My current charger is broken, but I found another charger which kind of fits, but im suspicious if it will harm my laptops battery in the long run, what commands can I run or what can I look at to see if a new type of charger is harming a laptops battery? as this isnt usb-c or anything really official.
Unless you have something completely esoteric, a power adapter you connect to your mains only provides a specific voltage and max amperage to your laptop. Assuming your connection to the laptop is appropriate you should be good. The charge controller is located in your laptop, not the adapter.
If you happen to have a relatively recent laptop with USB-C charging the key decision is already made - just get an adapter with a wattage that meets or exceeds what your laptop specifies and a decent USB cable.
For USB-C: Tiny little side note here, there are some cheap small-size adapters that overheat. Some adapters thotle down, but some rare ones just blink power on and off, which is bad for lithium batteries.
Search a good brand, preferably reviewed, and GAN-type. Spend a bit more than the cheapest. Check if it has the right protocol (probably Power Delivery at some voltage) to make sure it charges at a normal speed.
For a DC charger like OP asked. Match polarity, match Voltage. And at least match the current/watage to make sure you can charge in a reasonable amount of time
And, anybody who has played in RaspberryPi 5 land will probably know: there’s different voltages delivered in USB-C and each has its own amperage limit in a given charger, so the wattage rating of the charger doesn’t tell the whole story. Like a PC internal supply you need to ask: what’s the amperage capacity at 5V, 9V, 15V, 20V ? A “90W” USB-C charger might only deliver 100mA at 5V and 9V with most of the “juice” delivered at 15 and/or 20V - and what voltages is your laptop configured to be able to consume for battery charging?
It usually works out simply enough for most consumers, but not always…
+1 for GaN adapters - they pack a punch in a small package. I’ve replaced my original adapter for my Thinkpad as well as for my cell phone with a Belkin unit a while back. It takes much less space in my backpack.