DARK0717

Do batteries increase milliamp as long as there is a load?

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so, I hooked up a tiny LED to a 2 pieces D sized battery in series, they are almost dead by now as they've been stocked for more or less a year. At first I was reading 7.50 milliamps, then after more than 8 hours of the LED hooked up to the battery, I read the milliamps again and it reached 39.44 milliamps. Is this supposed to happen, does this happen normally? Don't ask me why I hooked up an LED to a battery for more than 8 hours, youll probably just laugh at me or not believe me or think im stupid.

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2 hours ago, DARK0717 said:

so, I hooked up a tiny LED to a 2 pieces D sized battery in series, they are almost dead by now as they've been stocked for more or less a year. At first I was reading 7.50 milliamps, then after more than 8 hours of the LED hooked up to the battery, I read the milliamps again and it reached 39.44 milliamps. Is this supposed to happen, does this happen normally? Don't ask me why I hooked up an LED to a battery for more than 8 hours, youll probably just laugh at me or not believe me or think im stupid.

No, it is not supposed to happen, the current (and light emitted) should reduce as the batteries drain.

You haven't reported what happened to the light output from the LED?

Possible explanations:

  1. You misread which scale you were using and it was actually 75mA initially.
    Did you have to change scale to go from 7.5 to 40?
  2. The batteries were initially very cold and their output voltage was low. They then gradually and warmed up through ohmic heating
    Were there no intermediate readings? 8 hours was a long time between.
  3. There was intiially at least one very poor contact which improved with the passage of current.

 

Edited by studiot

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A LED proper connection to two cells in series should include a resistor also in series to limit the current.

Lacking current limitation, the thermal properties of the LED can increase the current demand as the LED warms up with elapsed time on.  The batteries can also change their internal resistance with temperature with the elapsed time on.  As the cells deplete, the current should decrease as the battery voltage gets lower in time.  The time can be many hours, depending on the capability and charge state of the battery.

Unequal state of charge for each cell can also cause unusual readings.

 

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1 hour ago, Externet said:

A LED proper connection to two cells in series should include a resistor also in series to limit the current.

Lacking current limitation, the thermal properties of the LED can increase the current demand as the LED warms up with elapsed time on.  The batteries can also change their internal resistance with temperature with the elapsed time on.  As the cells deplete, the current should decrease as the battery voltage gets lower in time.  The time can be many hours, depending on the capability and charge state of the battery.

Unequal state of charge for each cell can also cause unusual readings.

 

Yes it's possible that overcurrent might have damaged the LED so that it has become a low value 75 ohm resistor.  +1

But would it still be giving off light?

Edited by studiot

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~40mA as reported is usually twice the maximum rated current for a "tiny" LED as described.  If still emitting light, we do not know.

The missing resistor value that needed when first connected depends on its color (chemistry).

image.png.c93c78e06ac80f63e1883645108653d3.png

Example :   If it is a red LED, and the battery is at 2.8V state

Sustract the red Vf :  2.8V - 1.8Vf =1.0V

For a 10mA recommended current by LED manufacturer,  1.0V / 0.01A = 100 Ohms series resistor.

image.png.033bd6bf012ef5e1c94843f9bbfb8acd.png

Edited by Externet

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I seem to remember that many LEDs have built in limiting resistors.

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It's (just about) possible that the LED is packaged with a driver circuit that tries to maintain constant power to the LED itself using a buck/boost converter.

In that case, as the available voltage from the battery fell, the current drawn would increase to maintain constant power.

It's an idea- but I'd not bet on it.


It's also important to recognise that the current available from a nearly flat battery is quite strongly temperature dependent

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Ok, the LED still lights up, it even got to 41 mA, it wasn't 75 mA, its 7.54, seven (point) fifty four and the battery was already tested for some hours before the LED test, so it should've warmed up pretty well. To be clear, the scale WENT UP FROM 7.54 TO 41 mA, a huge 34 mA difference. I can also assure you guys that there was no misconnection as the whole hours its being tested, the system didn't get touched, moved, or any physical disturbance at all. So have I provided enough information to conclude that its not supposed to happen or its just a normal thing for batteries to do?

 

Edit: The LED is also just one piece and is very small, about the size of 2 rice grains, there were no resistors, diodes whatsoever so its just a raw connection.

Edited by DARK0717

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1 hour ago, DARK0717 said:

it wasn't 75 mA, its 7.54, seven (point) fifty four

Why are you saying this?
No one quoted 75 mA.

 

1 hour ago, DARK0717 said:

I can also assure you guys that there was no misconnection as the whole hours its being tested, the system didn't get touched, moved, or any physical disturbance at all.

How do you know?
If you were there watching, why did you not take intermediate readings?

Also have you repeated the test and found the same result?

 

1 hour ago, DARK0717 said:

So have I provided enough information to conclude that its not supposed to happen or its just a normal thing for batteries to do?

No you haven't.
You have left too many questions unanswered, both from myself and others for verification.

 

What is the type number of your LED?

Do you have any photographs of the setup and the meter readings?
Not long back there was a thread about parallel/series connection of batteries.
In order to help I posted several photos and closeups of the meters in different configurations.
Perhaps someone will remember this thread.

 

 

 

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6 hours ago, studiot said:

Why are you saying this?
No one quoted 75 mA.

 

How do you know?
If you were there watching, why did you not take intermediate readings?

Also have you repeated the test and found the same result?

 

No you haven't.
You have left too many questions unanswered, both from myself and others for verification.

 

What is the type number of your LED?

Do you have any photographs of the setup and the meter readings?
Not long back there was a thread about parallel/series connection of batteries.
In order to help I posted several photos and closeups of the meters in different configurations.
Perhaps someone will remember this thread.

 

 

 

The first comment stated that "You misread which scale you were using and it was actually 75mA initially."

I know because I storeed the device where it wont be bothered

I have done the test repeatedly and it just keeps on increasing

I don't know what type of LED Diode specifically, but it came from a desktop computer case, the LED is the one on the power button which is a red one

I couldn't provide pictures at the moment, try concluding with the information I gave.

Ill give a hint: Coil

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2 hours ago, DARK0717 said:

The first comment stated that "You misread which scale you were using and it was actually 75mA initially."

Yes you are right, I did.

But that was a hypothetical situation that you might have misread the meter (it happens) and your reaffirmation without proof 

2 hours ago, DARK0717 said:

I know because I storeed the device where it wont be bothered

has not increased confidence in your supplied information.

Particularly in view of these two statements

10 hours ago, DARK0717 said:

there were no resistors, diodes whatsoever so its just a raw connection.

followed by this

2 hours ago, DARK0717 said:

Ill give a hint: Coil

These statements contradict each other,

Are you trying to trick us?

2 hours ago, DARK0717 said:

I know because I storeed the device where it wont be bothered

So you can't say how long the D cells were supplying 40 mA for.

2 hours ago, DARK0717 said:

I have done the test repeatedly

But you didn't mention this at the outset?

And now you expect us to believe that D cells which are

Quote

DARK0717

almost dead by now

 

2 hours ago, DARK0717 said:

and it just keeps on increasing

 

Pull the other one.

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1 hour ago, studiot said:

Yes you are right, I did.

But that was a hypothetical situation that you might have misread the meter (it happens) and your reaffirmation without proof 

has not increased confidence in your supplied information.

Particularly in view of these two statements

followed by this

These statements contradict each other,

Are you trying to trick us?

So you can't say how long the D cells were supplying 40 mA for.

But you didn't mention this at the outset?

And now you expect us to believe that D cells which are

 

 

Pull the other one.

Obviously I put the device in a cabinet. How hard is it to conclude that I put the device in a cabinet so it wont be bothered and will still be able to get checked??????? How hard is it that I already gave a hint which is a coil and I used a specific type of coil that is powered by the battery and is connected to the LED????????? So its Batery > Coil > LED 

Edited by DARK0717

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4 hours ago, DARK0717 said:

How hard is it that I already gave a hint which is a coil and I used a specific type of coil that is powered by the battery and is connected to the LED????????? So its Batery > Coil > LED 

But that is not what you said. You repeatedly said it was just the battery and the LED.

I can't see how the coil would change things much. A coil will just act as a resistance to a DC current. So, unless there is enough current to warm it slightly and reduce its resistance, I can't see it being relevant. Or the ambient temperature changed enough to change its resistance. 

Have you measured the resistance of the coil? Or its temperature?

The presence of the coil might explain why the LED didn't just breakdown immediately, which I would expect from a 3V supply. Or it might be there is a current limiter in the LED.

Did you measure the voltage of the batteries before you started? Have you measure it now? Both under the load (LED) and no load?

8 hours ago, DARK0717 said:

I have done the test repeatedly and it just keeps on increasing

What do you mean "the test"? Just repeatedly measuring the current with the same battery and LED? Or with new sets of batteries?

It just keeps on increasing? What is it up to now? A couple of hundred amps? :)

Presumably you also have the ammeter in series with the LED and the coil. Again, not sure how that could be significant. Is it a digital meter? (I assume it is from the 7.50 and 39.44 figures.)

22 hours ago, Externet said:

Lacking current limitation, the thermal properties of the LED can increase the current demand as the LED warms up with elapsed time on.  The batteries can also change their internal resistance with temperature with the elapsed time on.  As the cells deplete, the current should decrease as the battery voltage gets lower in time.  The time can be many hours, depending on the capability and charge state of the battery.

Good points. I particular like the suggestion of the LED warming.

I don't know how the internal resistance changes for different types of batteries. I think that for most, it increases as the battery runs down. I imagine there could be complex reactions where batteries that have been stored a long time increase their internal resistance as crystals grow (or something!) which then drops when they are used. Just guessing now, though.

@DARK0717 what type of batteries are these?

When you say "they are almost dead by now as they've been stocked for more or less a year" do you mean they were new and have just been left in a drawer. (Do they have expiry date on?) Or they have been used and so discharged? Some types of batteries will self discharge quite quickly others will hold their charge better. 

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19 minutes ago, Strange said:

But that is not what you said. You repeatedly said it was just the battery and the LED.

I can't see how the coil would change things much. A coil will just act as a resistance to a DC current. So, unless there is enough current to warm it slightly and reduce its resistance, I can't see it being relevant. Or the ambient temperature changed enough to change its resistance. 

have you measured the resistance of the coil? Or its temperature?

What do you mean "the test"? Just repeatedly measuring the current with the same battery and LED? Or with new sets of batteries?

It just keeps on increasing? What is it up to now? A couple of hundred amps? :)

Presumably you also have the ammeter in series with the LED and the coil. Again, not sure how that could be significant. Is it a digital meter? (I assume it is from the 7.50 and 39.44 figures.)

Didn't I told you to not ask me why I hooked up an LED for a while to a bettery. Its because im using a specific type of coil attatched to the battery, which you may or may not believe me that's why I tend to not disclose it to you guys, I repeatedly said battery and LED, but I also gave a hint on why I did it in the first place which is I want to test a specific type of COIL. I haven't measured the resistance of the coil but the coil is a bit colder than room temps. I tested it the LED with and without the coil, without the coil, the mA decreases slightly, with the coil, the mA increases significantly and the increase and decrease results show after more than 8 hours of testing with the LED. The mA increased to 49 mA after a an hour of waiting since I commented the one above this. My multimeter is a digital one, a WinAPEX ET8102. The tests I conducted is the same battery, im also not using an ammeter, it consists of 2 basic D sized Sony batteries in series. But Ive tested it for a bit on AA batteries and same results show (which is the significant increase of mA).

Edited by DARK0717

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11 minutes ago, DARK0717 said:

Didn't I told you to not ask me why I hooked up an LED for a while to a bettery.

I didn't ask you why. I just asked you a few details about measurements, etc.

17 minutes ago, DARK0717 said:

Its because im using a specific type of coil attatched to the battery

The type of coil won't make any difference in a DC circuit. The resistance is the only significant factor. (Unless it is near a high voltage AC line and picking up some extra current that way.)

12 minutes ago, DARK0717 said:

I tested it the LED with and without the coil, without the coil, the mA decreases slightly, with the coil, the mA increases significantly and the increase and decrease results show after more than 8 hours of testing with the LED.

The decrease with the coil is probably due to the resistance of the coil.

Have you measured the resistance of the coil?

Does the current increase over time both with and without the coil in the circuit?

14 minutes ago, DARK0717 said:

The tests I conducted is the same battery, im also not using an ammeter, it consists of 2 basic D sized Sony batteries in series.

What type of batteries (zinc-carbon, alkaline, NiMH, etc)?

Are they used or unused before this? (Your "nearly dead" comment was confusing.)

If they are old, are they past their expiry data?

What is the voltage output of the batteries? When in the circuit and when out of the circuit?

15 minutes ago, DARK0717 said:

im also not using an ammeter

You must be if you are measuring current? (As you don't have a standard resistance to measure the voltage across.)

 

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22 minutes ago, Strange said:

I didn't ask you why. I just asked you a few details about measurements, etc.

The type of coil won't make any difference in a DC circuit. The resistance is the only significant factor. (Unless it is near a high voltage AC line and picking up some extra current that way.)

The decrease with the coil is probably due to the resistance of the coil.

Have you measured the resistance of the coil?

Does the current increase over time both with and without the coil in the circuit?

What type of batteries (zinc-carbon, alkaline, NiMH, etc)?

Are they used or unused before this? (Your "nearly dead" comment was confusing.)

If they are old, are they past their expiry data?

What is the voltage output of the batteries? When in the circuit and when out of the circuit?

You must be if you are measuring current? (As you don't have a standard resistance to measure the voltage across.)

 

The decrease is when there is no coil, the increase is when there is a coil. Its not an ordinary coil, if u know what I mean, you know what it is. I haven't measured the resistance of the coil, but im quite sure, that kind of coil is the one you would call least resistance. The current increases only when there is the coil. It deacreases when there is no coil. Yes coil = increase, no coil = decrease. I think its waaaay past the expiry data, I dunno. Its a NiMH battery. The batteries were used on a casio piano since the piano can be used with D sized batteries and I used it for quite a while. The voltage output of the batteries is about 1.5 each, so its about 3 volts in series. Speaking of volts, it also increases to around 6 when the coil is attatched.

 

The Increase in mA and voltage wont happen if there is no load, so a load is required to see changes.

Edited by DARK0717

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7 minutes ago, DARK0717 said:

The voltage output of the batteries is about 1.5 each, so its about 300 volts in series

Did you measure this?

7 minutes ago, DARK0717 said:

Speaking of volts, it also increases to around 600 when the coil is attatched.

I don't believe that.

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5 minutes ago, Strange said:

Did you measure this?

I don't believe that.

im sorry, I meant 3 volts and 6

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44 minutes ago, DARK0717 said:

im sorry, I meant 3 volts and 6

Did you measure 3V?

Did you measure 6V? (I still find that implausible?)

Presumably you had to take the meter out of the circuit where it was measuring current, so you could measure the voltage instead. Is that correct?

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@Strange

Here is video how to increase voltage from 6 V (4x 1.5V batteries) to over 600 V. https://www.youtube.com/watch?v=iI47ZSRxVro

It's using coil, NE555 timer, in boost step-up converter.

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

Automobile coils (aka "ignition coils") and step-up converters are changing 12-24 V from automotive battery to e.g. 20 kV ... 45 kV.

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

 

 

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5 hours ago, Strange said:

Did you measure 3V?

Did you measure 6V? (I still find that implausible?)

Presumably you had to take the meter out of the circuit where it was measuring current, so you could measure the voltage instead. Is that correct?

 

19 minutes ago, Sensei said:

@Strange

Here is video how to increase voltage from 6 V (4x 1.5V batteries) to over 600 V. https://www.youtube.com/watch?v=iI47ZSRxVro

It's using coil, NE555 timer, in boost step-up converter.

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

Automobile coils (aka "ignition coils") and step-up converters are changing 12-24 V from automotive battery to e.g. 20 kV ... 45 kV.

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

 

 

I know that coils do in fact can increase voltage, and yes I measured the volts before and after. So im sure of what I am saying here and they are not just wild guesses. Its just that voltage can increase but with the mA as well??, I cant believe it either that's why I had to ask here in the forums and explain to me if this is natural for batteries or some kind of overunity which is quite impossible.

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30 minutes ago, Sensei said:

Here is video how to increase voltage from 6 V (4x 1.5V batteries) to over 600 V. https://www.youtube.com/watch?v=iI47ZSRxVro

It's using coil, NE555 timer, in boost step-up converter.

But that is not quite the same as a DC current through an inductor and an LED. 

9 minutes ago, DARK0717 said:

I know that coils do in fact can increase voltage

Not with a static current.

10 minutes ago, DARK0717 said:

So im sure of what I am saying here and they are not just wild guesses. Its just that voltage can increase but with the mA as well??

You didn't measure them at the same time, did you? (I can't be sure because you refuse to clearly describe what you did. And you cannot answer simple questions.)

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8 minutes ago, Strange said:

But that is not quite the same as a DC current through an inductor and an LED. 

Not with a static current.

You didn't measure them at the same time, did you? (I can't be sure because you refuse to clearly describe what you did. And you cannot answer simple questions.)

I how could I measure before and after at the same time, of course I have to measure before first which is 3 volts, then I hooked it up with the coil then LED to the coil, and voltage became 6 volts and the mA increased. The answer to your questions about measurement is simple, I measured volts and mA, before, after, in between, etc, except the resistance of the coil. I just need an answer to my question, IS THAT SUPPOSED TO HAPPEN OR DOES IT NORMALLY HAPPEN????

Edited by DARK0717

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21 minutes ago, DARK0717 said:

 

I know that coils do in fact can increase voltage, and yes I measured the volts before and after. So im sure of what I am saying here and they are not just wild guesses. Its just that voltage can increase but with the mA as well??, I cant believe it either that's why I had to ask here in the forums and explain to me if this is natural for batteries or some kind of overunity which is quite impossible.

No, one coil will not increase (or decrease) the voltage.

It can, however lead to switching transients which can be of quite high voltage.

 

I'm sorry but you have lost all credibility with me, as well as wasting  a substantial amount of my time.

In particular you concealed the fact that there was some connection to a coil but have not told us how this coil was connected.

You also initially omitted to mention the cabinet though I don't see how the absence or presence of a cabinet can affect the activity of the circuit.

 

So what else are you not telling us ?

Edited by studiot

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1 minute ago, DARK0717 said:

then I hooked it up with the coil then LED to the coil, and voltage became 6 volts and the mA increased.

How did you measure both voltage and current at the same time? (Talk about blood from a stone...)

2 minutes ago, DARK0717 said:

I just need an answer to my question, IS THAT SUPPOSED TO HAPPEN OR DOES IT NORMALLY HAPPEN????

Of course not. So I am trying to understand what you measured and how so we can come up with a better idea of what has gone wrong.

1 minute ago, studiot said:

You also initially omitted to mention the cabinet though I don't see how the absence or presence of a cabinet can affect the activity of the circuit.

I don't know what the OP means by "cabinet" (I assumed a cupboard/closet, but that sounds weird now I think about it.) If it is a small box, then it could affect the temperature rise of the LED, coil, batteries, meter ...

So @DARK0717 what is this "cabinet" of which you speak?

3 minutes ago, studiot said:

It can, however lead to switching transients which can be of quite high voltage.

There shouldn't be any switching transients. But god only knows what else the OP hasn't told us yet...

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