Question for the electronically inclined

[andyptak]

Nothing to do with computers but I figure it's the same kind of brain who would know such things. I want to use a power brick as an external power source for my laptop. Although both of my laptops have USB C, unfortunately they are not USB C in. I have a couple of good Omnicharge externals, both with a barrel tip connection for DC out. Try as I might I can not find the right kind of connectors. I have one laptop with a 1.1 mm X 3mm incoming port and the other has 1.35 mm X 4mm. Tough sizes to find. I presume the battery end barrell connectors are a standard size (?) I've had half a dozen shipments from Amazon of multi tip sets and haven't found the right size yet. Anyone have any ideas? Thanks.

[BobShaw]

Nothing to do with computers but I figure it's the same kind of brain who would know such things. I want to use a power brick as an external power source for my laptop. Although both of my laptops have USB C, unfortunately they are not USB C in. I have a couple of good Omnicharge externals, both with a barrel tip connection for DC out. Try as I might I can not find the right kind of connectors. I have one laptop with a 1.1 mm X 3mm incoming port and the other has 1.35 mm X 4mm. Tough sizes to find. I presume the battery end barrell connectors are a standard size (?) I've had half a dozen shipments from Amazon of multi tip sets and haven't found the right size yet. Anyone have any ideas? Thanks.

I don't know what type of connector it is but it will probably be hard to source.
You could get a correct charger and cut the cable about 60cm from the end and put readily available connectors on it from an electronics shop. Then you can use any power supply of the same voltage and just put the same connector on to power the device.

I charge all of my various battery powered flash units this way.

[andyptak]

Thanks Bob. I actually thought of that and bought a couple of appropriate bricks, one for each laptop so I had the correct connectors. Then it occured to me that even if I got the barrel tips for the power bank on other end I wouldn't know how to attach the wires because I have no idea which wire is positive and which is negative. Needless to say I know nothing about electronics.

[mcbroomf]

Just hook up a volt meter to the bricks you bought, or the OEM supplies.  That will tell you the polarity and also the voltage they are putting out so that the batteries you use match.

[Peter McLennan]

Power bricks usually have a diagram of the connection polarity right next to the voltage indication on the brick's compliance label.  It's an image of a hollow circle with a line connecting to the center of the circle.  Polarity is shown there.  Commonly positive at the center, negative on the outer shell.

[andyptak]

Thanks Peter.