Selling Cheap Dry Batteries from PT. Best Energy System in Jakarta. An accumulator or commonly called a battery is a device that can store energy (generally electrical energy in the form of chemical energy). There are many types of batteries, including dry batteries, wet batteries, etc. This dry battery is also known as Maintenance Free. Although it is called a dry battery, it does not mean that there is not the slightest liquid in it. This type of battery still uses electrolyte liquid but contains calcium lead.