Storing van batteries in winter

Cold weather and battery chemistry

Cold affects every battery, but not in the same way. Capacity drops as temperature falls because chemical reactions slow, internal resistance rises, and voltage sag appears under load. The goal in winter is to preserve health by controlling state of charge, temperature, and charging behavior.

Lithium iron phosphate specifics

For lithium iron phosphate, store around half charge in a cool, dry place. Most LiFePO4 cells are happiest near 40 to 60 percent state of charge for long rests. Do not charge below freezing unless your system has a low temperature charging feature that warms the cells or blocks charge until safe. Many battery management systems include a low temp charge cutoff that protects the pack, but you still want to avoid forcing charge in subfreezing conditions.

AGM and flooded lead acid

Absorbed glass mat and flooded lead acid prefer to sit full to prevent sulfation. Top them up to 100 percent, then keep them on a smart maintainer with temperature compensation so they float at the correct voltage as the mercury drops. Flooded cells need ventilation and periodic checks on electrolyte level. AGM needs no watering but still benefits from clean, tight terminals and a gentle float.

BMS, heaters, and insulation

If your lithium pack includes a heater, let it do the work before any charge cycle in the cold. If not, give the battery a warm environment or time to come up to temperature before charging. Insulated battery enclosures help buffer temperature swings and reduce cycling stress through repeated deep chills.

Step by step winter storage prep

A systematic approach keeps surprises away in spring. Focus on charge, isolation, and environment.

Charge level targets

• Lithium iron phosphate: settle near 50 percent state of charge for storage. This reduces calendar aging and stress.
• AGM or flooded lead acid: store fully charged. Float with a smart charger set to the manufacturer’s winter profile.
• Mixed systems with solar: either disable charge sources for lithium in freezing conditions or ensure your controller respects low temperature charging rules.

Isolation and parasitic loads

Parasitic draws from inverters, DC DC chargers, monitors, or trackers can quietly drain a bank. Open the battery disconnect or remove the negative cable if your system allows it. Shut down inverters, disable alternator charging modules, and sleep all Bluetooth devices. The goal is zero idle consumption while the van sits.

Storage environment

Choose a cool, dry, and clean space. Ideal storage temperature is roughly 32 to 68 degrees Fahrenheit. If your van lives outside in harsher climates, consider moving the bank indoors for the season, or use an insulated compartment with minimal exposure to wind chill. Avoid direct contact with concrete floors by placing batteries on wood or a rubber mat to temper rapid temperature changes.

Maintenance during storage

Storage does not mean neglect. A light cadence of checks keeps the bank healthy.

Periodic checks

Check voltage monthly. Lithium self discharges slowly, so a small drop is normal. If it trends low, briefly charge to about 50 percent, then disconnect again. Lead acid chemistry discharges faster; schedule a maintenance charge every 30 to 60 days if your charger is not left connected. Inspect cables for corrosion and apply dielectric grease to keep terminals clean.

Charging practices

Use a temperature compensated smart charger matched to your chemistry. For lithium, confirm the charger respects low temperature charging limits or simply avoid charging below freezing. For lead acid, float at the recommended winter voltage, commonly a touch higher than summer settings. Do not equalize AGM, and only equalize flooded cells if the manufacturer calls for it.

Safety and spring reactivation

Ventilate any area with flooded lead acid during charging. Keep batteries away from ignition sources. When spring returns, allow cold soaked batteries to reach room temperature before a full charge and load test. Bring systems online one component at a time and watch for abnormal voltage drops or heat at connections.

OZK Customs builds and maintains power systems that hold up when the weather turns. If you want a system designed for cold climate use, explore our Recreational vans, see how we approach interiors, wiring, and thermal management in Custom build vans, or browse platform options at Mainstream vans.

Ready for a winter health check or a smarter battery setup before next season. Talk with our team about inspection, smart charging upgrades, insulated enclosures, or complete electrical redesign. We design around how you travel, then deliver a clean handoff so you roll out confident your batteries will wake up strong when the snow melts.