I have a 150w laptop in need of a power supply. How safe is it

>>1208967
it just wont work, probably no damage

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>>1208967
no it won't work. don't open wall adapters up, the caps in there can seriously hurt you.
if you find a wall charger that fits the plug and has the correct voltage output, it'll work. the amperage doesn't matter to much, because of ohms law. just make sure that it has enough amperage to supply the laptop.

but this is /diy/, let's get carelessly creative and dangerous

whatever voltage your laptop is, figure it out. get a voltage step down transformer that can handle 120V input, make sure it steps down to the voltage of your laptop's rating.
the voltage output will be the desired voltage but it's AC. laptops use DC, so get a bridge rectifier and solder wire from the transformer out to the AC in. now you'll have + and - output. attach a polarized capacitor, id say 1-20 microfarads, rated at 200V or more.

make it more stable by adding a regulator at the output.

this would literally be the shittiest ac to dc adapter ever. hell i don't know if it'll work, i think it will tho.

just buy one.

>>1208967

You can totally run 2 switching power supplies in parallel. Just make sure they are the same brand and model, and to test them for a couple minutes first, making sure that they don't heat up or buzz. Most of them can handle the load, but some can't and they pop really fast.

>>1208982
I'm not attempting to open up any wall adapter, i'm just trying to just wire the cables in parallel to double up the amperage.

A 150w replacement costs $40 plus while I can get old dell adapters for $2-3 at goodwill. I'm open to any other cheap solutions.

>>1209006
my old laptop wouldn't recognize a lower wattage adapter. it would run at limited power since it wasn't 95 watt. the laptop would run on battery + adapter till the battery was dead. then I had to let it charge overnight while the laptop was off. I ended up finding the correct dell adapter on amazon for 28 bucks and works perfectly.

/g/ here. If it's Dell, make sure that you are using a Dell charger. Anything off brand will power the laptop, but it won't charge it.

Voltage is the only thing that matters. Amperage is just a maximum rating. If you use a charger with lower amperage, it will just charge slower. If you use one with a higher amperage, your laptop will limit it internally.

>>1208967
theres communication between the psu and the laptop. It doesnt just "check the watts" it actually passes data back and forth to ID the charger as a high wattage or low wattage.

putting them in parallel will double the wattage but the laptop will still think its being powered by a lower wattage charger.

The dell chargers are 3 wire output. inner barrel, outer barrel and the pin. I believe pin is for comm.

tl;dr it wont fucking work. You wont fool the laptop.

>>1210017
>I believe pin is for comm.
Yes
https://en.wikipedia.org/wiki/1-Wire
scroll down to 'Dell power source'

>>1209006
What's wrong with the origional one? Have you thought about repairing it?

If it randomly bricked then in all likelyhood it's a frayed wire on the output side, a cracked solder joint, or a dead thermal fuse/fusable resistor, all of which can be fixed for a few cents.

>>1210193
It doesn't exist. I bought this i7/quadro laptop from goodwill for $20 and don't feel right paying double or triple the cost for a power adapter.

>>1209103
>>1210017
Good to know. I powered it on with another 120w dell adapter I have but the battery wasn't charging. I just thought the battery was dead.

>>1208967
Almost all Dells and HP's have smart chargers; the main power is carried on the outer (-) and inside (+) of the big barrel, with the tiny center pin being a data connection for the charger to ID itself to the laptop (mainly for determining maximum power draw). The laptop adapts its operating mode (CPU clock / how much power goes to battery charging) based on the wattage.

Pro tip: HP's happily work with either HP or Dell chargers, including recharging the battery while operating; Dells, on the other hand, won't full operate (won't charge while operating) on HP chargers.

ProTip 2: Acers, Sonys, Toshiba, Asus don't use smart chargers, there are no data comms between charger and laptop. They either have circuitry that ramps up current towards max until it detects voltage drop, and adjust operation accordingly, or it just demands full current all the time and refuses to work when the voltage drops.

ProTip 3: Never use aftermarket chargers of any kind. They are always built crappy and run hot, sometimes to the point of melting the plastic housing.

Source: I've been repairing laptops a long time, and I run my personal HP on a Dell charger.