Battery Terminals Preferred by Auto Electrical Repair Professionals

Oxygen-Free Copper (OFC) Multi-Type Battery Terminals (Ionis Coating / SK Specification)

Oxygen-Free Copper (OFC) Multi-Type Battery Terminals
DMPL-1 / DMPL-2

Oxygen-Free Copper (OFC) Multi-Type Battery Terminals
DMPS-1 / DMPS-2

Singular masterpiece born of the pursuit of true quality and unmatched performance.

With the unwavering mission of "relentlessly pursuing superior conductivity," Hero Electric has taken on the challenge of developing a multi-type battery terminal—an endeavor considered extremely difficult—by adopting top-grade oxygen-free copper (OFC) with a purity of 99.9% or higher. It features an exceptional surface treatment that offers corrosion resistance equivalent to stainless steel (SUS304), and meets stringent quality standards capable of withstanding the harsh conditions of automotive environments and the demanding requirements of professional use. Staying true to a steadfast commitment to purely domestic Japanese manufacturing, this one-of-a-kind battery terminal embodies self-driven innovation and pioneers a completely new product category.

In most vehicles, the chassis (body) serves as the ground, meaning it functions as the negative side of the circuit. When installing additional accessories, it is common practice to first locate a point where positive voltage is present—such as near the key switch or fuse box—and branch off from there. For the negative connection, a metal part of the chassis is typically used as the grounding point.

Hero Electric’s proprietary multi-type battery terminals, constructed with high-purity Oxygen-Free Copper (OFC), allow for direct and stable circuit integration without the need to locate external power supply points. In response to field-specific requirements—such as the need to draw power directly from the lead-acid battery or to return the ground line directly to the battery—we have engineered a new class of battery terminals that expands conventional system design possibilities.

"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.

Bolt Type
Multi-Conversion Plate

Images are for illustration purposes.
Not available for sale in bare (non-plated) form.

What is Oxygen-Free Copper (OFC) ?

Oxygen-Free Copper (JIS H 3100, C1020)
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 (%)
CuPbFeSnZnAlMnNiPZr
C 1020"Minimum
99.96%"		－－－－－－－－－

(Reference): Japanese Industrial Standard JIS H 3100:2018 Copper and Copper Alloy Plates and Strips

■ 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.

Hero Electric has obtained its first design right in the Original Battery Terminal Series

Leveraging over half a century of expertise and know-how cultivated primarily in the automotive aftermarket, we are strongly committed to developing high-value-added products that bring users a true sense of ownership and pride.As part of these efforts, we have newly commercialized a multi-conversion plate for oxygen-free copper (OFC) battery terminals.This product fully embodies our original ideas and creative ingenuity, and boldly adopts OFC—a material long considered extremely difficult to use in mass production—as its base material.Furthermore, this marks the first acquisition of an intellectual property right (design right) within the Hero Electric Original Battery Terminal Series.

Multi-Conversion Adapter for Battery Terminals
"Registered Design No. 1741715"

Surface coated with "Ionis Coat / SK" offering corrosion resistance equivalent to stainless steel (SUS304)

The surface of the oxygen-free copper (OFC) is treated with Ionis Coat / SK, a highly corrosion-resistant composite alloy plating.This advanced coating offers corrosion resistance equivalent to that of stainless steel (SUS304), ensuring excellent protection against rust.In addition, it features a thin-film structure with self-healing properties, providing enhanced resistance to surface scratches.

What is Ionis Coat / SK?

Ionis Coat / SK is an advanced next-generation surface treatment offering excellent corrosion resistance, protection against galvanic corrosion, and self-healing capabilities.

A trivalent chromate process is applied to a zinc-nickel alloy base, followed by a topcoat containing a water-soluble silica-based rust-proof coating. Even if the plating layer is scratched, the topcoat dissolves to cover the damaged area, providing self-healing protection.

Ionis Coat / SK is now widely used across a variety of applications.One prominent example is its adoption as a surface treatment for fastening screws used in the installation of mega solar panels, which are exposed to harsh environmental conditions over long periods.

*Note: Deep scratches that physically peel off the topcoat or cut through it—such as those caused by tools or sharp objects—will not self-heal.

Verification conducted using our proprietary composite cycle test (See details: Test materials – DTPL-1S and DTPL-1SK)

[General View of the Composite Cycle Test Apparatus]

(Image used with permission from Suga Test Instruments Co., Ltd.)

Condition during testing

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
  1. Structural Reinforcement
    While copper is a relatively soft material, increasing its thickness enhances its strength, thereby improving both rigidity and durability.
  2. Improved Electrical Conductivity
    While oxygen-free copper (OFC) already offers excellent electrical conductivity, increasing its volume through thicker material design further enhances the efficiency of electrical signal and power transmission.
Slitless Structure
  1. Enhanced Strength and Durability
    The absence of slits (cuts or cracks) improves the overall strength and durability of the product.
  2. Reduced Risk of Product Damage
    The slitless structure minimizes the risk of cracks or fractures, helping to avoid issues like poor contact and voltage drops.

Thickness Verification of Oxygen-Free Copper (OFC) Battery Terminals

Products Plate Thickness
Multi-Type Model DMPL Series 1.8 mm (0.071 in)
DMPS Series 1.5 mm (0.059 in)

(Dimensional tolerance: ±0.1 mm / ±0.004 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:

  1. Lead
  2. Mercury
  3. Cadmium
  4. Hexavalent Chromium
  5. Polybrominated Biphenyls(PBBs)
  6. Polybrominated Diphenyl Ethers(PBDEs)
  7. Diisobutyl phthalate(DIBP)
  8. Dibutyl phthalate(DBP)
  9. Butyl benzyl phthalate(BBP)
  10. 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.

A dedicated cover for multi-type battery terminals, designed with maximized material thickness and an unwavering commitment to safety.

A uniquely designed, one-of-a-kind cover that highlights the distinctive aesthetics of oxygen-free copper (OFC) multi-type battery terminals. Like the OFC terminals themselves, the cover was developed entirely in-house, with a strong emphasis on both functionality and refined form. To ensure uncompromising reliability, it is manufactured in Japan, and—like our other product lines—features increased wall thickness for superior safety.

Cover for Oxygen-Free Copper (OFC) Multi-Type Battery Terminals (DVC-DMR)

Cover for Oxygen-Free Copper (OFC) Multi-Type Battery Terminals (DVC-DMB)

[Reference] Wall Thickness Verification of OFC Multi-Type Battery Terminal Covers
ProductsWall Thickness

DVC-DMR

2.0mm(0.079 in)

DVC-DMB

(Dimensional tolerance: ±0.5 mm / ±0.020 in)

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
 

One-Point Advice for Using Oxygen-Free Copper (OFC) Battery Terminals

At Hero Electric, we have consistently upheld our core philosophy of “Perfect Wiring for Perfect Maintenance” since our founding. Based on this principle, we recommend the crimping method for connecting wires and terminals, as it ensures secure and stable contact over long periods of use.

By using the simple crimping tools "D-19N" and "D-20N," the tensile strength of the crimped area satisfies the standard defined by the Society of Automotive Engineers of Japan (JASO), specifically "JASO D616: Minimum Tensile Strength of Conductor Crimped Parts."JASO D616 is a specification used in the automotive industry to ensure the quality and safety of conductor crimped connections.Meeting this standard indicates that the crimped area possesses the required tensile strength and delivers a highly reliable electrical connection.

Cross-Sectional Analysis of Crimped Area for Round Terminal (Product No. DR14-8)

Both D-19N and D-20N meet the JASO standard for minimum tensile strength of conductor crimped parts.

Example of Product Crimping: AV Wire 14mm² (AWG#6)and Round Terminal (Product No. DR14-8)
(Wire Side)

By securely and safely performing the installation (crimping) of battery terminals, ring terminals, and wires, the battery can fully deliver its intended performance.

Vibrations generated by a car's engine and during driving can affect the connection between battery terminals and wires. Loose connections may cause contact failure, resulting in voltage drops, battery drain, or even malfunctions in electronic devices. Therefore, a secure connection between the wire and terminal is extremely important.

[Reference] JASO Standard: Industrial standards established by the Society of Automotive Engineers of Japan (JSAE)

Product Specifications for Crimping Tools
Product Lineup: *Click the part numbers for product details
Photo Type Parts number Standard specification
Pole size Application Polarity Materials Surface finish
Multi-Type DMPL-1 For Large Pole [L] (Type D Terminal) Vertical Bolt Section: M8 (All 3 Bolts Identical) ＋ Oxygen-Free Copper (OFC) (OFC) Ionis Coating / SK
DMPL-2 －
DMPS-1 For Small Pole [S] (Type B Terminal) ＋
DMPS-2 －
Photo Type Parts number Standard specification
Wall Thickness Compatible Combination Part Numbers Materials
Exclusive Cover for Multi-Type Model DVC-DMR 2.0 mm (0.079 in) DMPL-1/DMPL-2
DMPS-1/DMPS-2		 Polyvinyl Chloride (PVC)
DVC-DMB
(Dimensional tolerance: ±0.5 mm / ±0.020 in)
Example of use
Real-World Vehicle Installations of Oxygen-Free Copper (OFC) Multi-Type Battery Terminals
Nissan skyline R34
Nissan Silvia S15
SUZUKI Jimny JB23
Quick Tip for Installing an Oxygen-Free Copper Battery Terminal onto a Lead-Acid Battery Post

*The illustration above shows the bolt-type specification.

  1. Firmly insert the oxygen-free copper (OFC) battery terminal onto the post of the lead-acid battery.
  2. Tighten the M6 nut until Point A comes into contact with the opposite surface.
  3. 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.)
  4. Immediately after installation, check for any looseness.
  5. 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.