Your solar lights turn on at dark, but don’t stay on as long as you’d like. The fact that they turn on is a good sign and tells you that there’s probably nothing wrong with the solar panel, circuit board or connections.
So what’s the problem? Likely one or both of the following: the solar panel doesn’t get enough sunlight, or the batteries don’t store enough energy.
So, how to make solar lights stay on longer?
- Check to see if your solar lights have a low light mode
- Optimize the quality of sunlight hitting your solar panels
- Check the batteries
- Conclusion: How to make solar lights stay on longer
Check to see if your solar lights have a low light mode
Many solar lights come with two or even three lighting modes. This is especially true of motion sensing security and street lights. Some solar landscape lights also have low and high brightness settings.
By choosing the low light setting you can greatly extend the daily hours of service. Surprisingly, reducing the power draw by half can more than double the hours of service. It’s a bit like the difference between walking and running. We can walk for hours, but running saps our energy very quickly.
If you haven’t bought yet, then be sure to check for variable brightness modes. And if you have already made your purchase, take another look at the lights or instruction manual to see if there’s a low light mode.
Optimize the quality of sunlight hitting your solar panels
Do solar lights need direct sunlight?
There is no question that direct sunlight is best. Solar panels will collect some energy even if the sunlight is indirect, but you want to do everything you can to provide direct sunlight.
Placement of solar panels
The solar panel of your solar light should be placed in a location that gives direct sunlight for as many hours a day as possible. 6 hours is a minimum but 8 or more is better.
Take note of how shadows shift during the day. Moving your lights just a short distance can help them stay on much longer if this buys them another couple hours of sunlight.
If your panels are able to tilt, then you should have them tilted facing south, since this will allow them to face the sun more directly and for as many hours as possible.
Consider solar lights with a separate solar panel
What can you do if the sunlight isn’t great at the spot where you want to put your solar lights?
Consider purchasing a solar light with a separate solar panel, so that you can place the light where you want it and the panel somewhere else where it gets better exposure to sunlight.
For most such products, the cord between the solar panel and the light is about 10 feet (3 m) in length. If this isn’t long enough, look for a model that includes the option of an extension cord. (You can’t use a regular extension cord since the plugs will not fit and the connections won’t be waterproof.)
If you haven’t bought yet, now is the ideal time to think about this.
Adjust your use of solar lights to fit your geographical location
Obviously solar lights are going to do better in locations that get lots of sun. The weather is out of your control but you can stretch the service hours of a single battery charge by taking advantage of lights with a low light mode. Or, if you really want to be able to enjoy your lights on the patio when the weekend comes around, turn them off a couple days before that to ensure that the battery gets a full charge before use.
Another factor to consider is latitude.
The closer your home is to the equator, the easier it is to capture solar energy. But, if you live at some considerable latitude north or south of the equator, all is not lost. To some degree you can compensate for the indirect sunlight by adjusting the angle of tilt on your solar panel so that the panels receive sunlight as close to a 90 degree angle as possible. For a deep dive into this topic, check out this article from altenergymag.com .
Check the batteries
Batteries are a key and often overlooked part of a solar lights system. Perfect sunlight all day long won’t do you any good if your batteries are losing their storage capacity or never had much to begin with.
Can I replace the batteries in my solar lights?
Absolutely! And eventually you’ll need to. Rechargeable batteries used in solar lights should last at least 1.5 to 2 years and will often give 3 or 4 years of service.
If it’s time to replace them, have a look at what is currently installed. You may find AA or AAA sized batteries. These will be either Ni-MH or NiCd. Be sure to purchase replacements of the same AA or AAA size. The choice of Ni-MH or NiCd is up to you, though we recommend Ni-MH since these are more environmentally friendly.
Or, you may find that the current battery is lithium ion. If so, again, just be sure to replace with a lithium ion battery of the same size.
Can you use regular batteries in solar lights? No, make sure you use rechargeable batteries. Click the link for our article explaining why.
The battery capacity of your solar lights
The capacity of the rechargeable batteries in your solar light is a major determining factor when it comes to hours of light output.
Hours of battery capacity is measured in milliamp hours, or mAh. Rechargeable batteries that you would buy for a solar light should have their mAh rating clearly indicated on them. A higher mAh rating means greater battery capacity and longer life from a single charge.
Ni-MH or NiCd batteries are the typical options for AA or AAA size. They are available in small and large capacity formats. Small would be something around 400 mAh, medium around 1000 mAh and large capacity versions boast around 2000 mAh.
Can I replace a battery with a new battery having a higher mAh rating?
You “can” – meaning that you won’t damage the batteries or your solar lights. But don’t overdo it. If the manufacturer ships the light with a 400 mAh battery, chances are the light has a small solar panel that will struggle to fill a 2000 mAh battery to capacity. That leaves you paying for battery capacity that you won’t be able to take advantage of.
However, it is sensible to replace a 400 mAh battery with a 600 mAh version. If your lights are getting good sunlight then they should be able to fill the 600 mAh batteries to capacity, giving you significant benefits from the extra charge.
Conclusion: How to make solar lights stay on longer
The top three things you can do:
Take advantage of low light modes or motion sensing modes to extend the run time of a single charge.
Do what you can to maximize the hours of direct sunlight received by the solar panel. Consider solar lights with a separate solar panel if the lights themselves must be placed in the shade.
Replace the rechargeable batteries, possibly with batteries that have a somewhat higher mAh rating. Don’t overdo it though. A battery that is grossly mismatched with the solar panel will struggle to achieve maximum charge.
Thank you for reading. Other articles that you might be interested in :
Solar lights with a separate solar panel (coming soon)