VFLEX Datasheet

A USB-C charger decides for itself what to put on the pins. VFLEX lets you decide instead — a voltage you set, held steady, with no negotiation in the way. That fixes two problems a normal USB-C charger can't.

1. The device that only powers up from its old USB-A charger

You replaced the charger it came with and now it does nothing. Same cable, same wall socket, no power light.

A USB-C charger won't switch on its output until the device asks for it, and that request is made through a pair of resistors inside the device. Plenty of USB-C powered gear — fans, lamps, LED strips, pumps, label printers, small IoT boxes — leaves them out to save a few cents. It never mattered, because the USB-A charger in the box doesn't ask any questions: it simply puts 5V on the pins. Plug that device into a modern C-to-C charger and the conversation never starts, so the power never arrives.

VFLEX behaves like the charger it shipped with. Voltage on the pins, no handshake, no negotiation — the device just works.

2. The Raspberry Pi that keeps flashing the undervoltage warning

The official Raspberry Pi supply isn't 5V — it's 5.1V. That extra 100mV isn't a rounding error, it's headroom for the drop across the cable, the connector and the board under load. The Pi's low-voltage detector trips below 4.63V, and a well-behaved 5.00V charger at the wall can arrive under that at the SoC the moment the CPU ramps or a drive spins up. That's the lightning bolt, the throttling, and the reboots.

A generic USB-C charger gives you 5V and no say in the matter. With VFLEX you set 5.1V to match the official supply — or trim a little higher if a long cable or a hungry HAT is still pulling you down.

What's Included

• VFLEX Base: Programmed to a 5–6V range. It cannot be set outside that window, so the cable can't be dialed up to a voltage that would damage a USB-C device.
• USB-C Adapter Cable: Terminates in a standard USB-C plug for a plug-and-play fit into the device's power input.

Why 5–6V

USB-C devices expect 5V, and a plug carrying much more than that will damage them — so this bundle's base is locked to the safe window rather than left open across the full VFLEX range. The room above 5V is the whole point: it's what lets you match the Pi's 5.1V, or claw back the drop on a long run. Move in small steps and stop as soon as the device is stable.

Requirements

• USB-C Power Delivery (PD) capable wall adapter or power bank
• A device that takes 5V through a USB-C power input

Raspberry Pi 5 owners, one caveat: the Pi 5 looks for Raspberry Pi's own 5A/25W PD supply before it will give downstream USB devices their full 1.6A. With any other supply — this one included — it restricts USB peripherals to 600mA. The Pi itself runs fine; if you're driving bus-powered SSDs or several USB devices, use the official 27W supply instead.

Note: This cable delivers a fixed voltage and does not negotiate fast charging. Phones, tablets and laptops that expect to request a higher voltage will charge slowly or not at all — use their own charger for those.