When sourcing solar deck lights, prioritize Luminous Efficacy (Lumens) to ensure adequate brightness; typically, 10-30 lumens are sufficient for ambient lighting, while 50+ lumens are needed for safety paths. Check the Battery Capacity (mAh) and type—Lithium Iron Phosphate (LiFePO4) batteries are superior to Ni-MH due to their longer lifespan and better temperature resistance. Additionally, verify the Solar Panel Conversion Rate, aiming for Monocrystalline Silicon panels with an efficiency of 20% or higher for faster charging in low-light conditions.