September 28, 2021

Best AA Rechargeable Batteries – The Eneloop – Why I Like Them

aa-rechargeable-battery

I consider the Panasonic ‘eneloop’ to be the best AA rechargeable batteries.

This update confirms that I still maintain this position after many years of use.

The eneloop battery chemistry is nickel metal hydride (NiMH or Ni-MH) rather than alkaline. A Low-Self-Discharge chemistry attributes to making it a great choice.

AA eneloop
(view on amzn)
eneloop rechargeable battery, AA size

Number of recharge cycles

The technology design of the eneloop will recharge up to 2,100 times! That’s another reason why (in my opinion) they are the best AA rechargeable batteries.

Factor in the cost of constantly replacing new batteries. The cost savings of these rechargeable batteries are excellent over time.

A more technical explanation about their superior number of recharge cycles:

Improvements to the conductive surface layer of the active (positive) electrode material (made primarily from nickel-metal hydride) produce greater conductivity and durability.

Limiting the degradation of the conductive layer increases the number of times that the eneloop battery can be recharged. ..up to 2100 times.

-from the manufacturer

No Memory Effect

The eneloop battery can be recharged when fully, or partially drained. It doesn’t matter.

Why? Because of its Ni-MH chemistry.

Charge with a Ni-MH type quick charger, smart chargers, plug in charger or universal chargers.

Long Storage Life (shelf life)

The eneloop is a ‘low self discharge’ (LSD) battery.

When fully charged, shelf life (holding a charge over time) is very long compared to older type rechargeable batteries.

A fully charged eneloop battery cell will maintain ~70% of their charge for up to 10 years (when not in use and stored properly).

High Capacity Battery Life

Capacity rating is an important thing to know when comparing batteries.

The capacity of AA (and other similar batteries) are rated / labeled as mAH, or milliamp hours. This represents how much energy the battery can hold.

This rating (capacity) is analogous to the gas tank in your car…how much fuel can be stored inside.

The higher the number, the more energy the battery can hold inside.

The standard Panasonic eneloop is rated for 2,000 mAh, 1,900mAh minimum. Yet another reason it’s one of the best AA rechargeable batteries.

Temperature Performance

All alkaline batteries perform poorly when they’re cold. However the eneloop performs pretty well in cold temperatures. Reportedly delivering good performance down to –4 degree Fahrenheit.

Tip: For even better cold weather performance, consider Lithium batteries. Though most consumer types are not rechargeable.

Battery Charger for the best AA rechargeable batteries

Be sure to use a ‘smart’ battery charger designed for Ni-MH batteries when charging the eneloop battery. Most modern battery chargers are ‘smart’ these days. But be sure to check.

This is the charger that I’ve been using for many years. I like it because it will recharge 8 batteries at once. It also charges ‘D’ size!

Maha Professional Charger for (8) AA/ AAA/ C/ D type
Maha PowerEx battery charger

If C-type or D-type batteries are not a concern, I recommend the following charger:

La Crosse Technology BC1000
(view on amzn)

[ Read: Solar Charger For AA or AAA batteries ]

Best AA Rechargeable Batteries – SUMMARY

The AA battery size is the most common consumer type used in portable radios, LED flashlights, and much more. The reasons that I believe this battery to be one of the best rechargeable batteries include the following:

1. High number of recharge cycles (2100)
2. No memory effect
3. Low self-discharge (long shelf life, 10 yrs.)
4. High capacity battery life (1,900 – 2,000 mAH)
5. Good low-temperature performance
6. My years of experience with the eneloop

Plus, it has the best overall reviews.

Note: In case you were wondering, they’re made in Japan.
Note: I have been using these for many years, and couldn’t be more pleased.

Panasonic (the ‘eneloop’ battery) has been an industry leader in Ni-MH battery technologies. They produces quality cells in consumer sizes (including the popular AA, AAA).

To save some money per battery, you can also purchase in bulk:

(24) AA eneloop
(view on amzn)

I really like this AA battery storage case. Years ago I bought a handful of them. Weather resistant, great to toss into a pack, camping, or whatever:

Rugged AA Battery Storage Case
Storage Case for 8 AA batteries

[ Read: Batteries That Will Not Leak Or Corrode ]

[ Read: Battery Corrosion, Why They Leak And How To Prevent It ]

Voltage Difference Between Alkaline and Ni-MH

Regarding the the battery voltage difference between alkaline and Ni-MH rechargeable batteries:

Alkaline batteries have a voltage of around 1.5 – 1.6v off the shelf. However they quickly drop to around 1.25v under actual load. They drop further over time to around 1v when almost discharged. This is due to their inherent ‘sloped discharge curve’.

Eneloop Voltage Discharge Curve

(source)

The rechargeable Ni-MH battery has a voltage of around 1.35v when fully charged. However under load they start around 1.2v but they continue to stay at 1.2v until the battery is almost fully depleted.

So under these typical conditions, there’s little or no effective difference between the two while under load (in my opinion).

Regarding electronic gear requiring 4 or more batteries in series, it is apparently rare to encounter a device which won’t operate or power on. Though always refer to the manual of any given product for recommendations.

Additionally most electronic gear design and manufacturers take into account the voltage characteristics of rechargeables.

That said, if the instructions say no rechargeable batteries, then it means the device will be slightly under-powered due to the device design.

…hope this helps.

 
This post has been updated with new information since it’s original publish date. Add your own comments and opinion below:

[ Read: Off-Grid Charging System For AA-AAA Batteries, USB ]

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