Prioritize Monocrystalline Silicon solar panels over polycrystalline ones, as they offer higher conversion efficiency (up to 20-22%), ensuring the lights charge even on cloudy days. For the battery, ensure the supplier uses Lithium Iron Phosphate (LiFePO4) batteries rather than standard Lead-acid or Ni-MH, as LiFePO4 offers over 2,000 charge cycles and better thermal stability. The battery capacity should be at least 3 times the daily power consumption to ensure the light can operate for 2-3 consecutive rainy days.