HHO for RVs and Motorhomes: Large Engine Applications

RV Engine Characteristics

Class A motorhomes use 8.1L gasoline or 8.9–12.9L diesel engines producing 300–450 hp. These large engines consume 6–12 MPG on the highway with fuel costs of $500–$1,000 per extended trip. A 10–15% HHO improvement saves $50–$150 per trip — making RV among the most economically compelling HHO applications.

HHO System Sizing for RVs

A 7–9 liter diesel engine needs 1.5–3.0 LPM HHO for effective supplementation. This typically requires a dual-cell configuration: two 19-plate cells connected in parallel to the same PWM controller, providing combined output without requiring higher voltage. Alternator capacity in motorhomes is usually 130–160A — adequate for dual HHO cells drawing 15–20A total.

Generator Integration

RVs often have a diesel generator (Onan, Generac) separate from the drive engine. Installing a small HHO cell on the generator provides fuel savings during dry-camping. The generator's fixed RPM operation (3,600 RPM for 60 Hz output) means constant HHO conditions — the most favorable scenario for consistent performance.

Mounting in an RV

The large engine bay of a motorhome provides ample mounting space. Mount the primary cell on the firewall or frame rail near the engine, secured to a rubber-isolated bracket to minimize vibration transfer. The reservoir can be larger than automotive installations (2–4 liters) for extended intervals between top-ups — important when traveling far from home for maintenance access.