Battery-Ready Mini-Fridge Kit — 24→12V Buck + DC Compressor Cooler
Quiet DC cool. Fewer watts wasted, more hours chilled. Built for camps, outages, and dawn-to-dusk grinds.
Why This Kit
Run a 12V compressor cooler directly from a 24V LiFePO₄ pack with a high-current buck. No inverter needed, so you win on efficiency, noise, and surge. Pair it with your 2kW station or use it solo as the “cold core” of a weekend setup.
Parts You Need
- 24V LiFePO₄ battery (50–100Ah) w/ BMS
- 24→12V buck, 20–30A continuous, adjustable
- 12V compressor cooler (locking DC plug preferred)
- Main fuse (Class-T/ANL) near battery +
- 12V blade fuse block (5–15A branches)
- 10–12AWG to cooler; 6–10AWG buck input/output runs
- Anderson SB50/Powerpole connectors (avoid cig sockets >10A)
- Crimper, heat-shrink, cable glands, vent grills
Layout Snapshot
24V (+) → Class-T/ANL Fuse → [ 24→12V Buck (20–30A) ] → 12V Fuse Block → (10–12AWG) → SB50 → Cooler
24V (−) -------------------------------------------------------------------→ Common Neg → Cooler (−)
Keep runs short. Set buck to ~12.2–12.6V under load. Fuse the cooler branch 10–15A per its spec.
Build Steps
- Dry-fit: Place battery low; buck on a metal plate with airflow; mark outlets and glands.
- Cut & mount: Deburr edges; install grills and strain-relief; bolt buck and fuse block.
- Main fuse: Install Class-T/ANL within ~8–10″ of battery (+).
- Wire buck: 24V (+/−) to buck; adjust output to 12.2–12.6V under a small test load.
- 12V rail: Buck → fuse block (10–12AWG). Add branch for the cooler with a 10–15A blade fuse.
- Outlet: Install a locking DC connector (SB50/2-pin). Label polarity and “12V ONLY”.
- Commission: Test with a lamp; then plug cooler and observe watts/amps. Expect 35–60W while running, then cycling down.
- Tidy: Strap the battery; loom the cables; label fuses and connectors.
Mini Runtime Planner
Estimate hours of chill. Uses buck efficiency and duty cycle. Add extra devices if needed.
Battery & Buck
Cooler Load
Extras (optional)
| Device | W | Duty % | Avg W | |
|---|---|---|---|---|
Results
Cooler Average: — Extras Average: — Total Average: — Usable Energy: —
Tip: Pre-chill contents & add a thermal cover to drop duty cycle.
Estimated Runtime
—
12V Branch Sizing
Peak fridge draw often 6–10A @ 12V. Use 12AWG to outlet, 10–15A fuse on that branch.
Pro Tips
- Pre-chill contents; use frozen water bottles as thermal mass.
- Keep cooler shaded and covered; tilt the lid shut fast.
- Eco mode after pull-down, Normal mode to pull temp quickly.
Do Not
- Rely on cig sockets for >10A continuous.
- Skip fuses; shorts arc faster than reflexes.
- Reverse polarity. Label your connectors.