DIY USB Type-C charging for Dell Venue 11 Pro 7140

I recently bought a used Dell Venue 11 Pro tablet for online classes. It is a decent windows tablet with Synaptics pen support which makes it possible to write directly on-screen, and it can be bought second hand for < 200€.

I strongly suggest getting the second revision (7140) because it is fanless and has marginally better performance compared to the older model (7130).

The hardware configuration on my machine is decent: 1080p IPS screen, 5th gen Intel Core m3 5Y10c, 4GB of soldered DDR3, 128GB M.2 2260 SATA SSD, Intel 7260 AC WiFi card (2×2) and even LTE support. Plenty for notetaking and online lessons.

The downside of this tablet is that it pre-dates USB-C and thus comes with a weird, proprietary, 19.5 V 1.2 A charger that uses a microUSB port. The tablet can “charge” also form a 5V supply, but only at a measly < 2 W which are not even enough to even keep it topped up when using the device.

Nor the charger nor the tablet itself support any “normal” fast charge protocol such as QuickCharge, meaning that you are forced to use the provided power adapter. The charger outputs 5 V unless the tablet requires the 19.5 V output by juggling the USB D+ and D- lines. However, reports online show that the tablet is fine being fed directly the 19.5 V without the initial handshake.

So…

The information reported below is for your information only and comes with no warranty. It could cause irrepairable damage to your devices and will definitely void any manufacturer warranty. Do it on your own responsibility.

My laptop (Lenovo Thinkpad T480) uses a USB type-C charger that support the Power Delivery (PD) protocol and can provide up to 65 W at 20 V. How nice would it be to bring the Dell Tablet into the 2020s by making it compatible with the USB-C PD protocol, and thus allow me to avoid carrying a different charger?

Well, China got us covered: on Aliexpress/eBay/etc it is possible to find some small, cheap (<2 € delivered) boards that are specifically designed to trigger a PD-compatible charger into providing a predefined voltage (9 V, 12 V, 15 V or 20 V). 20 V is close enough to the 19.5 V specification (a measly + 2.5%) of the Dell Tablet that I figured it should just work.

AND IT DOES.

The tablet is quite happy pulling 20+ W from a 65 W PD adapter.

All you have to do is get a PDC004 20 V board and a whatever-to-microUSB cable: chop the microUSB connector off the cable with whatever length of wire you desire, strip the red (+) and black (-) wires and solder them straight to the pads onto the PDC004 board.

IT’S THAT EASY.

This is the minimal setup, with all the elecrical work required. You might want to keep the cable longer but I wanted a small portable adapter.

BUT!!!! SUPER-MEGA WARNING!

You have just created an adapter that will blissfully provide 20 V to whatever device you plug it into. That means that if you connect this adapter to a device which is not designed to handle the 20 V,

YOUR DEVICE COULD BE OBLITERATED TO DEATH IN MILLISECONDS.

Don’t be a dick: do NOT use this device to prank people. You may easily cause hundreds of euros worth of damage.

You might want to add a warning label to the adapter. I just printed a small enclosure with the warning “⭍ 20V ⭍ ” embossed onto it.

3D printed container with warning label. It’s not pretty, but it’s functional.