Engineering Reference

Battery Chemistry and Nominal Voltage Reference

Condition-aware reference for common battery chemistries, nominal cell voltage, charge limits, discharge endpoints, pack voltage, and selection caveats.

Reading Time: 11 min
Format: Conditioned lookup
Updated: September 29, 2026

Use Typical Values Only for Orientation

Chemistry names do not define one universal charge voltage, cutoff, current or temperature range. Cell construction and manufacturer specifications control. Never use this table as a charging procedure or pack-construction authorization.

Chemistry and Voltage Lookup

Typical battery chemistry voltage lookup
Chemistry	Typical nominal	Typical charge / maximum	Typical discharge endpoint	Common context	Critical caveat
Li-ion, cobalt-based (typical)	3.6-3.7 V	4.20 V	About 2.5-3.0 V	Portable electronics	Exact upper and lower limits are cell-specific; protected packs may disconnect earlier
LiFePO4	3.2-3.3 V	3.60-3.65 V	About 2.0-2.5 V	Energy storage, motive and industrial systems	Flat discharge curve makes voltage-only SOC estimates weak
Lithium titanate (LTO)	About 2.3-2.4 V	About 2.7-2.8 V	About 1.5-2.0 V	High-cycle and fast-charge systems	Use the cell maker's charge profile and temperature limits
NiMH	1.2 V	No universal fixed-voltage endpoint	About 0.9-1.0 V under stated load	Consumer and industrial rechargeable packs	Charging normally uses current, temperature and/or voltage-change termination
NiCd	1.2 V	No universal fixed-voltage endpoint	About 0.9-1.0 V under stated load	Legacy high-rate applications	Cadmium restrictions and disposal rules apply in many regions
Lead-acid, 6-cell nominal 12 V	About 12 V	About 14.1-14.7 V cyclic at 25 C	Application-defined; about 10.5 V is a common loaded endpoint	Starting, standby and deep-cycle systems	Charge voltage requires temperature compensation and product-specific mode
Alkaline primary	1.5 V	Not rechargeable	Load- and application-defined	Low-drain primary applications	Open-circuit voltage does not directly equal remaining capacity
Zinc-carbon primary	1.5 V	Not rechargeable	Load- and application-defined	Low-cost, low-drain primary applications	Capacity and voltage sag depend strongly on load
Primary lithium Li-MnO2	3.0 V	Not rechargeable	Product- and load-defined	Memory backup, meters and primary electronics	Do not apply rechargeable lithium-ion charging limits
Silver oxide primary	1.55 V	Not rechargeable	Application-defined	Watches and precision low-drain devices	Coin-cell chemistry must be identified before replacement

Voltage Terms Are Not Interchangeable

Nominal voltage

A representative rated value used for naming, pack arithmetic and nominal energy. It is not a guaranteed operating voltage.

Maximum or charge voltage

An upper limit under specified charging, temperature and timing conditions. It is not the value to use as nominal voltage.

Loaded terminal voltage

The instantaneous voltage includes SOC, current, internal impedance, temperature, age and transient electrochemical effects.

Discharge endpoint

A product- and application-specific lower boundary. Protection may disconnect earlier, and repeated deep discharge may shorten life.

Series and Parallel Pack Arithmetic

Battery pack voltage relationships
Quantity	Relationship	What changes	Boundary
Nominal pack voltage	Vpack,nom = Ns × Vcell,nom	Series count	Matched cells and one explicit nominal-voltage convention
Maximum pack voltage	Vpack,max = Ns × Vcell,max	Series count	Use exact manufacturer maximum and charger tolerance
Minimum arithmetic voltage	Vpack,min = Ns × Vcell,min	Series count	Protection and load behavior may set a different practical limit
Parallel connection	Voltage remains approximately one cell voltage	Capacity and current sharing	Requires approved matching, interconnect and protection

4S lithium-ion example

Using 3.6 V nominal and 4.20 V maximum per cell gives 14.4 V nominal and 16.8 V maximum. Both values must be labeled by meaning.

4S LiFePO4 example

Using 3.2 V nominal and 3.65 V maximum gives 12.8 V nominal and 14.6 V maximum. It is not charger-compatible with the 4S 4.20 V-per-cell example.

Selection Boundaries

Battery selection boundary lookup
Check	Why it matters	Do not assume
Exact chemistry and cell model	Sets voltage and charging behavior	All lithium cells use 4.20 V
Charge profile and termination	Controls safety and life	A voltage label defines the whole charger
Continuous and pulse current	Controls heating and voltage sag	Capacity alone defines current capability
Operating and charging temperature	Limits kinetics and safe charging	Room-temperature limits apply everywhere
Series count and balancing	Determines pack voltage and cell divergence risk	Series cells remain balanced automatically
BMS and protection thresholds	Defines practical disconnect behavior	Typical chemistry cutoffs equal pack thresholds
Mechanical format and venting	Affects thermal and fault behavior	Equal voltage means drop-in replacement

Common Interpretation Errors

Using maximum charge voltage as nominal voltage.
Treating a chemistry-wide typical value as a cell guarantee.
Using one lithium charger for every lithium chemistry.
Multiplying parallel count into pack voltage.
Ignoring charger and resistor tolerances at the upper limit.
Treating discharge endpoint as zero remaining energy.
Estimating SOC from terminal voltage without load and rest context.
Mixing cells of different chemistry, capacity, age or SOC.
Applying rechargeable charging rules to primary cells.
Ignoring temperature compensation for lead-acid charging.
Assuming a protection cutoff is the same as a recommended operating limit.
Replacing a pack solely because the connector and nominal voltage match.

Datasheet Workflow

1Identify exact chemistry and manufacturer part number.
2Confirm nominal, charge-maximum and discharge-limit definitions.
3Check charge method, current, termination and temperature limits.
4Calculate series-pack voltage using values with matching meanings.
5Check continuous, pulse and fault-current ratings separately.
6Verify BMS thresholds, balancing and charger tolerances.
7Review capacity test conditions and expected load profile.
8Validate the complete pack against the product datasheet and applicable safety requirements.

Support reference

FAQ

Is nominal voltage the fully charged voltage?

No. Nominal voltage is a representative rating. Fully charged, operating and discharge-endpoint voltages are different and depend on chemistry and product limits.

Why do 3.6 V and 3.7 V lithium-ion cells both exist?

They can reflect different chemistry, manufacturer naming and nominal-voltage conventions. The exact cell datasheet, especially its charge and discharge limits, controls the design.

Can a lithium-ion charger charge LiFePO4 cells?

Only when the charger explicitly supports the cell's required chemistry, voltage limits, current profile and temperature controls. Their charge limits are not interchangeable.

How is nominal pack voltage calculated?

For matched cells in series, multiply nominal cell voltage by the series count. Parallel cells increase capacity, not nominal voltage.

How is maximum pack voltage calculated?

Multiply the manufacturer-specified maximum cell voltage by the series count, then verify BMS, charger and component tolerances against the actual pack specification.

Is discharge cutoff voltage universal for a chemistry?

No. It depends on the exact cell, load, temperature, life target and protection strategy. Typical ranges are orientation only.

Can terminal voltage determine battery state of charge exactly?

No. Voltage also depends on load, temperature, rest time, hysteresis, age and chemistry. Flat-curve chemistries are especially difficult to estimate from voltage alone.

Can primary batteries be recharged?

Do not recharge a cell unless its manufacturer explicitly identifies it as rechargeable and specifies a compatible charging method.

Why does lead-acid charge voltage change with temperature?

Electrochemical voltage is temperature-dependent, so practical lead-acid charging commonly requires temperature compensation defined by the battery manufacturer.

Can cells with different chemistries be connected in one pack?

No. Cells in a pack must follow an approved architecture with compatible chemistry, model, capacity, age, SOC, protection and balancing requirements.

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