Michael Bluejay's

Your guide to types of household batteries (AAA, AA, C, D, and 9V sizes)

Which kind of battery is best for which purpose?

	Rechargeable				Disposable
	Nickel-Metal Hydride (NiMH)	LSD NiMH (low self discharge)	Nickel-Zinc (NiZn)	Rechargeable Alkaline	Alkaline	High-Drain Alkaline	Lithium (not lithium ion)	Carbon Zinc, Zinc Chloride "General Purpose" "Heavy Duty"
Summary	Good for most uses, except where you need long shelf-life.	Good for most uses, including needing long shelf life.	Good for devices which benefit from extra voltage (e.g. digital cameras), but the high voltage could burn out lights & fry electronics. Also, very short cycle life.	Longest shelf life of any chargeable, so it's good when batteries aren't replaced often, e.g. clocks & radios. But capacity drops each cycle, and prone to leaking.	Cheap, widely available, but usually can't be recharged, and can leak. Good for low-drain devices.	Not recommended for most uses. If you've got a high-drain device, a rechargeable is probably better, so you don't have to keep buying batteries.	Powerful, but can't be charged, and small risk of explosion. NiMH or HD Alkaline are usually better. Great in smoke detectors: Ultralife brand lasts up to 7 years.	Cheapest & least powerful. Good only for low-drain devices like clocks and remote controls.
Use is for Digital Camera or other high-drain device						(These 2 are okay, but since cameras go through batteries fast, you're better off with a rechargeable battery that you can reuse.)
You go through batteries quickly
You want more than 50 deep-discharge cycles (i.e., you fully use up the battery before charging)
Use is for low-drain devices (clocks, remote controls, blinky lights)
You want the brightest light from your flashlights or headlamps	see note 1		see note 2
You're worried that excess voltage could fry your device
Long shelf-life (i.e., want the battery to hold a charge after months of non-use)
You don't want to risk a battery leaking in your device
You want to use the C or D size ?				Rare; see sources
For use in smoke detectors		see warning		see warning
You want the cheapest battery and don't care how long it lasts
Need to use in cold temperatures	Works well down to -4° to 14°F, depending on brand.			Performance often noticeably worse below even 60°F, depending on brand/variety and rate of discharge. (source)				voltage & current ok, but capacity so low it's irrelevant
Want to recycle them when they're dead	Over 30,000 locations in U.S. & Canada such as Sears, Office Depot, Home Depot, Target, Wal-Mart, Best Buy, and others (find nearest)			Drop-off recycling for these kinds of batteries is nearly non-existent. You generally have to mail in your batteries to recycle them.

Which battery should I use?

To make it simple, you can just use Imedion LSD NiMH's by Powerex, which are good for just about any purpose, along with a good charger.

For smoke alarms, use either the Lithium brands that are marked "7-year" or "10-year", or if you want a rechargeable, see my smoke alarms page for details and warning.

For low-drain devices like clocks, alkalines are acceptable, since they'll last a long time in clocks, so their lack of recharging ability isn't such a big downside (although personally I still use LSD NiMH for that application).

Which brand of battery is best?

NiMH: Powerex Imedion; beware of off-brand batteries

My favorite AA is the Imedion by Powerex. It's a good balance of capacity (2400 mAh), charge cycles (500), and low self-discharge rate (retains 85% after one year). The only downside is that they're slightly larger than regular AA's, so they might not fit in your device. If they don't, then my next recommendation is eneloop XX (similar to Imedion but a little pricier), or regular eneloops, which are cheaper but have only 2000 mAh.

That's the summary, but I have a whole page on NiMH battery brands (including a snazzy table comparing all the flavors of eneloops).

ALKALINES: Anything

You won't get lots better performance by buying one company's alkaline battery over another. "But what about the Energizer Bunny?!" you cry. Well, it makes a good commercial, but capacity is pretty similar from one alkaline maker to the next, according to the findings of Consumer Reports, ZBattery.com, and Lauri Nieminen. But alkalines are probably the wrong battery for the job anyway. For most uses you're better off with NiMH rechargeables, since the charging ability means you can stop buying batteries, and because NiMH's work better in high-drain devices like digital cameras anyway.

Household Battery Types Compared (AAA, AA, C, D, and 9V)

	Rechargeable				Disposable
	Nickel-Metal Hydride (NiMH)	Nickel-Zinc (NiZn)	Nickel-Cadmium (NiCd)	Rechargeable Alkaline	Alkaline	Lithium	Carbon Zinc, Zinc Chloride "General Purpose" "Heavy Duty"
The Basics
Summary	Good for most uses.	Good for devices which benefit from extra voltage (e.g. digital cameras), but the high voltage could burn out lights & fry electronics. Also, possible reliability problems. Requires special charger.	Obsolete. Low capacity and toxc. Go with NiMH or NiZn instead.	Lowest self-discharge of any rechargeable, making it good for devices where batteries are replaced infrequently, like clocks and radios. But the capacity drops every time it's charged, and prone to leaking.	Cheap, widely available, but usually can't be recharged, and can leak. Good for low-drain devices.	Powerful, but can't be charged, and small risk of explosion. NiMH or HD Alkaline are usually better. Great in smoke detectors: Ultralife brand lasts up to 7 years.	The cheapest (and least powerful) batteries available. Good only for low-drain devices like clocks and remote controls.
Sample Brands	Low Self Discharge: eneloop, Tenergy, Duracell, Kodak (rebranded GP Recyko), Rayovac Non-LSD: Sanyo/ Panasonic, Duracell	PowerGenix (the only name-brand), but discontinued anyway. Generics are available on eBay	Golden Power (NiCd is obsolete.)	Juice, Pure Energy, Lenmar Chargeables, Accucell (just these 4)	Normal: Energizer, Rayovac High-Drain: Energizer e2 Titanium, Kodak Photolife, Duracell Ultra	Energizer Ultimate Lithium, Energizer Advanced Lithium	usually a no-name brand
Where to Recycle	Over 30,000 locations in U.S. & Canada such as Sears, Office Depot, Home Depot, Target, Wal-Mart, Best Buy, and others (find nearest)			Drop-off recycling for these kinds of batteries is nearly non-existent. You generally have to mail in your batteries to recycle them.
Other important info
Capacity	High	High	Low	High at first but less each cycle	High	High	Low
Performance in high-drain devices (e.g., digital cameras)	Very Good 1.8x more pix than standard alkalines	Excellent	Poor (because capacity is low)	Poor	STANDARD: Poor HI-DRAIN: Good 1.4-2.5x more pix than standard	Excellent 3-13x more pix than standard Alkalines	Super Poor
Self-discharge rate (calendar life if not used)	LSD NiMH: Slow-Medium (retains 75% after 1, 2, or 3 years depending on brand) Non-LSD NiMH: Fast (loses 15%/mo)	Fast (loses 13%/mo.)	Fast (loses 10% in 1st 24hrs, then 10%/mo.)	Very Slow (<0.5%/mo.; shelf life 5-7 years)	Very slow (retains 80% capacity after 5-7 years)	Very slow (loses 0.6% per year; 7-15 year shelf life)	Slow (retains 80% capacity after 3-4 years)
% of capacity avail. when used at freezing temps (0°C), instead of room temp.	91%	(researching...)	(researching...)	35-75% (more capacity lost at higher drain rates)	31-75% (more capacity lost at higher drain rates)	82-98% (more capacity retained at lower drains)	100%
Temperature range (use)	-4F°-122° F (0°-50° C)	-4° to 140° F (-20° to 60° C)	-22° to 140°F (-30° to 60°C)	-4° to 140°F (-20° to 60°C)	0-131°F (-18° to 55°C)	-40° to 140°F (-40° to 60°C)	0° to 130°F (-18° to 55°C)
Self-discharge is slowed by freezing or refrigeration?	Yes (10% loss after several months)	(researching...)	(researching...)	No, and doesn't matterâ€”long shelf life already	Not really, and doesn't matter -- long shelf life already	Doesn't matter -- long shelf life already	Doesn't matter -- long shelf life already
	Nickel-Metal Hydride (NiMH)	Nickel-Zinc (NiZn)	Nickel-Cadmium (NiCd)	Rechargeable Alkaline	Alkaline	Lithium	Carbon Zinc, Zinc Chloride "General Purpose" "Heavy Duty"
Capacities. Comparing mAh/mWh specs isn't really an apples-to-apples comparison because real-world performance differs. See "Performance" above for a better idea.
Capacity (AAA) varies by brand	Normal: 750-1200mAh LSD: 800 mAh	700 mAh	300-800 mAh	800 mAh	1077 mAh	1100-1250 mAh	325-550 mAh
Capacity (AA)	Normal:1200-2700 mAh LSD: 2000 mAh	1350-1500 mAh but capacity drops sharply as cells are cycled	600-1000 mAh	1440-2000 mAh but drops each cycle	2400 mAh	2100-3000 mAh	500-1100 mAh
Capacity (D)	2200-12,000 mAh eneloop C & D available only in Japan	not made in this size	1800-5000 mAh	8000 mAh at first	13,875 mAh	not available in this size	3000-6880 mAh
Recharging
Rechargeable?	Yes	Yes	Yes	Sort of*	Not really	No	No
Recharge cycles (deep)	Normal: 100-1000 LSD: 500-1500	100-800, claimed ~10, my opinion	500-2500	25-100 with less capacity each time	<10	N/A	N/A
Memory effect	No	No	No, but overcharging reduces capacity	No	No	N/A	N/A
Miscellaneous
Initial Voltage	1.2 V	1.65 V (1.85 at first)	1.2 V	1.5 V	1.5 V	1.5-1.8 or 3.6 V	1.5 V
Weight (AA)	30g	25g	22g	22g	23g	14.5g	Heavy Duty: 15g
Commonly available since...	Non-LSD: ~2000 LSD: 2005	2009	(researching...)	1994	1960's	1990's	(researching...)
Sample spec sheets	Energizer AA	(researching...)	(researching...)	Juice	Energzer AA: Regular, High-Drain,	Energizer Ultimate Lithium,	Eveready AA (HD)
Typical price for 4 AA	$8.22	$16.50	$5.97	$6.00	$3.78	$9.97	$1.29

Notes on the Table: Lithium-ion. Lithium-ion is another kind of rechargeable but it doesn't fit in the table, though it's not available in standard voltages anyway, except for 9V. See my Lithium-ion and 9V batteries sections for more. Volts. The lower voltage of NiMH's & NiCD usually isn't a problem unless your device takes â‰¥4 batteries and it's not designed to take rechargeables. The higher voltage of NiZn and Lithium might fry your device, especially if your device takes â‰¥4 batteries, especially if it's designed to take 1.2V NiMH's or NiCD's instead of 1.5V alkalines. See the Battery TIps page. Capacity. (1) Varies by brand. (2) Capacity is misleading because different kinds of batteries perform differently under different kinds of loads, so you can't compare the mWh ratings on a 1:1 basis. For example, a standard alkaline in a high-drain device will supply less than half of its rated capacity. (Energizer PDF, p. 5) (3) In general, higher drains mean less capacity (e.g., doubling the draw means less then half as much capacity). (4) Most figures are rounded. Recharge cycles (aka "Cycle Life"). The number of times the battery can be deeply drained (down to around 1.0V) and then recharged, and still have at least 60% of its original labeled capacity. NiMH upper limit from Sanyo eneloop specs. Self-discharge rate. How quickly the batteries lose their charge just sitting around, unused. "LSD" refers to the "Low Self-Discharge" versions of NiMH, such as Sanyo eneloop. Percentage decline each month is in terms of the initial charge, not the remaining charge that month. Prices. Pricing is from Home Depot 2012 except for Walmart for NiZn, and Sundance Solar and Rechargeable Alkaline. CheapBatteries.com may have cheaper pricing. Sources. See my sources page.

Other battery resources

Brand Comparison. Lauri Nieminem's charts comparing different brands of disposable batteries. (There's not a big difference between manufacturers, but there are big differences between battery types.)
Battery University. A whole site dedicated to educating people about batteries.
Battery size, weight, and energy specs from All About Batteries
Energizer Technical Data. The specs on every kind of Energizer batteries.
Energizer Alkaline Battery FAQ (PDF). What it says.