An off-road caravan is built to take a beating on the trail. It is not built to sit for four months with water in the lines and a lithium battery drifting toward zero. Most of the spring repair calls we get at the counter in Upland trace back to something that took ten minutes to prevent in October.
This is the order we do it in on an HQ12 through HQ22T. The same steps apply to most off-road campers with a tankless water heater, a lithium house bank, and independent suspension.
Budget an afternoon. You will need a compressor with a blow-out plug, a gallon of RV antifreeze, a can of dry silicone lubricant, a tube of marine grease, and either a multimeter or the VictronConnect app on your phone.
1. Drain every tank
Open the fresh tank drain, the gray tank drain, and any low-point drains. Open every faucet, the shower, and the outside shower while the tanks empty so air can get in behind the water. Tank drain valves live under the chassis. If a valve is stiff, do not force it with pliers. A cracked drain valve in October is a leaking tank in April.
While you are under there, look at the tank straps and the tank itself. Off-road tanks take rock strikes. A hairline crack that seeps now will split when the last cup of water in it freezes.
Shop this step: replacement water tank, tank drain valves, tank straps.
2. Blow out the lines
Fit the blow-out plug to the city water inlet and set the compressor to no more than 40 psi. Open one fixture at a time, hot then cold, and hold it until it spits dry air. Do the toilet, the outside shower, and the washing machine feed if you have one. Then do the whole loop again. The second pass always finds more water.
Low pressure matters. Higher pressure will not clear the lines faster, but it will pop a push-fit fitting behind a cabinet wall where you cannot see it.
Shop this step: blow-out plug, push-fit fittings, hose clamps.
3. Bypass and drain the tankless water heater
This is the step that gets skipped, and it is the most expensive one to skip. A tankless heater holds water in its heat exchanger. If that freezes, the exchanger splits and the unit is scrap.
Close the inlet and outlet valves, pull the drain plugs on the bottom of the unit, and remove the inlet filter screen. Let it drain fully, then blow low-pressure air through it. Leave the drain plugs out over winter and put them in a labeled bag taped to the unit. If your heater has a freeze-protection mode that relies on 12 V power, do not count on it once the battery is disconnected.
If the unit was already acting up before storage, read the tankless water heater troubleshooting guide before you put it away. Ignition faults do not fix themselves over winter.
Shop this step: tankless water heater, inlet filter screens, drain plugs.
4. Antifreeze the traps
You do not need to fill the lines with antifreeze if you blew them out properly. You do need to pour a cup into every P-trap, the shower drain, and the toilet bowl so the seals stay wet and the traps do not freeze. Use RV-rated (pink) antifreeze only. Automotive antifreeze is toxic and will ruin the plumbing.
Shop this step: RV antifreeze.
5. Seals, windows, and doors
Wash the exterior first so you are inspecting clean seals. Then walk every window, hatch, and the entry door. Press on the rubber. If it is hard, cracked, or pulls away at the corners, replace it now. Winter rain finds a bad seal in the first storm.
Check every window strut. A strut that will not hold the window open is a strut that will let it slam in wind, and a slammed acrylic window cracks. Cycle the entry door lock and the hatch locks with the key and with the interior handle. If the latch is sticky, clean it and use a dry lubricant, not a penetrating oil. If the lock body is loose or the key binds, swap it before storage. The door lock troubleshooting guide covers the common failures and which part fixes each one.
Not sure which window you have? The Black Series window size chart lists every HQ opening by model.
Shop this step: replacement windows, window struts, entry door, door locks and latches, hatch locks, seal kits.
6. Awning
Extend it fully, hose it down, let it dry completely, then retract it. A damp awning rolled up for four months comes out with mildew and fabric that cracks along the roll. Check the arm pivots and the roller end caps while it is out. The awning care guide has the cleaning and lubrication steps.
Shop this step: awning fabric, awning arms and end caps.
7. Batteries and power
Lithium and lead-acid want different things in storage.
LiFePO4 batteries store best at 50 to 60 percent state of charge, disconnected from all loads. Do not store a lithium bank at 100 percent for months, and never let it sit below about 20 percent. Read the state of charge on your SmartShunt or BMV-712, bring the bank to the target, then open the main disconnect. If the camper sits in a heated space, a Blue Smart IP65 charger in storage mode is fine, but most owners are better off disconnecting and checking the voltage once a month in the VictronConnect app.
If you run a Cerbo GX, note the firmware version and your settings before you power down. Parasitic draws from a GX device, a fridge controller, or a stereo will flatten a bank over a winter.
Lead-acid batteries want the opposite: a full charge, and a maintainer left connected.
Full detail on storage voltages and BMS behavior is in the Victron lithium battery guide.
Shop this step: SmartShunt, BMV-712, Blue Smart IP65 charger, LiFePO4 batteries, battery disconnect switch.
8. Solar
If you store outdoors with the battery connected, a SmartSolar MPPT will keep a lithium bank topped up. Lower the absorption and float voltages to a storage profile so you are not holding the bank at 100 percent all winter. If the battery is disconnected, disconnect the panel side of the MPPT too, or cover the panels. An MPPT with PV connected and no battery on the output can be damaged.
Shop this step: SmartSolar MPPT controllers, MC4 disconnects, panel covers.
9. Chassis, suspension, and wheels
Drop the stabilizer legs onto pads so the suspension is not carrying full weight for months. Inspect every suspension bushing for cracks, splits, or rubber squeezing out of the housing. Bushings are cheap, and they are the most common thing we replace on trail-used HQs. Grease the trailing arm pivots and the shock mounts.
Inflate tires to the sidewall maximum for storage, chock both sides, and if the camper will sit on dirt put a board under each tire. Clean the aluminum wheels and coat them. Road salt and mud pit bare aluminum.
Check the rock guard mounts and the mesh. Loose mounts rattle a guard to death over one trip.
Shop this step: folding stabilizer legs, suspension bushings, BlackSeries aluminum wheels, rock guard (large), wheel chocks.
10. Hitch and coupler
Clean the DO35 or DO45 coupler, grease the ball and the pin, and fit the dust cap. Pull the hitch pin from the Y-hitch receiver, grease it, and store it inside so it is not seized in spring. Retract the electric trailer jack fully, wipe the ram, and put a light coat of grease on it.
Shop this step: Cruisemaster DO35 and DO45 couplers, hitch pins, Y-hitch receiver, electric trailer jack 3500 lb.
11. Steps, fans, and interior
Retract the electric entrance step, clean the pivots, and lubricate them. Prop the fridge door open. Put a moisture absorber in each cabin. Pull the batteries from the CO detector and smoke alarm, or check the expiry date and replace the unit if it is within a year of it. Crack a roof vent under a cover for airflow.
Shop this step: electric entrance door steps, CO detector, roof vent fans, moisture absorbers.
12. Cover and document
Use a breathable cover, not a tarp. A tarp traps moisture and rubs the paint. Take photos of every setting you changed and the state of charge you left the bank at. Tape a note inside the door: heater drain plugs out, water lines dry, battery disconnected. You will thank yourself in March.
Want us to do it
Our Winterization Service is $183.20 and covers the water system, heater bypass, and battery storage setup. Pair it with the Off-Grid Power & Heating Service ($349) if you want the Victron bank, solar, and heater checked and set to storage profiles at the same visit. If you cannot bring the camper to Upland, the Mobile Service Call-Out is $149 plus the service.
Shop the Winterizing & Storage Kit, book the Winterization Service, or email support@rvpartsgiant.com with your model and where the camper is parked.
Every part on this list ships from our Upland, CA warehouse. Most orders ship free, and you have 30 days to return anything that turned out to be the wrong fit.