Best Rechargeable Batteries AA Size

by Braxton Taylor

The best rechargeable batteries AA size, in my opinion, are the eneloop (Made in Japan by Panasonic). Okay, being fair, one of the best.

Especially for their reasonable price point, features, and established decade+ excellent history, here’s why I like them, and why you should too.

Now in their 5th generation design (since 2022), I can absolutely vouch for the eneloop – which I first began to purchase during 2011 (3rd generation), just prior to the Sanyo acquisition by Panasonic.

A dozen years since their introduction, I’ve used all generations of their batteries. My opinion has not changed. Are you looking for AA rechargeable batteries? Allow me to try and convince you about these.

eneloop batteries AA

The eneloop battery chemistry is nickel metal hydride (NiMH or Ni-MH). One important ‘claim to fame’ is their low self-discharge (while resting ‘on the shelf’ waiting for use). More on that in a minute..

By far, the most popular eneloop AA is the gen 4, which was first introduced during 2013. It has been their work horse ever since.

View eneloop gen-4 on amzn:
4-pack
8-pack

How to identify which generation eneloop AA batteries that you might have

Locate the part number on the battery. Also, generation 1, 2, 3 indicate Sanyo. Gen 4 and beyond indicate Panasonic.

  • Gen 1 (HR-3UTG)
  • Gen 2 (HR-3UTGA)
  • Gen 3 (HR-3UTGB)
  • Gen 4 (BK-3MCC)
  • Gen 5 (BK-3MCD)
How to identify which generation of eneloop batteries

For the differences between them, check this Wikipedia page.

Number of recharge cycles (eneloop gen-4)

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

Let me put that into perspective. If you used up and recharged this battery once a week, its lifetime would be 40 years! Once a day? Almost 6 years!

Just think how much it would cost to keep buying new batteries.

Improvements to the conductive surface layer of the active (positive) electrode material 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

Low Self Discharge

Rechargeable batteries will slowly self discharge and lose capacity over time during idle storage, just sitting in the drawer between charges. The eneloop has improved upon this throughout each generation cycle.

Sure you can recharge them back up to 100% before you use them, but it’s nice to know that you can grab a pair out of the drawer and their still 90% full after a whole year.

The current mainstream eneloop gen-4 rechargeable battery maintains the following idle-time capacities over time. That’s pretty darn good!

  • 90% at 1 year
  • 80% at 3 years
  • 75% at 5 years
  • 70% at 10 years

eneloop rechargeable AA batteries – Capacity

Capacity is the amount of stored energy the battery can hold when its fully charged.

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

The capacity of AA (and other similar batteries) are rated and labeled as mAh, or milliamp hours. They are measured by testing them at a standardized discharge rate. Typically 25, 100, 250, and 500 mA (milliamps).

For example, a 2,000 mAh battery may run a 500 mA load for 4 hours, depending on its rated results.

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

The eneloop gen-4 is rated for 2,000 mAh, 1,900mAh minimum.

Incredibly, their spec. sheet (link) graphs nearly 2,000 mAh capacity at a heavy load of 500 mA discharge rate. That even beats the Energizer Max (non rechargeable) which specifies (link) approx. 1,500 mAh at that rate.

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 them with a Ni-MH type smart charger.

eneloop 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.

[ Read: Lithium AA Batteries vs Alkaline ]

Battery Charger for eneloop rechargeable batteries AA size

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.

I have two nice chargers for thise. One that holds 8 AA batteries, while the other holds 4.

The following 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 ‘C’ and ‘D’ size! Right now it’s in my primary EMP protection, just in case.. I love this charger.

Powerex Maha MH-C808M
(amzn)

Powerex Maha MH-C808M battery charger

I purchased the following battery charger a few years ago. I like it. It’s the OPUS BT-C3400. It has additional test features that battery geeks may like (grin). It has been my ‘go to’ charger, setting on my desk (next to a Baofeng charger).

[ Read: Baofeng Extended Battery ]

(view OPUS features on amzn)

Opus BT-C3400 battery charger

If you’re just looking for a decent no frills smart charger for these eneloops, just browse the Panasonic chargers on amzn (specifically linked here).

[ Read: Solar Charger For AA or AAA batteries ]

Best Rechargeable Batteries AA – 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 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
7. Good price

Plus, it has the best overall reviews.

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

Malamute Rugged AA Battery Storage
(amzn)

Rugged heavy duty AA battery case

Voltage Difference Between Alkaline and (Ni-MH) AA rechargeable batteries

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’.

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).

Eneloop Voltage Discharge Graph – Curve

Check the manual of the product that takes AA batteries. If the instructions say that rechargeable batteries are not recommended, then it means the device will be slightly under-powered due to its design. Just use Energizer Max instead 🙂

[ Read: Batteries That Will Not Leak Or Corrode ]

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

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

Read the full article here

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