EQ Systems Stay Charge #8400 | Truck + Trailer Harness Kit | 4 Gauge, 100A Breaker

Keep your trailer battery charged from the tow vehicle with the EQ Systems Stay Charge — Truck and Trailer Harness Kit (Part 8400) — so your hydraulic jacks have power the moment you arrive. Available at The RV Surplus.

A trailer that sits between trips, or that runs its jacks repeatedly on setup, can flatten a battery quickly. EQ Systems hydraulic pumps need real current.

⭐ What's In This Kit

Premium components throughout, and easy to install.

⭐ Which Kit to Order

• Part 8400 (this listing) — harness for BOTH truck and trailer
• Part 8427 — harness for tow vehicle with quick-connect jumper cable harness instead (25 ft truck + 12 ft jumper cables)

Order 8400 if you're wiring both vehicle and trailer, and 8427 if you want the jumper cable option.

⭐ Why Battery Condition Matters

EQ Systems hydraulic pumps are not light loads. Battery should load-test at 150 amperes minimum at 10.5 VDC for 30 seconds, with terminals kept tight and free of corrosion.

Documents

• EQ Systems Lifting Systems for Any Size Trailer (PDF)
• Required Maintenance Items for EQ Hydraulic Jacks & Slide Systems (PDF)

Related Battery-Support Options

• Stay Charge with Jumper Cables #8427
• Solar Panel Kit for AM Trailer Jacks #70486
• Solar Panel Kit for AJ Trailer Jacks #70487

90-Day Warranty

Backed by EQ Systems' 90-day replacement part warranty. Check documentation for full terms.

Specifications

• Brand: EQ Systems
• Model: Stay Charge — Truck and Trailer Harness Kit
• SKU: 8400
• Truck Harness: 25 ft
• Trailer Harness: 16 ft
• Cable: 4 gauge copper
• Breaker: 100A resettable
• Connectors: Weatherproof self-locking quick-connect
• Warranty: 90-day replacement part warranty