Duracell Coppertop AA alkaline battery
| [ | Date | | | 2019-01-10 22:58 -0500 | ] |
| [ | Mod. | | | 2019-02-28 12:47 -0500 | ] |
Duracell Coppertop AA alkaline battery
It always seemeed to me that all the "information" that came with name-brand batteries was pure marketing hype, and no technical descriptions, or even any precise claims were available. This is at least true on the packaging: I didn't see any mentions of mAh capacities, or any specifics, there, be it for Energizer or for Duracell. While I understand that alkaline batteries can be expected to be higher-capacity than salines, and lower-capacity than lithium, for example Duracell has at least two sub-brands of alkaline AA batteries; the classic copper and red "Coppertop" and a newer type, copper and red, named "Quantum":
Coppertop Battery
Get dependable, long-lasting power from Coppertop batteries.
These batteries have been engineered to deliver the power you need for all your household devices.
— Duracell on the Coppertop
Quantum Battery
Duracell Quantum Alkaline batteries give you a one-of-a-kind Quantum Leap in Power. It’s the only battery with Hi-Density Core™ technology featuring more power boosters
— Duracell on the Quantum
"More power boosters" definitely sounds like snake oil.
It turns out that Duracell does publish proper technical documents describing their products! That includes a third sub-brand, "Procell", apparently aimed at professionals. From there, we can extract proper figures and compare alkaline batteries:
| Name | weight (g) | mAh@25mA | mAh@100mA | mAh@500mA | mAh@1A |
|---|---|---|---|---|---|
| Coppertop | 24 | 3000 | 2700 | 1650 | 1250 |
| Quantum | 24 | 3125 | 2900 | 1900 | 1400 |
| Procell | 24 | 3000 | 2450 | 1375 | 1000 |
| Energizer | 23 | 3000 | 2600 | 1600 | 1000¹ |
Capacities are based on discharging until the voltage reaches 0.8V at 21°C (this appears to be an industry standard). The numbers are approximated to how best I could read the graphs since neither manufacturer gives a table. The first three brands, Coppertop, Quantum, and Procell, are Duracell.
From this, we can see that all four brands of alkaline battery have nearly identical characteristics, with the "Quantum" variation giving a very modest premium in capacity (about 4% at low intensities, up to about 10% at 1A).
When AA lithium batteries first came out, they seemed so incredibly expensive that I chose to completely ignore them. The fact that the apparent absence of published numbers meant that I didn't think I could decide whether they were worth the price. Behold:
| Name | weight (g) | mAh@25mA | mAh@100mA | mAh@500mA | mAh@1A |
|---|---|---|---|---|---|
| Energizer | 23 | 3000 | 2600 | 1600 | 1000¹ |
| Ultimate Lithium | 15 | 3500 | 3500 | 3500 | 3250 |
¹: Based on my reading of the comparative graph in the Ultimate Lithium datasheet.
The lithium battery has a nearly-constant capacity of 3500mAh up until about 500mA, where a very slight drop occurs, down to 3250mA. While its capacity is higher than that of an alkaline, the difference is especially marked for high-power applications, where they can last about threen times as long as an alkaline. Indeed, the datasheet for the Energizer AA Ultimate Lithium battery indicates that a single battery can discharge continuously at up to 2.5A, or can deliver 4A bursts two seconds every 10 seconds.
On 2019-01-10, amazon.ca stocked stocked the Energizer AAs at about $45 for 24 lithiums (bestbuy.ca: $15 for 12), and alkalines at $16 for 24 (bestbuy.ca: $20). That is an average of $1.56 per lithium AA battery, and $0.75 per alkaline AA battery; a factor slightly above 2.
Lithium AA batteries are monetarily a good deal for applications where their effective capacity is at least twice that of alkalines, which means above about 500mA. (This assumes that one would buy brand-name alkalines, whereas many lower-cost alternatives exist for non-lithium AA batteries; for example, AmazonBasics AAs were available at $15 for 48, another factor of two over Energizer alkalines, making the lithium's break-even point beyond 1A.)
Even for applications where lithiums do not truly shine, one could value the time saved by not having to replace batteries quite as often above the strict monetary cost of the items, and choose to buy them for this reason avoided inconvenience alone. Reduced weight, by a factor of about one-third, may also be a reason.
The same, for AAA batteries.
Quick links:
David Haguenauer
<www@kurokatta.org>
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