diff --git a/README.md b/README.md
index dc0c743..2cedd7c 100644
--- a/README.md
+++ b/README.md
@@ -11,8 +11,8 @@ A cyberdeck built from salvaged ASUS K501U laptop components and Orange Pi 3B SB
 - [x] Display identified — eDP controller board ordered ($35)
 - [x] SBC: Orange Pi 3B 8GB/256GB — purchased and delivered
 - [x] **SBC boot from eMMC — verified** (Orange Pi OS, 3-OS partition layout, multi-boot ready)
-- [ ] Display controller board — awaiting delivery (~2 weeks)
-- [ ] Power system — board selection and cell testing
+- [x] Display controller board — awaiting delivery (~2 weeks)
+- [x] Power system — Banggood board + cells + amp ordered Jun 3
 - [ ] Case fabrication
 - [ ] Full assembly and software configuration
 
@@ -80,11 +80,13 @@ A cyberdeck built from salvaged ASUS K501U laptop components and Orange Pi 3B SB
 
 | Category | Cost |
 |----------|------|
-| SBC (w/ 256GB eMMC, WiFi+BT) | $189 |
-| Display controller | ~$24 |
-| Storage (hub + enclosure) | ~$30 |
-| Power system (board + cells + fuse + charger) | ~$44 |
-| HDMI switch + panel cables + SD reader | ~$33 |
-| **Subtotal** | **~$320** |
+|| SBC (w/ 256GB eMMC, WiFi+BT) | $189 |
+|| Display controller | ~$24 |
+|| Storage (hub + enclosure) | ~$30 |
+|| Power system (board + cells + holders + fuse) | ~$64 |
+|| PAM8403 audio amp | ~$4 |
+|| OPi 3B metal case + fan | ~$17 |
+|| HDMI switch + panel cables + SD reader | ~$33 |
+|| **Subtotal** | **~$361** |
 
-(Excludes case materials and misc hardware. $189 SBC cost is actual after tax/shipping.)
\ No newline at end of file
+(Excludes case materials and misc hardware. SBC cost is actual after tax/shipping.)
\ No newline at end of file
diff --git a/docs/parts-list.md b/docs/parts-list.md
index 96a5e51..d85d191 100644
--- a/docs/parts-list.md
+++ b/docs/parts-list.md
@@ -31,16 +31,17 @@
 
 | Item | Specification | Source | Est. Cost | Status |
 |------|--------------|--------|-----------|--------|
-| IP5389 power board | USB-C PD, 3S, bare PCB | AliExpress | $8-15 | Board model TBD |
-| 18650 cells (x6) | 3S2P, matched, 2500-3500mAh | Shopping | $12-30 | To purchase |
-| 5A blade fuse + holder | Automotive | Amazon | $2 | To purchase |
+|| Banggood power board | QC3.0 3S-5S 65W-100W PD, bare PCB | Banggood (ID 1990904) | $14.39 | **Purchased** — 3S-65W variant |
+|| 18650 cells (x6) | 3S2P, matched | Banggood | $48.04 | **Purchased** |
+|| Cell holders (x8) | Single 18650 slot | Banggood | $7.99 | **Purchased** (6 + 2 spares) |
+|| 5A blade fuse + holder | Automotive | — | $2 | To purchase |
 
 ### Audio
 
 | Item | Specification | Source | Est. Cost | Status |
 |------|--------------|--------|-----------|--------|
-| PAM8403 amp module | 3W+3W, 5V, Class D | Amazon | $3-5 | To purchase |
-| 4Ω 3W speakers (x2) | Small drivers, ~31×70mm | Amazon | $5-10 | To purchase |
+|| PAM8403 amp module | 3W+3W, 5V, Class D, single turn knob | Banggood | $3.59 | **Purchased** |
+|| 4Ω 3W speakers (x2) | Small drivers, ~31×70mm | — | $5-10 | To purchase |
 
 ### Networking
 
@@ -71,29 +72,33 @@
 
 | Item | Cost | Status |
 |------|------|--------|
-| Orange Pi 3B 8GB + 256GB eMMC | $189 | **Purchased** |
-| Display controller | $24 | Ordered (may be optional) |
-| **Spent so far** | **$213** | |
+|| Orange Pi 3B 8GB + 256GB eMMC | $189 | **Purchased** |
+|| Display controller | $24 | Ordered (may be optional) |
+|| Power board (Banggood 3S-65W) | $14.39 | **Purchased** |
+|| 18650 cells (x6) + holders (x8) | $56.03 | **Purchased** |
+|| PAM8403 audio amp | $3.59 | **Purchased** |
+|| OPi 3B metal case + fan | $16.78 | **Purchased** |
+|| **Spent so far** | **$303.79** | |
 
 ### Remaining to Purchase
 
 | Category | Cost |
 |----------|------|
-| Storage (USB enclosure) | ~$12 |
-| USB hub (powered 10-port) | ~$22 |
-| Power system (board+cells+fuse) | ~$32 |
-| Audio (PAM8403 amp + speakers) | ~$10 |
-| HDMI switch | ~$10 |
-| Panel-mount cables + SD reader | ~$23 |
-| **Remaining** | **~$110** |
+|| Storage (USB enclosure) | ~$12 |
+|| USB hub (powered 10-port) | ~$22 |
+|| Power (fuse + misc) | ~$2 |
+|| Speakers | ~$8 |
+|| HDMI switch | ~$10 |
+|| Panel-mount cables + SD reader | ~$23 |
+|| **Remaining** | **~$77** |
 
 ### Total Project
 
 | | |
 |---|----|
-| Spent | $213 |
-| Remaining | ~$110 |
-| **Estimated total** | **~$323** |
+|| Spent | $303.79 |
+|| Remaining | ~$77 |
+|| **Estimated total** | **~$380** |
 
 ---
 
@@ -101,21 +106,20 @@
 
 | Item | Date Ordered | Est. Arrival | Source | Tracking |
 |------|-------------|--------------|--------|----------|
-| Orange Pi 3B 8GB + 256GB eMMC | Before May 24 | Delivered | Amazon | — |
-| Display controller board | TBD | 2-4 weeks | Amazon/eBay | TBD |
+|| Orange Pi 3B 8GB + 256GB eMMC | Before May 24 | Delivered | Amazon | — |
+|| Display controller board | TBD | 2-4 weeks | Amazon/eBay | TBD |
+|| Banggood power board + cells + holders + amp + case + fan | Jun 3 | TBD | Banggood | TBD |
 
 ## Pending Purchases
 
 - Powered USB hub (10-port USB 3.0)
 - USB enclosure or flash drive
-- IP5389 power board + 18650 cells
 - 5A fuse + holder
+- 4Ω 3W speakers (x2)
 - Mechanical HDMI A/B switch
 - Panel-mount cables (USB-A, USB-C, HDMI, Ethernet, audio)
 - Panel-mount SD card reader
 - Heatsink for RK3566
-- PAM8403 audio amp module
-- 4Ω 3W speakers (x2)
 
 ---
 
diff --git a/docs/power-system.md b/docs/power-system.md
index f7bd5c2..b09f31d 100644
--- a/docs/power-system.md
+++ b/docs/power-system.md
@@ -1,8 +1,20 @@
 # Power System
 
-## Decision: IP5389 Power Bank Board (Preliminary)
+## Decision: Banggood QC3.0 3S Power Bank Module
 
-All-in-one power management PCB. Replaces separate charger module, BMS, and boost/buck converter with a single board.
+All-in-one power management PCB ordered from Banggood. Replaces separate charger module, BMS, and boost/buck converter with a single board. Uses Injoinic IP5389-family chip (likely IP5389H variant based on feature set: bi-dir PD, 3S-5S, digital display, 65-100W).
+
+**Board:** ID 1990904, 3S-65W variant ($14.39)
+
+### Key Specs
+- 72×27×6mm board
+- USB-C1 (bi-dir PD input/output), USB-C2 (PD output), USB-A1, USB-A2
+- 65W max output with 3S pack
+- PD3.0/PD2.0, QC3+, QC3.0, AFC, FCP, SCP, VOOC
+- Digital tube battery indicator
+- Temperature protection
+- Passthrough charging (simultaneous charge + discharge)
+- 3S-65W (also available: 4S-100W, 5S-100W variants)
 
 ## Why This Approach
 
@@ -106,10 +118,10 @@ K501U battery (B31N1429, 4240mAh, 11.4V, 3S) assessed and rejected:
 ## TODO
 
 - [x] Cell configuration: 3S2P (6 cells, ~300g)
-- [ ] Select specific IP5389 board model with verified reviews
-- [ ] Source matched 18650 cells (Samsung 35E, LG MJ1, or equivalent)
-- [ ] Verify passthrough charging on selected board
-- [ ] Select PAM8403 audio amp module + small 4Ω speakers
+- [x] Select and order board — Banggood ID 1990904, 3S-65W
+- [x] Source matched 18650 cells — ordered via Banggood
+- [x] Select PAM8403 audio amp — ordered via Banggood
+- [ ] Verify passthrough charging on board once received
 - [ ] Select powered USB hub with 5V DC barrel input (not AC wall wart)
-- [ ] Order board + cells + amp + hub
+- [ ] Order 5A blade fuse + holder
 - [ ] Test charging and output before case integration