Does the alternator load cancel out the gain?

No, but it is not zero. A 160 W draw is small relative to engine output on a loaded truck; on a lightly loaded light-duty vehicle it is a larger fraction of the equation, which is one reason light-duty payback is slower.

Learn · Fuel efficiency

Fuel Efficiency and Hydrogen Enrichment

Fuel efficiency is the number that decides the purchase, and also the number most easily fooled by seasonality, route mix and driver behavior. Measure it properly or don't quote it.

Baseline first

60+ days of consumption data before fitment
Same routes, same load profile, same drivers where possible
Full-tank method or ECU telemetry — not trip computer estimates
Record idle share; high-idle duty dilutes any combustion-side gain

What to expect

We state up to 15% under favorable conditions — sustained mid-to-high load, well-maintained engine, consistent routes. Light-load, stop-start and high-idle duty cycles typically see materially less. Results vary by engine, duty cycle, fuel quality, maintenance state and baseline. Any figure quoted here is an upper bound observed under favorable conditions, not a guarantee for a specific vehicle.

Running cost of the system

Consumables are purified water and a resin filter every 6 to 9 months. Electrical load is 90 to 340 W depending on unit, drawn from the alternator, and must be included honestly in any efficiency calculation.

FAQ

Questions.

Does the alternator load cancel out the gain?: No, but it is not zero. A 160 W draw is small relative to engine output on a loaded truck; on a lightly loaded light-duty vehicle it is a larger fraction of the equation, which is one reason light-duty payback is slower.