But you can’t just buy a VFLEX and expect your existing chargers to do everything else. For example, my Apple 140W USB-C power adapter, the most powerful the company makes, can’t deliver the 19 volts my desktop monitor wants.

Like every 100W USB-C PD charger, it’s comfortable delivering 5V, 9V, 15V, or 20V, and because it’s a 140W Extended Power Range (EPR) charger, it can do 28V as well. Those voltages might be fine for many of your gadgets, and Werewolf claims the VFLEX can even go up to 48V if you’ve got a 240W USB-C power adapter to feed it.

But if you need USB-C voltage below or between the standard 5, 9, 15, 20, 28, 36, or 48, you need what’s called a programmable power supply (PPS), and Apple’s charger isn’t that. Thankfully, you don’t need to think about most of this.

You can save profiles for each gadget and charger to the Werewolf app — and use the VFLEX dongle itself to test your power sources. Press the scan button, plug the dongle into your charger, plug it back into your phone, and the app will store your charger’s capabilities.

When it’s time to plug in my 19-volt monitor, I don’t need to pick “19 volts” or remember which of my chargers can deliver — I just tap the picture of my monitor, and the app tells me which of my saved chargers are compatible. Tap that charger, hit “Update” to program the dongle, then plug everything in correctly.

How did I know my monitor needed 19 volts to begin with? The VFLEX can’t test a dumb barrel jack, unfortunately.

I had to look up that spec on the monitor itself, or the old power brick. Usually, you’ll find the device’s input voltage or the charger’s output voltage, though you can also look them up online.

But there is one additional wrinkle: Some devices, including guitar pedals and my Nintendo Game Boy and Super Famicom, have a negative center pin instead of a positive one, so you have to use a reverse-polarity connector to avoid feeding them backward. The Werewolf app doesn’t let you program this (even though there’s a non-working toggle there) and you can’t just flip the connector upside down.

If you see the center negative symbol on your gadget, you need to use an orange-tipped plug: Werewolf’s Kevin Spangler (who has since left the company) said the team knows VFLEX “may not resonate with the average consumer” because of these wrinkles; it’s working on specific adapter cables for retro gaming consoles, CPAP machines, and M12 connectors for industrial environments too. “The main reason why is that it can convert any adapter size to reverse-polarity, so we do not need to build two variants of each connector,” he says.

Once that happens, the Werewolf app will also be able to warn you if you’ve got the wrong type of VFLEX connected. I’m selfishly loving my modular USB-C power trip, and I want my Werewolf to be even more powerful and flexible than it is already.

The dongles are already firmware updatable, there’s a public API and a web app, and Spangler said the company might even build its own power supplies to unlock more voltages in the future. Follow topics and authors from this story to see more like this in your personalized homepage feed and to receive email updates.

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