Can I use the old charger?

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@DellTomSan wrote:

I just purchased a Dell Latitude 5591 laptop with a 90W power adapter, but I have an old adapter with 65W output too. The output voltages are the same on both chargers but they have different amperage. When I attach the old adapter to the new laptop it displays a warning: "You have attached an undersized power adapter to your system...etc." 

Can I use this old adaptor or rather not?

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undersized = under performance

you decide

I hope this reply is the correct one, thanks!

If Dell gives you a 90W charger, I don't recommend you use a 65W charger. Because in the process of running a laptop, smaller power input may damage your laptop. If you need new 90W charger, you can purchase it via this link.

https://www.usalaptopbattery.com/index.php?route=product/search&keyword=5591&category_id=0

Hi, There is some shockingly bad misinformation in some replies.

The Voltage must be the same.

The Amperage is the amount of electricity that the power supply can give. In most cases a lower amperage charger will just charge your laptop battery slower.

However if the laptop during actual use uses more current (measured in amperage [Amps])  that the power supply can give, it will also partly drain the battery.

But in most cases the power supply can more than cope with both running the laptop and charge the battery (at varying rates), the larger power supply just ensures the battery is charged quicker for convenience, the smaller chargers are very good as secondary power supplies and travel use.

Shockingly bad misinformation?????

There isn't except for the one posted by JAC8513 who clearly is ignorant of the subject matter.

@Wedders  setting aside the double negative nature of "bad misinformation", which technically means "good information", or I suppose a poor attempt to provide incorrect information, the information provided in this thread before you arrived was for the most part correct, except JAC8513's post, which incorrectly claimed that using an undersized power source could damage your laptop.  Note that I'm assuming for the purposes of this thread that we're talking about Dell power adapters in all cases, in which case voltage will be correct, and not third-party chargers that might not provide the correct voltage for Dell systems.

In terms of your own post here, it's incomplete at best.  It's true that if the system requires more power than the power source can provide, it will drain its own battery to make up for the shortfall -- but you failed to mention that BEFORE the system resorts to doing that, it will first attempt to reduce its power consumption as much as possible by taking measures including performance throttling.  So it's not the case that either everything will be fine or your laptop will continue draining its battery.  The intermediate option is that using an undersized power source will allow your battery to charge slowly (or perhaps not at all) and ALSO cause your system to perform poorly while that source is attached.  This is considered preferable to continuing to drain the battery to maintain normal performance because of course that option isn't sustainable.  Eventually the system would die in that condition even while connected to power, so Dell instead designed the system to first attempt to operate sustainably, even if at lower performance, rather than unsustainably at normal performance.

If you doubt this, go get an XPS 15 that requires a 130W power source for proper operation and then connect a 60-65W power source to it. You will notice that the CPU speed will be throttled, as will the GPU if you're using that as well, even though the system will perform normally while on battery power disconnected from that power source.  So if you're going to use an undersized power source for travel, be prepared to either accept slower performance while it's connected, or else plan to use that power source only to charge the system while it's asleep or shut down rather than while you're actively using it.

I also find it a bit strange for you to jump into this thread disparaging the quality of other people's information and then write a post where the level of detail is limited to "in most cases" rather than providing any specifics, on top of your failure to mention the throttling scenario. That's not especially helpful.

I have a Dell Latitude 3310, is it safe for me to use a 130w ac battery charger or should I stick to the 65-wttt cable I have, it occasionally says that I have used a less capable charging wire, and my laptop flashes orange, and white whenever I try to turn it on, eventually it turns on, but it gets repetitive.