Golf cart battery voltage chart: how to tell if a battery is bad
A voltmeter tells you a lot about a lead-acid battery pack, as long as you read it the right way. Here are the numbers and how to use them.
Take the reading the right way
Measure resting voltage: the cart off, not charged or driven for a few hours. A reading right after charging or driving looks better or worse than the truth.
State of charge chart
These values are from Trojan Battery's maintenance guide for flooded lead-acid batteries, with specific gravity corrected to 80°F.
| Charge | Specific gravity | 6 V battery | 12 V battery | 36 V pack | 48 V pack |
|---|---|---|---|---|---|
| 100% | 1.277 | 6.37 | 12.73 | 38.20 | 50.93 |
| 80% | 1.238 | 6.25 | 12.50 | 37.49 | 49.99 |
| 60% | 1.195 | 6.12 | 12.24 | 36.72 | 48.96 |
| 50% | 1.172 | 6.05 | 12.10 | 36.31 | 48.41 |
| 40% | 1.148 | 5.98 | 11.96 | 35.87 | 47.83 |
| 20% | 1.098 | 5.83 | 11.66 | 34.97 | 46.63 |
Source: Trojan Battery maintenance guide.
Finding the weak battery
A pack is only as good as its weakest battery. After a full charge, measure each battery. Trojan says a spread of more than 0.15 V between 6 V batteries points to a problem. One low battery can make the whole cart feel slow and short on range.
Why voltage isn't the whole story
A battery can show good resting voltage and still collapse under load. A load test, or a full discharge test, shows how the pack holds up while actually driving. That's the test that settles whether batteries need replacing.
Lithium is different
Lithium packs hold a nearly flat voltage until they're almost empty, so this chart doesn't apply. Use the pack's gauge or app, and its battery management system's readings.
Not sure what your numbers mean?
A free battery check tests every battery in the pack and writes the results down for you.
Call or text Poncho(352) 356-8868More guides
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