Strongest 6 Volt Car Batteries For Classics

This article may contain affiliate links where we earn a commission from qualifying purchases.

You need a new battery for your antique car, but you want to get one that will stay fully charged. What is the best 6-volt classic car battery?

The best 6-volt batteries are listed below, with a brief description and pricing information.

  • Optima 6V RedTop Starting Battery
  • NAPA Commercial Battery BCI No. 1
  • Duralast Battery BCI Group Size 1
  • Interstate 1-VHD 6 Volt Battery

For the first half of the twentieth century, vehicles were powered by six-volt batteries with limited cranking power. Until the mid-50s, when the electrical systems of cars became more complicated, requiring heavier fire loads, batteries were required for basic operations, like delivering cranking amps for starting or providing a steady flow to the spark plugs to keep the engine purring. Even though the design of cars changed often, the standard BC1 or BC2 battery stayed consistent. Over the years, a six-volt powered over 80% of the passenger cars on the road. But finding antique batteries for your pre-50s classic car can be confusing. Since automakers no longer make original batteries, what is the best six-volt battery to purchase? This article will examine the best 6-volt batteries on the market so that you can get cruising down the road in your vintage vehicle.

Table of Contents


When Did Six-Volt Batteries Begin Being Used?

The first domestic use of the six-volt battery was Hudson’s use of the BCI (Battery Council International - the group that sets dimensional standards) Group 2 in 1918. A few years later, Chevrolet began to use the Battery Group 1 (a standardized six-volt at the time) in the early twenties because it was about an inch and a quarter smaller. The batteries spread throughout the automotive world (with a couple of exceptions) and would power vehicles until the mid-50s. Most vintage cars can use a Group 1 or version of Group 2 without difficulty because the electrical load or cranking amps were not substantial like current vehicles today.

The development of polymers like neoprene and fiberglass in 1931 - ‘32 allowed manufacturers to add lead plates inside the battery box, which generated more power as cars became more sophisticated. The creation of polycarbonate plastic in 1953 revolutionized the automotive industry, and parts made of the new material lighted the vehicles considerably, improving fuel economy and vehicle efficiency.

The introduction of larger engines with more load-bearing amenities required automakers to adapt to 12-volt batteries. Ford, Lincoln, and Mercury were the first domestic manufacturer to use a BCI 29N 12-volt battery in their large, high-powered sedans in the mid-50s. While the  move to the larger battery was quickly adopted by other automakers, some British makers like Jaguar used 6-volt batteries until 1961. Interest in the smaller battery waned in the 1970s as electrical systems became complicated and demanded more power from existing batteries.

What Are The Best Six-Volt Batteries?

The following list contains what we believe are the best 6-volt batteries for classic car applications. We have included brief descriptions of them and some pros and cons for each one.

Optima 6V RedTop Starting Battery

Optima 6V RedTop Starting Battery
Optima 6V RedTop Starting Battery

This Optima RedTop 6-volt battery is a dependable, high-performance starting battery with enough amps to be reliable even in inclement weather. The battery has over 800 cold-cranking amps and is mountable in almost any position. The case is made of polypropylene, making it remarkably light (18.4 lbs) and compact (10 inches long x 3.63 inches wide and 8.13 inches tall). The battery has a reserve capacity of 100 minutes of constant performance, which makes it one of the most robust 6-volt products on the market.

The Optima battery is made of individual spiral cells situated between two lead plates. The case is spill-proof and weather-resistant, makings it perfect for heavy-duty use. The battery is 15 times vibration resistant, has a long shelf life, and is helpful for vari of applications (hot-rod, truck, or classic car).

The Optima battery offers a 36-month replacement on the battery, and the SAE terminals make

s connecting to cables quick and efficient. The company makes red-top batteries, but also the manufacturer’s yellow-top and blue-top batteries for times when high electrical loads are required, or marine/RV applications need a six-volt for starting purposes.

Optima Batteries are owned by Clarios (formerly Johson Controls), the largest producer of automotive batteries. The company manufactures its batteries in Monterey, Mexico, but they are headquartered in Milwaukee, WI. Their batteries are known for their excellent quality and are often listed in multiple “best of” lists. The battery is sold through Amazon or the company website. Shipping is quick and efficient.


  • Strong starting capacity
  • The plastic case is bulletproof
  • 800 cold cranking amps
  • Small design fits more classic/vintage cars or trucks
  • 36-month warranty
  • Good lasting power


  • American company, but not made in the USA.

NAPA Commercial Battery BCI No. 1

NAPA Commercial Battery BCI No. 1
NAPA Commercial Battery BCI No. 1

This strong commercial battery is ideal for truck applications that need a strong 6-volt battery. The Napa Commercial Battery is designed to deliver consistent daily performance and premium start capabilities. Napa offers many options in this line, so finding a replacement for your current 6-volt will not be an issue.

The battery uses tightly placed plates and grids to prevent vibration damage. The battery is maintenance-free, with a solid casing to prevent acid leaks. The NAPA commercial has 785 cold cranking amps and 130 minutes of reserve capacity. It comes with full-SAE terminals. The height of the battery is 8.75 inches (6.875 width), so it should fit into most receptacle areas.

NAPA is a leading distributor of automotive parts globally and farms out the battery production to East Penn or Clarios (Clarios also makes the Optima batteries). East Penn is a family-owned company that produces lead-acid batteries for all kinds of automotive, scooter, marine, and heavy-duty trucks. They do have manufacturing centers in Pennsylvania and Iowa.


  • 130 minutes of reserve
  • Plenty of cold cranking amps
  • 6-month warranty
  • Well-reviewed by classic truck owners
  • American-made
  • Reasonably priced


  • Warranty not as good as Optima batteries.

Duralast Battery BCI Group Size 1

Duralast Battery BCI Group Size 1
Duralast Battery BCI Group Size 1

The Duralast 6V battery is a compelling lead acid battery that works in many truck and large car applications. The battery has 575 cold-cranking apps, weighs a hefty 31 lbs, and has enhanced starting power in cold weather. The battery has a 1-year warranty and is available through Autozone automotive stores.

The polypropylene case resists vibration damage and strategically placed venting keeps gases from building up creating leakage or corrosion issues. Fully framed stamped power grid stores current with 66% more charging resistance and 70% better electrical flow. Thin plates are effective in delivering adequate starting charges every time.

Duralast is the label of Autozone and makes a wide variety of battery applications. The Duralast brand name is one of the best-known 6-volt batteries, but it does not make it in-house. Instead, most Duralast batteries are produced by Clarios, East Penn, or Exide. The company offers a full one-year replacement warranty.


  • Good cold cranking amps
  • Effective for classic truck use
  • One-year warranty
  • Great customer service through Autozone.
  • Reasonable price


  • Not necessarily American-made

Interstate 1-VHD 6 Volt Battery

Interstate 1-VHD 6 Volt Battery
Interstate 1-VHD 6 Volt Battery

This Interstate Battery fits a lot of car and truck applications from pre-55. The battery is a sealed lead acid battery with great cranking amps (800) and 130 minutes of reserve capacity. The wide variety of vehicles that this battery is suited for makes it a popular choice among classic car and truck owners. The battery is a heavy-duty unit with excellent longevity and delivers consistent starting amps every time.

At nine inches long, the battery fits into most battery shelves, although some classic owners will need to make modifications to accommodate the unit. Interstate offers a six-month replacement warranty which can give owners confidence about the quality of the battery.

Interstate Batteries is one of the most recognized battery brands. The company started from the trunk of a car, as the original owners made a living selling batteries to wholesalers. Over the years, the company has made many innovations in lead recycling, environmental and humanitarian causes. The company offers a six-month warranty and sells its products through its many retail centers nationwide. Due to the number of batteries that Interstate sells every year (19 million), it is difficult to know where the 1-VDH is made.


  • Excellent longevity
  • 6-month warranty
  • Popular brand name
  • Excellent viability for many classic cars and trucks
  • Good reserve time


  • None