What kills a battery in a RV?

RV batteries die primarily from over-discharge, sulfation, and temperature extremes. Draining below 50% capacity (12V) accelerates lead-acid degradation, while lithium-ion cells suffer below 2.5V/cell. Sulfation crystallizes on plates, reducing conductivity. Heat above 113°F (45°C) degrades electrolytes; freezing temps slash cranking amps. Poor maintenance like infrequent charging and ignoring voltage checks compounds these issues.

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How does over-discharging kill RV batteries?

Over-discharging strains batteries by depleting active materials and causing irreversible sulfation. Lead-acid batteries hit 50% DoD (12.1V) lose 30% lifespan; lithium-ion BMS cutoff at 10% protects cells but risks BMS lockout if prolonged.

Repeated deep discharges below 12V in lead-acid batteries corrode positive plates, reducing charge acceptance. For example, a 100Ah AGM battery cycled to 20% DoD lasts 500 cycles, but only 150 cycles at 80% DoD. Pro Tip: Install a low-voltage disconnect (LVD) at 12.2V to prevent over-discharge. Lithium batteries handle deeper cycles better—LiFePO4 tolerates 80% DoD without lifespan penalties. But what if you accidentally drain a lithium battery to 0%? The BMS may permanently disconnect cells, requiring professional rebalancing.

Why is sulfation a battery killer?

Sulfation occurs when lead sulfate crystals harden on plates, blocking charge reactions. It’s triggered by undercharging, storage at <50% charge, or prolonged discharges. Crystals reduce capacity by 40% in 6 months if unchecked.

At 25°C, a lead-acid battery stored at 12.2V (50% SoC) develops 200mg/cm² sulfate vs. 50mg/cm² at 12.6V. Desulfators using 15-20V pulses can reverse early-stage sulfation. For example, a Trojan T-105 left at 11.8V for a month might lose 30% capacity, needing a 3-stage charger with desulfate mode. Pro Tip: Equalize flooded batteries every 10 cycles—apply 15.5-16V for 2-4 hours to break down sulfates. Lithium batteries don’t sulfate, making them ideal for RVs with irregular usage.

Do temperature extremes affect all RV batteries?

Yes, but heat impacts lead-acid more, while cold reduces lithium performance temporarily. Lead-acid loses 50% lifespan at 95°F vs. 77°F; lithium-ion degrades 2x faster at 113°F but operates from -4°F to 140°F.

Lithium batteries lose 20-30% capacity at -4°F but recover at warmer temps. For example, a Battle Born 100Ah LiFePO4 delivers 70Ah at 10°F but needs internal heaters below -20°F. Pro Tip: Insulate battery compartments and avoid engine bay installations. Lead-acid batteries in freezing temps require 1.265+ specific gravity—check with a hydrometer monthly. But why does heat kill lead-acid faster? High temps increase grid corrosion and water loss—AGM batteries lose 3x less water than flooded in heat.

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