic field creates an electric current in that conductor.

This Wiki article is a fair introduction to the subject, including the historical discoveries and developments. > Electric motor

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But I though that's why I had a charge regulator. Are you saying a diode can both rectify and regulate a current at the same time?

Rectifying diode is passing current one way, and blocking the other way (if it's not broken).

Rectifying bridge (or four rectifying diodes) is turning sinusoid AC wave, to pulses in one direction current.

Smoothing capacitor(s) will smooth these pulses to something more resembling flat DC.

I also can't figure out why a generator draws energy if all it does is complete a circuit when it's sitting stationary.

Do ferromagnetic materials somehow use up energy to create a static magnetic field?

Electric motor is typically three or more electromagnets, and same quantity magnets. Not just one.

Current passes through 1st electromagnet (wire+iron core f.e.), and creates magnetic field.

This field is repelling from stationary magnet (polarization f.e. N on electromagnet and N on magnet). And rotor is spinning to 2nd position. Electromagnet is disconnecting from external power wires.

After spin, 2nd electromagnet is connecting to these wires, powered up, and again repelling, and it's going in circle.

Here you have example three electromagnet rotor:

This one has 15-16

Also there is induction in ferromagnetic cores of electromagnets.

If you connect DC to motor one way (+ to +, - to -), it'll be spinning in one direction f.e. clockwise,

after swapping polarization of DC (+ to -, - to +), it'll be spinning in opposite direction. anti clockwise.

After connecting AC to motor, it'll be spinning in one direction for some time (typically very short), and in other for some time.

With high frequency AC, it'll be invisible spinning. Switching f.e. 50 Hz is so fast, rotor appears still.

But you won't be able to spin it by hand. It will have great resistance for any manual spinning (unlike when power is turned off).

Edited by Sensei
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Ok so I have another question: What if I have a situation where the rotor can rotate in either direction? I'll still get an AC current, but won't the polarization reverse every time the rotation goes from being clockwise to counterclockwise? How would I rectify that to make a single DC current through the whole thing? Would I need a diode on both sides of the circuit, both going into and coming out of the alternator, and, would both diodes have the same orientation?

And then, if I have one wire running through the whole alternator, is there any sort of phase differential caused by different parts of the wire being exposed to different parts of the magnetic field? Or, do phase differentials only occur when all the wires are separate for each magnet in the stator?

And that smoothing capacitor...If I'm not mistaken, a charge regulator converts a lower DC current to a higher DC current by absorbing a bit of current at a time and then re-releasing it in the form of higher-voltage pulses. So the smoothing capacitor takes those pulses and then turns them into a regular DC current? Why wouldn't charge regulators automatically be built with that? Also if the pulses are occurring at like 1000000 times a second, why would it matter if I have a continuous current vs a pulsating current?

Edited by MWresearch

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