Q. How long does a solar light battery last?

When used regularly the batteries in most outdoor solar lights can last for up to 3-4 years before needing to be changed. In fact LEDs can function reliably for ten years or more. When the lights stop holding their charge well enough to provide adequate lighting at night a buyer will know it's time to make repairs. The watt-hour capacity of a 300Ah 12v battery system is 3600 since multiply the amp-hours by the voltage (Wh). Approximately 12 hours of use for a device with a 300-watt power need is possible from such a battery bank. The durability of the outdoor solar lights can also be affected by a few tweakable aspects.