Increase output voltage from 12v to 19.5v for laptop power supply

[GEOrifle]

Hi. I have Dell d220p-01 power supply with 220w and 12v 18a output which i wanted to convert for Dell laptop with requirement 240w 19.5v power. I googled but couldn't find anything positive except this post but i have some doubts. Your help will be much appreciated. Thanks.

https://www.helifreak.com/showthread.php?t=188279

QUOTE:''

If my charger could take 24V, for instance, I could have used a more-common high-wattage 19.5V laptop supply (Dell laptop adapters are mostly 19.5V).

I bought a Dell D220P, rated at 12V, 18A, 220W. It was $14 on eBay. This is a big improvement over my 15V 6A "90W" adapter, which starts to overheat and reset around 4.5-5A (75W). The old adapter makes for really slow charges, when I need it to be quiet.

Using the info here, I tested it a few ways (including checking it by opening the case), and found that it will power up if I connect the small red & blue wires to ground.

I cut off the big connector at the end of the cable, near the adapter, and bundled the 3 white wires together, and soldered them to a 4mm female bullet. Then bundled the 3 black wires, along with the red and blue wires, and soldered them to another 4mm female bullet. I cut back the small exposed wire you see in the third pic, which I presume was maybe another ground, and did not use it.

Mine puts out 12.4V with no load. While drawing 17A from it, the voltage read by the charger only dropped to 12.2V, so combining the 3 wires seems sufficient, no need to solder in a single big wire from within the case. So the mods can all be done externally.

During a charge drawing 17A, it barely got warm. This is a big change from the previous laptop adapter I was using, which would get *hot* if drawing 4.5-5A.

Pics attached. I just wanted to post this in case someone with a similar charger was looking for a silent power supply. It's just about as big, and just as expensive, as my DPS-600PB 575W supplies, but it's dead silent, which is nice.

As I'd shown in the pictures, I just connected the red & blue wires to all the black wires (ground). That makes the power supply turn on as soon as I plug it in. I did not have a need for a switch, so I did not try to add one.

I just plug my charger into the power supply, then plug the power supply into the wall." QUOTE

I'm not sure how it can help me but looks pretty questionable.

 

[dave_the_nerd]

The wiring hack is what it is, but the real key here is simple: watts = volts * amps.

You can get a transformer and "step up" the voltage from 12v to 19.5v, but the 12v PSU will only provide about 140w max at that voltage.

Also, you're hacking it when you should just be buying a proper 240w 19.5v PSU.

 

[GEOrifle]

Thanks, i thought the same. But laptop is old one even it's Alienware 17x r4.
Much appreciated.

 

[dave_the_nerd]

Thanks, i thought the same. But laptop is old one even it's Alienware 17x r4.
Much appreciated.

Looks like they're about $50 on Amazon, if that's worth it to you.

A voltage step-up doodad is probably like $10, if you're comfortable wiring things. But if it uses pots, you'd need a voltmeter to get it dialed in. (If you don't already have one.) And you might light your house on fire.

 

[GEOrifle]

No, i got an Voltmeter but for me it's a new hobby after lots of repairs all kind of electronics and before to do anything stupid trying double check all my projects (LOL).
Thanks a lot man.

 

[Red Squirrel]

Check the voltage directly after the transformer, if it's over 19.5 it may just be the thing of modifying the buck converter. There may be some resistors you can tweak. I'd look for the chip that controls the buck converter part of the psu and check for a datasheet to see how you can set the voltage. It may or may not be possible though, as they may be using a chip that is fixed. Never done this myself but in theory I think it would be doable. Just make sure that the rest of the components can handle the voltage increase, such as the capacitors. 12 to 19.5 should not really be an issue though. The caps are probably rated for 35v.

If you just want something that works and don't want to mess around it's probably easier to just buy the right psu though.

 

[dave_the_nerd]

Never done this myself but in theory...

When these words appear, one of two things will happen. Either you will have material for a TED talk, or you will have material for a great story to tell in bars.