Are Regular Batteries Okay for Solar Lights?

Are regular batteries okay for solar lights?

Solar lights are a reliable and environmentally friendly way to produce electricity. Like any electronic device, eventually their rechargeable batteries must be changed, leaving the ultimate question:

Are regular batteries Okay for solar lights? The quick answer is no; however, for very short periods of time (a week at most), alkaline batteries can be used for solar lights.

The long answer is a little more complicated.  

Rechargeable Batteries Versus Alkaline Batteries

Every electronic device uses a type of battery for storing energy. Though solar lights get their energy from the sun, they use batteries to store the energy they collect so that they can output that energy when they no longer have a light source, such as during the night.

After some time, however, the batteries start to store less and less energy, until they can no longer store any energy and need to be replaced. Solar panels use one of two forms of batteries:

  1. NiMH rechargeable battery
  2. NiCd rechargeable battery

Thankfully, both of these these batteries are conveniently sold in many stores, are easily replaceable, and can even be upgraded. NiMH and NiCd batteries are also interchangeable, so you can use whichever you prefer.

Solar lights need somewhere to store the energy they absorb from the sun, which is why they require rechargeable batteries. Regular batteries cannot store energy the way NiMH and NiCd batteries do, resulting in damage to your solar lights.

Both batteries are rechargeable, unlike regular alkaline batteries, and so the use of alkaline batteries in solar lights can lead to permanent damage to your solar lights including corrosion and solar panel failure.

While NiMH and NiCd rechargeable batteries can be easily installed, installing alkaline batteries in your solar lights can damage them to the extent that you may no longer be able to replace them with rechargeable batteries. Alkaline batteries also only power your solar lights for a short period of time.

Rechargeable batteries in need of replacement may not hold sufficient charge resulting in less power from your solar lights. However, once regular batteries have been installed in your solar lights, there is a possibility of them severely corroding the battery terminal of your lights.

Eventually, the corrosion will destroy the connection between the terminal and the battery itself, stopping any power from going through to the panels. This might render your solar lights unusable, so it is best not to risk installing alkaline batteries in your solar lights.

There is a way to clean the corrosion that regular batteries might cause, though it is hazardous and can result in the destruction of your solar lights anyway. By using a brush with soft bristles and baking soda diluted in water, you can clean the battery terminal if corrosion does happen. However, if any excess water happens to seep through to the solar lights inner mechanisms, it can potentially cause permanent damage to the solar lights. Despite how careful you might be when cleaning them this way, the smallest amount of water seepage may slip through and damage your solar lights.

The best course of action is to simply use rechargeable batteries, such as NiMH and NiCd batteries, when replacing the batteries in your solar lights. The risk of using regular batteries is not worth the potential permanent damage to your solar lights.

Now, if, for example, rechargeable batteries are not available right away, you should be able to get away with using regular alkaline batteries in your solar lights for a couple days while you are in the process of getting your new rechargeable batteries. Just be sure you know the risks of doing so.

How Long Do Rechargeable Batteries Last in Solar Lights?

Rechargeable batteries will discharge over time until they no longer work. It is imperative that you charge your batteries at least every three or so months to maintain the lifespan of your rechargeable batteries and your solar lights, even when the lights are not in use.

On average, the standard rechargeable battery will last about one to two years, though depending on the brand, quality, and type of battery, it can be more or less. Expect to see a decline in the brightness and performance of your lights during that time frame.

Once you notice that your solar lights have considerably diminished in brightness, charging ability, and overall performance, it is probably time to replace the rechargeable batteries.

A simple way to check to see if your rechargeable batteries need replacing, and that the solar panels themselves are not faulty, is to temporarily replace the rechargeable batteries with regular alkaline batteries.

With regular batteries in, place your solar panels in direct sunlight for a day and then make sure to go into a dark room and switch your solar lights on to see if the regular batteries work in your solar lights. If the brightness of your lights is back to normal, then your rechargeable batteries need to be replaced.

Don’t forget to remove the alkaline batteries from your solar lights afterwards to prevent long term damage to the battery terminal.

NiMH Versus NiCd Rechargeable Batteries

Both NiMH and NiCd batteries are:

  • Rechargeable
  • Interchangeable
  • Conveniently sold in stores and online

These batteries make finding a replacement battery for your solar lights a very easy process. There are some differences between the two, however. NiMH batteries are generally preferred over NiCd batteries for a few reasons.

NiMH batteries:

  • Have a higher capacity
    • NiMH batteries contain more than twice the amount of storage space for energy as standard NiCd batteries do, in addition to having longer output times
  • Have no memory effects
    • NiCd rechargeable batteries must be fully drained before they can be recharged in order to prevent damage to the battery life
    •  If not, the batteries will not fully charge and the next charge will be set to a lower energy capacity
    •  If the battery is continually not emptied, the process will repeat itself until the battery will no longer hold any charge
      •  This is what is referred to as the memory effect
    • NiMH rechargeable batteries have the capability of storing new energy while there is still energy in its storage, without affecting the battery life
  • Are environmentally friendly
    • NiCd (Nickel Cadmium) contains the harmful chemical element, cadmium, that is hazardous to the environment            
    • Unlike NiCd, NiMH (Nickel Metal Hydride) contains no cadmium making it the better choice where environmental health is concerned
  • Are similar in price to NiCd rechargeable batteries

How Do You Charge Brand New Solar Lights?

Most solar lights now come with an on and off switch that is very helpful for things like storing your lights. When you are installing a brand-new light, however, it is recommended that you leave the switch in the off position and then leave your solar lights in direct sunlight for a couple days to charge.

This will allow the battery to charge to full capacity, which is healthy for the solar lights’ lifespan and prevents battery discharge during initial use.

Tips to Prolong the Life of Your Solar Lights

Solar lights last, on average, about two years before the batteries must be replaced. However, there are a few ways to ensure they last a while longer.

  1. Make sure to clean your solar lights regularly by wiping them with a clean cloth about every two weeks
  2. Replace the batteries if the lights are unable to provide light for 8 hours
  3. Turn lights off and store in a cool environment with some access to sunlight during extreme weather
  4. Be cautious of placing lights in garden areas, as dirt buildup can prevent them from receiving adequate power

Make sure to turn lights off when they will not be exposed to light for long periods of time


Title image by Greg Goebel

spgenie

Hi I'm Harris the spgenie! As an engineer, I found myself doing tons of research about solar power, the types of panels, how to store the energy and the best way to finance the project. I thought I'd start this blog to share my findings. I hope you find this useful.

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