How long should an RV battery hold a charge?
An RV battery should typically hold its charge for 2–6 weeks under idle conditions, depending on battery type and ambient temperature. Lead-acid batteries self-discharge at 5–10% monthly, while lithium-ion variants lose only 1–3% per month. Critical factors include parasitic loads (e.g., CO detectors), storage temperature extremes, and battery chemistry. Pro Tip: Use a maintenance charger or solar trickle system for long-term storage to prevent sulfation in lead-acid units or cell imbalance in lithium packs.
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How does battery chemistry affect charge retention?
Lithium-ion batteries outperform lead-acid types with slower self-discharge and temperature resilience. A lithium iron phosphate (LiFePO4) RV battery loses ≤3% monthly vs. flooded lead-acid’s 8–10% drain. Deep-cycle AGM batteries sit mid-range at 3–5% monthly loss. Why does this matter? Extended dormancy without recharge risks lead-acid sulfation, permanently reducing capacity.
Lithium batteries maintain voltage stability even at 20% state of charge (SOC), while lead-acid units suffer voltage sag below 50% SOC. For example, a 100Ah LiFePO4 battery stored at 25°C retains 97Ah after 30 days idle, whereas a comparable AGM battery drops to 92Ah. Pro Tip: Never store lead-acid batteries below 80% SOC—partial charges accelerate plate corrosion.
What parasitic loads drain RV batteries?
Common energy vampires include LP gas detectors (15–30Wh/day), clock displays, and inverter standby draws. A typical RV’s passive consumption ranges from 0.5–3Ah daily—enough to deplete a 100Ah lead-acid battery in 3–6 weeks. Modern RVs with smart touchscreens or Wi-Fi routers may drain 5Ah/day, cutting standby time by 50%.
Practical example: A 2023 Thor Motor Coach with factory-installed telematics consumes 1.2Ah daily just maintaining GPS tracking and remote access. Combined with the propane detector’s 0.8Ah draw, this system empties a standard lead-acid battery in 42 days vs. 68 days in analog RVs. Always disconnect negative terminals or install a master cutoff switch for storage.
| Parasitic Load | Power Draw | Daily Consumption |
|---|---|---|
| LP Gas Detector | 0.5W | 0.4Ah |
| Inverter Standby | 5W | 1.04Ah |
| Security System | 3W | 0.63Ah |
How does temperature impact charge retention?
Battery self-discharge doubles every 10°C above 20°C. A lead-acid battery stored at 35°C loses 15–20% monthly vs. 8% at 20°C. Conversely, sub-zero temperatures slow chemical reactions but increase internal resistance—lithium batteries can’t charge below 0°C without risking metallic plating.
Consider this: Storing an AGM battery in a 40°C RV storage lot accelerates monthly discharge to 25%, cutting standby time from 60 days to just 24 days. Lithium batteries fare better with 5% loss under the same conditions. Always insulate battery compartments and avoid asphalt storage surfaces radiating heat.
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FAQs
Yes—use a master disconnect switch to eliminate parasitic drains. For lead-acid batteries, recharge every 30 days; lithium units can go 6–12 months if pre-charged to 50% SOC.
Can solar panels maintain battery charge during storage?
Only if properly sized—a 100W panel provides 15–30Ah daily in full sun, offsetting typical drains. Use a charge controller to prevent overvoltage damage.