It is not necessary to refill a battery after it has been charged, unless specifically recommended by the battery manufacturer.

With modern batteries, such as the lithium-ion batteries commonly used in electronic devices, it is usually not possible to refill them. These batteries are designed to be repeatedly charged and discharged without needing any additional fluid or electrolyte added.

In the past, there were lead-acid batteries that could be refilled. These batteries had an electrolyte fluid that could evaporate or decrease over time. In such cases, you needed to add distilled water to bring the electrolyte level back up.

It is always important to follow the manufacturer's instructions regarding battery maintenance and usage. If there are specific instructions to refill the battery after charging, you should follow them.