Battery Terminals Preferred by Auto Electrical Repair Professionals
Oxygen-Free Copper (OFC) Battery Terminal (Conversion Type)
Oxygen-Free Copper (OFC) Battery Terminal (Conversion Type)
DXL SET / DXL PEAR SET Series
Oxygen-Free Copper (OFC) Battery Terminal (Conversion Type)
DXS SET / DXS PEAR SET Series
To ensure the efficient and stable delivery of power from lead-acid batteries used in automobiles to various electrical components, we have adopted oxygen-free copper (OFC) of exceptional quality—with a purity of 99.96% or higher and minimal impurities or additives—as the main material. Renowned for its outstanding conductivity, OFC enables superior electrical performance. Drawing on over half a century of expertise as a specialized manufacturer of automotive replacement parts, we have infused this product with our accumulated know-how. Manufactured entirely in Japan to meet Hero Electric’s exacting standards, this battery terminal is truly one of a kind.
When automotive audio systems are upgraded or in-vehicle theater systems are installed, the overall power demand increases significantly. To accommodate this higher demand, it becomes necessary to install higher-capacity lead-acid batteries, which, by design, feature thicker battery poles (electrodes).
This groundbreaking battery terminal functions as an adapter, enabling the use of the vehicle’s original terminal designed for smaller-diameter posts, even when upgrading to a high-capacity battery. It eliminates the need to replace the vehicle-side terminal, allowing for a smooth and modification-free installation.
"MADE IN JAPAN" – a mark of trust and reliability
By integrating the extensive knowledge and specialized expertise that Hero Electric has cultivated over more than half a century into every aspect of the design phase—and manufacturing exclusively at domestic facilities under innovative technologies and a rigorous, comprehensive quality control system—we achieve exceptionally high precision and reliability in the products themselves.
To meet the supreme mission of achieving both "quality" and "durability" as professional-use products, all of our products are designed and developed entirely in-house.
Uses Oxygen-Free Copper (OFC) with impurities removed to the utmost limit
For the first time in Japan's automotive aftermarket industry, we adopted Oxygen-Free Copper (OFC) as the core material for our battery terminal bodies. OFC is significantly purer and more conductive than standard copper, and is widely used in electronics and high-performance cables.
Images are for illustration purposes.
Not available for sale in bare (non-plated) form.
What is Oxygen-Free Copper (OFC) ?
High-purity copper with a purity of 99.96% or more
Oxygen-Free Copper is an exceptionally pure type of copper with minimal trace elements, impurities, and oxygen, resulting in a significantly higher purity compared to general copper.
High Electrical Conductivity
Oxygen-Free Copper has excellent electrical conductivity and is widely used in electronics, wiring, and conductors. Its high conductivity allows efficient transmission of electrical signals.
■Types, Grades, and Symbols of Materials Used in Oxygen-Free Copper (OFC) Battery Terminals
| Name | Type | Gradea) | Type Symbol | Key Features and Representative Applications (Reference Only) | |
|---|---|---|---|---|---|
| Alloy Number | Form | ||||
| Oxygen-Free Copper (OFC) | C1020 | Strip | Standard Grade | C1020Rb) | It has excellent electrical and thermal conductivity, ductility, and drawability. It also offers good weldability, corrosion resistance, and weather resistance. Even when heated to high temperatures in a reducing atmosphere, it does not risk hydrogen embrittlement. |
(Reference): Japanese Industrial Standard JIS H 3100:2018 Copper and Copper Alloy Plates and Strips
[Note]
b) For plates and strips used for electrical conduction, a "C" shall be added after the type symbols P, PS, R, or RS.
■ Chemical Composition of Oxygen-Free Copper (Alloy Number: C1020)
| Alloy Number | Chemical Composition (%) | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Cu | Pb | Fe | Sn | Zn | Al | Mn | Ni | P | Zr | |
| C 1020 | "Minimum 99.96%" | － | － | － | － | － | － | － | － | － |
■ Mechanical Properties of Materials Used in Oxygen-Free Copper (OFC) Battery Terminals
| Alloy Number | Grade | Product Symbol | Tensile Test | Bending test a) | Hardness test a) (for reference) |
|||||
|---|---|---|---|---|---|---|---|---|---|---|
| Thickness Range mm |
Tensile Strengthb) N/mm2 |
Elongationb) ％ |
Thickness Range mm |
Bending Anglee) |
Inner Radiuse) |
Thickness Range mm |
Vickers Hardnessb) HV |
|||
| C1020 | ½H | C 1020 P-½Hd) C 1020 PS-½Hd) |
0.10~<0.15 | 235~315 | - | 0.10~2.0 | 180° | 1xThickness | 0.20~20 | 75~120e) |
| 0.15~<0.30 | ≧10 | |||||||||
| 0.30~20 | 245~315 | ≧15 | ||||||||
| C 1020 R-½Hd) C 1020 RS-½Hd) |
0.10~<0.15 | 235~315 | - | ≧0.20 | ||||||
| 0.15~<0.30 | ≧10 | |||||||||
| 0.30~4.0 | 245~315 | ≧15 | ≦4.0 | |||||||
(Reference): Japanese Industrial Standard JIS H 3100:2018 Copper and Copper Alloy Plates and Strips
[Notes]
a) Products that fall outside the specified thickness categories are not subject to bending or hardness tests.
b) Numerical values are rounded to the nearest whole number.
d) Also applicable to plates and strips used for electrical purposes.
e) Minimum test force is 1.961 N.
[Reference] Comparative Table of Conductivity of Various Materials Commonly Used for Battery Terminals
| Comparative Materials | Oxygen-Free Copper (OFC) (Material used in our products) |
Brass | Zinc Alloy Die-Cast | Lead |
|---|---|---|---|---|
| Material Conductivity (% IACS) | 101% | 28% | 26% | 9% |
*1. IACS refers to the International Annealed Copper Standard, which defines 100% IACS as the conductivity of annealed standard copper.
*2. The above values are general reference values and not absolute (guaranteed) values.
(*Note) Cu-Zn alloys are referred to as brass; the academic term is "黄銅" (ōdō).
(Reference): Osawa, Nao. "Illustrated Introduction to the Basics and Mechanisms of Copper." Shuwa System, 2010, p.106.
[Point] Easy-to-understand conductivity explained with illustrations
Conductivity can be compared to "road width," where smoother traffic flow represents higher efficiency.
Copper is a critical material for realizing a sustainable, decarbonized society through renewable energy and electric vehicles
■Renewable Energy Generation
Copper plays a vital role in renewable energy systems. Solar and wind power equipment requires large amounts of copper wiring. Copper's high conductivity and durability enhance the efficiency and sustainability of renewable energy generation.
■Electric Vehicles and Charging Infrastructure
Copper is an essential material in the production of electric vehicles. Motors, batteries, and charging infrastructure for electric vehicles require large amounts of copper. Its excellent conductivity and durability contribute to improved performance and efficiency in electric vehicles.
■Electronic Devices
Copper is also essential in electronics manufacturing. Copper wiring is used in computers, smartphones, and TVs. Its excellent heat conduction makes it suitable for use in cooling systems. As high-performance electronics become increasingly important in a decarbonized society, copper plays a crucial role in supporting this demand.
To prevent oxidation of the copper itself, tin plating is applied to the surface
Since oxygen-free copper (OFC) tends to lose its excellent conductivity due to surface oxidation when left uncoated, a tin plating with low contact resistance and long-term stability is applied as the surface treatment.Tin plating is widely used in electrical components. By forming a coating layer, it shields the material from exposure to air, thereby protecting the base metal while ensuring both reliable conductivity and corrosion resistance.
Developing products with a strong emphasis on unleashing maximum performance
To ensure the highest priority of achieving both reliability and robustness as battery terminals under the extremely harsh conditions of automotive engine compartments, we have established key specifications that include thickened materials and a slitless structure—free from notches or cracks. From the design stage onward, our in-house product development integrates the technical expertise and know-how that Hero Electric has cultivated over the years.
| Development Concept | Background Behind the Development Concept |
|---|---|
| Enhanced Durability through Thicker Base Material |
|
| Slitless Structure |
|
Wall Thickness Evaluation of Oxygen-Free Copper (OFC) Battery Terminal (Conversion Type)
| Products/th> | Wall Thickness | |
|---|---|---|
| Conversion Type | DXL SET / DXL PEAR SET Series | 1.8 mm |
| DXS SET / DXS PEAR SET Series | 1.5 mm | |
(Dimensional tolerance: ±0.1 mm / ±0.039 in)
[Reference] Validation Based on Real-World Use Cases of Slit-Type Battery Terminals
Slits (cuts or cracks) can weaken the strength of objects or structures. When external force or load is applied to the slit, that area may become a point of weakness, increasing the likelihood of cracking or breakage.
Furthermore, Slit-type battery terminals that develop cracks due to vibrations from automobiles may cause unexpected vehicle issues, as increased contact resistance or poor connections can lead to voltage drops.
Verified by "Vibration Test" Based on JIS Standards (Test materials: DTPL and DTPS)
[Overview of Vibration Testing Equipment]
Actively promoting environmentally conscious manufacturing with consideration for issues such as climate change and biodiversity conservation
We place great importance on environmentally conscious manufacturing. As part of this commitment, over 30 years ago, Hero Electric took the lead in developing oxygen-free copper (OFC) battery terminals for automotive aftermarket use—completely free from hazardous substances such as lead, mercury, and cadmium—in compliance with the RoHS2 Directive. In line with RoHS2, Hero Electric will continue to actively contribute to global environmental preservation by providing compliant products and working toward a more sustainable future.
The RoHS2 (Restriction of Hazardous Substances Directive) is a directive issued by the European Union (EU) that restricts the use of specific hazardous substances in electrical and electronic equipment and their components. The goal of RoHS2 is to reduce harmful effects on both the environment and human health.
The ten substances restricted under the RoHS2 Directive are as follows:
- Lead
- Mercury
- Cadmium
- Hexavalent Chromium
- Polybrominated Biphenyls(PBBs)
- Polybrominated Diphenyl Ethers(PBDEs)
- Diisobutyl phthalate(DIBP)
- Dibutyl phthalate(DBP)
- Butyl benzyl phthalate(BBP)
- Bis(2-ethylhexyl) phthalate(DEHP)
These substances are recognized as harmful to the environment, particularly when they leak during waste disposal, potentially contaminating soil and water sources and negatively impacting ecosystems and human health.
Hero Electric's Exclusively Designed Battery Terminal Cover — Where Function Meets Form
To improve usability, HERO Electric has expanded its original battery terminal cover series by introducing dedicated covers designed to fit both types of oxygen-free copper (OFC) battery terminals—standard and conversion models. These covers have been developed using HERO’s proprietary technologies and know-how, refined over many years, while also pursuing a sophisticated and functional design. In order to ensure high product reliability, domestic production is maintained without compromise. Like other products in the lineup, the covers feature increased wall thickness for enhanced durability and safety.
Cover for Oxygen-Free Copper (OFC) Battery Terminal – Bolt Type (Compatible with DTPL and DXL models)
Cover for Oxygen-Free Copper (OFC) Battery Terminal – Bolt Type (Compatible with DTPS and DXS models)
Verification Results of Leakage Current Testing Based on Our In-House Standards (Test Material: DVCP60)
[On-Vehicle Installation Example of Dedicated Cover for Oxygen-Free Copper (OFC) Battery Terminals]
State During Testing
| Photo | Parts number | Standard specification | |||
|---|---|---|---|---|---|
| Applicable Conditions | Polarity | Materials | Surface finish | ||
 |
DXL_SET DXL_PEAR_SET |
Conversion terminal used when the vehicle’s battery cable terminal is for a small post (Type B) and the replacement battery has a large post (Type D). | Includes one positive (+) and one negative (–) terminal per set | Oxygen-Free Copper (OFC) (Main Body), Brass (Sleeve) | Tin Plating (Main Body), Uncoated (Sleeve) |
 |
DXS_SET DXS_PEAR_SET |
Conversion terminal used when the vehicle’s battery cable terminal is for a large post (Type D) and the replacement battery has a small post (Type B) | Includes one positive (+) and one negative (–) terminal per set | ||
Step 1 Check the size (diameter) of the battery post currently installed in the vehicle
[L]: Large Pole / [S]: Small Pole
(Based on the JIS standard for lead-acid batteries)
When the battery terminal in the vehicle is designed for small posts (Type B), and the new replacement lead-acid battery has large posts (Type D) for higher capacity
Use the following Oxygen-Free Copper (OFC) Battery Terminal (Conversion Type) Model: DXL PEAR SET
When the battery terminal in the vehicle is designed for large posts (Type D), and the new replacement lead-acid battery has small posts (Type B) for higher capacity
Use the following Oxygen-Free Copper (OFC) Battery Terminal (Conversion Type) Model: DXS PEAR SET
Step 2 Disconnect the vehicle’s battery cables
Step 3 Install the Oxygen-Free Copper (OFC) Battery Terminal (Conversion Type)
Step 4 Connect the vehicle’s battery cables to the Oxygen-Free Copper (OFC) Battery Terminal (Conversion Type)
Quick Tip for Installing an Oxygen-Free Copper Battery Terminal onto a Lead-Acid Battery Post
*The illustration above shows the bolt-type specification.
- Firmly insert the oxygen-free copper (OFC) battery terminal onto the post of the lead-acid battery.
- Tighten the M6 nut until Point A comes into contact with the opposite surface.
- By further tightening the M6 nut, Point A acts as a fulcrum, causing the oxygen-free copper battery terminal to clamp securely onto the post of the lead-acid battery.(The fulcrum effect ensures that the oxygen-free copper terminal is firmly and reliably fixed in place.)
- Immediately after installation, check for any looseness.
- Periodically inspect to confirm that the oxygen-free copper battery terminal remains securely tightened.
 | When installing the oxygen-free copper battery terminal,always check that there are no abnormalities on the post of the battery (lead-acid battery).Also, please make sure not to touch the battery fluid under any circumstances. |
How to Use the Oxygen-Free Copper (OFC) Battery Terminal (Conversion Type – DXL) [Video]
Video Format: GIF Animation, File Size: 4.6MB
