Using A Higher Amperage PS for Notebook

D

dancer

New Member
I have an extra PS for an old Compaq notebook that's rated at 19V and about 4.9 Amps. Is it unsafe to use this PS with a Gateway notebook that originally came with an 18.5V, 3.4 amp PS? Is there danger of system damage?
 
I would be worried about the difference in amp rating. Would most likely destroy something.
 
A machine will only draw as much amperage as it needs. It's higher voltage you don't want to use.
 
Depends on the power of the regulator. They require a range of volt and amps.
Have to be within the range. related to the power.
as mentioned.
 
It's perfectly ok to you a power supply with a higher amperage rating so long as the voltage is correct. You don't want to go lower though, you'll damage the power supply with extended use.
 
PohTayToez said:
It's perfectly ok to you a power supply with a higher amperage rating so long as the voltage is correct. You don't want to go lower though, you'll damage the power supply with extended use.
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And in some cases, the laptop itself. A customer had a highly underpowered PS on an Acer Aspire and it fried both the charger and the laptop.
 
Thanks for the feedback, guys. To clarify, the PS from my old Compaq is rated at 18.5V and 4.9 amps, and the Gateway notebook label (the sticker on the bottom of the unit), states that it's rated 19V and 3.42 amps. If the computer only draws the amperage that it needs, then the 4.9 amps won't hurt it I guess. The 18.5V of the Compaq PS is really close to the 19V on the Gateway label, so it's probably close enough and not so under-powered as to be a great risk?. If I only use this Compaq PS for recharging the Gateway battery until I get a new PS for the Gateway, then my assumption is that it should be safe to use, right?
 
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More than likely the voltage regulator in the laptop could handle the 1/2 volt difference (especially since that voltage can fluctuate quite a bit depending on the voltage coming out of the wall). No one could guarantee it would work but you should be OK.
 
If the power plug fits the socket on your lappy you should be OK as most laptops have their own voltage regulators, do not worry if the amps exceed the defunct PSU....will not harm it.
It is best to have sufficient amps than not enough.... Half of volt difference is nothing for lap tops.
 
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One other thing to check is the polarity of the DC plug. Most have the center tip as + but the occasional oddball has it reversed.
 
Well darn. Using the 18.5V compaq power supply/charger did not work. The Gateway just lies there and acts dead with no lights like nothing is plugged into it at all. The Gateway voltage regulator must be able to sense that something is wrong.

The Gateway did not fry because I left it plugged in for quite awhile (hoping the battery might charge) and then unplugged the charger and attempted to boot up on battery power. It did boot up but with only 6% battery power remaining, I shut her down again right away. Only reason I have this problem is because I lost the Gateway power supply. Have a generic replacement (rated at the full 19V, with 4.7 amps) on order now - overnight delivery.

Thanks for the help. It was a good discussion.
 
If I would have seen this earlier I would have told you that most laptop mobos will notice that much of a voltage difference and refuse to boot. And if it did I still wouldn't recommend it, I've seen a couple of laptops that have stopped working after extended use with a charger with only a small voltage difference.
 
Yes this increased amperage does matter because unlike a standard PC, a laptop requires battery charging. That is what the amperage figure is refering to. It will cause battery damage and increase fire risk, however this only applies if you are intending to use the battery.

If this laptop is a desktop replacement, and therefore not moved (no battery required), remove the battery and it will work fine.
 
bigfellla said:
Yes this increased amperage does matter because unlike a standard PC, a laptop requires battery charging. That is what the amperage figure is refering to. It will cause battery damage and increase fire risk, however this only applies if you are intending to use the battery.

If this laptop is a desktop replacement, and therefore not moved (no battery required), remove the battery and it will work fine.
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Regardless of whether or not the laptop is charging the battery, it will only draw as much current as it requires, period. That's why you want to have a supply that can deliver AT LEAST the current specified. Any additional current capability will simply not be used.
 
bigfellla said:
Yes this increased amperage does matter because unlike a standard PC, a laptop requires battery charging. That is what the amperage figure is refering to. It will cause battery damage and increase fire risk, however this only applies if you are intending to use the battery.

If this laptop is a desktop replacement, and therefore not moved (no battery required), remove the battery and it will work fine.
Click to expand...
Excess amperage will not cause battery damage unless the charger circuit in the laptop is faulty, which is causing over charge of battery.

Strollins comment is quite valid......
 
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