Should the RV battery disconnect switch be on or off?
The RV battery disconnect switch should typically be turned off when the vehicle is not in use for extended periods to prevent parasitic drain from devices like clocks or alarms. Keep it on during active use to power lights, appliances, and onboard systems. For lithium batteries, disconnect during storage to avoid BMS standby consumption (0.5–3W/month). Always turn off before maintenance to eliminate short-circuit risks.
When should I turn off my RV battery disconnect switch?
Turn the switch off during storage exceeding 1 week. This stops parasitic loads from draining batteries—critical for lead-acid types vulnerable to sulfation below 50% charge. Pro Tip: For lithium batteries, disconnect even during short storage to preserve BMS lifespan.
Extended storage demands full disconnection. Lead-acid batteries lose 3–5% charge monthly through self-discharge, accelerating in temperatures above 25°C. Lithium-ion fares better with 1–2% monthly loss, but their BMS still draws微量电流. For example, a 100Ah lithium battery left connected for 3 months could lose 5–10% capacity. Always store batteries at 50–80% charge to minimize degradation.
Can I leave the disconnect switch on while plugged into shore power?
Yes, but only with a smart converter-charger that prevents overcharging. Older RVs with basic converters risk overcharging batteries when left connected indefinitely. Modern lithium systems often integrate voltage regulation, making safe long-term charging possible.
Shore power typically charges house batteries through the converter. If your converter lacks float-stage voltage control (e.g., older units fixed at 13.6V), disconnect once batteries reach full charge. Lithium batteries require precise charging up to 14.6V (for NMC) or 14.2V (LiFePO4), then immediate voltage reduction to avoid stress. A 2023 study showed LiFePO4 batteries maintained at 100% charge lose 15% more capacity annually versus those cycled between 20–80%.
| Scenario | Lead-Acid | Lithium |
|---|---|---|
| Shore power with basic converter | Disconnect after 8hrs | Always disconnect |
| Shore power with smart charger | Safe indefinitely | Safe indefinitely |
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FAQs
No—some parasitic loads like propane detectors often bypass standard disconnects. Use a multimeter to check for >50mA residual draw after switching off.
Can a faulty disconnect switch drain batteries?
Yes. Corroded contacts create resistance, generating 0.5–2W phantom loads. Test switch resistance annually; replace if exceeding 0.1Ω.
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