How To Tell If A Golf Cart Battery Is Bad?

Golf cart batteries typically show degradation through voltage drops, reduced runtime, and physical swelling. Lead-acid batteries should maintain 6.3–6.4V per cell (37.8–38.4V for 6×6V packs) under load. Lithium-ion variants exhibit failure via sudden capacity cliff (e.g., 72V 100Ah pack dropping below 70Ah usable). Use a multimeter to check resting voltage 12 hours post-charge—below 48V for 48V systems indicates cell imbalance or sulfation.

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What voltage indicates a failing golf cart battery?

Healthy 8V lead-acid batteries measure 8.4–8.5V fully charged, dropping to 7.2V under load. Voltage sagging below 6V during acceleration signals imminent failure. For lithium batteries, voltage plateaus disappear—72V packs might show erratic 65–75V fluctuations instead of stable 3.2V/cell behavior.

Lead-acid batteries experience sulfation when discharged below 50% repeatedly, causing permanent voltage depression. Test individual cells: variance >0.3V between 6V batteries requires equalization charging. Pro Tip: Measure voltage while climbing hills—consistent drops below pack rating confirm weak cells. Imagine a 48V system struggling to maintain 42V on inclines—that’s like a car engine stalling on mild slopes.

How does capacity testing identify bad batteries?

Capacity tests reveal actual energy storage versus rated specs. For 225Ah golf cart batteries, discharge at 75A (C/3 rate) should sustain 3 hours to 50% depth. Lithium batteries failing capacity tests often show sudden voltage drops after 80% discharge rather than gradual declines.

Use a carbon pile tester or specialized battery analyzer. Lead-acid packs losing >20% original capacity need replacement—for example, a 5-year-old 48V system that now only provides 25 miles instead of 35. Pro Tip: Always test at 80°F (27°C)—cold temperatures temporarily reduce capacity by 30–40%, mimicking failure. Think of it like trying to breathe thin air versus normal oxygen levels.

What physical signs indicate battery failure?

Swollen cases, terminal corrosion, and electrolyte discoloration signal trouble. Lead-acid batteries with bulging sides indicate excessive gassing from overcharging. Check electrolyte levels—exposed plates in flooded batteries accelerate sulfation. Lithium batteries may show thermal expansion at weak cell joints.

Inspect terminals monthly—white/green crust (lead sulfate) increases resistance, causing voltage drops. For example, a corroded terminal adding 0.2Ω resistance in 48V systems wastes 96W during 20A draws. Pro Tip: Clean terminals with baking soda solution, but avoid getting liquid in vent caps. It’s like clearing artery blockages to restore proper blood flow.

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