RV 12V Smart Lock Wiring: Buck Converter Done Right

No drama, just clean DC. This is the reliable way to power a smart lock from your RV's 12 V system.

What You’ll Need

• Inline fuse + holder (1 A slow-blow near source)
• Buck converter if your lock requires 5 V (12→5.1 V)
• Correct AWG wire run + ferrules for screw terminals
• Cable glands/grommets + strain relief
• Quick-disconnect at door (XT30 or locking barrel)
• Neutral-cure silicone + closed-cell foam gasket

Wiring Plan (High Level)

1. Tap your 12 V distribution panel (switched or unswitched as preferred).
2. Install inline fuse within 8–12 inches of the source.
3. Route through cable glands; protect any metal pass-throughs.
4. Crimp ferrules on all ends going under screw terminals.
5. If the lock is 5 V, mount the buck converter close to the door cavity.
6. Add a quick-disconnect just inside the door for serviceability.

Related Reading

• Serviceability First: Quick-Disconnects & Door Panel Access — Design for easy maintenance.
• Parasitic Loads Audit: Keep the "Always-On" Crew Under Control — Measure and optimize your power draw.
• Boondocking Battery Math — Calculate your lock's true battery cost.

Vibration-Proofing

• Use blue threadlocker on mounting screws.
• Add a thin neoprene shim behind the interior housing to damp resonance.
• Verify strike alignment after driving over a few speed bumps.

Voltage Check Under Load

Set your DMM to DC and actuate the lock. You want ~5.0–5.1 V at the lock (if bucked) without sag. If it sags, shorten the run or upsize wire gauge.

Energy Reality

Most locks idle at 0.2–0.5 W. Use the Energy Calculator to estimate Wh/day and panel size if you’re on solar.

Troubleshooting

• Motor stutters: voltage drop → check buck output & wire gauge.
• Random resets: flaky contacts → re-terminate with ferrules.
• Warm buck: undersized module → step up to a higher current spec.

Clean wiring now = silent, predictable locking later. Future you says thanks.