Amazon.com: Synergy Digital Power Tool Battery, Compatible with Ryobi BPP- 1815 Power Tool, (Li-ion, 18V, 4500mAh) Ultra High Capacity, Replacement for Ryobi BPL-1815 Battery : Tools & Home Improvement
18V 6000mAh Li-ion Rechargeable Battery for Ryobi for ONE+ Power Tool BPL1820 P108 P109 P106
15*18650 Battery Plastic Case Charging Protection Circuit Board PCB for RYOBI 18V 9Ah P103 P108 BPL-1815/1820G/18151/1820 ONE+ - AliExpress
Amazon.com: GOPEO Battery Replacement for Ryobi Part Number: BPL-1815, BPL18151, BPL1820, BPL-1820G, P102, LFP-1802S, LRS-180, OBL-1801, OCS-1840, OGS-1820, OHT-1850, OLT-1830 : Health & Household
2PCS 3.6Ah 18V 3600mAh High Capacity Lithium-Ion for Ryobi P108 BPL-1815 Battery | eBay