Solar Garden Light Battery Life Calculator
Calculate battery runtime and estimate how long your solar garden lights will stay on.
Capacity of your battery (milliamp-hours)
Total wattage of LEDs in light
Average daily sunlight for charging
How long do solar garden lights batteries last?
Solar light batteries typically run 8-12 hours on a full charge. Quality Li-ion 18650 cells (2000-2600mAh) last 1-3 seasons (2-4 years). NiMH AA (1000-2000mAh) last 1-2 seasons. Cheap NiCd or alkaline disposables last weeks to months. Replace rechargeable batteries annually for best performance. Look for low self-discharge (LSD) NiMH if using that type.
Why do my solar lights stop working?
Solar lights fail mainly due to: Dead battery (replace yearly), Dirty/degraded solar panel (clean or replace), Corroded battery contacts (clean with vinegar), Bad photocell/sensor (stays on or off incorrectly), LED burnout (rare), or water damage. Most failures are battery-related. Try fresh batteries before buying a new light. Check the solar panel for cracks and dirt accumulation.
Can I upgrade my solar light batteries?
Yes - upgrade to higher capacity or better chemistry for longer runtime. Use LSD NiMH (Eneloop) for NiMH systems. Use 18650 Li-ion for light that came with lithium. Match voltage - don't mix chemistries. Higher capacity (2600mAh vs 1000mAh) doubles runtime. Don't exceed original battery dimensions. Check if your light has protection circuit for lithium.
How many hours of sun do solar lights need?
Solar lights need 4-8 hours of direct sunlight for full charge. More sun = longer runtime. South-facing placement optimal. Winter/snow reduces output 20-50%. Trees/buildings blocking light cause dim lights. Cloudy days charge but less - expect 50-70% runtime. In northern climates, consider solar light placement carefully or upgrade to larger panels. Partial sun is rarely enough.