Buying guide for Best D Batteries
D batteries, or D-cells, are the most common large single-cell batteries in consumer use. Their size makes them ideal for devices that have high power requirements or long run times. D batteries, like AA, AAA, and C batteries, are single-cell batteries, meaning they are constructed around a single electrical cell. In contrast, 9-volt batteries contain six cells.
D cells are also dry cell batteries. Dry cell batteries have electrolytes in paste form, which are less prone to leakage than the liquid electrolytes of wet cell batteries. Car batteries are examples of wet cell batteries.
D cells were invented in 1898 to power flashlights, which were brought to the market the next year. Their creator, the National Carbon Company, eventually acquired the maker of the first battery-operated flashlights, the American Ever Ready Company, for which it supplied battery parts. The trademark was shortened to Eveready. The company eventually became part of Union Carbide and later Ralston Purina. It is currently Energizer Holdings, Inc. after its flagship battery brand.
The IEC, or International Electrotechnical Commission has standardized names for batteries depending on size and chemistry. Carbon zinc D batteries are R20, alkaline D batteries are LR20, nickel cadmium D batteries KR20, and nickel metal hydride HR20.
How to choose and use D batteries
Cell chemistry
D batteries, like other consumer batteries, differ in the cell chemistry they use. Batteries have different capabilities depending on their cell chemistry.
The two most common cell chemistries are carbon zinc and alkaline. Carbon zinc, known also as zinc-carbon, is the older technology, originally developed as a wet cell battery by French inventor Georges Leclanche in 1866. It was the primary kind of consumer battery available until the mid-twentieth century.
Alkaline batteries are the most popular battery on the market. Alkaline batteries are known for having larger capacities, longer durations, and longer shelf lives than carbon zinc batteries. They are better suited to intermittent or constant light loads than carbon zinc batteries. Alkaline batteries came to market in the 1960s.
Three other kinds of cell chemistry are commonly available in the D cell format: nickel cadmium, also called NiCad; nickel metal hydride, or NiMH; and lithium. These batteries have the capability of being conveniently recharged by the consumer.
Usage
Due to their capacity, D batteries are ideally used for high-power, high-drain duties. Large, heavy-duty flashlights were the original reason D batteries were invented and remained their most popular use for a long time. They’re also ideal for radio transmitters, classic boomboxes, radio-controlled toys and devices, and electric motors. D batteries have also been used to power emergency and weather radios, which can be lifesavers in natural disasters.
Rechargeability
Rechargeable single-cell batteries have become a viable alternative to old-fashioned disposable batteries. While costing more upfront, they can be recharged multiple times, saving you money in the long run. By reducing waste, they can be more friendly to the environment, although they are made with heavy metals. If you choose rechargeable D batteries, you usually also need to purchase a battery recharger compatible with them.
Disposal
Don’t throw your used batteries in the household trash. Many batteries use toxic materials including acids and heavy metals. Rechargeable batteries in particular need proper disposal when their lifespans run out. The only batteries safe to throw in household trash are alkaline batteries, which no longer contain the metal mercury. Dispose of all batteries according to your local waste authority’s guidelines.
A popular test for alkaline batteries involves dropping them to see if they bounce. However, what this really shows is whether they’ve been used or not, not how much power is left in them.
STAFF
BestReviews
Features of D batteries
Voltage
As a general rule, all single-cell consumer batteries of any size offer 1.5 V (volts) of power. However, there is a nominal voltage variance between disposable and rechargeable chemistries. Carbon zinc and alkaline disposable batteries have 1.5 V nominal voltage, but nickel cadmium and nickel metal hydride batteries usually top out at 1.2 V, while expensive lithium D-cells can exceed 3 V.
Capacity
The capacity of D batteries is what sets them apart from smaller single-cell batteries. Their size gives them more physical storage capability and thus more capacity. Capacity is measured in amp hours (Ah) or milliamp hours (mAh). Capacity differs depending on the battery chemistry. A good alkaline D cell battery usually boasts 10,000 mAh of capacity.
Shelf life
Shelf life, or longevity, measures how long a battery retains its charge without use. D batteries with different chemistries have different shelf lives. A carbon zinc D battery has a shelf life of three to five years, while an alkaline D battery has a shelf life of 5 to 10 years.
Lifespan and cycles
If you choose rechargeable D cell batteries, look at their lifespans – how many times they can be recharged. Rechargeable D batteries, like the batteries in a smartphone or laptop, can be recharged only so many times before they begin to lose capacity. A good lifespan for rechargeable D batteries is around 1,200 cycles.
DID YOU KNOW?
American inventor Benjamin Franklin was the first to use the military term “battery,” or a series of artillery pieces, to refer to devices that store electricity.
STAFF
BestReviews
Accessories for D batteries
Battery tester
A household battery tester allows you to take the guesswork out of which batteries are used, which are drained, and which are almost new. Many models fit all common sizes of single-cell dry batteries, up to and including D batteries, and have a gauge or display that indicates how much charge is left.
Battery recharger
Part of the upfront cost of rechargeable batteries includes their recharger. It’s often possible to purchase a combo pack from many brands, with a charger and some batteries to begin with, but you can also purchase universal battery chargers that fit multiple rechargeable battery sizes, including D batteries. Some lithium D batteries now integrate a USB port into their construction for recharging.
Battery box
A battery box or case is a great way to store batteries safely. They can be as simple as small plastic boxes or sleeves that can be tossed in a backpack or bag or as full-featured as a large carrying case with foam cutouts that hold dozens of batteries of different sizes. Battery boxes and cases not only keep batteries organized but also store them properly so that they don’t touch metal or each other’s terminals, which can cause leaks and drains.
How much do D batteries cost?
Inexpensive
D batteries can cost as low as $0.50 per count, usually at a minimum in packs of two in many gas stations, convenience stores, drugstores, and sundry shops. These may be store-brand or off-brand batteries that may have cut corners in construction, perhaps in their casing or their terminals, and they might be more prone to leakage.
Midrange
Brand-name disposable D batteries, such as from Duracell, Energizer, and Ray-O-Vac, cost between $1.50 to $2.50 per count, typically in packs of two, four, eight, ten, or twelve. These long-standing brands have proven trustworthy and are generally the standard against which better or worse batteries are measured.
Expensive
Rechargeable batteries start at around $6 per count but may cost $10 per count or more. Their high upfront cost, however, should be considered with their far longer lifespans compared to disposable batteries. High-capacity 3 V lithium D batteries can cost around $15 per count.
D batteries are not the largest single-cell batteries. F-cell batteries are larger, but they are less common and are not easy to find.
STAFF
BestReviews
Tips for batteries
- Remove batteries for storage. Don’t keep batteries in devices if they won’t be used for long periods. Batteries expire, and they may leak, which can damage any device they’re inside.
- Freezing may harm batteries. While batteries don’t fare well in the heat, the cold and humidity of a refrigerator or freezer could also damage them. Keep batteries in a cool, dry place around room temperature.
- Keep them in the same direction. If the positive and negative ends of the batteries touch, current may start flowing, making the batteries expend their charge.
- Buy a little more than you need. Batteries are one of those items that tend to cost less the more you buy at once. The same D battery that costs over $2 per unit in a two-pack could cost just over $1 in a 10-pack.
Despite being officially designated as BA-30 batteries by the U.S. military, D-cell batteries were called Type C batteries by the U.S. Navy in World War II, leading to confusion regarding actual C-cell batteries.
FAQ
Q. Are all D batteries the same size?
A. D batteries, despite being a standardized size, do sometimes have small size differences. D batteries should have a nominal diameter of 33.2 mm, give or take a millimeter, and a length that can vary from 59.5 mm to 61.5 mm. This may affect how well they fit in the battery compartment of a device, especially devices that don’t use flexible springs or tabs as connectors.
Q. What items require D-size batteries?
A. When you think of D batteries, a flashlight may be the first item that comes to mind. Indeed, many flashlights require D batteries to run. Other household items that require an extended runtime may also require D batteries, such as a radio, CD player, or boombox.
Q. Can D batteries be recharged?
A. Some D batteries are rechargeable. If you’re interested in this type of battery, you must also own a battery charger that is appropriate for D batteries. Some people try to recharge alkaline D batteries, but this is not cost-effective, and even more importantly, it is unsafe.
