How much longer bigger batteries last
Does a D-cell battery last twice as long as a C-cell battery, or four-times as long as a AAA?
These were the office questions which inspired our latest battery test.
MyBroadband recently conducted tests on numerous brands of batteries to determine the best-value AA battery in South Africa.
Following this test, we wanted to find out the lifespans of different size batteries.
Specifically, we measured how long AAA, AA, C, and D batteries from the same manufacturer would last.
MyBroadband used a computerised battery analyser (CBA) to provide a controlled and accurate endurance test. The CBA connects to a PC to test batteries, providing an analysis of the results.
The results
For the tests, we used a CBA IV – which is designed to test small cells and batteries.
The CBA IV is capable of testing batteries at load currents from 10mA to 40,000mA. Our tests discharged the cells at a rate of 200mA to ensure accuracy.
To see how long it took for a battery to go flat, we tested the time it took for each type of battery to drop below their suggested cut-off voltage limit.
AAA, AA, C, and D Energizer Max alkaline batteries were used in the tests, and their “lifespans” compared.
The results – as detailed in the tables below – show a notable increase in battery life relative to the increase in size of the battery.
All battery tests used a initial test voltage of 1.5V.
| Battery | Time on 200mAh |
|---|---|
| AAA | 1 hour 7 minutes |
| AA | 6 hours 28 minutes |
| C | 18 hours 9 minutes |
| D | 36 hours 3 minutes |
It must be noted that the Energizer Max D battery experienced a voltage fluctuation during the test, which may have been caused by extraneous environmental conditions.
Its test was then stopped at 1.148V, due to the battery reaching its “double the lifespan of a C-cell battery” target.
Minutes per rand
The table below shows the “minutes per rand” value of each battery, which provides an indication of the effective value consumers receive.
The fact that different devices are only compatible with certain batteries, and that smaller batteries are lighter and more convenient, was not taken into account.
Pricing from Loot was used in the comparison.
| Battery | Price per battery | Time on 200mAh | Minutes per rand |
|---|---|---|---|
| AAA | R17 | 1 hour 7 minutes | 3.94 |
| AA | R17 | 6 hours 28 minutes | 22.82 |
| C | R26 | 18 hours 9 minutes | 41.88 |
| D | R34 | 36 hours 3 minutes | 63.62 |
