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Help with Chargers

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9 replies

by niktone 1 view

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I have a Compaq Presario CQ50-142US and i can't find my charger. i have a Dell Inspiron 1501 with a charger. that laptop does not work so i was thinking of using the charger from it but i am not sure if its safe for the Compaq computer. the dell charger's specs are

Input: AC 100-240V~1.5A(1.5A)
Output: DC 19.5V(19,5V) 3.34A(3,34A)

I did some research and i think these are the specs for the Compaq (i had to do research because i cant find my charger so i could not read the label)

Compaq Charger
Input: 100-240V,50/60Hz
Output: 18.5V 3.5A

Any Feedback appreciated
Thanks

9 replies

by thechas

First, in order for a power supply to work properly without the risk of damage to the laptop, you must match both the voltage and current ratings.

Second, you need to make sure that the plug has the correct polarity.

Even just the 1 volt of extra voltage provided by the other charger can damage the mainboard on any laptop and render it useless.

Finally, while it may be best to go with the manufactures power supply, there are options available. Either third party power supplies from battery and laptop parts suppliers. Or, you could try ebay and see if someone is selling the exact power supply you need.

Chas

by 1bn0

You do need the correct voltage and amperage ratings.

Voltage is pressure for electricity.

Not enough and the device you are powering will not work. Too much and the charger will damage the device. And yes 1 volt is enough to cause issues.

Current rating is capacity or flow. How much power at one time. An under rated charger will overheat and probably fail early due to the stress. An over rated charger is a waste of money.

by oh smeg

But a .16 AMP difference in the available current is a different story. It's not powerful enough for this NB and will fail even if it actually can be plugged into the NB which is unlikely anyway. It will also overtax the M'Board of the NB causing premature failure so in the long run it's cheaper to replace with the correct unit.

Even if it has the same plug at the NB end you have not listed the Polarity of the Plug which may or may not be important depending on how standard the NB Maker has made their NB.

The Chas is correct here follow the directions given above to source a new or replacement Mains Adapter and if you are really pushed for funds sell the Dell Mains Adapter on a Place like E Bay to recoup some money.

Col

by thechas

If I thought that the design engineers were allowed to design in proper margins, I would not be overly concerned by 1 volt.

That 1 volt of difference equates to a 5% increase in power that will be dissipated somewhere. Every voltage regulator on the mainboard that is supplied by the adapter will need to dissipate that additional power.

And, while the battery will aid in smoothing out the voltage increase, the extra voltage on the charger side will reduce the functional life of the battery due to over-charging.

In a world driven by engineers that 5% would not be much of an issue. However, very few consumer electronic devices have a nominal 5% design margin. In order to lower the cost, trade-offs are made that reduce the design margins to the bare minimum of component tolerance.

Chas

by 1bn0

15 vdc charger to replace 16 vdc charger of the same amp rating. Same plug, same polarity. 15 vdc charger was a woprking unit from another notebook.

The unit requiring the 16 vdc would NOT turn on. THis was tested WITHOUT a battery installed in the unit.

by oh smeg

If it is 1 V DC Under the old Charger. But here the OP stated that the Dell Charger was 1 V DC Over the old Mains Adapter.

Under those conditions with all else being equal which in this case it isn't I wouldn't expect a Major problem.

But here the Amp Ratting is lower than the Original and while the Dell Mains Adapter may be close to the correct Wattage I wouldn't expect it to actually work. ;)

Col

by niktone

I found my charger and this information was very useful thanks again

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