In this entry, I will be focusing only on primary, or non-rechargeable types. I will be following up to talk about rechargeable batteries in the near future. Despite in the leaps in improvement and reduction in cost of rechargeable battery chemistries, I believe that there is still a place for non-rechargable batteries in this time for the reasons of cost, capacity and dependability.
Here, I will discuss the situations and devices that will be best suited for the these 3 common battery chemistries - Carbon Zinc, Alkaline and Lithium.
Powering up many (really low drain) devices at Low Cost - Carbon Zinc
For devices that require intermittent usage across many many months
Really cheap stuff. Its ironic that the 'heavy duty' marketing speak is used here. It might have been worthy of heavy duty tasks during its hay days but time isn't too kind on old technology. Expectations have changed.
Sure, rechargeables cost next to nothing to run after the initial cost of buying the batteries and a good charger to go along. The price of electricity to charge them up during their entire lifespan is negligible compared to buying new cells all the time. But there are times when we need a lot of batteries for several low power items such as remote controllers. My home has at least 6 controllers for my TV, sound system, and other appliances. These controllers sip very little energy and can last for several years on a pair of AAAs or AAs.
Carbon Zinc types (those that are sold as 'General Purpose', 'Heavy Duty' and 'Extra Heavy Duty') are very economical. SG$1 can get a pack of 8 AA or AAA. They have the lowest capacity compared to the other two options but they can still last a good amount of time if used in low drain devices such as clocks, remotes and small toys.
High Capacity (at low drain) - Alkaline
For devices that gobble up batteries in several days to weeks
I re-purposed these Geonaute alkaline batteries from a headlamp I bought from Decathlon. The headlamp was starting to lose its brightness and the batteries were probably half depleted when I re-purposed them. They can still last a really long time in a low drain device like this remote controller
The reason why all battery manufacturers do not state the capacity of non-rechargeable battery is because the capacity of non-rechargeable batteries greatly depend on the rate of power use. Typically, the higher the power needed, the less capacity the battery is able to deliver.
There is a short period of time when some digital cameras used AA sized batteries and rechargeable batteries were still not really there yet. People brought loads of Alkaline batteries to power up their cameras on holiday. These cameras, with their energy guzzling LCD screens, tend to last about an hour of continuous usage on a set of 4 AA batteries. It was expensive to sustain a digital camera and these were pushing the limit of Alkaline batteries.
According to Energizer's datasheet, a AA battery can provide up to 3000mAh of energy if it was used in a device that required a constant current of 25mA. Its capacity can drop to half of that if used at 1500mA. Practically speaking, many portable devices drain at a rate between 25mA to 500mA. For a general idea of how long a AA battery can last at these rates:
At 25mA the battery will last 120 hours,
At 500mA, only 3 hours.
Naturally, I try to use alkaline batteries in sensor lights, slow motorised toys and stove igniters. In general, I put them in low-medium drain items that does not require frequent re-loading of batteries.
Dependability - Lithium
When you really need it to work in a very expected and reliable manner (compared to other non-rechargeables)
Lithium non-rechargeables are the most expensive battery type and they cost just a hair less than its equivalent NiMh sizes and in recent years, Lithium-ion of similar capacity have also gotten quite competitive in price.
A pack of 4 AAs cost a whopping SG$17.80 at NTUC Fairprice, a local supermarket in Singapore. A few dollars more and you can buy a nice pack of NiMH rechargeables.
Nevertheless, for its weight and size, it packs a lot of energy. A single Lithium AA battery holds about 3500mAh but unlike the cheaper Alkalines, its capacity is less dependent on the rate of discharge. This means that it is possible to make full use of its capacity even at high discharge rates of 1000mA (Source: Energizer L91 datasheet).
For comparison, for a device that draws a constant 1000mA,
Lithium AA: 3.5h
Alkaline AA: 1h
I haven't bought AA/AAA sized Lithium battery in years. I find that almost everything I need from non-rechargeable Lithium batteries can be met by NiMH rechargeables.
My most recent Lithium battery purchase was a uniquely shaped CR223 battery that my old camera, Nikon F601 uses. Lithium batteries are still widely used by film cameras and there is no non-recharegable equivalent in other chemistries. Some of Fujifilm's instant film cameras use a very small CR2 lithium battery for power. These Lithium batteries are great at giving cameras a consistent performance particularly for flash photography and high frame rate shooting.
A common photo battery is the CR123. Shown inside my compact film camera
I'm happy that most battery manufacturers still churn out odd sized batteries that keeps my old cameras alive. Had my old cameras used some proprietary rechargeable battery, it would be extremely difficult get my hands on them.
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