The V2 design arc, combined from my March–May 2024 updates to the DCBuddy thread.

March 2024 — time for a batch build

After months of using the original without issue, I wanted to add a smart battery backup option and charger capability — which means port switching and a little bit of smarts. And since folks up-thread kept asking “can I have one” (I’m a terrible supplier when I build things to the piece), this felt unique enough to be worth quoting a contract manufacturer for a proper double-digit batch build.

The V2 lineup sketched out: a base board with dual 24V inputs and per-input current measurement, 8 controllable ports; stackable 12V and 5V boards; and a DC Battery Buddy targeting LiFePO4 packs, built around the highly integrated TI BQ25756 bidirectional charger — which massively simplifies a very flexible design. Plenty of open questions came back from the thread: whether 36V matters (Vectra owners say yes), how common 5V loads really are, and what controllable ports should do on battery (cycle loads to stretch runtime, feed timers, remote control).

April 2024 — going to 20A

A structural upgrade mid-design: support a 20A load (400W DC range) from a single supply instead of the original 200W target. That swapped the input to a 5mm pluggable terminal block (or the 6-pin MicroFit) — the DIN4 connector on Meanwell supplies tops out around 10A and barrel connectors even less — and pushed the PCB to 2oz copper everywhere. It also opened the door to the sealed bare-wire supplies sold as LED drivers.

May 2024 — the polish

Where it ended up, and I’m happy with it:

  • Open Hardware design — BOM, schematics, pick-and-place, and Gerbers in the repo.
  • 12V to 36V design. All ports share the input voltage; pick the adapter of your choice. (Dual-adapter input is gone — backup becomes an external module.)
  • ESP32-C3 powered, USB-C programming port, OTA — with an ESPHome firmware configuration for sheer simplicity, deep customization, and dead-drop-simple Home Assistant tie-in.
  • Per-port current monitoring, up to 5A per port.
  • 2.1×5.5mm output jacks with male-to-male cables — because inexpensive cables you can just buy beat custom cables I’d have to get made.
  • Three power input types (2.1×5.5mm, DIN4 for Meanwell OWA, MicroFit 3.0), and the MicroFit module connector carries a CAN bus for reliable signaling from the upcoming battery backup system.
  • 5mm port LEDs shining through the top case.

Originally posted to the DCBuddy thread on Reef2Reef.