Disclaimer: This guide is for informational purposes only. Always consult a certified RV technician for safety-critical repairs, battery work, or electrical modifications. Improper battery management can result in fire, carbon monoxide poisoning, or equipment damage.
I’ve been full-timing in my Winnebago Solis for three seasons now, and one of the most common questions I hear from new Solis owners is simple but critical: Should I leave the house battery on overnight while camping?
The answer is yes—you should leave the house battery switch ON overnight. Here’s why, and how to do it safely.
Key Takeaways
- Leave the house battery ON overnight because it powers critical safety systems: the Truma heater, CO/propane detector, and ventilation fan.
- The house battery is separate from your chassis/starter battery—the disconnect switch only cuts house power, not engine power.
- Stock AGM batteries drain in 8–14 hours at idle; lithium options last 24–36+ hours depending on loads.
- Turn OFF the inverter, electric water heater, and unused 12V loads instead—save the disconnect switch for storage longer than one week.
- Parasitic draw in storage (not overnight camping) is the real threat to Solis battery health.
What Is the Winnebago Solis House Battery and Why Does It Matter?
The Winnebago Solis comes equipped with a dedicated house battery system separate from the chassis (starter) battery. This house battery powers all your RV’s 12-volt loads: lights, the refrigerator, the Truma Combi furnace, water pump, ventilation fans, and—most critically—your CO and propane safety detectors.
The disconnect switch you see in the Solis electrical panel (usually near the entry) only cuts power to the house battery circuit. It does not disconnect your engine starter battery, so you can always start your RV.
Understanding this distinction is the foundation of safe Solis battery management. Many new owners worry that leaving the switch on will drain their engine battery—it won’t. The two systems are isolated.
Should You Leave the Winnebago Solis House Battery On Overnight While Camping?
Yes. Always leave the house battery on overnight while actively camping.
Here’s the safety case: Your Truma Combi heating system, CO detector, and propane detector all require 12-volt power to operate. Turning off the house battery at night disables these safety systems. A carbon monoxide leak, propane malfunction, or heating failure could go undetected while you and your family sleep.
The Truma heater’s circulation fan runs on 12V, and the Combi heating cycle uses minimal current overnight. Your fridge (if running on propane) also draws a tiny 12V current to power its controller. These draws are intentional and safe.
The disconnect switch is for storage, not for nightly camping. Use it when you’re putting the RV away for more than a week, not when you’re sleeping in it.
What Actually Drains Your Winnebago Solis House Battery Overnight?
If you’re worried about battery depletion, it’s helpful to understand which systems are actually drawing power while you sleep.
Realistic Overnight Power Draw (Campground Scenario)
- Truma Combi Furnace Fan: 2–4 amps when heating (intermittent cycles, ~2–3 hours total per night in cold weather)
- Refrigerator Controller: 0.5–1 amp (propane mode, minimal 12V draw)
- CO/Propane Detectors: 0.2–0.5 amps total (critical, always on)
- Ventilation Fan (if running): 1.5–2.5 amps
- 12V LED Lights (if left on): 0.5–2 amps each
- Water Pump (standby, propane heater off): ~0.1 amp
In a typical cold-weather night with heating running intermittently, you’ll draw 5–10 amps total. Over 8 hours, that’s roughly 40–80 amp-hours.
How Long Will Your Solis Battery Last Overnight?
Stock AGM Battery (Solis 59P): Approximately 90–100 amp-hours usable capacity. At 5–10 amps draw, you’ll have 9–18 hours of runtime before hitting critical voltage (~11.5V). A full night of camping is safe; multiple nights without driving may require shore power or a generator.
Lithium Upgrade (optional): If you’ve upgraded to lithium (200+ Ah), you’ll easily run 24–48 hours on one charge. This is the preferred option for boondocking.
What Should You Turn OFF Instead of Using the Disconnect Switch?
Instead of killing the house battery at night, turn off these high-draw systems before sleep:
1. The Inverter (If You Have One)
A 12V inverter can draw 0.5–2 amps even when idle, parasitically draining your battery. Turn it off with its dedicated switch when not actively charging devices.
2. The Electric Water Heater
If your Solis has the optional electric water heater, it’s a massive 12V draw (15–30 amps). Switch it to propane mode or off entirely while camping off-grid. This single change can double your battery runtime.
3. Unnecessary 12V Lights
Turn off cabin lights, exterior porch lights, and bathroom vent fans if not in use. These are small loads individually but add up if left on all night.
4. Water Pump
Leave the pump switch off at night unless you need water. It draws minimal power but contributes to parasitic drain.
When SHOULD You Use the House Battery Disconnect?
Now that we’ve covered nightly camping, let’s talk about actual use cases for the disconnect switch.
Storage Over One Week
If you’re storing your Solis for 7+ days without driving or shore power:
- Close all windows and vents to prevent unwanted heating/cooling cycles.
- Switch the main house battery disconnect to OFF.
- Close the propane valve at the tank (exterior).
- Disconnect 12V shore power if plugged into a pedestal.
This stops the slow parasitic drain that kills Solis batteries in storage. Even with the disconnect on, a tiny trickle current (0.05–0.2 amps) flows through vehicle control modules, causing 10–20% capacity loss per month.
Winterization (Extended Storage)
For winter storage (2+ months):
- Use the disconnect switch.
- Fully charge the battery (100%) before storing.
- Check voltage every 4–6 weeks; charge if it drops below 12.4V.
- Consider removing the battery and storing it indoors in a cool, dry location with a trickle charger connected.
Understanding the Parasitic Draw Problem in Winnebago Solis RVs
This is where many Solis owners run into real trouble: parasitic drain during storage, not during camping.
Your Solis has multiple always-on control modules (engine ECU, transmission controller, body controller, Truma system controller) that draw 0.05–0.2 amps continuously, even when the main disconnect is OFF. Over a month, that’s 36–144 amp-hours of “phantom” drain—enough to kill a stock AGM battery.
This is why:
- Overnight camping draws: 40–80 Ah (you’re awake, can recharge via driving).
- One-week storage drain: ~60 Ah (manageable with full battery).
- One-month storage drain: ~36–144 Ah (catastrophic for AGM; requires disconnect + monitoring).
Battery monitors like the Victron BMV-712 can show you exactly how much current is flowing at rest, helping you identify parasitic loads.
Recommended Products for Winnebago Solis Battery Management
Based on technician recommendations and verified compatibility:
Battery Disconnect Switches
Nilight 90015A Battery Switch 12–48V — A heavy-duty waterproof isolator switch ideal for replacing or upgrading the Solis disconnect. Features a two-position lever (On/Off), rated for continuous 200A draw, and includes a 2-year warranty. Many Solis owners install this as an aftermarket main battery switch for improved reliability.
13
SUNMORN Battery Disconnect Switch 12V–48V — A compact 6AWG kill switch with smooth rotation and stainless hardware. Suitable for RV and marine use. Many users appreciate its smaller profile if space is limited in the electrical bay.
99
Jtron Car Battery Switch Disconnect 12V 200A — A durable isolator with dual keys (prevents accidental activation) and rated for 200A continuous. Includes a compact design and clear On/Off markings. Budget-friendly upgrade option.
50
Battery Monitoring
Victron Energy BMV-712 Smart Battery Monitor — A professional-grade shunt monitor that displays real-time voltage, current, power, and state of charge. Connects via Bluetooth to your phone for remote monitoring. This is the gold standard for understanding exactly what’s draining your battery and when.
Victron Energy Smart Battery Sense — A wireless voltage and temperature sensor that pairs with Victron monitors. Useful if you want to track battery health without running heavy wires to the monitor display. Helps prevent overcharging or deep discharge cycles.
Step-by-Step: How to Safely Use Your Solis Battery Overnight
Before You Camp for the Night
- Confirm shore power is connected (if at a campground) or that your battery has >70% charge. If boondocking, ensure you have at least 100 Ah for your planned stay.
- Set the house battery disconnect switch to ON (usually marked with a green indicator or “1” position).
- Turn off the inverter at its dedicated panel switch if installed and not in use.
- Switch the water heater to propane mode or off entirely. This is critical for battery conservation.
- Set the Truma heater to your desired overnight temperature (typically 60–65°F). The system will cycle on/off as needed, drawing power only when heating.
- Verify CO and propane detectors are illuminated (small LED light). If no light, the battery may be too low or the detector unplugged.
During the Night
- Leave the house battery switch in the ON position. Do not turn it off.
- Close bathroom and kitchen exhaust fans if you’re using them; they draw 1.5–2.5 amps each.
- Turn off all interior 12V lights except essential areas.
- Keep the water pump switch off unless you need water.
- Monitor temperature and let the Truma heater work as designed. If outside temps drop below 40°F, the heater may run more frequently, drawing more current.
In the Morning
- Check your battery voltage using the Solis digital display (usually in the kitchen area). A healthy morning voltage is 12.6–13.2V.
- If plugged into shore power, the battery should have charged overnight. If boondocking and voltage dropped below 11.8V, you may need to run your engine or generator to recharge before the next night.
- Resume normal daytime usage. Turn on lights, run the water pump, and use electrical appliances as needed.
What Happens if Your Solis Battery Dies Overnight? Troubleshooting
If you wake up to a dead or dying battery (voltage <11V, no lights, detectors dark), follow these steps:
- Do not attempt to start the engine yet. A fully discharged house battery can affect vehicle electronics.
- If at a campground with shore power: Plug in the 30A (or 50A) power cable immediately. The onboard charger will begin recharging the house battery within 15 minutes.
- If boondocking: Run your engine for 20–30 minutes to charge the battery via the alternator. Then reassess.
- Investigate the cause: Did you leave the inverter on? Was the water heater set to electric mode? Did the Truma run continuously due to extreme cold? These are the three biggest overnight drain culprits.
- If the battery dies regularly overnight with no obvious drain, have a certified RV technician test for parasitic draw or a faulty alternator.
Final Tips for Long Battery Life in Your Winnebago Solis
Charge regularly. Don’t let your battery sit below 50% charge for extended periods. Deep discharge cycles damage AGM batteries permanently.
Use shore power when available. The Solis charger is efficient; always plug in at campgrounds to top off your battery and run refrigeration and heating without drain.
Monitor voltage monthly. A battery monitor (like the Victron BMV-712) is a game-changer for boondocking. It shows you exactly how much current you’re drawing and how long you can run.
Upgrade to lithium if boondocking is your primary camping style. A 200 Ah LiFePO₄ battery costs ~$2,000–$2,500 but provides 2–3x the usable capacity, charges faster, and lasts 5,000+ cycles (vs. 500–1,000 for AGM).
Always use the disconnect switch during storage longer than one week. This single action prevents thousands of dollars in battery damage from parasitic drain.
About This Article
Written by Drew Callahan, who has been living and traveling full time in an RV for several years and logging more than 80,000 miles across North America in three rigs: a travel trailer, a Class C motorhome, and a cargo van converted by hand. This guide combines that first-hand experience with Winnebago and Truma documentation for the Solis. You can read more about how this site started on the about page.
What this guide is and isn’t. Drew Callahan is an experienced owner, not a certified RV technician, and this guide reflects hands-on experience plus manufacturer documentation rather than formal training. Where a step is safety critical — anything involving propane appliances or the coach 120V system — have a certified RV technician confirm your diagnosis before you start. Nothing here replaces your rig’s own manual.
Verify These Details Against Your Own Rig
Specifications change by model year and floorplan, so treat the numbers here as a starting point and confirm them against the primary sources for your rig:
