This is the small black rubber plug that you insert into the charging port after you disconnect your charger on a Radrunner Plus (I assume most/all Radpower bikes are the same).  Mine split in two.  Now if my e-bike is ever in the rain, the battery may short. 

I just spent about twenty minutes looking for one of these on line but can't find one anywhere. 

Any ideas?

This one?
https://biggamebikes.com/product/rad-battery-terminal-protector/

Thanks, but it's the little black round rubber one that seals where the charging cable attaches.  It's attached to the battery via a rubber flap. 

I think this may be like what you're looking for, but you probably don't need this many.

https://www.amazon.com/Replacement-Waterroof-Threaded-Connector-Lsgoodcare/dp/B07WNTFMCB/ref=sr_1_10?crid=3NU67QIXCT8TT&dib=eyJ2IjoiMSJ9.2Jc261NfTlThWP_KZhZi6b4pREUfU2AS7wOgzMxLHDyxHKusdZcsXLT7ZzrojDAgkoN2NC32ti1MKzSAVu9l0UouA4EDPXnytByxfsoGxKtDZ3BatFDM-oBPeYA2cj6zF6RQ-vjGIndrpYK7ps2o8pySjA1mjNNZyKHnAmwQ86EkNuvhH2zLcYGuOjyBqwJyqaSXdakacJSkEJdjqrY9uOYwlOerhd_Ff7OWIVvKDZs.jbotmHLWTVs9IViImIcNxH4VVUAxPbdcF2KG0rAzCfU&dib_tag=se&keywords=5.5+x+2.1+MM+connector+cover&qid=1740066104&sprefix=5.5+x+2.1+mm+connector+cover%2Caps%2C159&sr=8-10

https://www.amazon.com/YPBEW-Waterproof-Wholesale-5-5x2-5-Protective/dp/B0D1YG8RT8/ref=pd_vtp_strm_d_sccl_2_5/138-3048672-5893067?pd_rd_w=p3KOq&content-id=amzn1.sym.8c8432aa-1bf0-4437-b5fa-12091a348861&pf_rd_p=8c8432aa-1bf0-4437-b5fa-12091a348861&pf_rd_r=01MTC4P8M7FK142P1XDK&pd_rd_wg=CCFIU&pd_rd_r=8d27c087-4adb-40cf-acb0-79b4067c6cf1&pd_rd_i=B0D1YG8RT8&th=1

https://www.amazon.com/GINTOOYUN-Dustproof-Silicone-Protector-Ethernet/dp/B09WGWRK6Y/ref=pd_vtp_strm_d_sccl_2_3/138-3048672-5893067?pd_rd_w=p3KOq&content-id=amzn1.sym.8c8432aa-1bf0-4437-b5fa-12091a348861&pf_rd_p=8c8432aa-1bf0-4437-b5fa-12091a348861&pf_rd_r=01MTC4P8M7FK142P1XDK&pd_rd_wg=CCFIU&pd_rd_r=8d27c087-4adb-40cf-acb0-79b4067c6cf1&pd_rd_i=B09WGWRK6Y&psc=1