Battery Charging Service

As a supplier of rechargeable batteries and custom battery packs, Epec also offers inhouse charging services to support customer requirements. Using a combination of standard charging equipment and custom-developed charge programs, Epec can accommodate a wide range of charging profiles. This approach enables rechargeable batteries and battery packs to be delivered fully charged to specification, allowing them to be immediately inserted into the end product without additional handling or setup.

Understanding best practices for charging custom battery packs is essential to maximizing performance, safety, and battery life. Epec’s charging services are designed to align the charging method with the specific battery chemistry and application.

Find out what the best practices when charging custom battery packs are.

At a Glance: Battery Charging Service

• Provides inhouse battery charging services for rechargeable batteries and custom battery packs using standard equipment and custom charge programs.
• Enables battery packs to be delivered fully charged to customer specifications and ready for immediate installation into the end product.
• Supports multiple controlled charging methods to match battery chemistry, application requirements, and performance needs.

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Basic Battery Charging Methods

Battery charging methods vary based on how voltage and current are applied during the charge cycle. The sections below outline common charging techniques used across different battery chemistries and use cases.

Constant Voltage

A constant-voltage charger functions as a DC power supply, often using a step-down transformer and rectifier to provide a fixed DC voltage to the battery. Simple versions of this design are commonly found in low-cost car battery chargers. Lead-acid cells used in automotive and backup power systems typically employ constant-voltage charging. Lithium-ion cells also often rely on constant voltage charging, though these systems are generally more complex and include additional circuitry to protect both the battery and the user.

Constant Current

Constant current chargers adjust the applied voltage to maintain a steady current flow into the battery. Charging continues until the battery voltage reaches the level associated with a full charge, at which point the charger switches off. This charging method is commonly used for nickel-cadmium and nickel-metal-hydride cells and batteries.

Taper Current

Taper current charging uses a crude, unregulated constant voltage source and is not considered a controlled charge method. As the battery voltage increases, the charging current naturally decreases. There is a significant risk of overcharging and cell damage if the charging rate and duration are not carefully limited. This method is suitable only for sealed lead acid (SLA) batteries.

Pulsed Charge

Pulsed charging delivers current to the battery in pulses rather than continuously. The average charging rate is controlled by adjusting pulse width, typically around one second. Between pulses, short rest periods of 20 to 30 milliseconds allow the battery’s internal chemical reactions to stabilize and equalize throughout the electrode material. This process helps the chemical reaction keep pace with energy input and may reduce unwanted surface reactions such as gas formation, crystal growth, and passivation. During rest periods, the open-circuit voltage of the battery can also be sampled if needed.

Burp Charging

Also known as reflex or negative pulse charging, this method is used alongside pulse charging. During the rest period, a very short discharge pulse, typically 2 to 3 times the charging current for about 5 milliseconds, is applied to depolarize the cell. These pulses help dislodge gas bubbles that form on electrodes during fast charging, accelerating stabilization and the overall charging process. While claims exist regarding improved charge rate, battery life, and dendrite removal, the established outcome is that this method does not damage the battery.

IUI Charging

IUI charging is a fast-charge profile developed for certain standard flooded lead acid batteries and is not suitable for all lead acid types. The process begins with a constant current (I) bulk charge until the battery voltage reaches a preset level near the onset of gassing. The charger then switches to constant voltage (U), during which the current gradually decreases until it reaches another preset value. Finally, the charger returns to constant current (I), allowing the voltage to rise to a higher preset limit before switching off. This final phase equalizes individual cell charge levels to help maximize battery life.

Trickle Charge

Trickle charging compensates for a battery’s self-discharge by applying a continuous, long-term constant current. It is commonly used for standby applications, with the charge rate varying based on discharge frequency. Trickle charging is not suitable for some chemistries, such as NiMH and lithium batteries, which are susceptible to overcharging damage. In some systems, the charger automatically switches to trickle mode once the battery reaches full charge.

Float Charge

In float charging, the battery and load are permanently connected in parallel across a DC charging source held at a constant voltage below the battery’s upper voltage limit. This method is primarily used in emergency backup power systems and is most commonly associated with lead-acid batteries.

Random Charging

Some applications involve charging energy that is delivered in an uncontrolled or variable manner. Examples include automotive systems where charging depends on engine speed, as well as EV and HEV systems that generate large power spikes through regenerative braking. Solar panel installations present another case, where charging occurs only when sunlight is available. These applications require specialized techniques to limit charging current or voltage to levels the battery can safely tolerate.

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Charging Method Timing and Pulse Characteristics

Parameter	Value	Units
Pulse width (pulsed charging)	~1	second
Rest period between pulses	20–30	milliseconds
Discharge pulse duration (burp charging)	~5	milliseconds
Discharge pulse current	2–3× charge rate	relative

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Frequently Asked Questions

Quick Links

• What charging services does Epec offer for battery packs?
• Can battery packs be delivered fully charged?
• Why are different charging methods required?
• Which batteries commonly use constant voltage charging?
• What is the purpose of pulsed charging rest periods?
• Is trickle charging suitable for all battery chemistries?
• Why do some applications require special charging techniques?

What charging services does Epec offer for battery packs?

Epec provides in-house charging services using standard equipment and custom charge programs for rechargeable batteries and custom battery packs.

Can battery packs be delivered fully charged?

Yes. Epec can deliver rechargeable batteries and packs fully charged to customer specifications and ready for immediate installation.

Why are different charging methods required?

Different battery chemistries and applications require specific voltage and current profiles to charge safely and effectively.

Which batteries commonly use constant voltage charging?

Lead-acid batteries typically use constant voltage charging, and lithium-ion cells often use it with additional protective circuitry.

What is the purpose of pulsed charging rest periods?

Rest periods allow chemical reactions inside the battery to stabilize and equalize before charging resumes.

Is trickle charging suitable for all battery chemistries?

No. Trickle charging is not suitable for some chemistries, such as NiMH and lithium batteries, due to the risk of overcharging.

Why do some applications require special charging techniques?

Applications with variable or uncontrolled energy input, such as automotive, regenerative braking, or solar systems, need charging methods that limit current or voltage to safe levels.

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Efficient Charging Solutions

Epec supports a wide range of controlled charging methods to match battery chemistry, application demands, and performance requirements. By selecting the appropriate charging technique and program, Epec helps ensure safe operation, consistent performance, and long-term reliability for the custom battery packs it manufactures.

Power up your products with precision charging. Choose from various battery charging methods tailored to your needs on all the custom battery packs we manufacture.

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