03 — Power Supply Guide

ℹ️ NOTE

The BC-250 requires a quality 12V-only PSU with a PCIe 8-pin connector.
Minimum 300W stock, 400W+ recommended for overclocking, 500W+ for max OC.

PSU Requirements Summary

Voltage: 12V DC only — NOT 24V

Minimum: 300W on 12V rail (stock operation)

Recommended: 400W+ (moderate overclocking)

Max OC: 500W+ (sustained loads can exceed 420W at wall)

Connector: PCIe 8-pin (6+2 pin)

Rail: Single +12V rail strongly recommended

TDP: 220W rated, up to 235W typical gaming, 320W+ Furmark OC

Real-world: ~120W CPU+VRAM, ~230W GPU at OC load; 480W+ at wall with max OC (nexgen3d)

Flex ATX PSUs (Recommended for Small Cases)

Model	Wattage	Verdict	Price	Notes
FSP500-30AS	500W (396W on 12V rail)	HIGHLY RECOMMENDED (US)	~$10-22 + shipping (eBay)	80+ Platinum, single +12V rail. PCIe 6+2 pin. 10-pin needs PS_ON bridged to GND. eBay shipping varies outside US. Caveats (gennro): only 396W on 12V rail, known coil whine at no-load, can fail under sustained high draw (reported killed at 350W+ sustained). One unit cooked at 1160mV/2400MHz (nexgen3d). US-only best deal.
Metalfish Flex 500W	500W	Best non-US Flex (stock 24 CU only)	~$37-80 (AliExpress)	80+ Gold, modular. More efficient than generic cheap PSUs (~63W idle vs 79-84W generic). Build quality rivals Corsair. Stock 40mm fan is loud — replace with 24V GDStime dual ball bearing for quieter operation. Fan may lock up in off position requiring PWR_ON cycle (nexgen3d). ⚠️ Not safe for 40 CU — melted under sustained 40 CU loads (.strykur, May 2026). For 40 CU, use FSP500 or dual-connector setup instead.
Enhance ENP-7660B	600W	High quality	~$50-80	Premium build, more headroom.
Apevia ITX-PFC500W	500W	Budget	~$50	Fully modular. Fan may not spin properly under load.
Apevia ITX-PFC400W	400W	Budget	~$35-45	Amazon B0CWN49V13. Fully modular, 1U/Flex ATX.
Apevia TFX-PFC500W	500W	Works	~$60	TFX form factor, 80mm fan, fixed cables.
Silverstone Flex ATX	Various	Works	Varies	Well-regarded, various models.

Problematic PSUs

Model	Issue
Dell D220P-01 / D250AD-00	220W/250W insufficient — "cut out or even break" under gaming load
Metalfish Flex 600W (BD650M)	Protection circuit prevents boot with PCIe 8-pin only
Any 24V PSU	BC-250 requires 12V — will not work
Mean Well GST280A24-C6P	Wrong voltage (24V)
Dell DA-2	220W — insufficient for stock operation, but can run 40 CU undervolted at ~1700 MHz (hoodyracoon, May 2026). Not recommended for daily use.
Generic no-name Flex PSUs	Hit OCP at ~420W at wall; very inefficient (79-84W idle vs 63W Metalfish); built like "garbage" internally (nexgen3d). Sold under 20+ different word-salad names. Avoid.

Server PSUs (with Breakout Board)

Server PSUs offer excellent value but require a breakout board (~$10-20) and wiring. They are extremely loud — suitable for rack/garage only.

Model	Wattage	Verdict	Price	Notes
HP DPS-800GB	800W	Works	Cheap (secondhand)	Very loud, requires breakout board
Delta DPS-750RB	750W	Works	Cheap (secondhand)	Very loud
Bitmain APW3++	~2000W	Works	Cheap (secondhand)	220W idle draw! Not recommended for single board

Breakout Board Sources

Board	Price	Link
Alkly Designs V2.1	~$20	https://alklydesigns.com
AliExpress generic	~$5-10	Search `1005002523558890`
KCORES CSPS-to-ATX	DIY	GitHub KCORES/KCORES-CSPS-to-ATX-Converter
Amazon JMT Board	~$15	Amazon B0CTCLV6Y1

Mean Well / Open Frame PSUs

The Mean Well LOP series has become the community's preferred PSU for custom case builds. They share the same 5" x 3" footprint (127mm x 76mm) for LOP-400/500/600, are ~95% efficient, medical-grade, and more compact than any Flex ATX unit.

Model	Output	Verdict	Price	Dimensions	Notes
Mean Well LOP-300-12	12V @ 25A (300W)	Entry level	~$40	101.6 x 50.8 x 25.4 mm	92.5% eff, fanless at 180W. Becoming underpowered for OC builds — "LOP-300 isn't really going to cut it" (nexgen3d). Now considered entry-level only.
Mean Well LOP-400-12	12V @ 33.3A (400W)	RECOMMENDED	~$65	127 x 76.2 x 27.5 mm	94% eff, 250W convection / 400W with 23CFM fan. 150% peak @ 3s. "Perfect for most of you" running 4000MHz/2400MHz (nexgen3d). Best balance of cost/power.
Mean Well LOP-500-12	12V @ 41.6A (500W)	For max OC	~$78	127 x 76.2 x 30.5 mm	93.5% eff, 320W convection / 500W with fan. Recommended if pushing maximum overclocks.
Mean Well LOP-600-12	12V @ 50A (600W)	Top end	~$84	127 x 76.2 x 35 mm	93% eff, 400W convection / 600W with fan. Most efficient PSU nexgen3d has tested — beats Metalfish and Silverstone SFX 80+ Platinum. 65W idle with full system (pump, fans, RGB).
LRS350-12	350W	Budget	~$25	Standard	Needs fan mod.

LOP series common features:

Input: 80-264VAC with active PFC

No-load power < 0.5W

Medical-grade (2 x MOPP), ITE, Household, Industrial certifications

-40 to +80°C operating range

Built-in 12V/0.5A auxiliary output for external fan

Built-in remote sense (LOP-400/500/600)

Output via M3 screw terminals — use yellow automotive loop crimps

No PS_ON signal — always live when AC is connected

Requires 23CFM fan for full rated output; convection rating is ~60-65% of max

Real-world efficiency comparison (nexgen3d, Feb 2026):

LOP-600: 65W idle (with pump + 3 fans + RGB + Commander)

Metalfish 500W: 63W idle (similar)

Generic no-name Flex: 79-84W idle

At load, LOP is more efficient than Metalfish and Silverstone SFX 80+ Platinum

Selection guide:

Stock / light OC: LOP-300 (under 300W at wall)

Moderate OC (4000MHz/2400MHz): LOP-400

Heavy OC (4200MHz/2475MHz+): LOP-500

Maximum OC + headroom: LOP-600

ℹ️ NOTE

LED/Industrial 12V PSUs are NOT recommended — unreliable ripple current and variable quality.

Standard ATX PSUs

Any quality ATX PSU works when paired with PCIe 8-pin cable:

Minimum: 400W total, 20A+ on 12V rail (240W+)

Efficiency: 80 Plus Bronze or better recommended

Use existing: Spare ATX PSU works fine with standard PCIe 8-pin cable

Model	Verdict
Corsair SF600 / SF750	Works — SFX quality
Corsair RM750e / RM750x	Works — Standard ATX
Any 400W+ ATX PSU	Works

Wiring and Connectors

J1000 — PCIe 8-pin (6+2 pin) Pinout

CODE

[ GND GND GND GND ]
[ GND 12V 12V 12V ]

8-pin is preferred for OC loads. 6-pin works for most setups (missing pins are sense/ground).

FSP500-30AS 10-Pin Pinout

CODE

_________Latch__________
  3.3V   GND   PS_ON  GND   GND
  3.3V   GND   5VSB   12V   12V
________________________

Pin	Signal	Wire Color	Notes
1	3.3V	Orange
2	GND	Black
3	PS_ON	Green	Short to GND to power on
4	GND	Black
5	GND	Black
6	3.3V	Orange
7	GND	Black
8	5VSB	Purple	Standby power
9	12V	Yellow	Main power
10	12V	Yellow	Main power

Generic Power-On Methods

Auto Power-On (default): Board starts when 12V is applied. Set AUTO_PWRON1 jumper (pins 1-2).

Power Button (soldering required): Solder wires to onboard button, connect to momentary switch.

ATX PSU Control: Short PS_ON (pin 16, green) to GND for always-on, or wire external switch.

Cable Safety — Wire Gauge (AWG)

AWG	Verdict	Max Current (~)	Notes
12-14 AWG	Oversized	20-35A	Too rigid, overkill for BC-250
16 AWG	RECOMMENDED MINIMUM	13A	Safest choice for any configuration
18 AWG	Risky	9.5A	Works for stock/light OC, but melted in Furmark under 1 min (capt.cat_13)
20-22 AWG	DANGER — DO NOT USE	5-7A	Will melt under BC-250 load

Use silicone wire (handles high temperatures), NEVER PVC/nylon (melts)

Avoid CCA (Copper-Clad Aluminum) and steel cables — some cheap PSUs (Apevia) use steel

Be wary of Chinese cables that fake AWG (painted copper or iron)

Verify the wire is pure copper before using

Do NOT use SATA-to-PCIe adapters — fire hazard (SATA is rated 54W, board draws 235W)

Do NOT use cheap 6-pin to 8-pin PCIe adapters for power delivery — they will melt

Avoid Apevia PSUs — reports of steel wires in cables (essdee4336)

Metalfish PSUs also reported to melt under 40 CU loads (.strykur, May 2026)

The FSP500-30AS cables are high quality and rarely an issue (astrocast, essdee4336)

325W from wall at 2000 MHz / 40 CU in Furmark VK; ~200W during gaming (hecto_77113, May 2026)

Single 8-pin safe limit: ~260W from wall during gaming (dznuts, May 2026). Using 2 connectors (8-pin + Micro-Fit) is safer for 40 CU.

fforduck warns: 250W+ on single 8-pin at 40 CU significantly increases melting risk.

At-wall consumption examples (nexgen3d, 2026): ~120W CPU/VRAM + ~230W GPU at OC load; total can exceed 420W with Furmark VK + CPU stress, up to 480W+ with Metalfish PSU. LOP-600 measured 65W idle (pump + 3 fans + Commander + RGB).

Onboard Micro-Fit Power Mod

The BC-250 has proprietary onboard Micro-Fit 3.0 power ports (J2000 and J2001) that can supplement the PCIe connector. These provide additional power delivery paths to the board, reducing load on the PCIe 8-pin cable. Old Lamer (YouTube) demonstrated using them as alternate power delivery to avoid melted cables.

Important context: The boards were originally designed to be powered through these Micro-Fit connectors in the mining chassis. The PCIe 8-pin was NOT the primary power path in original use — it was added for repurposing (keroppl_wizard, Jul 2026). Running 40 CU + CPU OC through a single PCIe 8-pin means the connector carries far more current than ever intended.

Connector Selection Guide:

Setup	Power Connectors	Safe For	Notes
Single 8-pin	PCIe 8-pin only	Stock 24 CU, light gaming (~200W from wall)	Minimum. Risky at 40 CU or heavy OC.
8-pin + Micro-Fit	PCIe 8-pin + 1 Micro-Fit	40 CU daily, gaming (~260W from wall)	Recommended daily setup (dznuts: "two is fine"). Safer but not foolproof.
8-pin + 2 Micro-Fit	PCIe 8-pin + both J2000 + J2001	40 CU OC, Furmark (~325W+ from wall)	Maximum safety. "If you try to run it through the single PCI-E cable, it'll fry" (discombobulateddunce).
2 Micro-Fit only	Both J2000 + J2001, no PCIe 8-pin	Experimental	Alternative path. Less tested.

Micro-Fit safety notes:

Connectors held by friction alone — a securing bracket is recommended (astrocast)

Wire only the middle two pins on both rows to prevent damage if connectors are swapped (cyrixblack)

Use 16 AWG minimum silicone wire for Micro-Fit connections

Community PCB adapter: ded811/BC250-Power-Adapter ↗ — adapts J2000/J2001 to standard PCIe 8-pin + EPS 8-pin headers (UNTESTED, waiting for fab boards)

essdee4336 tested the Micro-Fit mod: "it did seem to help slightly."

ATX Power Control Community Projects

Plug-and-Play Adapter

BC250 ATX PSU Control Adapter (pilimmm / mosfet.party) — Commercial add-on board for FSP500 10-pin that handles PS_ON automatically. No soldering for basic use. Press button to boot, OS shutdown turns PSU off. Optional isolated button output for BC250's internal power button. Also available as 24-pin ATX edition with pre-wired 16mm backlit power button. FSP500 and ATX versions ship with all connection cables.

Website: mosfet.party ↗ | Discord project-forums, March 2026.

ESP32 Controller Wake Projects

These projects use an ESP32 microcontroller to detect a Bluetooth controller powering on and pulse the BC-250's power button to boot the system. The controller connects directly to the PC's OS after boot — the ESP32 only handles the wake signal.

BC-250 Remote PSU Controller (wisserbasser / PetteriLah) — ESP32 with Bluepad32 library. PS5 DualSense wake via BLE. Web interface for configuration. MAC address lock so only your controller can start the machine. When the BC-250 is on, the ESP32's Bluetooth turns off. Requires LOP PSU (not ATX). Momentary press = power on, hold 5s = force off. OS shutdown puts PSU in standby.

GitHub: PetteriLah/BC-250-PC-Remote-Control ↗ | Discord: 142 messages across project-forums threads, most active controller wake project.

ESP32-BC250-LOP_PSU-PowerON-Xbox (.dexik / dexikdex) — ESP32_Relay X2 board with passive BLE scanning for Xbox Series X/S controllers (or any BLE controller). Does not hijack the gamepad connection — listens to BLE broadcasts and triggers the power relay. Features: sniper pairing mode (point-blank, -45 dBm RSSI threshold), hardware MAC blacklist, zombie-wake protection (60s deaf period after OS shutdown), LED and 12V peripheral power sync. Also supports DualSense via separate sketch. Requires LOP PSU.

GitHub: dexikdex/ESP32-BC250-LOP_PSU-PowerON-Xbox ↗ | Discord project-forums, June 2026.

BC250 ESP32 Power Switch (Thunkar) — ESP32-C3 firmware for ATX PSU control via PS_ON# line. Push-button power (tap on, hold 5s force off), boot watchdog (releases PSU if board does not come up in 10s), optional BLE controller wake for bound controllers (e.g. 8BitDo), WiFi setup portal for configuring the bound controller from a phone without reflashing. Powered from ATX 5V standby. Reads board power state from TPMS1 pin 9.

GitHub: Thunkar/bc250-esp32-switch ↗ | Discord project-forums.

Pi Pico Controller Wake Projects

BT Dongle with PC Wake (huzhekun / victorhu) — Pi Pico 2W used as a USB Bluetooth dongle that also wakes the PC. When the board is off, the Pico stops being a dongle and listens for Bluetooth connections. If it sees a connection attempt from a paired controller, it pulses the power button to boot the PC and returns to dongle mode. Requires ATX power control mod (IAMDarkyoshi) and soldering to power button + LED leads. Linux only (emulates HCI dongle). Early stage — creator noted "a lot of jank" with full dongle emulation.

GitHub: huzhekun/bt-dongle-with-pc-wake ↗ | Discord project-forums, July 2026.

DS5Dongle (awalol) — Pico2W as a wireless DualSense bridge. Controller pairs to Pico over Bluetooth, Pico plugs into PC via USB. Supports HD haptics, headset audio (controller speaker + 3.5mm jack), microphone input. BOOTSEL button for pairing management (short press = pair/switch, double click = reboot, triple click = bootloader, long press = forget all). Runs at stock 150 MHz. Wake from sleep is a secondary feature — controller reconnecting to the bridge can wake the PC.

GitHub: awalol/DS5Dongle ↗

DS5_Bridge (djanice1980, fork of SundayMoments) — Linux/CachyOS port of DS5 Bridge. Pico 2W DualSense bridge with native Linux companion app (PipeWire audio, audio-driven haptics, libusb device access, uinput chord injection, CachyOS/Arch packaging). Supports DualSense and DualSense Edge. USB wakeup configured automatically by the companion. Same BOOTSEL control scheme as DS5Dongle.

GitHub: djanice1980/DS5_Bridge ↗ | Upstream: SundayMoments/DS5_Bridge ↗

Other

Xbox 360 Controller Wake (az4521) — Independent implementation for Xbox 360 controllers. Mentioned in Discord project-forums (July 2026) but no public repository available.

ATX Power Control Mod (Advanced)

By iamdarkyoshi: Allows full ATX PSU standby and sleep/wake support.

Wire gauge specs (iamdarkyoshi, May 2026):

Purple (5V standby): spec for 3A max. Testing never exceeded ~2A even with USB-powered monitor.

Green (PSON) and Grey (PWRGOOD): logic-level signals, few milliamps, any thin wire acceptable.

Ground return path via main EPS12V ground wires -- no extra ground wire needed.

5V standby current drops to ~500mA when powered on (BC250 reroutes main 5V to USB ports).

1. Remove surface-mount inductor (internal 12V-to-5V standby converter)

2. Solder three wires: Violet (5VSB) to inductor pad, Green (PS_ON), Grey (Power Good optional)

3. Connect to matching ATX PSU colors

VRM Telemetry via I2C (PMBus) + Web Dashboard

By punsh1734. Monitor per-rail VRM/PMIC voltage, current, power and temperature in real time with a live web dashboard, plus a small 2-wire hardware mod.

Software: onlinermm/BC250-Telemetry ↗ — telemetry daemon + bundled web server. Merges hardware (PMBus over I2C) and software (hwmon/sysfs: die temps, clocks, PPT, fan RPM) into one JSON snapshot every ~700 ms, written to /run/apu_telemetry.json. Two dashboard variants: / (classic HUD) and /v2/ (animated board diagram), served on port 8090. Runs on Bazzite, SteamOS and CachyOS from the same binary.

Install: sudo ./install.sh (compiles daemon, sets up the nct6683 fan-controller module, installs both systemd units; --dashboard=v2 to skip the prompt). If the I2C bus isn't found it logs and retries every ~10 s while still serving everything that doesn't depend on I2C.

The VRM chip is an Intersil ISL69247 PMBus controller at address 0x60, read via the kernel's built-in i2c-dev support — no custom hardware, no extra chips. The bus number isn't fixed, so the daemon scans /dev/i2c-* to find it.

Hardware mod (required): I2C_HEADER1 and TPMS1 are not connected to each other on the board — you must bridge them with two jumper wires. SCL → TPMS1 pin 4 (SMB_CLK_MAIN), SDA → TPMS1 pin 6 (SMB_DATA_MAIN). No separate GND jumper needed. ⚠️ Wiring on a bare PCB with power disconnected; double-check pinouts before powering back on.

📌 Note: the community hardware docs on elektricm were wrong about this pinout (SDA/SCL swapped and/or mislabeled) — punsh1734 fixed the correct mapping while developing the mod (Aug 2026). Use the header table in hardware.md ↗, not the old pinout doc.

Practical use (Aug 2026): lets you see per-rail VRM power draw and temps while tuning GPU overclocks — punsh1734 found 1900 MHz to be the GPU sweet spot for balancing temperature vs power. Once the 8-core CPU unlock is active, VRM monitoring is especially useful for re-tuning (see 02-bios-and-firmware.md).

Purchase Links

Item	Source	Link/ASIN
FSP500-30AS	eBay	Search 389522369783
FSP500 10-pin connector	DigiKey	0469931011
Mean Well LOP-300-12	DigiKey / Mouser	LOP-300-12
Mean Well LOP-400-12	Mouser / DigiKey	LOP-400-12 (~$65)
Mean Well LOP-500-12	Mouser / DigiKey / TRC	LOP-500-12 (~$78)
Mean Well LOP-600-12	Mouser / DigiKey / TRC	LOP-600-12 (~$84)
Arctic P12 Pro 5-pack	Amazon	B0DJDDCG4M
Apevia ITX-PFC400W	Amazon	B0CWN49V13
Apevia TFX-PFC500W	Amazon	B0CWNDFKHF
HP Breakout Board	Alkly Designs	alklydesigns.com

Sources: elektricM/amd-bc250-docs hardware/power.md (primary), FSP spec sheets (80+ Platinum verified), Mean Well official specs (LOP-400/500/600 datasheets), Discord community (nexgen3d, gennro, essdee4336, big_trov, dznuts, hecto_77113, capt.cat_13, astrocast, cyrixblack, fforduck, .strykur, wisserbasser, .dexik, _nk10, leafjerky, greatapo, pilimmm, victorhu, huzhekun, az4521, djanice1980, awalol, Thunkar). Discord sources verified from export files Jan-Aug 2026.