Why does it take literally days for an electronic toothbrush to reach full charge but a device with larger battery can become fully charged in a few hours
In: Engineering
All common batteries are characterized by charge current which determines how fast it is possible to charge them without damaging the internal chemistry. This figure depends on the chemistry and specific design of the battery and isn’t really affected by size. The lowest charge current to capacity ratio among common batteries belongs to NiMH that can be charged fully within around 2 hours if maximum rated current is applied.
Another common bottleneck is the charge circuitry. In modern microelectronics, higher currents require much more expensive components compared to higher voltages. If you pair this notion with the low nominal voltage of some types of batteries (1.2V for NiMH for example) that make the batteries current capacity more important in relation to its energy density, you’ll find it results in many products that save costs by implementing a charge circuitry that provides far below the rated maximum charge current for the battery it is charging.
In conclusion – It doesn’t really matter what size of a battery you got, all modern batteries are capable of achieving full charge within a maximum of around 2 hours. What you are witnessing is likely the result of manufacturing cost savings in your device.
Latest Answers