Most Lipo battery chargers have a Storage mode. If you dont plan on using them in the next few days it is always best to bring your batteries down or up to storage voltage (approx 3.8v per cell). Amazon.com: PCEONAMP 2S Lipo Battery 7.4V 80C 5200mAh with T Plug Rechargeable High Capacity RC Cars Battery Hard Case Fit for RC Car Trucks 1 8 1 10 High Speed RC Cars with Storage fireproof explosionproof large capacity lipo battery storage Temu Amazon.com: Crazepony 4 Ports LiPo Battery Storage Charger and Discharger, 1S 3S RC Balance Charger Tiny Whoop Charger with Storage Mode : Toys & Games Lipo storage : r fpv VIFLY WhoopStor 3 1S LiPo LiHV 6 Channel DC USB C Battery Storage Charger Compatible w BT2.0 and PH2.0 White