1. Rechargeable batteries have a limited lifespan of 1 to 3 years.
2. An old or dead battery will not charge, which may not be due to the charger.
3. Uncertain if the battery or charger is faulty? Use a volt meter to test the charger's functionality.
Kircuit New Global 2-Prong AC / DC Adapter Compatible with Lydsto S3 Model YM-S3-01 YM-S301 YMS3-01 YMS301 15000mAh 15Ah 15000 mAh 15 Ah Lithium ion Li-ion Liion Rechargeable Battery Pack IPX8 Waterproof Wall Climbing Cordless Robotic Automatic Swimming Pool Vacuum Cleaner Class 2 Switching Power Supply Cord Cable PS Charger Mains PSU (w/ 2-pin Connector)
Compatible with listing item ASIN: B0D1BZHYFF -- Lydsto Cordless Robotic Pool Cleaner-Pool Vacuum for In ground Pools with Wall Climbing-Lasts up to 180 Mins, Quad-Motor, Smart Navigation, IPX8 Waterproof, for Most Pools up to 2,000 Sq.ft, Sliver
World Wide Input Voltage 100-240VAC 50/60Hz OVP, OCP, SCP Protection (OVP: Over Voltage output Protection. OCP: Over Current output Protection. SCP: Short Circuit output Protection) Tested Units. In Great Working Condition.