A $3 boost converter module gives up the moment your load pulls more than a few amps. Nick Electronics needed 48 V at up to 200 A to run a trolling motor from a 12 V battery, and no off-the-shelf board comes close, so he built one from scratch.
The trick is splitting the work. Instead of asking one boost stage to carry all 200 A, his design runs six interleaved power stages, so each phase handles roughly 33 A. Lower current per phase means lower conduction losses, and the heat spreads over six sets of parts instead of one hot spot. Interleaving also staggers the switching edges, which smooths the ripple on the input and output.
Why the board is not FR4
The power board is a four-layer insulated-metal substrate (IMS) PCB with an aluminum base. Thick copper carries the current, and a thermally conductive dielectric passes heat down into the aluminum. The board then bolts straight onto a CNC-machined aluminum enclosure, so the case doubles as the heat sink.
Here is the gotcha. During the first reflow attempt on a hot plate, the thin aluminum board bowed upward, lifted off the plate, and the solder paste in the center never melted. The fix was a 5 mm aluminum backing plate, drilled and tapped, so the PCB could be bolted perfectly flat before heating. After the surface-mount parts were reflowed, he preheated the board to around 150 °C and hand-soldered the big through-hole parts, including six vertical inductors.
Power and control are separate
Current moves through 4 mm tinned copper bus bars cut, drilled, and tapped for M8 terminals. A second PCB sits above the power stage and carries an STM32 microcontroller plus dedicated multiphase PWM controllers. It connects through dense pin headers, which keeps the switching noise away from the sensitive control side and leaves the power planes uninterrupted.
The parts bill lands near $1,000, so this is not a weekend breadboard job. It is a great case study for an ECE thesis on power electronics, battery-powered robots, or electric boats, where students usually only meet the tiny 5 V modules.
Build it yourself
- Start small: breadboard a single-phase boost with a library-driven STM32 or Arduino PWM output at 12 V in, 24 V out, and measure the efficiency with a shunt resistor.
- Add a second phase 180 degrees out of phase and watch the input ripple drop on a scope.
- If you reflow at home, clamp thin or metal-core boards flat before heating. Warping is what killed the first attempt here.
Read the original write-up at Hackster.io, then pick up an STM32 board and a PWM-capable dev kit at circuit.rocks to test the single-phase version first.
Frequently Asked Questions
How does this boost converter reach 200 amps?
It splits the load across six interleaved boost stages, so each phase carries roughly 33 A. That cuts conduction losses per stage and spreads the heat over six sets of components.
What parts and skills does a build like this need?
Parts run close to $1,000, including a four-layer aluminum-core PCB, six large inductors, 4 mm copper bus bars, and a CNC-machined enclosure. You need reflow and through-hole soldering skills plus basic power-electronics design.
What will I learn if I build this?
A scaled-down single-phase version teaches PWM duty-cycle control on an STM32 or Arduino, inductor selection, switching-loss measurement, thermal design, and why interleaving reduces ripple. These are core topics for ECE power-electronics thesis projects.
