new power adapter has lower output than old one - Page 1
Forum section: electronics / beginners

author: blueagent004
author_rank: Contributor
timestamp: June 27, 2024, 06:44:51 am
content: *old laptop computer adapter specification:input: 100-240v~1.5A, 50-60hzoutput: 19v-4.74a*new replacement adapter specification:input: 100-240vac, 50~60hz, 16.5w (max)output: 12v-1.0a, 12w (max)voltage output of new power adapter is lower, but if I use it anyway, will the new adapter fried my old 2008 laptop or catch fire?laptop has no battery, will be running on power adapter solely.thanks for your expert input on this.

author: Zero999
author_rank: Super Contributor
timestamp: June 27, 2024, 07:26:15 am
content: I doubt it'll damage your laptop, but there's a risk the adaptor might be damaged. The only one had a power rating of 19*4.74 = 90W, whist the new one is only 12W. Fortunately the laptop won't draw as much power, now it doesn't have a battery to charge, but it could still be a problem.

author: Haenk
author_rank: Super Contributor
timestamp: June 27, 2024, 07:38:42 am
content: This will not work, the voltage and wattage are there for a reason.Those 19V power supplies are readily available and pretty cheap (used; don't buy from the manufacturer), as hundreds of millions of laptops have been sold with them.

author: Vovk_Z
author_rank: Super Contributor
timestamp: June 27, 2024, 08:17:56 am
content: Quote from: blueagent004 on June 27, 2024, 06:44:51 amI'm not sure it is a true replacement.

author: radiolistener
author_rank: Super Contributor
timestamp: June 27, 2024, 12:03:23 pm
content: Quote from: blueagent004 on June 27, 2024, 06:44:51 amThis new one is not compatible with your laptop, your laptop needs adapter with 19V, just ignore adapters which has different voltage, it is not compatible with your laptop.Since your old laptop adapter has 19V 4.74A, you're needs to make sure that new adapter has exactly the same 19V voltage.Also make sure that the new adapter current also the same 4.74 or higher.For example 19V 6A is ok.

author: jzx
author_rank: Regular Contributor
timestamp: June 27, 2024, 01:36:46 pm
content: Look in the laptop' s label to know the voltage and the minimum current. As said, if the old adapter give 19 volts, probablily you will need a 19 V adapter. Perhaps you can work with less current not having battery, but normally that only work with some models, when the laptop can identify the charger as "normal" (runandcharge) or "travel adapter" (runorcharge).

author: blueagent004
author_rank: Contributor
timestamp: June 27, 2024, 04:38:40 pm
content: thank you everyone for sharing a wealth of knowledge on this, I greatly appreciate all the input.the laptop is from 15 years old ago, and I threw away the battery and charger last year, because I thought they are old enough to be a fire hazard, and I figured I can buy a new charger from the manufacturer.but the service center refused to sell me a compatible charger with identical 5.5mm x 1.7mm jack, and insisted that identical input/output voltage does not mean it was designed to power the old laptop, and they dont want to be held legally liable if I get injured....etc

author: radiolistener
author_rank: Super Contributor
timestamp: June 27, 2024, 04:44:56 pm
content: Quote from: blueagent004 on June 27, 2024, 04:38:40 pmModern Chinese PSU will be more fire and electric choke hazard than an old branded one.

author: jzx
author_rank: Regular Contributor
timestamp: June 27, 2024, 05:12:11 pm
content: The battery surely was very dead, perhaps not a risk, because commonly they are well protected, but useless, so you have done well.Power bricks normally stand better.

author: kevin.gibbs
author_rank: Regular Contributor
timestamp: February 27, 2025, 05:39:46 pm
content: A laptop with such a power supply will most likely not even turn on; it will not work stable if it does! However, it is unlikely to be damaged (unless the polarity is accidentally reversed) because the adapter should limit the current to 1A.

author: Gyro
author_rank: Super Contributor
timestamp: February 27, 2025, 06:48:10 pm
content: Necropost