If you’re thinking of spending money on solar lights, it’s natural to ask, “How long do solar lights last?”
Sometime soon I’ll be writing on the related question, “How long will the lights stay on each night?” but for now I’m assuming you mean, “What is the lifespan of the solar lights?”
What is the lifespan solar lights?
Short answer :
A solar light can easily last upwards of five years, though this won’t always be the case, especially with inexpensive solar lights.
If there is going to be a problem, it will often present itself early so check the warranty and return policy of the seller before you buy.
Aside from obvious damage like a broken stake, the most likely sources of failure are the battery (easy to fix) and the circuit board. (Possibly repairable, see below.) The other components tend to be quite reliable.
The components of solar lights (and their reliability)
Regardless of any fancy design, every solar light consists of roughly the same set of components. The lifespan of the solar light depends on the lifespan of these components and the care with which they are connected to each other.
The solar panel
Barring any accidental damage, solar panels have a useable life of 25 years, often more. So the solar panel itself is unlikely to be the factor that determines the lifespan of a solar light.
LEDs (light emitting diodes) last much longer than incandescent bulbs because they don’t produce anywhere near the heat of an incandescent bulb. LED lifespans upwards of 10 years are not uncommon. Like the solar panel, the LEDs are generally reliable and long lasting components of a solar light.
The rechargeable batteries
The rechargeable batteries of a solar light should provide a minimum of two years of service. In many cases they will last for three to four years. Either way, the good news is that the batteries are replaceable and inexpensive.
The circuit board
The circuit board manages the light’s daily switch from off to on to off again. It also manages the flow of energy into the rechargeable battery.
Although circuit boards *can* function problem-free for decades, they are a vulnerable point in a solar light system. What can go wrong?
(For the curious, here is a deep dive into quality assurance in circuit boards. For the short version, read on…)
If poorly manufactured, dropped, or subjected to excessive vibration, elements of the circuit board can shake loose. This damage will often be invisible to non-experts. If your solar light refuses to work from the get go, or gives up the ghost early on, and you have tried these remedies to no avail, then there could be a circuit board issue and you should ask for a replacement from the seller or manufacturer. Many manufacturers are keen to protect their ratings on Amazon and will offer stellar service to see a poor review updated with a positive comment.
Moisture, not surprisingly, will also damage a circuit board. And since solar lights are often exposed to the elements, this is a potential problem. See “housing”, below, for more detail.
If dust collects on the circuit board, this too can shut things down. (True story: Years ago, my desktop PC suddenly refused to boot up. “Try vacuuming the circuit board,” said a friend. Believe it or not, this solved the problem. Just be careful to hover the vacuum nozzle above the circuit board, withour scraping or bumping the board.)
Bugs finding their way to the circuit board is another potential solar light killer.
Moral of the story: Pay attention to IP (ingress protection) ratings. See “housing”, below.
Aside from just looking nice, the housing performs the crucial function of keeping the circuit board, batteries and LED dry and clean. If your solar lights are exposed to rain then look for an IP rating of IP64 or better – “better” meaning IP65 or IP66. And if there is any chance that the light could become submerged then look for IP67 or, even better, IP68.
If a product advertises an IP68 rating – meaning that it can handle submersion in 3ft of water for a prolonged period – be aware that this may mean the battery is not replaceable. Why? Because some – not all – designs achieve their waterproof credentials by sealing off the battery compartment.
In our view, IP68 is overkill for most solar lighting situations. The more common factor limiting the lifespan of your outdoor solar lights will be the battery, so you’ll want to make sure it is replaceable. If IP68 protection comes at the cost of not being able to replace the battery, and your solar lights stand no chance of being submerged, take a pass.
If the light is staked into the ground, then this is another component to think about and a potential source of failure. Cheaper lights will tend to have plastic stakes. These can be broken during installation if pushed too hard, or if pushed into ground that offers too much resistance.
Use steel rebar, a section of pipe or whatever else is at hand to clear a hole in the ground for the stake.
Some manufacturers sell replacement stakes. You might want to see if the product you are considering is among them, before you buy.
It is a truism that you get what you pay for. If buying an inexpensive 10 pack of path lights, don’t be surprised if one or two develop problems. Check the customer service reputation of the manufacturer before buying (you may find relevant comments in the reviews on Amazon.) Many manufacturers are very good about replacing defective lights.
There are other factors that may not affect the lifespan of the lights but that will limit their effectiveness.
Interference from other light sources
If light from a window or streetlight falls on the light sensor, your solar light may be fooled into thinking it’s not dark yet. Try repositioning the light to ensure that it is in a dark spot.
Dirty solar panels
Especially if your lights sit near ground level in a dusty spot like a garden, windblown dirt can accumulate on the solar panel. This will decrease the ability of the solar panel to convert solar energy to useable electricity. A quick wipe every now and then with a wet cloth will fix the problem.
Solar lights need 6 to 8 hours of sunlight to achieve a full charge. The panel should be facing south if at all possible. If it is difficult to achieve these conditions, consider a solar light with a separate ( or “remote”) panel so that your light can be where you need it and the solar panel can be somewhere else.
How long will solar lights last? It varies, but by paying attention to the quality of the components you can make good buying decisions. There is an element of luck (you’ll never know if there were any serious jolts in transit) so it pays to check the seller’s refund policy before you buy. Many are great about handling returns if needed. And in most cases that won’t be needed. A light with good components and proper care can easily last for more than five years.
Thank you for reading. Please join us for more thoughts on the best outdoor solar lights for your home.