aa-rechargeable-battery

I have considered the Panasonic ‘eneloop’ to be among the best rechargeable batteries for all the years and recharge cycles that I’ve put them under. Especially the rechargeable AA battery.

This battery is ‘Ni-MH’ (instead of alkaline). It uses Low-Self-Discharge chemistry, making it one of the best.

Keep reading for the five reasons why, in my opinion, they’re a great choice. Also read my opinion about the slight voltage difference between the alkaline and rechargeable battery:

AA eneloop
eneloop rechargeable battery, AA size

 

 

Number of recharge cycles

The technology design of the eneloop battery lets them recharge up to 2,100 times!

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

 

There’s no ‘memory effect’

Each battery can be recharged when fully, or partially drained.

Because it’s made of Ni-MH (Nickel-Metal Hydride) it can be recharged at any time without causing a ‘memory effect’.

They can be rapidly charged with any ‘Ni-MH’ style quick charger, smart chargers, plug in charger or universal chargers.

 

Long Storage Life (shelf life)

The eneloop rechargeable Ni-MH battery 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.

Fully charged eneloop battery cells maintain 70% of their charge for up to 10 years (when not in use and stored properly).

 

High Capacity Battery Life

An important thing to know when comparing batteries is their capacity rating.

For the rechargeable AA (and other battery sizes), it’s labeled ‘mAh’. This is how much energy the battery can hold.

The (mA) stands for milliamps. The (h) stands for hour. The rating is milliamp-hours.

This rating (capacity) is like the size of the gas tank in your car. The rating represents how much energy can be stored inside the battery for a full charge.

This is where some tend to differ. The higher the number, the more energy the battery can hold inside.

The Panasonic eneloop rechargeable AA battery is rated for 2,000 mAh, 1,900mAh minimum.

 

Temperature Performance

Most all batteries perform poorly when they’re cold. However the eneloop reportedly performs well in cold temperatures. Evidently delivering great performance down to –4 degree Fahrenheit.

 

Battery Charger for the eneloop battery

When charging the eneloop battery, be sure to use a ‘smart’ battery charger designed for Ni-MH batteries. 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

Read more: Solar Charger For AA or AAA batteries

 

Best 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 are:

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 (to -4F)

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).

AA eneloop (check them out here)

 

 
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

 
Continue reading: Batteries That Will Not Leak Or Corrode

Read more: 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 discharge. This is due to their inherent ‘sloped discharge curve’.

The rechargeable Ni-MH battery has a voltage of around 1.35v when fully charged. However under load they start around 1.2v and they continue to stay around 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.

Regarding electronic gear requiring 4 or more batteries in series, it is apparently rare to encounter a device which refuses to run or power on.

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:

 
Continue reading: Off-Grid Charging System For AA-AAA Batteries, USB