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Replacing batteries by AC or DC adaptor

Joined
Oct 15, 2007
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Hey guys,

I was just wondering if one could replace the use of batteries in any electronics with an AC or DC adaptor or maybe even a switching adaptor. For example: My 445 nm laser pulls around 2.2 A from my 4.2V battery. Could it be okay to connect a power supply of 4.205 V, that can supply a maximum current of say 3 or 1 A?
I am asking this because I want to transform some build from being a portable handheld to a labby style. If this is not possible, then how exactly should i approach this?

Thanks!
 





You can use an AC to DC wall converter but the current must exceed the needed current by the laser. For example if the laser pulls 2.2A you would need at least a 2.5A wall adapter. You must make sure the output voltage is constant and within the drivers limits. So a 4.2V AC-DC converter with at least 2.5A output is great.
 
Word of warning:

Make sure you measure the voltage coming from your ac/dc adapter and add a capacitor if possible. I have a "12v" AC/DC and it outputs over 20 volts.
 
Word of warning:

Make sure you measure the voltage coming from your ac/dc adapter and add a capacitor if possible. I have a "12v" AC/DC and it outputs over 20 volts.

Don't worry, I always measure the voltage of the adaptor before connecting it to any source.
I have two cheap chinese adaptors that can be voltage regulated and output twice the voltage they are rated at. I can accurately test voltages to 4 decimal places so that shouldn't be a problem!
 
You can use an AC to DC wall converter but the current must exceed the needed current by the laser. For example if the laser pulls 2.2A you would need at least a 2.5A wall adapter. You must make sure the output voltage is constant and within the drivers limits. So a 4.2V AC-DC converter with at least 2.5A output is great.

If the current does not meet the requirements of the driver, how would that affect the output power? I am guessing it would just not be as powerful as it should be.
Also, would there not be any danger of using a 3A output if the driver is pulling 2.2A from the batteries? I know that a drive pulls as much current as it needs to, but what if the battery is limiting its discharge rate to protect itself?
 
Might fry the adapter if you suck too much current from it ;)
 
If the current does not meet the requirements of the driver, how would that affect the output power? I am guessing it would just not be as powerful as it should be.
Also, would there not be any danger of using a 3A output if the driver is pulling 2.2A from the batteries? I know that a drive pulls as much current as it needs to, but what if the battery is limiting its discharge rate to protect itself?

Yup... you will damage the wall adapter. Some adapters have a feature that will stop all output to the driver and it just simply will not work.
 
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If the current does not meet the requirements of the driver, how would that affect the output power? I am guessing it would just not be as powerful as it should be.
Also, would there not be any danger of using a 3A output if the driver is pulling 2.2A from the batteries? I know that a drive pulls as much current as it needs to, but what if the battery is limiting its discharge rate to protect itself?

Only use "switching power supplies", since they are voltage regulated.

Most switching plug in supplies will deliver ~10% over the rated current.

Voltage will sag a little at that over-current level.

Loads less than the rated current are fine.

LarryDFW
 
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good topic- wallwarts are everywhere- scrap only pays 10cents a pound for them- I recyce for use not grinding them up --duh!
I dont trust the numbers on the labels.

ty for the info all.. tell me more- hak
 
How much of a labby do you want actually?
Lab styles are usually made for the functionality of it and a continuous duty. If thats
what you desire, you cant get away with just a wall-wart adaptor.. You would only be
powering the laser off a dc source and thats it.. The driver&LD would still overheat and a
duty cycle is necessary, So it will not actually be a labby i think!!!
 


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