Solar Water Pump Battery Backup, 14.8V-16.8V 2200mAh Solar Fountain Pump Battery Pack Rechargeable for 12W/20W Solar Fountain Pump Kit Long Life :3000 times, 3 years. Special Design: Specially designed for 's 12W/20W solar water pump kit Suitable Size: 4.92*3.15*1.26 in. Tip: 1. Please place the battery backup under the solar panel to avoid sun and rain. 2. It is recommended to place the battery under the solar panel or avoid rain. ?Long Life and Durable?14.8-16.8V/2200mAh battery lithium backup adopt advanced technology and heat-resistant high-quality materials which is more durable and and long-lasting, it can cycle more than 3000 times. ?Special Design?The battery backup is specially designed for our 's 12W/20W solar water pump kit, it stored energy when sunny days to help the solar fountain pump keep sufficient power to work even on heavy cloudy or sunset 3-5 hours when fully charged. (Working hours depend on how much power is stored) ?Multi-protection Easy to Use?The backup lithium battery has better sealing and waterproof, prevents the dust or water drop from getting into the battery and damaging battery lifespan. The backup lithium battery is easy to use, just plug and play. (Tip: please place the battery backup under the solar panel to avoid sun and rain) ?Rechargeable 2200mAh Battery?The Li-ion 2200mAh rechargeable battery will fast charging with solar panel when get sufficient sunlight, 6 hours to full (won't charged fully on cloudy day). The battery pack will assist the fountain working on couldy day or sunset.