RHYTHMIC 12V 100Ah LiFePO4 LITHIUM IRON PHOSPHATE BATTERY WITH BLUETOOTH MONITORING. RHYTHMIC 12v 100Ah SMART LITHIUM PHOSPHATE LiFePO4 Battery for Leisure, Solar, Wind and Off-grid 12 volt etc. RHYTHMIC 12v 100Ah LiFePo4 battery bluetooth function can monitor the following status from smart phone.