1. Inside there is a high capacity rechargeable lead-acid free maintain battery 2. Alternating current: 220/50Hz, keep the charging 12 hours. And most charge time shouldbe less than 15 hours
3. Output voltage: DC 4V
4. Durable rechargeable period more less than 300 times
5. When the battery is fully charged. The lamp can be lighted continuously about 20 hours.