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How We Test Batteries

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All our battery tests are done using the Ultimate Battery Analyser (UBA4) which allows for very accurate and repeatable routines to be defined and results to be recorded.

All the batteries go through at least three stages and will ultimately have a fourth and fifth stage added when time permits.

Stage 1 - Battery Conditioning

All rechargeable batteries can take 3 or 4 charge cycles to settle down, often giving a very low capacity in one of the first runs, because of this we put all the test batteries through a 5 cycle charge/discharge routine. This ensures all the batteries are in a known condition before we start the real testing.

Stage 2 - Typical Usage Test

The UBA4 allows us do define some very complex charge and discharge routines, so we have taken a Kodak DC240 camera, measured the current usage of taking a typical photograph and created a routing that simulates this process. This routine is applied to a battery and repeated continuously until the battery reaches 0.9V. The number of times the routine repeats equates to the number of photographs you would expect to take.

It's not perfect and the Kodak camera uses 4 batteries, is quite frugal with the battery usage and gave a lot of pictures, but it is a good comparative reflection of the performance of and particular battery. Here are the stages:

  1. Camera On
  2. LCD On
  3. Focus
  4. Take Photo With Flash
  5. Write to Card & Charge Flash
  6. LCD Off
  7. Camera Off

Stage 3 - Typical Cycle Life Test

In this test we run the battery through a full charge and discharge cycle using quite aggressive charge and discharge currents, this is repeated for 100 charge/discharge cycles to see how a batteries capacity changes over time. We chose 100 cycles, because not only is it a nice round number, but this represents about 2 years of use when charging your batteries weekly and about 8 years for those who only charge the batteries once a month. It seemed to us that most people would feel like they had had their moneys worth after this sort of length of time.

Because we are using an aggressive charge and discharge current the reported capacities are lower than those declared by the manufacturers. This should be expected as their capacities will be based on laboratory conditions designed to maximise the reported figures or on IEC standard conditions which are less stressful on the batteries.

There are 2 reasons for using this technique, firstly it allows the tests to run more quickly, but secondly we believe it better represents how the batteries will be used in real life.

Stage 4 - Comparative Discharge Test

This effectively takes a standard 1.5A discharge current from the batteries and all the data is plotted on a graph to get a consistent comparison between each of the batteries. this differs from the normal cycle life tests which are based of a discharge current of 0.5C (half the batteries reported capacity), so for a 2600mAh battery that would be 1.3A and for the 1800mAh battery that would be 0.9A.

Stage 5 - Absolute Cycle Life Test

This is not something we have implemented yet, but will basically keep charging and discharging the batteries until the capacity drops to a level of about 50% of the manufacturers quoted capacity. we may take this further, but as the test will take several weeks to run a battery, it may be a while before we get round to it.


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