Most homes have some fancy solar garden lights in their yard. They look great and provide security and lighting around the property. The problem is that most people think that because they are solar they will run forever.
If your solar garden lights are dim, don’t run long, or won’t turn on at night you could have a problem with the battery or the charging circuit.
In this post, we will explain why these cheap garden solar string lights fail after a few years and how you can repair them yourself for only a few dollars and 1/2 hour of your time.
Why are your Solar lights failing?
There are 3 main parts to your Solar Garden light that make them work. If either one fails your lights will stop working at night.
- Small solar panel
- Electrical charge circuit
- Battery Backup
So can solar garden lights be repaired? Yes, they can.
Every time I have opened up some solar lights I have found that it is the battery that has failed. Often there will be 2 or 3 AA batteries. Sometimes water ingress will cause a problem but usually, it is the battery.
The most common type of battery is AA NiMH. These will have around a 500 charge cycle life. After which performance and usability will drop off significantly.
The only way to repair and improve performance is to replace the battery. Sometimes this is a relatively straight forward process and just plug in new batteries. But more often than not these solar lights use a proprietary battery pack.
Now you could search for the battery pack online with the special plug socket or you can reuse the plug end and solder up a new battery pack. I like to use some old AA rechargeable batteries I have around the house.
How to make up a new solar lighting battery pack.
- Soldering Iron and Solder
- Emmery Paper
- Electrical tape or heat shrink
- Multimeter to test your battery pack
- AA NiMH Batteries
Solar-powered garden lights repair can be a simple process. Start by opening up the old garden light and take out the battery pack.
If you are reusing the plug end remove the battery pack and disconnect the plug end. We will be reusing this on our new NiMH battery pack. I used a multimeter to test the old battery pack and found one of the cells had failed to 0v.
While you are removing these wires just check how the batteries are wired up. Usually, they are all wired up in series. This means the positive end of a battery is connected up to the negative end of another battery and so on.
If each battery is 1.5v when we add them together they will make 4.5v. Having the correct polarity is important on how to repair your solar garden LED lights.
To save space manufacturers will build this pack into a small triangle pyramid is using 3 batteries. If there are only 2 they will be side by side. They also like to use very low capacity batteries. I’m using 1000mah AA batteries in this example.
Use your pliers and a soldering iron to remove the metal tabs from each of the old battery pack. We can reuse these on our new batteries.
Once you have all of your pieces you can now start to assemble the new battery pack.
Soldering Up your Battery Pack for the Solar Spot Light
Be sure to fully charge each battery prior to making up the battery pack. They will last longer if each battery is at the fully charged state. Make sure each NiMH battery is the same brand and capacity.
I like to use the Opus smart charger to charge all of my batteries. I can highly recommend it.
Use the sandpaper to remove any tin, oil, grease, dirt, and rust on every part that you want to solder together. You will get better results with a clean piece of metal. This included the terminals on your battery.
At this point, I like to quickly put a fine layer of solder on each piece of metal strips and the battery terminals. This is called tinning.
Once you have prepared your batteries and rotated them the correct way use some electrical tape to wrap them together. Some heat shrink also works well.
Turn your soldering iron to the maximum setting and start to solder the wired and tin strips to the batteries. Once you remove the heat hold the wires onto the battery for a few seconds until the solder sets.
You will now have a completed battery pack using the old plug. Use a multimeter on DC voltage settings to test the voltage. It should be between 3.5v to 4.7v depending on the charge of each battery.
Twist the cable ends together and wrap the whole homemade battery pack in electrical tape or heat shrink. Pay particular attention to the end of the battery that all the terminals are insulated.
How to make a battery spot welder
If you don’t have access to a soldering iron you could make yourself a battery spot welder.
All that is required is a 12v car or motorcycle battery, some heavy-duty wires, a starter solenoid from the wreckers, and a push-button.
Replacing the battery on your solar garden lights will fix your problem in 99% of cases. This procedure also works for repairing solar Christmas lights as well as solar fairy lights.
Be sure to use high-quality NiMH batteries, Eneloops are often my choice for a good long-lasting AA battery. They will make your garden lights run longer as long as they get a full sun charge from the solar panel.
Make sure to replace any seals that may cause water ingress into your lights. If they are weather-worn a good dab of silicone sealant will do the job.
For peace of mind, I like to replace my garden LED light batteries every 3 years.