Deployed both, sharing data after 18 months.
18650 (recycled laptop cells): cheap (~PHP 80/cell from surplus), 2500mAh typical, lifespan in PH heat: 12-14 months before noticeable capacity loss. Cell-level failures common, need protection circuit. Voltage sag at low SOC is annoying.
LiFePO4 (32700 single cell, 6000mAh): much more expensive (~PHP 600/cell), but flat discharge curve, way more cycles, basically zero capacity loss after 18 months. Safer chemistry, no thermal runaway worries.
For solar IoT in PH conditions, LiFePO4 wins long-term despite the upfront. Pero need a TP5000 (LiFePO4-specific charger), not the typical TP4056.
Sino na nag-deploy ng LiFePO4 with solar here? Curious sa your charger setup.