A Real-World Cost Comparison
Less fuel. Less runtime. Less wear. More usable power.
This comparison shows how a traditional generator-only setup stacks up against a solar + battery system with Automatic Generator Start (AGS). The difference isn’t theoretical—it shows up in fuel use, maintenance, and wear on generator components.
All numbers below are illustrative placeholders and will vary based on usage, weather, and equipment.
Baseline Assumptions
RV used off-grid 120 days per year
Daily power use: ~8 kWh/day
Generator: Cummins/Onan QG 5500 LP (see usage specs here)
Generator fuel cost: $3.5 per gallon (propane)
These assumptions represent a typical full-time or extended-trip RV user.
Scenario 1: Generator-Only Power System
With no solar or battery buffer, the generator must run anytime power is needed.
Typical operation:
Generator runtime: 4 hours per day
Average load: low to moderate
Frequent short run cycles
Power used immediately, not stored
Estimated Annual Impact
Runtime: ~500 hours/year
Fuel consumption: ~288 gallons/year
Fuel cost: ~$1008.00/year
Oil changes: Every ~100 hours
Oil Change Cost: ~$720.00/year
Total Cost: ~$1,728/year
Key issue:
Most of this runtime happens at poor efficiency. The generator burns fuel even when lightly loaded.
Why Generator-Only Is Inefficient
Generators are most efficient when heavily loaded.
In generator-only setups:
Coffee, microwave, electronics = poor fuel/kWh
Short runs waste fuel
Idling and light loads still consume fuel
More hours = more wear
You’re paying for runtime, not usable energy.
Scenario 2: Solar + Battery + Generator (With AGS)
This changes how the generator is used.
How it operates:
Solar covers daily loads first
Batteries store excess energy
Generator only runs when batteries need charging
AGS starts and stops the generator automatically
Generator runs at high, efficient charge rates
Instead of many inefficient hours, you get fewer productive ones.
Estimated Annual Impact (Placeholder)
Generator runtime: ~60-150 hours/year
Fuel consumption: ~ 36-90gallons/year
Fuel cost: ~$126–$315/year
Oil changes: 1–2 per year
Oil change cost: ~$54-$135/year
Total cost: ~$180-$450
Result:
Significantly less fuel used, fewer service intervals, and much lower wear.
Fuel Efficiency Comparison
| Setup | Generator Hours / Year | Fuel Used / Year | Maintenance + Fuel Cost |
|---|---|---|---|
| Generator-Only | ~500 hrs | ~288 gal | $1,725 |
| Solar + AGS | <150 hrs | <90 gal | <$450 |
Solar Savings | >350 hrs | >198 gal | >$1,275 |
Same generator. Same RV. Completely different usage pattern.
The Role of Automatic Generator Start (AGS)
AGS is what enforces discipline.
With AGS:
Generator runs only when batteries or loads actually need it
Configurable for periodic running, most generators recommend running for an hour every 28 days
No “just in case” runtime
No dead batteries from underuse
No overuse from convenience
The system makes smarter decisions than manual operation.
Maintenance and Generator Lifespan
Generator wear is hour-based.
Generator-only systems:
High annual hours w/ much lower average load = poor fuel economy
Faster wear on engine components
Shorter overall lifespan
Solar + AGS systems:
Fewer runtime hours w/ higher average load = better fuel economy
Longer service intervals
Generator used as intended: backup + bulk charging
Over several years, this difference matters.
3–5 Year Ownership Perspective
Over 5 years, a solar + battery system with AGS can result in:
Up to $6,375 in fuel savings
Fewer maintenance events
Extended generator lifespan
Significantly quieter camping
Far less day-to-day involvement
Solar doesn’t just offset fuel, it removes another concern from your plate when camping, reduces maintenance & wear on your generator, and saves money over time.
The Bottom Line
A generator-only setup is cheaper on day one.
A solar + battery + AGS system is cheaper to live with.
You’re not paying to remove the generator.
You’re paying to stop relying on it.