What to Look for in Solar Lights
Whatever type of solar light you are installing for your home, business or garden, you will want something that will last and perform well. We have had many people come to BlackFrog Solar after experiencing the disappointment of discount and chain hardware store solar lights. Invariably they have bought them because they were a ‘bargain’. Unfortunately buying cheap is not the approach to take if you want something to last more than a few months. You must consider the quality of the light fitting. By that, we mean materials, light output, functions and solar panels.
Size does matter (with current technology). More solar cells mean faster battery charging. Most solar lights discharge overnight and have to start from scratch each day to recharge their batteries. The panels should be designed to achieve a full charge over the course of a day, but this may entail 8-10 hours direct sunlight for smaller panels. Larger panels may only require 4-6 hours.
Most solar lights have resin covered panels for weather protection. These will gradually craze (become opaque) due to UV exposure and in some cases even lift from the battery pack. The more opaque the cover becomes, the less efficient the panel will be and consequently lighting time will be affected. Generally, this happens over a 3-6 month period depending on the quality of the resin and the amount of exposure.
A less common method of weather protection due to cost, but will not craze and will last considerably longer than their resin counterparts.
Separate Solar Panel:
Separate solar panels can be placed several metres away from the light head to gain better access to the sun. This helps ensure adequate power when needed and is much less restrictive with light head placement.
Solar Light Batteries:
All solar lights have rechargeable batteries. These are what store the energy during the day and are the power source for night time operation. There are three main types used in solar lights: Ni-cd (nickel cadmium), Ni-MD (nickel metal hydride) and lithium.
Ni-cd batteries have a memory and will not charge to full capacity after receiving short charge cycles (consistent inclement weather). These are the cheapest solar light batteries to buy so may not affect the price of the light unit, but you will need to replace batteries at least every 12 months.
Ni-MD batteries sit somewhere in between nickel cadmium and lithium. They don’t have the memory disadvantage of Ni-cd, but will still need to be replaced every 1-2 years, depending on usage.
Lithium batteries are the best at receiving and retaining the charge and have the longest lifespan (typically 4-5 years) before replacement batteries are required. Lithium batteries, however, are quite expensive and this will reflect in the initial price of the solar unit.
Solar light batteries differ in their storage capacity. Higher numbers (eg 2000Mah) have a greater energy storage capacity, and therefore, longer lighting times than similar lights with smaller capacity batteries (compare lights with similar lux or lumen output). As a rule, the batteries supplied with your lights are suitable for the charging capacity of the solar panel. Replacing larger capacity batteries than those supplied, will not necessarily result in more lighting time for your lights. The batteries can only store what the solar panel can bring in.
The lighting times stated are based on the unit receiving maximum charge during the day and the batteries at maximum storage capacity. Remember batteries become less efficient over time. Resin solar panels also become less efficient over time. Therefore 6-8 hours lighting time can, in reality, reduce to 3-4 hours after 6 months.
Life expectancy of your lights will depend upon the environmental conditions they are exposed to. Long exposure to sun, wind, rain and pollution will eventually lead to failure. The time it takes for this to occur differs greatly depending on levels of exposure and the overall quality of the light unit. Good quality lights will last considerably longer than their cheaper counterparts.
The quality of the lights will directly affect the expectancy as discussed above.
Look for lights that have replaceable parts such as batteries and solar panels. Remember all solar lights have batteries and these will eventually need to be replaced after 12 months onwards depending on the battery type.