At first glance you may believe that all solar fairy lights are created equally, but this is certainly not the case. There is a reason why some fairy lights are more expensive than others. It simply comes down to quality. Quality of the solar panel, the light string itself, the batteries contained within, the quality of lighting time and any additional features that they may have.
You can find solar fairy lights in many retail stores, especially around Christmas time, but just be aware that you pretty much get what you pay for. a 300 LED string that fits into something less than the size of a tissue box will be almost guaranteed to have a tiny solar panel that will struggle to power your lights for 4 hours and a flimsy string that is prone to breakage. So prior to purchasing, it would be wise to consider what your requirements are:
- How long do you want then to last: days, months or years?
- How long do you need them to light each night?
- Do you need different lighting functions other than “continuous on” and “blinking”
- Where are you planning to place them? Will they be exposed to high winds or animals?
- How much sun exposure will they receive?
- What length do you require?
The following is a guide on the different qualities and their pros and cons:
Size: Size does matter. More solar cells means 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.
Resin Covered: Most solar fairy 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.
Glass covered: A less common method of weather protection, but will not craze and will last considerably longer than their resin counterparts.
Light Functions: The number of functions a light string has will affect the price. Not just because the circuit board is more complex, but the number of wires required along the length doubles, as does the amount of work soldering each LED.
Thickness and Material: LEDs last a long time, but they are only as good as the wire they are attached to. Fairy lights can have between 2 to 6 wires that are intertwined to make the string. The quality and width of wire on which the LEDs are attached does vary from product to product. Thicker wires are more durable and are less prone to breakage from overstretching, wind and animals. Wire widths can vary from 0.6mm to 2mm thick, and be made from Zinc metallic mix, to a full copper wire. Copper being the best conducted and most resistant to breakage when bent.
Wire Sheath: Wires are covered in either plastic, PVC or rubber. Plastic breaks down very fast and will discolour easily. PVC is the most common, and if UV treated, is quite durable. Rubber strings are the best, but are expensive.
Colour: Wires are either dark green, white, clear or black. Select the colour that will suit your application best. Light colours for light coloured backgrounds such as white soffits and walls, and darker strings for darker backgrounds such as trees trunks and foliage.
Type: Ni-MH are better than Ni-cd. Ni-cd have a memory and will not charge to full capacity after receiving short charge cycles. Lithium batteries are the best but more expensive.
Capacity: Batteries differ in their storage capacity. Higher numbers (eg 2000Mah) have a greater energy storage capacity, and therefore, longer lighting times than strings with smaller capacity batteries with the same number of LEDs (always compare strings with the same number of LEDs). As a rule, the batteries supplied with your lights are suitable for the charging capacity of the solar panel. Placing 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.
Lighting Time: 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.
Environment: 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. Light strings that are placed in sheltered locations such as under eaves or roofs will take longer to show signs of wear.
Quality: The quality of lights will directly affect life expectancy as discussed above.