cell phone charger as power source

[ScottinSC]

I have several cell phone chargers I am considering using for various applications on the layout. My question is the label on the charger says the output is 5.0V but it doesn't say whether its DC or AC. I would think its DC. Is my thinking right?

Thanks

[richg1998]

Obviously you should use your multimeter to check.

Rich

[rrinker]

 Almost certainly DC, but check. But it will also be VERY low power and probably mostly useless. Maybe enough to run a couple of LEDs, that's about it.

           --Randy

[MisterBeasley]

I'd agree.  Look closely at the power supply.  It should have its voltage rating, AC or DC, and how much current it puts out.

But, Randy is right.  Cell phone chargers put out very little power.  You will be able to run some stuff on them, but not much.

Also, these wall-wart units don't have circuit breakers.  Instead, they have a one-time internal fuse designed to keep them from burning your house down if shorted or overloaded.  Once the fuse goes, the unit becomes a paperweight with some useless wires attached.

[selector]

Yes, these charge with 5 volts or so, but how many micro-amps?  A few tens, maybe?  These power supplies are only charging batteries, not running even tiny cam motors.  About all they'll do is power up the LCD display on your phone if it is plugged in and the battery hooped.  On a really fine locomotive drive, you may get some driver revolutions, but they'll be slllooooowwwww....

Crandell

[jeffrey-wimberly]

In my opinion you shouldn't waste your time trying to use a cell phone charger as a power unless it's going to be pulling maybe two or three LED's. If you want serious power at 5 volts DC get an old AT type computer power supply. It'll put out more than enough amps for most anything you want to do with it.

[CSX Robert]

 

ScottinSC

...the label on the charger says the output is 5.0V but it doesn't say whether its DC or AC...

As others have said, it is probably DC.  It almost certainly says which it is, but many do not actually say AC or DC on them, but instead use graphic symbols.   If for the output, it has a graphic that looks like a tilde(~), then it is AC, if it has a straight line with 3 dashes underneath it, kind of like this:

______

 _  _  _

then it is DC.

"it will also be VERY low power and probably mostly useless. Maybe enough to run a couple of LEDs, that's about it"
"how many micro-amps? A few tens, maybe?"
"two or three LED's"

 

Have you guys making these comments actually looked at the power ratings on some of these chargers?  I have several that are over 500 ma, some as high as 850ma.  No, these are not 500 watt PC power supplies, but they are certainly capable of running more than two or three LED's.  I could easily power over 50 LED's with one of these supplies.  ScottinSC did not say what he planned to use these for, but they may very well be powerful enough.

 

[selector]

Robert, you are correct.  I have just looked at two different chargers.  One has an output of 350 mA and the other has an output of 750 mA.  More than a few tens.  Frankly, I am surprised, particularly at the associated low voltages meant to deliver that much power.

Crandell

[MisterBeasley]

When I said these things don't deliver much power, I was thinking of the 500 milliamp range.  Yes, that will drive a bunch of LEDs, but you would be surprised how quickly you run through 500 milliamps.

I use mostly 16-volt incandescent "grain-of-wheat" bulbs on my layout.  I run them at 12 volts, which gives a nice, subdued glow rather than a harsh bright light.  It also substantially extends bulb life.  These are Miniatronics bulbs, and they are rated at 30 milliamps.  The Walthers Cornerstone street lamps are similar bulbs.  Do the math.  16 bulbs at 30 milliamps each is 480 milliamps, so that's about all that a 500 milliamp supply will handle, and that's running it close to its limit.  After that, you need another supply, and another wiring bus for another set of bulbs.  You need another outlet to plug it into, also.

I broke down and bought a couple of 12 volt, 4-amp supplies.  They will drive all the lights I want.  I also bought fuse holders and fuses, so I can protect my investment in the power supplies by fusing the line at a bit below the supply rating.

[rbettig]

Two things you need to know when using phone chargers: the Voltage,  in your case 5VDC and then the Amperage, most likely 500 mA. This will help you when adding up the light bulbs or LED's knowing that your limit is 1/2 an Amp and the average bulb about 30 mA. Using 10 bulbs would be safe. I'm using Motorola chargers 4,4VDC rated at 1.1 A,  They are just great for the Miller Engineering animated Billboard requiring 4.5 VDC (it replaces the 3 AAA batteries). With the current draw I can run 6 signs per charger.

 

[jrbernier]

  Some of the cell phone chargers are 3.3v - Just go buy some good 'wall warts' on-line.  I was able to find 12VDC/1 amp wall warts for under $10.  I have an old 15VAC/850ma charger that powers my Tortoise motors.  Look at the local Salvation Army/Goodwill stores.  Many times they have a box of 'wall warts' and they sell them for a $1 each...

Jim

[Mark R.]

Something to remember with battery chargers is that they will only provide their full potential if the proper load is detected (the item it was designed to charge). If it is rated at 500ma and 5 volts, it needs to detect a load that requires those specs before it will provide it, otherwise the output will be considerably lower than what is stated on the charger. You may only get a couple volts at minimal amperage when tested unloaded with a meter.

Not really the best suited source as an auxiliary power supply.

Mark.