19.5v Laptop Power from approx. 14v

[MG01]

I'm trying to put together a power box and would like to provide 19.5VDC at 4-5A for my laptop.  I believe I need some sort of DC/DC convertor but can't for the life of me find anything on RS to do the job.  It will be connected to my PSU which will be outputting close to 14.5V to account for drop in the cable and wanting 13.8V for my camera.

Any suggestions welcomed, or I may just have to buy the Dell 12V adaptor and hope it can handle the extra voltage!

[AstroKeith]

https://www.amazon.co.uk/LANTRO-JS-Converter-Voltage-Regulator/dp/B0933G42RT/ref=sr_1_5?crid=33DPWES5YG7V&keywords=12+to+19v+dc+converter&qid=1673265414&sprefix=12+to19v+dc+%2Caps%2C63&sr=8-5

[Cosmic Geoff]

7 minutes ago, MG01 said:

I'm trying to put together a power box and would like to provide 19.5VDC at 4-5A for my laptop.

That seems a lot.  I have two Dell Vostro laptops of different ages, and actually measured their mains power consumption once running.  One (with HDD) consumed  20+ watts, and the other (with SSD) about 7 watts.    For reference, 5 amps at 19.5v = 97.5 watts.  If there is a Dell +12v adaptor, the obvious choice is to use it (and read its spec. sheet first.)

[Dr_Ju_ju]

something like this https://uk.rs-online.com/web/p/dc-dc-converters/1793346

[MG01]

2 minutes ago, Cosmic Geoff said:

That seems a lot.  I have two Dell Vostro laptops of different ages, and actually measured their mains power consumption once running.  One (with HDD) consumed  20+ watts, and the other (with SSD) about 7 watts.    For reference, 5 amps at 19.5v = 97.5 watts.  If there is a Dell +12v adaptor, the obvious choice is to use it (and read its spec. sheet first.)

That's a good point.  I was going off the output on the power brick which is 90w at 19.5V, so about 4.6A.  But I guess that is also charging the battery so the output is going to be higher.

[MG01]

4 minutes ago, Dr_Ju_ju said:

something like this https://uk.rs-online.com/web/p/dc-dc-converters/1793346

but the other way around... 😛

 

[MG01]

20 minutes ago, AstroKeith said:

https://www.amazon.co.uk/LANTRO-JS-Converter-Voltage-Regulator/dp/B0933G42RT/ref=sr_1_5?crid=33DPWES5YG7V&keywords=12+to+19v+dc+converter&qid=1673265414&sprefix=12+to19v+dc+%2Caps%2C63&sr=8-5

that's the ticket...but do I trust amazon with stuff like this? 🤔

[AstroKeith]

1 minute ago, MG01 said:

that's the ticket...but do I trust amazon with stuff like this? 🤔

That's a fair response - I do consider the source too.

But in this case, I have used this many times.

[Alien 13]

You might find that the laptop will run off the 14V supply directly, lots of mini PCs that use mobile components will run on 12V rather than the 19V specified..

Alan

[MG01]

45 minutes ago, Alien 13 said:

You might find that the laptop will run off the 14V supply directly, lots of mini PCs that use mobile components will run on 12V rather than the 19V specified..

Alan

It's an 11 year old Dell Latitude E6520 and I'm struggling to find the power specs beyond the official brick specs. 

I have found this though, so this may be the easiest option : https://www.pcadaptersdepot.co.uk/dell-ac-adapters-c-122_72/original-19v-dc-adapter-car-charger-dell-latitude-3450-p-117674.html?gclid=CjwKCAiAk--dBhABEiwAchIwkZnSzfbPvsmmrokib33_Slmep2SgCte7QopRWFzwYR6l1auBZUitEhoCG0cQAvD_BwE

[AstroKeith]

1 hour ago, MG01 said:

It's an 11 year old Dell Latitude E6520 and I'm struggling to find the power specs beyond the official brick specs. 

I have found this though, so this may be the easiest option : https://www.pcadaptersdepot.co.uk/dell-ac-adapters-c-122_72/original-19v-dc-adapter-car-charger-dell-latitude-3450-p-117674.html?gclid=CjwKCAiAk--dBhABEiwAchIwkZnSzfbPvsmmrokib33_Slmep2SgCte7QopRWFzwYR6l1auBZUitEhoCG0cQAvD_BwE

I wouldn't go near that adapter. 

a) the cigarette lighter connector isn't reliable enough for a computer

b) The size is too small to handle that sort of power.

c) I have heard that company has some reputation issues. I believe referrals have been made to Trading Standards.

Edited January 9, 2023 by AstroKeith

[Clarkey]

I have a 12V version of this that seems to be OK. Given it is a sealed unit I cannot be 100% regards reliability, but the one I use works well.

Topteng Waterproof DC 12V to 19V 8A Step-Up Power Supply Converter Voltage Regulator : Amazon.co.uk: Automotive

You would have to wire your own plugs, but not too much of an issue if you can use a soldering iron.

[CCD-Freak]

This is the one I use to power my remote mini PC.

https://www.amazon.com/CASIMY-Universal-Satellite-ThinkPad-Notebook/dp/B09LLQW74N/ref=sr_1_5?crid=4HV5F6OKGNBS&keywords=12v+power+adapter+for+laptop&qid=1655415730&sprefix=12v+power+adapter+for+laptop%2Caps%2C110&sr=8-5

I have a lighter plug adapter right now but I will be putting a Power Pole connector on it once the warranty period is out.   It has adapters to fit many different PCs and laptops.  

[MG01]

2 hours ago, AstroKeith said:

I wouldn't go near that adapter. 

a) the cigarette lighter connector isn't reliable enough for a computer

b) The size is too small to handle that sort of power.

c) I have heard that company has some reputation issues. I believe referrals have been made to Trading Standards.

Thanks for the heads up!! Dodged a bullet there!

2 hours ago, Clarkey said:

I have a 12V version of this that seems to be OK. Given it is a sealed unit I cannot be 100% regards reliability, but the one I use works well.

Topteng Waterproof DC 12V to 19V 8A Step-Up Power Supply Converter Voltage Regulator : Amazon.co.uk: Automotive

You would have to wire your own plugs, but not too much of an issue if you can use a soldering iron.

I should be able to reuse the connector from the power brick in theory.  Although I think I read somewhere that the centre pin is used to register the supply as genuine or something like that.  So not sure what it communicates to where, but may need some more research before committing to chopping things up!

1 hour ago, CCD-Freak said:

This is the one I use to power my remote mini PC.

https://www.amazon.com/CASIMY-Universal-Satellite-ThinkPad-Notebook/dp/B09LLQW74N/ref=sr_1_5?crid=4HV5F6OKGNBS&keywords=12v+power+adapter+for+laptop&qid=1655415730&sprefix=12v+power+adapter+for+laptop%2Caps%2C110&sr=8-5

I have a lighter plug adapter right now but I will be putting a Power Pole connector on it once the warranty period is out.   It has adapters to fit many different PCs and laptops.  

 

I might have a look around for something similar in the UK...agree power pole is way to go.  although I'll probably just crimp some rings on as my PSU doesn't have PP connectors!

[Synchronicity]

7 hours ago, CCD-Freak said:

This is the one I use to power my remote mini PC.

https://www.amazon.com/CASIMY-Universal-Satellite-ThinkPad-Notebook/dp/B09LLQW74N/ref=sr_1_5?crid=4HV5F6OKGNBS&keywords=12v+power+adapter+for+laptop&qid=1655415730&sprefix=12v+power+adapter+for+laptop%2Caps%2C110&sr=8-5

I use this one for my laptop when we're off grid in the motor-home.  Same idea but this is variable 15-20v.
Doesn't seem to be in stock just now though.

https://www.amazon.co.uk/gp/product/B071SDW4QG

Michael

[MG01]

Well I've found the official one... https://www.dell.com/en-uk/shop/cusadpt90wdcauto-airdww/apd/450-15098/pc-accessories#tabs_section !!!

Looks as though I won't be able to use something like this though because the PC plug has a proprietary centre pin that needs to tell the laptop it's a legit power source.  So I might just resort to putting the power brick in a waterproof box.

[CCD-Freak]

Did you search using the phrase "19V computer travel adapter" ???  That is how I found the one I use and it came with adapters to fit a whole slew of laptops and mini PCs. 

Travel adapters typically work fine with voltages as high a 14 or 15v since they are designed to run from car battery systems that charge at a nominal 13.8V.  I use a LiPO4 battery and a power gate to power all my equipment with a power supply so that I have power backup in case the grid goes down.  If I want to image at a remote off grid site I charge the battery with a solar panel. 

Edited January 10, 2023 by CCD-Freak

[kbrown]

Can't say anything about the products mentioned here but here's my £0.02: I once bought an aftermarket 12V to 19V car laptop charger that was meant for my laptop back then. While it technically worked it only did so if the car was running i.e. the actual voltage of the 12V system was around 13.8V. As soon as you turned the car off, it would stop charging. I can see the point why they've done it this way but it was really disappointing to find out...

I've also had various cheap DC-DC step up converters and while on the multimeter they look like they're producing the specified RMS DC voltage, they're actually pumping out quite ugly looking square wave ripple especially under heavy loads...

Edited January 10, 2023 by kbrown

[MG01]

23 hours ago, CCD-Freak said:

Did you search using the phrase "19V computer travel adapter" ???  That is how I found the one I use and it came with adapters to fit a whole slew of laptops and mini PCs. 

Travel adapters typically work fine with voltages as high a 14 or 15v since they are designed to run from car battery systems that charge at a nominal 13.8V.  I use a LiPO4 battery and a power gate to power all my equipment with a power supply so that I have power backup in case the grid goes down.  If I want to image at a remote off grid site I charge the battery with a solar panel. 

 

Thanks John, that's brought up a few more.  I'm slightly concerned that most of them look cheaply constructed.  But it's an old laptop so might take the plunge with one and see how it pans out.

[AstroKeith]

3 minutes ago, MG01 said:

Thanks John, that's brought up a few more.  I'm slightly concerned that most of them look cheaply constructed.  But it's an old laptop so might take the plunge with one and see how it pans out.

The one I recommended way back, really does work to the specification and I've measured the negligible  output ripple.

[MG01]

1 minute ago, AstroKeith said:

The one I recommended way back, really does work to the specification and I've measured the negligible  output ripple.

Thanks for getting back to me Keith.  The trouble with that one is that I have no way of wiring the centre pin on the Dell connector.

From what I've read the inside of the ring is +ve and the outside -ve but the pin needs a chip or something, to communicate with the laptop to identify the charger power and set the relevant charging mode.  So I've given up on making one myself this time.  But thanks again for your suggestion.  That unit would have been perfect for a less proprietary connector.