Laptop charger power ratings

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Rickles

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#120926 18-Jun-2013 18:44

I'd like to get a universal power adapter that can be used on a range of laptops. These are readily available and come with multiple tips to accommodate power connections on the laptop, and also accommodate the voltages and amperages usually associated with popular laptop brands.

However, I notice that these multi-use items are often rated in the 70 to 90 Watts range, whereas the computers are mostly in the 40 to 75 Watts.

Would the higher wattage affect the computer/s adversely?

R.

ubergeeknz

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#838881 18-Jun-2013 19:35

No. Provided the voltage is set correctly, it just means the power supply will have capacity to spare.

Rickles

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#838912 18-Jun-2013 20:27

Thanks for that.

raytaylor

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#840597 20-Jun-2013 20:24

On the bottom of the laptop will be the input voltage and amperage
volts x amps = watts
However watts are not what you are looking for.

If your laptop uses a 19v supply @ 3.42 amps then you must specifically have a 19 volt output of the supply with a minimum of 3.42 amps.

If the laptops requires 19v @ 3.42 amps and you have a 19v @ 4.45 amps then you are perfectly fine.
If the laptop requires 15v and you use a 19v then you risk blowing the laptop
If the laptop requires 19v and you use a 19v but the amps arent enough, then the supply will be overworked and blow, possibly damaging the laptop with a 'brown out' effect.

So you will need to confirm that
1) All your laptops are 19v or the same voltage
2) Find the laptop with the maximum amperage required and buy a supply for that level of amperage draw so the other laptops that use less amps wont overload it.

a 19v @ 3.42 amps = 65 watts
But also
a 15v @ 4.33 amps = 65 watts
These are not compatible with each other because the voltage is different.

Ray Taylor

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Rickles

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#840737 21-Jun-2013 09:06

Hi Ray,

Good information, thanks. The unit I'm looking at apparently has auto-sensing/adjusting for voltages ranging from 12v to 24v. 96W rating.

R.

richms

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#841580 22-Jun-2013 16:18

The auto sensing ones are just set by a resistor in the detachable tips, so you cant rely on them if it fits but is for something else.

Richard rich.ms