Rechargeable Battery Data Sheets

A Rechargeable Battery Data Sheet or Specification Sheet is intended to represent factual information about the product. It attempts to describe the product and may provide information such as:

• Rechargeable battery product physical description possibly including dimensions.
• Rechargeable battery performance limitations ( how long it is expected to last ).
• Rechargeable battery performance expectations ( how it is supposed to perform ).
• Rechargeable battery applications ( where or how to use the product ).
• Rechargeable battery exclusions ( where or how NOT to use the product ).
• Rechargeable battery product warranty or guarantee.

Generally speaking, a Data Sheet or Specification Sheet is derived from the product specification. In many cases, these documents are created in the design process and are based on how a product is intended to perform. It may also contain information from tested samples such as prototypes or initial production samples.

That being said, a Rechargeable Battery Data Sheet or Specification Sheet may not accurately describe a rechargeable battery product if it is not updated regularly. Many factors can affect product functionality and performance as described in a Rechargeable Battery Data or Specification Sheet such as:

• Quality and consistency of products from suppliers used in the rechargeable battery product;
• Quality of the rechargeable battery manufacturing facility and technology;
• Quality and consistency of the employees and the rechargeable battery production process;
• Errors in the original rechargeable battery product design;
• Undocumented changes between prototype and production phases;
• Undocumented changes between production versions or batches;

Various types of customers are the intended reader of these Rechargeable Battery Data or Specification Sheets. They are not intended for the general consumer. If they were, the same information would be written somewhere on the packaging or included inside with the batteries. The way these documents are written is entirely up to the manufacturer and information may be omitted or presented as they see fit.

In an ideal world, the Rechargeable Battery Data or Specification Sheets would describe a product in a way that is clear and precise. The reader would have a clear understanding of how a product performs and would know its limitations. This is not always true and the reader will often be left with questions as information presented might be vague, intentionally unclear and even missing.

Note the use of words in datasheets. As an example of what is unclear, look up the word “nominal” and how it might apply to a data sheet.

• nominal: named as a mere matter of form, being trifling in comparison with the actual value; minimal.

The following examples do not make any attempt to discredit the products or companies mentioned. In reality, the existence of rechargeable battery data sheets shows a sincere effort to provide real technical information to those that are interested.

GP AA 2700 mAh NiMH Battery Data Sheet Example

The GP 2700 AA NiMH Data Sheet can be found here. GP270AAHC-r0.pdf

Its nominal and minimum are both 2500mAh and the typical is 2600. So, when this datasheet says typical, what does that mean? Is it 2600 +/- 5%, 2600 +/- 10%, 2600 +/- 2%? This is an example of being vague.

In this case, we assume it is a 2700 mAh rechargeable battery, but there is no mention of it in the data sheet. We also assume the the typical is 2600 mAh plus or minus 100 mAh, but it is not really stated.

The graph and the table says 0.2C is 500 mAh. Therefore 1C = 0.2C x 5 = 2500 mA and that means this is a 2500 mAh rechargeable battery. When is it ever a 2700 mAh battery? An interesting question could be, how often is it a 2700 mAh rechargeable battery? 5% of the time, 10% of the time? How often is it a 2650 mAh rechargeable battery? How often is it a 2600 mAh rechargeable battery?

Some interesting questions you could ask yourself:

• If this is an AA 2700 mAh rechargeable battery ( according to the label ), shouldn’t the typical or maximum capacity be 2700 mAh?
• Is 2700 mAh just the expected design value?
• Charging is recommended at 250 mA which is less than 0.1C ( 0.1 x 2700 = 270 ) ?
• Service life is greater than 500 cycles and it is stated that it was determined by the IEC standard.
• If the IEC standard was used for the cycle test, was it used for the capacity test? No “IEC Standard” claim is made beside the capacity test?

Disclaimer:

The information (subject to change without prior notice) contained in this document is for reference only and should not be used as a basis for product guarantee or warranty. For applications other than those described here, please consult your nearest GP Sales and Marketing Office or Distributors.

Do you get that? If you are not using this rechargeable battery at a charge rate of 0.1C ( 250mAh ), or charging from 0.5C to 1C or a discharge rate of 0.2C ( 500 mAh, and not 2700 mAh ), please consult your nearest ......

That is not real life.

Sanyo AA 2500 NiMH Battery Data Sheet Example

The Sanyo Sanyo_HR-3U-2500 AA NiMH Data Sheet can be found here.

The Sanyo datasheet shows constant current discharge of 2C, 1C and 0.2C.

The datasheet table states that the typical capacity is 2500mAh and that the minimum capacity is 2300mAh at 0.2C. Notice the graph shows the 0.2C discharge at 2300mAh! Sanyo states a good honest range in the table and there's no Disclaimer.

There is also no mention of the number of life cycles or service life.

There is no mention of an IEC or any other standards testing used.

Vapextech AA 2700 NiMH Battery Data Sheet Example

The Vapextech 2700 mAh AA NiMH Data Sheet can be found here.

Its nominal is 2700mAh, the minimal is 2500 mAh and the typical is 2550 at 0.2C. It seems that the word nominal should be replaced with the word maximmum. Why can't the description typical be accompanied by a qualifying statement giving it a real meaning? In this case the 2550 mAh typical is 2% above the minimal of 2500mAh and the nominal of 2700 mAh ( or maximum ) is 5.8% above the typical.

Some interesting questions you could ask yourself:

• Service life is greater than 500 cycles and it is stated that it was determined by the IEC 61951-2 standard.
• If the IEC standard was used for the cycle test, was it used for the capacity test? No “IEC Standard” claim is made beside the capacity test?