Is that dangerous :
If possible, explain why.
Edit : Here are some more assumptions : Without the battery included, there is no risk of overheating the cell, or over charging them. But there is still some dc to dc conversion taking place on the motherboard. I assume this dc to dc stage to be quite tolerant. What kind of trouble can I run into when using 20V instead of 19V ? Overheating ?
It's always inadvisable to use the wrong voltage power supply. However, most power supplies are so cheap that they may vary a couple volts from design spec. Most electronics have some tolerance built in. Batteries themselves are even more tolerant (but special charging circuits, if they exist, may not be).
I can't recommend doing it since the risk of damage is high enough to make it a bad idea. However, the other posts that seem to suggest that using the wrong power supply will immediately cause the LHC to overpower and create an earth destroying black hole, are a bit extreme. :-) You might get away with it. You might cause a fire. You might not notice any problems at first, but have one of those early unexpected failures shortly down the road...
ATX specification (which describes power supply units for desktop computers) says that:
Generally, supply voltages must be within ±5% of their nominal values at all times. The little-used negative supply voltages, however, have a ±10% tolerance.
It applies to power delivered directly to sensitive microelectronics: mainboard and CPU, memory, graphics card, drives.
But in case of laptops, I belive, microelectronics are not fed directly from AC/DC adapter, because still various components need different voltages - it's not a desktop, but it still has CPU, memory and drives.
20V is 5,26% more than 19V. I wouldn't worry about damaging laptop or batteries. I'd just measure if it really produces 20V (or at least it's within 10% from 19V).
yes, it IS dangerous and may very well destroy the notebook.
higher voltage can cause serious damage to your mainboard, damage that is not covered by any warranty.
also the batteries can overheat, potentially causing burns, an explosion or a fire.
I have the definitive answer: IT DEPENDS.
It depends, not on the text "19V" or "20V" written on the power supply, but on the actual voltage and current profile as provided by that power supply... which can vary wildly from the writing on the outside.
Comparing the proposed replacement supply voltage and idle, medium current and full current versus the original (requires still having the original) is the only way to find out for sure. Another caveat is what happens in a short situation. If one power supply has OCP (over current protection) and the other happily provides more current, that can be an issue too.
Technicians and Engineers regularly replace power supplies on equipment, it is one of the most common mods that gets old equipment working again, especially where strange old proprietary battery packs were involved. Often performance can be improved by providing more consistant voltage over a broader range of current draw. These mods are well within the hobbyist's capability, provided they are able to spend the time, do the tests, and set up a test load (12V automotive light bulbs work well) and use a multimeter.
"if you use a 20v charger on a 19v rated thing, you will be "forcing" an extra 0.235A (V=IZ, Z is the appliance's impedance) into the device in addition to the 4.47A."
This does not make sense. I don't think impedance has a place in this?
Laptops have sophisticated DC-DC converters, and are fine with a little overvoltage.
Even my cheap 12V LED bulbs (halogen retrofits) have a little buck (step-down) converter build in, making sure the 3 led-chips in each bulb gets the right voltage and amperage. I tested this on a variable power supply, driving an LED bulb from 0 to 17 volts (I stopped going higher). At about 9V it started lighting and increased up to 11,3V, from where it actually got a little dimmer as current control kicked in. The light kept the same level all the way up to 17V, however the amps dropped as voltage increased. This is because the power draw (wattage) stayed virtually the same.
The same thing happens in a laptop's internal power converter.
Hope it makes sense :)
I have an Acer netbook that uses a 19 volt charger and I run it all the time on 24v dc. I watched the current in as I increased the voltage in and noticed that the current went down as the voltage was increased. This means that a switching power supply is changing that voltage to a different voltage inside. Keep in mind that the battery the powers a laptop is considerably lower than 19 volts. So voltage conversion is taking place within the device. The 19 or 20 volts is not being used directly on the motherboard directly. The reason I do this is so I can use the same charger to charge an external battery that I carry with me. This battery is made up of 6 x 2 18650 lithium ion cells. So it needs 24 volts to come near full charge. I have been doing this for over a year without any problems. This may not be true for all units but it works for me with my Acer. Ed
Disclaimeer: ... in my experience - your mileage may vary ...
The cells will be fine. One volt won't do much difference if the other parameters are the same.
I don't know about running the laptop directly from the brick - never done so.
DO NOT DO IT!
1V doesn't sound much, neither does 0.5V, but I had my external HDD fried because I used a 9v instead of 8.5v (or was it 9.5V instead of 9V?)
"Microelectronics", if you will, can't handle 1V more. It's not the same as putting in 240V to a 230V bulb. That'll shorten it's lifespan, but because a bulb is so simplistic, it'll hold much longer.
A laptop on the other hand is full of small electronic components who run at a much lower voltage. Giving them 1V more may and will cause them to say "Noez, I'm dead, kktxbai! U gief to much powah!", if you catch my drift. They can't handle such a huge surplus of power/voltage. They operate in millivolt, even microvolt area.
Long story short: DO NOT DO IT, if you want your laptop running.
Take a look at the AVERAGE specs of laptop charger:
Now you can see all of the symbols on any laptop charger and by these specs you can see that they have a MAX. This MAX means that is the MOST it will produce and that ALSO means that it will regulate the power to the devices needs UP TO the MAX. so your computer will be just FINE. Also i keep my battery OUT of my laptop and run on a UPS so as not to damage the battery (i keep my laptop plugged in 24/7).
While it is correct that there are tolerances built into machines and power supplies, note that these tolerances exist on both ends. As others here have said, it is not safe to exceed voltage thresholds. Also, note that connector polarities are not standard, so just because an adapter has the right voltage and the right connector, it does not mean that the polarity is correct, check the polarity as well. Doing any of this will cause overheating, immediately melting chips and likely causing a fire.
However, what I have not seen mentioned here is that it is not as dangerous to connect an under-voltage or under-current power supply temporarily. This is essentially a brown-out. Brown-outs are not good for your computer, but unless lengthy or frequent, they're much less likely to cause permanent damage.
It's best to use charger of same specification and model. 20v can be used for 19v as long as the current rating of 20v is the same or higher but only temporarily. Best to charge the battery and the then unplug and run the laptop, notebook etc on their batteries themselves to ensure the correct input to the circuitory. Runng 20v for 19v directly is not advisable. Hope that answers the questions.
No, it won't kill the PC. I run mine with battery in and I use it for ages.
There is a crowbar circuit on the battery to stop it overloading, and the laptop's power input is fused, so if it was excessive I'd know by now. Even with the battery pack installed the unit never overheats.
It's a myth as my Acer laptop stays at 55 degrees with standard 19v and 20 volt adapters
I used a lower voltage power supply for a laptop for a while (emergency solution) and the battery life seems to have drastically have shortened after that. In general you should stick to exactly the power supply needed, preferrably the one your laptop supplier provided.
19v supply sounds like a Dell. You can probably pick up a cheap replacement on Ebay or Craigslist. They are very plentiful in the marketplace.
usually the voltage is very important when it comes to chargers. an appliance will only draw the current it needs at the specified voltage. you usually have rating such as 19v 4.47A this means at 19v the safe max. current that can be supplied is 4.47A. so if you use a 20v charger on a 19v rated thing, you will be "forcing" an extra 0.235A (V=IZ, Z is the appliance's impedance) into the device in addition to the 4.47A. this raises the current to about 4.7A above the rated max. depending on other factor this might be with acceptable limits or not. if not high current causes heating as the device only uses the amperage thats required, have more amperage than required is safe as it only uses whats required.
