RV / caravan
For travel systems combining house loads, limited roof area, alternator charging and campsite power.
Sources and methodology
Updated: 2026-10-17
Source-based desk research and explicit calculations; no hands-on testing claimed. Missing values remain unknown. Installation compatibility needs a separate assessment.
Typical loads
Count refrigeration duty cycle, water pump, lights, ventilation and device charging over a full day. A kettle has high power but short use; compressor refrigeration has lower power over many hours.
System architecture
Alternator → DC-DC charger and PV → MPPT → house battery → fused DC distribution / inverter. Keep engine starting reserve separate. Shore AC charging needs a compatible charging profile.
Illustrative sizing
A 1.5 kWh daily budget and 80% usable storage suggest at least 1.88 kWh for direct DC loads before additional losses. For AC delivery at 92% efficiency this becomes about 2.04 kWh. Choose an inverter around measured simultaneous AC demand.
Solar and generator
Roof shade from vents and parked trees can reduce output. Portable panels add setup work but can be aimed independently. Alternator input must leave thermal capacity for the vehicle itself.
Worked one-day RV energy budget
The values below are assumptions for a reproducible example, not measurements. Replace power and time with your appliance data. Actual running time can differ from the period an appliance remains connected.
On small screens, scroll the table sideways to see all values.
| Load | AC/DC | W | Hours | Wh |
|---|---|---|---|---|
| DC refrigerator, total compressor running time | DC | 45 | 8 | 360 |
| DC lights | DC | 12 | 5 | 60 |
| DC water pump | DC | 60 | 0.25 | 15 |
| Laptop through inverter | AC | 60 | 3 | 180 |
| Total delivered to loads | 615 | |||
Calculation assumptions: 80% usable battery fraction; 92% inverter efficiency for AC loads only. Nominal storage is (DC Wh + AC Wh / 0.92) / 0.80. 788.3 Wh.
This threshold excludes inverter idle consumption, DC distribution losses, ageing and weather reserve. For example, an additional 10 W for 4 hours adds 40 Wh to the DC budget and 50 Wh to nominal storage at an 80% usable fraction. Enough energy does not establish startup capability, BMS limits or UPS operation.
What changes the result?
If compressor running time increases from 8 to 12 hours, the refrigerator adds 180 DC Wh, or 225 nominal Wh at an 80% usable fraction. Two days without recharging doubles the energy budget; it does not automatically double simultaneous power. Evaluate solar and alternator charging separately from battery capacity.
Recommended equipment categories
Solar kits
A kit is a starting bill of materials. Confirm which cables, fuses and mounting parts are actually included.
Batteries
Compare usable storage, DC voltage and discharge limits before choosing capacity.
DC-DC chargers
Controlled charging between alternator and house battery, with source and destination limits checked independently.
Guides for this solution
Frequently asked questions
Is this a final installation recommendation?
No. Verify model manuals, actual loads, protection and site conditions with a qualified professional. Calculations and equipment classes are preliminary planning aids.
Where do I buy and who sets the price?
Purchase is with the external supplier, who controls price, delivery, inventory and returns. Confirm delivery to Romania before ordering. Commercial disclosure →