Guest Editorial: Keeping Solar lights Burning

If your solar lights stop working, you can repair them if they are not too far gone. I am referring to the ones with AA or AAA batteries, not the new ones with 5-digit battery codes. Most often the cause of failure is a bad battery connection inside the unit. You can usually remove the reflectors and the poles, if they have them, by twisting them off. The battery may have a small door to open for replacement. If not, you have two or three small screws to remove. 

Take out the battery and temporarily replace it with a non-rechargeable battery of the same size. Hopefully the LED light will come on. Be sure to cover the solar cell with your hand. If you don’t, the room light may cause the unit to think it is daytime and turn the light off. If the light doesn’t go on, try cleaning the battery connections on the unit. They can get really cruddy. Any kind of file, sandpaper, a sharp tool, even a fingernail file, will take off the rust and corrosion and make the contacts shine again. If you are using a known good battery for the test, you can’t get the light flicker even for a moment, you probably have a bad LED (the light) or a broken wire (rarely), or the whole unit is defunct. You can solder a broken wire or simply discard the unit. Be sure to save the battery if it is not badly corroded. If you want to dispose of the battery, don’t throw it in the trash – take it to a hardware or “big box” store. It is illegal in New York State to put a rechargeable battery in the trash or recycle bin. 

If the light comes on with a good non-rechargeable battery, test the solar cell by holding it in a strong light: the LED should go out. If not, it’s not sensing any light and you probably have a bad unit. Most of the time, however, you will find that the unit is okay and either the battery connections are corroded, or the rechargeable battery is bad. If you have a multi-meter, you can check the charging function, but you can get by without this step. With the meter leads clipped or held onto the empty battery holder terminals, and the solar cell held up to a strong light, you should get around two volts or more. If not, the solar cell is not working and the battery will never charge.

Once you have cleaned the contacts and the LED is on and steady with a non-rechargeable battery, even if you have not tested the charging function, try reinstalling the rechargeable battery. If the battery has cruddy contacts, you should file them shiny, too. If you put it back together and put it in the sun all day and it still doesn’t go on at night, it will be the charging function, the battery, or the contacts are still flakey. You can go through these directions again or give up on the unit and/or the battery. If you have saved a battery from a known bad unit, it may very well work in a good one. If it doesn’t charge with a known good rechargeable battery, discard the unit.

You can often buy replacement batteries where they sell solar lights. Try to find a replacement battery that has similar specifications as the one in the unit. It will be either NI-Cad (Nickel-Cadmium) or Ni-MH (Nickel Metal-Hydride) and will display the discharge rate on the case, such as 100 mAh (milli-ampere hours) or more. The higher this number, the more charge the battery can take and the longer it will last on a charge cycle. These are all 1.2-volt batteries. You can also use a battery charger, which you can buy where they sell batteries, to test and charge rechargeable AA and AAA batteries. Be sure to use the right charger, as some only test Ni-Cad or only Ni-MH batteries. Of course, the real test is whether the unit charges in the sun. Although a new battery can be more expensive than a new solar light, you can often save money over the long haul simply cleaning the contacts and swapping working batteries.