Battery Voltage Chart: Car, AA, Lithium & Common Battery Voltages

Battery voltage reveals crucial details about a battery's type, charge level, and overall condition. Whether you're checking a car battery, replacing AA batteries, testing a solar power tool pack, or comparing home backup power options, a simple battery voltage chart helps you decode what the numbers mean.

In this guide, we break down common battery voltages, explain what constitutes a healthy car battery voltage, show the volts of standard AA batteries, and compare several battery types in easy-to-read charts.

Battery Voltage Chart: Common Battery Types

A battery's voltage depends primarily on its chemistry. Here is a simple chart of common battery types and their typical nominal voltages.

Note: These are typical nominal values. Actual voltage may be higher when fully charged and lower as the battery discharges.

Healthy Car Battery Voltage

While commonly referred to as a 12V battery, a healthy car battery doesn't sit at exactly 12.0V when fully charged. Instead, a fully charged 12V lead-acid car battery typically measures around 12.6V to 12.8V with the engine off and after a period of rest.

Here is a simple auto battery voltage chart for a resting 12V lead-acid car battery:

When the engine is running, the voltage should naturally be higher because the alternator is actively charging the battery. A typical charging voltage ranges from 13.7V to 14.7V, depending on the vehicle, temperature, and charging system.

If your car battery reads below 12.0V after resting, it likely needs to be charged or tested. If the voltage drops quickly after a full charge, the battery may be aging or failing.

Volts of an AA Battery

The voltage of an AA battery depends on its chemistry. A standard disposable AA alkaline battery is rated at 1.5V, whereas a rechargeable NiMH AA battery is typically rated at 1.2V. A lithium AA battery is also often rated at 1.5V, though its discharge behavior differs significantly from an alkaline one.

A rechargeable AA battery showing 1.2V isn't necessarily weak. That's perfectly normal for NiMH chemistry. This difference in nominal voltage is why some devices may perform differently with rechargeable batteries compared to disposable alkaline ones.

AAA, C, D, and 9V Battery Voltage Chart

Many household batteries share the same basic voltage despite their different physical sizes. AA, AAA, C, and D alkaline batteries are all typically 1.5V. The larger sizes simply store more energy capacity, rather than outputting a higher voltage.

While a D battery is much larger than an AA battery, both output 1.5V if they are alkaline. The D battery simply stores more energy, allowing it to power devices for much longer.

Lithium-Ion Battery Voltage Chart

Lithium-ion batteries are standard in phones, laptops, power banks, cameras, and many rechargeable tools. A single lithium-ion cell typically has a nominal voltage of 3.6V or 3.7V, though this fluctuates as it charges and discharges.

Many devices utilize multiple cells wired in series or parallel. For instance, a battery pack may combine several lithium-ion cells to achieve a higher overall voltage and capacity.

LiFePO4 Battery Voltage Chart

LiFePO4 (lithium iron phosphate) batteries are widely used in solar storage, RV systems, portable power stations, and home backup solutions. They are renowned for their long cycle life, superior safety, and stable voltage output.

A single LiFePO4 cell usually has a nominal voltage of 3.2V. A standard "12V" LiFePO4 battery contains four of these cells wired in series, resulting in a nominal voltage of 12.8V.

Because LiFePO4 voltage stays relatively flat for the majority of its discharge cycle, voltage alone isn't always a reliable indicator of exact remaining capacity. A Battery Management System (BMS) or a monitor provides a much more accurate reading.

Lead-Acid Battery Voltage Chart

Lead-acid batteries are commonly used in cars, motorcycles, boats, RVs, backup systems, and traditional solar setups. A standard 12V lead-acid battery contains six cells, each measuring about 2.1V when fully charged.

Lead-acid batteries should not be deeply discharged on a regular basis. Repeated deep discharging can drastically shorten the battery's lifespan, especially for starter batteries.

What Affects Battery Voltage?

Battery voltage isn't a fixed, static number. It fluctuates based on charge level, applied load, ambient temperature, battery age, and internal chemistry.

For example, a battery may show a higher voltage immediately after charging, only to settle down after resting. Conversely, a battery under load will often show a lower voltage than it does at rest. Cold temperatures can temporarily reduce both voltage and available capacity, while aging batteries might show normal resting voltage but experience a rapid drop as soon as they are used.

This is why voltage is a useful metric, but shouldn't be the only test you rely on. For car batteries, a load test provides a much clearer picture of overall health. For lithium solar battery packs, a Battery Management System (BMS) offers far more comprehensive data than voltage alone.

Conclusion

A reliable battery voltage chart helps you quickly determine whether a battery is full, low, healthy, or on the verge of failing. A healthy car battery typically sits around 12.6V to 12.8V when fully charged and at rest, while a standard AA alkaline battery measures 1.5V. Whether it's lithium-ion, LiFePO4, lead-acid, or standard household batteries, each chemistry has its own unique normal voltage range.

While voltage is a great initial diagnostic tool, it doesn't tell the whole story; load, temperature, battery age, and chemistry all play a vital role. For small devices, knowing the basic voltage helps you choose the correct replacement. For home solar backup, advanced AC-coupled units like the TSUN PowerTrunk provide a safer, smarter, and more convenient way to store and utilize battery power.

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