BiXPower 29.4V 4A AC Charger for 24V / 25.2V Lithium-Ion Batteries

High-Current 29.4V Lithium-Ion Battery Charger

The ACC-24V4A provides a maximum charging current of 4A, making it suitable for compatible battery packs that support charging at this current.

Compared with a lower-current charger, a 4A charger may reduce charging time for larger batteries, provided the battery manufacturer permits the higher charging rate.

The charger automatically controls charging current and voltage according to its charging profile. Its rated 4A output represents the maximum controlled charging current, not a fixed current throughout the entire charging cycle.

Compatible Batteries

This charger is intended for compatible lithium-ion battery packs with seven series-connected cell groups, commonly described as 7S lithium-ion batteries.

These batteries typically have:

• Nominal battery voltage: 25.2V (often marketed as 24V)
• Full-charge voltage: 29.4V
• Battery chemistry: Conventional 4.2V-per-cell lithium-ion chemistry
• Maximum permitted charging current of at least 4A
• Compatible DC charging connector and polarity

5.5 × 2.5mm DC Output Connector

The ACC-24V4A uses a standard DC barrel output connector with the following dimensions:

• Outside diameter (OD): 5.5mm
• Inside diameter (ID): 2.5mm
• Connector barrel length: approximately 12mm

Before ordering, verify that the connector size and polarity match your battery's charging input.

A connector that physically fits does not necessarily indicate electrical compatibility.

LED Charging Status Indicator

The ACC-24V4A includes an LED indicator to help identify charging status.

A green indicator may also appear when the charger is disconnected from the battery or when the battery is not accepting charging current.

Follow the battery manufacturer's instructions to confirm charging completion.

Battery Charger vs. Regular Constant-Voltage Power Adapter

A lithium-ion battery charger may look very similar to a laptop AC-to-DC power adapter. Both convert household AC electricity into DC power.

However, they are designed for different purposes and behave differently when connected to a load.

1. Lithium-Ion Battery Charger: Controlled Charging Current and Voltage

A dedicated lithium-ion battery charger controls both charging current and charging voltage according to the battery's charging requirements.

Most conventional lithium-ion battery chargers use a constant-current / constant-voltage (CC/CV) charging process.

Stage 1: Constant-Current Charging

During the main charging stage, the charger supplies a controlled charging current, up to its rated maximum of 4A.

As the battery charges, its cell voltage gradually increases. The charger adjusts its output voltage to follow the battery voltage while maintaining the controlled charging current.

The output voltage gradually rises toward the specified maximum charging voltage of 29.4V.

Stage 2: Constant-Voltage Charging

When the battery reaches the specified final charging voltage, the charger maintains approximately 29.4V.

During this stage, charging current gradually decreases as the battery approaches full charge.

Stage 3: Charging Completion

As charging current decreases to the charger's completion threshold, the charger indicates that charging is complete or nearly complete.

For the ACC-24V4A, the LED turns green when output current is at or below approximately 300mA.

2. Regular Laptop AC Power Adapter: Constant-Voltage Output

A conventional laptop AC-to-DC power adapter is designed to supply a constant DC output voltage, such as 19V, 20V, or 24V.

The adapter maintains its rated output voltage while the connected device draws the current it needs, up to the adapter's maximum output capacity.

For example, a regular 24V 5A power adapter provides approximately 24V constant-voltage output.

The connected device may draw 1A, 2A, 3A, or 5A depending on its power demand.

The adapter's 5A rating represents its maximum available output current. It does not mean that the adapter always outputs 5A.

Battery Charger vs. Power Adapter: Comparison

Why You Should Not Use a Regular Laptop Adapter to Charge an Unprotected Lithium-Ion Battery

Lithium-ion battery cells have relatively low internal resistance.

If a battery is connected directly to a constant-voltage power source without suitable charging control, excessive charging current may flow.

A conventional power adapter is generally designed to maintain its rated voltage while supplying the current requested by the connected load, within its output limits.

Without appropriate charging control, excessive current may cause:

• Battery overheating
• Battery cell damage
• Accelerated battery aging and capacity loss
• Power adapter overload or shutdown
• Damage to charging cables and connectors
• In severe cases, thermal runaway or fire

When Can a Regular AC Power Adapter Charge a Lithium-Ion Battery?

Some rechargeable battery packs include a built-in charging controller that manages the charging voltage and current delivered to the battery cells.

For these battery packs, a compatible constant-voltage AC-to-DC power adapter may be used as the external charging power source.

The internal charging controller regulates the battery charging process rather than relying on the external adapter to provide the complete charging profile.

Before using a regular AC power adapter, verify that:

• The battery explicitly supports charging from a constant-voltage DC source.
• The adapter output voltage is within the battery's specified charging input range.
• The adapter provides sufficient output power.
• The connector size and polarity are correct.
• The battery has appropriate internal charging control.

Some BiXPower batteries, including models with built-in charging controllers, can accept compatible external DC power adapters.

However, this capability must be verified for each individual battery model.

Why Charging Current Matters for Battery Life

Lithium-ion batteries should be charged within their manufacturer-specified current limits.

Moderate charging currents generally help reduce heat generation and battery cell stress.

Charging at higher currents may reduce charging time but can also increase battery temperature and long-term aging.

The ACC-24V4A provides up to 4A charging current. It is intended for battery packs whose charging specifications permit this level.

For smaller batteries or battery packs with lower recommended charging currents, a lower-current charger may be more appropriate.

Technical Specifications

Original Charger Specification Label

How to Charge a Compatible 24V Lithium-Ion Battery

1. Verify compatibility. Confirm that the battery requires a 29.4V CC/CV charger and permits charging current up to 4A.
2. Check the connector. Confirm the battery charging port accepts the charger's 5.5 × 2.5mm DC connector with matching polarity.
3. Connect the DC output. Insert the charger connector into the battery's designated charging input port.
4. Connect AC power. Plug the charger into a suitable 100–240V AC outlet.
5. Monitor charging. The LED normally turns red during active charging.
6. Check completion. The LED normally turns green when output current falls to 300mA or less.
7. Disconnect after charging. Follow the battery manufacturer's charging and disconnection instructions.

Frequently Asked Questions

Package Contents

• 1 × BiXPower ACC-24V4A 29.4V 4A AC Battery Charger
• 1 × Compatible AC Power Cord

BiXPower Technical Support

Not sure which charger is suitable for your rechargeable battery?

Contact BiXPower with your battery model number, required charging voltage, maximum charging current, connector dimensions, and polarity.

Our technical support team can help identify a compatible charging solution.

Product Code: ACC-24V4A

Maximum Charging Output: 29.4V DC / 4.0A

Warranty: One Year