Across 3,719 miles and 13 legs (July 2026), the V2V charging chain held at 7.70 kWh AC per gallon into the LightShip cells — a 22.7% full-chain efficiency from gasoline LHV to stored energy. ProPower delivered 74.74 kWh AC over the campaign, attributable to 9.71 gallons — just 3.8% of total fuel. The efficiency figure proved stable leg to leg across a wide range of conditions, confirming the theory sections below. The 557.6-mile June round trip that originally grounded this page is now superseded by Campaign 1 as the primary dataset; see the Test Data reports for per-leg detail.
The ProPower Onboard (PPoB) system is not a standalone generator bolted to the frame. It is a software-defined power export layer that draws from the same high-voltage (HV) bus that the motor-generator unit (MGU) uses for hybrid operation. Understanding this distinction is critical to evaluating the system's efficiency.
The MGU is the pivotal component. Because it is physically situated between the ICE crankshaft and the 10-speed transmission input shaft, it rotates at engine speed at all times the truck is in motion. This topology creates the efficiency argument at the heart of the in-motion generation claim.
The LightShip AE.1 is an all-electric trailer: its house loads, climate control, and TrekDrive axle motor all draw from the onboard HV battery. On a multi-day trip that battery has to be refilled, and the assumption that it can be topped up at destinations or en route does not hold in practice. Public charging built for cars is largely unusable for a 50-foot rig — most sites can't physically accommodate the length, pull-through access is rare, and DC fast charging carries real interoperability problems. Even ordinary AC charging in the field is a lottery: campground pedestals vary in amperage, condition, and availability, and a leg can end somewhere with no usable charge at all. In-motion V2V AC charging removes that dependency. The tow vehicle's inverter is always present, always compatible, and delivers energy across the entire drive rather than only at stops — so the trailer arrives with a useful state of charge regardless of what charging did or didn't exist along the route. The Charging Infrastructure page covers this problem in full.
The central premise is this: when the truck is moving, the mechanical energy required to spin the MGU rotor is already embedded in the drivetrain's friction budget. The bearing drag, windage, and rotor inertia of the MGU are paid for by the wheels turning, not by dedicated fuel combustion. Therefore, the incremental fuel cost to begin extracting electrical power from the MGU is limited to the thermodynamic conversion cost of combustion producing additional crankshaft torque — not the cost of spinning up a cold generator from a standing start.
This is subtly but importantly different from a conventional claim. A standalone generator at idle must consume fuel to: (a) overcome its own mechanical friction, (b) run through incomplete combustion at low load, and (c) manage thermal losses at a non-optimal RPM. The PowerBoost MGU in motion does none of these things — it is already thermally stabilized, mechanically spun to road speed, and operating in a regime where the ICE is in or near its BSFC-efficient cruise band.
To extract 5.8 kW from the MGU while moving, the ICE must produce approximately 6.9 kW of additional shaft torque (5.8 kW ÷ 83.9% chain efficiency). At 30% BTE, that requires about 23 kW of additional heat release, or ~0.68 gal/hr of incremental fuel. The rotor drag already paid by the drivetrain contributes an estimated 0.7 kW reduction, trimming the incremental figure to roughly 0.61–0.68 gal/hr — consistent with the speed-controlled regression from the telemetry.
Compare this to static generation (parked, ICE cycling at ~1,000 RPM): community-reported data and the physics of low-load ICE operation suggest 0.8–1.0 gal/hr for ~6 kW output. The implied brake thermal efficiency at that operating point is only 18–20%, versus 28–32% at cruise load. This is the fundamental efficiency advantage of in-motion generation — the ICE is running at a load point where it converts heat to shaft work far more effectively.
The 5.8 kW leaving the ProPower 240V outlet undergoes four conversion stages before resting as stored energy in the LightShip battery. Each stage introduces a measurable loss.
| Stage | Loss mechanism | Loss (W) | Loss (%) | Cumulative efficiency |
|---|---|---|---|---|
| NACS cable (~15 ft, 10 AWG equiv.) | I²R resistive heating at 24.2A | 23 W | 0.40% | 99.6% |
| NACS connector contacts | Contact resistance ~4 mΩ | 2 W | 0.04% | 99.5% |
| LightShip onboard charger (OBC) | AC-DC rectification, switching, magnetics | 464 W | 8.0% | 91.6% |
| LightShip battery cells | I²R cell resistance, coulombic loss | 107 W | 1.8% | 90.2% |
The LightShip onboard charger (AC→DC rectifier) consumes ~464 W converting the 240V AC from the ProPower outlet to the LightShip HV DC bus voltage. This is 8% of the input, or roughly 61% of all conversion losses in the chain. Cable and connector losses are essentially negligible at this current level. Battery coulombic efficiency at this very low C-rate (~0.075C into a 77 kWh pack) is excellent. Net delivery: 5.23 kW into the cells from 5.8 kW AC input — a 90.2% chain efficiency from outlet to stored energy.
Combining the in-motion generation efficiency with the AC-to-battery conversion chain gives the end-to-end efficiency of the V2V charging system.
The theoretical maximum: 30% × 83.9% × 90.2% = 22.7%. This means roughly 7.7 kWh of stored energy in the LightShip battery per gallon of gasoline consumed by the PowerBoost for generation purposes.
At ~7.7 kWh/gal stored into the LightShip battery, and gasoline at $3.50/gal, the effective cost of energy delivered to the LightShip is $0.45–0.49/kWh — approximately 2.7× the U.S. average residential electricity rate of ~$0.17/kWh. However, this is mobility-delivered energy with no charging infrastructure required, delivered at 62 mph. The correct comparison is not residential electricity but rather: (a) a campground hookup where available, or (b) the opportunity cost of a Supercharger stop adding significant time to the journey.
Campaign 1 provides the empirical ground truth against which to test the theoretical model — 3,719 miles across 13 legs, in conditions ranging from 80°F to 104°F ambient and from Colorado mountain grades to Nebraska plains.
| Metric | Theoretical (in-motion) | Campaign 1 measured | Δ vs theory |
|---|---|---|---|
| kWh AC per gallon (fuel→outlet) | 8.54 | 7.70 | −10% |
| Full chain eff. (fuel→cells) | 22.7% | 22.7% | ≈match |
| ProPower delivered (campaign) | — | 74.74 kWh AC | — |
| Fuel attributable to ProPower | — | 9.71 gal | 3.8% of fuel |
| Overall campaign economy | — | 14.38 mpg | 13 legs, 258.59 gal |
| Fuel reconciliation vs Trip Fuel PID | — | mean 0.21% | worst 0.87% |
The 7.70 kWh AC/gal figure held stable across the entire campaign despite dramatically varied operating conditions — mountain grades and plains, 80–104°F ambient, seven distinct ProPower legs. This confirms the structural model: generation efficiency is set primarily by the fixed chain losses (MGU→inverter at 83.9%) and ICE BTE at cruise, both stable across the operating range. Grade and headwind change the base towing fuel but do not materially alter the incremental generation efficiency. What the June round trip suggested with two data points, Campaign 1 established across 3,719 miles.
The per-leg loss-chain breakdown (stage-by-stage watts), implied-BTE detail, and speed-band incremental regressions are documented in the individual Campaign 1 nightly reports rather than reproduced here. The earlier June figures for those sub-tables (0.697–0.753 gal/hr allocated rate, PMU throttling events at specific mileposts) were single-trip observations superseded by the campaign dataset. See the Test Data reports for current per-leg telemetry.
| Mode | ICE operating point | BTE | Fuel rate (6 kW) | kWh/gal delivered | Best use case |
|---|---|---|---|---|---|
| In-motion | Cruise load, 1,400–1,800 RPM | 28–30% | 0.68–0.72 gal/hr | 7.7–8.3 | Highway towing, any distance |
| Static (engine warm) | ~1,000–1,200 RPM, cycling | 20–24% | 0.80–0.95 gal/hr | 6.3–7.5 | Campsite top-up, short sessions |
| Static (cold start) | <1,000 RPM, enrichment, cycling | 15–18% | 0.90–1.10 gal/hr | 5.4–6.7 | Avoid — worst efficiency |
The in-motion advantage is real and consistent — approximately 20–30% more stored energy per gallon versus parked operation. This is the payoff of the hybrid architecture: the ICE never operates at the low-efficiency idle cycling mode that a conventional generator must use when stationary. The MGU in motion is always at a thermally stable, mechanically efficient operating point.
Community-reported experience (F150gen14 forum) confirms 0.8–1.0 gal/hr for approximately 6 kW static output, with the ICE cycling on/off to maintain HV battery SOC. One reported observation: the ICE runs almost continuously at ~1,000 RPM when ProPower is at full load — the 1.5 kWh HV battery (with only ~600 Wh usable headroom) depletes within seconds at a 6+ kW extraction rate, so the engine cannot pulse-and-coast as it does under lighter loads. This is why static efficiency is limited: the engine is locked into a low-RPM, partial-load operating point with no ability to burst into a more efficient range.
The real-world implication: an overnight drive of 700+ miles would theoretically deliver a full charge to a depleted LightShip battery. For practical trip segments of 250–300 miles, the umbilical system delivers 17–22 kWh — enough to materially offset TrekDrive discharge during that leg or provide 1–2 days of campsite electrical autonomy. Campaign 1 confirmed this at scale: across seven ProPower legs, the system delivered a campaign total of 74.74 kWh AC into the LightShip battery, consistent with the per-leg delivery rates the model predicts.
The cumulative energy-delivery curve shown here previously plotted the single June round trip. Campaign 1's per-leg delivery is documented across the individual nightly reports; the campaign total of 74.74 kWh AC over seven ProPower legs supersedes the earlier 42.7 kWh / 557.6-mile figure. See the Test Data reports for per-leg delivery detail.
Forum posts from the LightShip owner note that early testing with the modified PowerBoost at sea level with no wind at 62 mph confirmed 17 MPG while the ProPower umbilical was connected. Campaign 1 provides much stronger context for this figure than the original June round trip did.
Campaign 1's overall economy was 14.38 mpg across 3,719 miles — but that blends mountain grades, plains, seven ProPower legs, and 10 legs above 86°F. The cleanest reference in the campaign is the Phase A pure-tow baseline: 15.43 and 15.27 mpg (Days 5 and 6, 1,080 miles, ProPower off, across only a 15°F ambient spread — a 1% economy spread, the most robust baseline collected). A flat sea-level highway with no grade penalty and no heat enrichment would sit above even those figures, making the owner's 17 mpg observation fully consistent with the campaign data. The 17 mpg figure reflects best-case conditions; 14.38 mpg reflects a demanding real-world mix. Both are explained by the same model — grade, heat, and headwind move base towing fuel without altering V2V generation efficiency.
A simple estimate validates the 17 mpg figure. At 62 mph, sea level, with TrekDrive off, the aerodynamic and rolling resistance load of the F-150 + LightShip is roughly 40–50 hp. The EcoBoost at ~50 hp cruise burns approximately 2.5–3.2 gal/hr at 30% BTE. Add 0.68–0.70 gal/hr for ProPower at 5.8 kW: total ~3.2–3.9 gal/hr. At 62 mph: 62 ÷ 3.5 = 17.7 mpg. The claim is credible within the margin of real-world variation, and Campaign 1's Phase A baselines corroborate the underlying model.
There are four reasons the measured telemetry shows 0.70 gal/hr rather than 0.50 gal/hr for the ProPower generation load, and understanding them is important for calibrating expectations.
| # | Factor | Effect on measured fuel rate |
|---|---|---|
| 1 | Allocation method vs. incremental method | The OBD-based fuel attribution (0.70 gal/hr) allocates total fuel consumed during ProPower-active periods. The incremental method (speed-controlled regression, 0.50–0.65 gal/hr) isolates only the additional fuel. Both are mathematically valid; the document's 0.5 gal/hr is likely the incremental figure. |
| 2 | PMU power throttling during climbs | During high-load grade events, the PMU limits ProPower output to protect HV battery SOC. Average measured output was 5.36 kW (outbound) rather than 5.8 kW, while fuel rate remained elevated from the grade load — dragging down the kWh/gal ratio. |
| 3 | High ambient temperature (measured via λ) | Ambient above ~86°F triggers EcoBoost open-loop fuel enrichment — a rich command that increases fuel consumption independent of load or ProPower. As of July 2026 this is directly measured via the commanded-λ channel (SAE 0x44) rather than inferred; with 10 of Campaign 1's 13 legs running above 86°F, it is a material and now-quantifiable contributor. See the TrekDrive TurboAssist page for the enrichment analysis. |
| 4 | Engine BTE at partial load | The measured implied BTE is 27.0% — slightly below the 30% modeled peak. At 1,400–1,800 RPM with moderate load, the actual EcoBoost BTE tends to 26–29% rather than the 30–32% achievable at optimal load. This ~3% BTE gap accounts for approximately 0.05 gal/hr of the discrepancy. |