Sanyo Eneloop Batteries Review: The Low Self- Discharging NiMH Cells

Sanyo Eneloop Batteries Review: The Low Self- Discharging NiMH Cells
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Greener Green Batteries

The use of rechargeable batteries is one of the many ways you could green your lifestyle. However, one setback about rechargeable batteries is that, you cannot use them straight from the packet if your need for battery power is immediate. Even the most advanced type of chargers still need 15 minutes of charging to power–up new batteries. Check out these batteries, and know why many consider them as the better source of renewable energy for environmental improvement and cost efficiency.

The following section provides information on how Sanyo Eneloop batteries have several more advantages over all other types of battery cells.

What Makes it Different?

As rechargeable batteries, you can buy them pre-charged and ready to use. They have a low self-discharge capacity, owing to the improvement made in its separator. Sanyo, the major manufacturer of these rechargeable batteries, claims that by improving the separator and the positive electrode, they have made the batteries capable of reducing the rate of battery discharge.

This make them different, as most users of NiMH batteries have often complained that stored charges do not even last long-enough to provide sufficient energy for travel purposes.They are more appropriately described as LSD NiMH or Low Self-Discharging Nickel-Metal Hydride batteries

Proof of their low-discharge ability is evidenced by the fact the NiMH cells were charged at least six months prior to reaching the shelves of battery retailers.These rechargeable batteries are capable of retaining as much as 70% to 85% of their stored power even after more than a year of storage. Most users give satisfactory feedback regarding the long shelf-life claimed by Sanyo Eneloop battery makers.

Explaining the “Low Self-Discharge” Mechanism

Since the key to the advantages of Sanyo Eneloop batteries is their low-self discharge, let us try to understand how this is made possible.

First, one should have an understanding of how the Ni-MH battery is structured. A single rechargeable cell consists of two metal strips; one is the positive electrode, and the other is the negative electrode. An insulator called the separator is placed between these two metal strips and all three layers are coiled together, as they will be placed inside a metal cylindrical container acting as the negative pole for the battery. The metal cylinder is filled with an electrolyte liquid before closing it with a cap. The cap itself has a vent, which allows the release of hydrogen in case of a battery overcharging.

The low self-discharge ability of these NiMH cells is made possible by integrating a super-lattice alloy. The electrical performance of a cell is said to depend on the composition of the electrodes,and how the separator uses the electrolyte. The super lattice alloy increases the electrical capacity of the battery chemistry through less internal resistance in delivering the available voltage output.

Before going any further, we should understand the importance of a low internal resistance or high internal resistance characteristic within the cell. It has been found that low battery power is due to high internal resistance. High internal resistance in batteries is said to be affected by the chemistry within the cell, particularly the composition of the electrodes. A battery may still have a lot of voltage available inside but having a high resistance means the cell will not be able to deliver the required amount of energy, resulting to an external reading of “low battery” capacity.

The said alloy allows the use of less cobalt to stabilize the chemical compound and increase electrical performance. An undisclosed substance used by Sanyo is said to prevent the natural break down of the chemical components that allow low self discharge in a battery cell. To sum it up, the improved chemistry quality, together with the improved ability to prevent chemical disunity or break-up, allows the Eneloop rechargeable batteries to maintain a low self-discharge quality.


800px-Eneloop AA ja on charger

Almost all user reviews are in agreement about the advantages of using this type of rechargeable batteries. There were even those who went as far as testing its charged capacity based on the claim that the NiMH cells can retain as much as 90% even at a stored state. The only dissenting opinion gathered from the test results is that, the cells can only retain up to 75% of stored capacity for more than a year of storage.

Although cost may be the single issue held against it, this issue is common for most eco-friendly products. The savings to be realized is not based on the initial cost in acquiring the green product, but more on the minimized cost for the length of time the product will be used.

Advantages in using Sanyo Eneloop batteries:

  • They can be used immediately upon purchase, and do not require a specific number of hours for the initial charging common to plain rechargeable batteries.

  • You can charge the NiMH cells if you feel you need to fill them up to their maximum capacity, without worrying if they will bust because of overcharging.

  • Their low self-discharge capacity affords the user the convenience of storing as many rechargeable batteries as they need in their most reliable capacity.

  • A single charging can be used many times over, yet remain consistent in its performance. The batteries are said to be capable of providing energy for about 500 camera shots versus an ordinary rechargeable battery’s capability of 100 shots.

  • Ordinary rechargeable batteries have a rate of 500 cycles in the charge/discharge capacity. Eneloop has 1,000 cycles, which obviously means more usage before it finally runs out. This represents a longer life cycle for optimizing the initial cost of investing in these rechargeable batteries, along with its compatible charger.

Some reviewers claim that these NiMH cells can be charged using normal or fast chargers intended for NiMH batteries. While this may be true, the dedicated Sanyo Eneloop charger has a feature that automatically stops the charging process. Once the charger receives signal that the batteries are almost fully charged or reaches the negative delta V status, the dedicated charger automatically shuts off. The manual for the charger states that all batteries be removed once they are fully charged, while the charger itself should be kept unplugged if not in use.

Environmental Impact :

A single Eneloop battery removes 999 disposable batteries from landfills or battery-return collection units due to its 1,000 cycle capacity. A person who consumes as many as 10 rechargeable batteries in a year, will need only five of these NiMH batteries per year. This prevents five plain rechargeable batteries from going to battery-return collection bins or landfills.

If these batteries are used on a global scale, simply multiply 999 by the millions of disposable battery-users; hence, it is possible that a tremendous number of batteries would be eliminated from the Earth’s environmental wastes.