Best Batteries for Solar Lights - 2021 Reviews
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The Best Batteries for Solar Lights

If your solar lights aren’t lasting as deep into the night as they used to, that might mean they are getting less direct sunlight during the day. The positioning of the light’s solar panels is extremely important, and small amounts of extra sun-time during the day will improve nighttime performance significantly. But more likely, poor solar light performance means it’s time for a battery replacement. Solar batteries aren’t meant to last forever—they are rated for certain numbers of charge cycles—and for optimal use you should probably replace them every three to four years.

Most require AA or AAA rechargeable batteries. If you’re not sure which you need, pop open the battery cover on your light to find out. When buying a solar light you should focus on battery capacity (measured in mAh) and battery chemistry.

We recommend nickel metal hydride (NiMH) over nickel-cadmium (NiCd) cells. Without getting into too much detail—we have a separate solar lights battery-type comparison article for that—NiMH batteries are a greener choice and will last longer at a higher level of performance. Given the low power draw of LEDs in most outdoor lights, you generally don’t need more than 1,000 – 1,200 mAh capacity, so there’s no reason to splurge just because you see a higher number.

Backyard Boss Top 6 Batteries for Solar Lights

Why You Can Trust Us

At Backyard Boss, we’ve used and reviewed every type of solar light (and solar battery!) you can imagine since they first started hitting the mainstream more than a decade ago. We’ve gotten excited as solar panel quality and light quality has improved over time—and gotten cheaper!—to the point where solar lights are as good if not better than most wired lights, provided they get enough sunlight. We believe in sustainability and want only to recommend products (including batteries) that will last as long as possible.

Best Overall Solar Batteries

BONAI Solar Rechargeable 1,100 mAh Battery
    Basic but high quality rechargeable batteries that can withstand extreme outdoor temperature changes.

      Pros:

      Cons:

What We Like: TheBONAI solar rechargeable batteries check all the right boxes: 1,100 mAh capacity, 2,000 charge cycles, and NiMH chemistry. We even appreciate that the company is honest about life-cycle: you should expect the battery to only hit 75% maximum charge after three years of use. That is in line with our expectations for most high-quality batteries.

Who Should Buy It: These are perfect for most solar outdoor lights: path lights, string lights, and more. We’ve linked to the AA models, but within the BONAI Amazon store, you can find AAA models and higher-capacity batteries, which might improve performance for brighter floodlights.

Best Name Brand: Energizer Rechargeable Batteries

Energizer Rechargeable NiMH Batteries
    Made with 4% recycled batteries, these offer an extended five-year life, unusually long for the 2,000 mAh capacity.

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What We Like: These are partially made from recycled batteries, so we suppose you could call it the green option. The 2,000 mAh capacity might be overkill, but Energizer tech is better than most; you’ll still get about three years of life out of these.

Who Should Buy It: Those who don’t want to risk it with an unknown brand and are willing to shell out the extra cost; they are about twice the price on a per-battery basis.

Longest-Life Solar Batteries

Tenergy Solla NiMH, 1,000 mAh Rechargeable Batteries
    We've had success with these, but the recent consumer reviews are extremely mixed.

      Pros:

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What We Like: I can’t say we’ve specifically tested the five-year battery claim, but if correct, these are the greenest possible option.

Who Should Buy It: Though these have thousands of reviews, there are a large handful of reports of dud batteries. We haven’t had problems with them, and we generally trust Amazon to process return requests. As a result, we believe they are a reasonable alternative to our top pick.

Best NiCd Rechargeable Batteries

EBL NiCAD Rechargeable Batteries for Solar Lights
    If you need NiCd for any reason these are the best.

      Pros:

      Cons:

What We Like: The EBL NiCAD rechargeable batteries will work across all outdoor temperatures, will hold a charge for many years, have plenty of capacity, and a reputation for reliability.

Who Should Buy It: People who need to replace old NiCd batteries.

Best High-Capacity Solar Batteries for Floodlights or Christmas Lights

Brighttown NiMH Pre-Charged Batteries
    Massive 2,400 mAh capacity rechargeable batteries at a reasonable price.

      Pros:

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What We Like: The Brittown NiMH pre-charged batteries have a huge capacity, so they are very long-lasting, but that’s not always the most important factor for solar lights!

Who Should Buy It: These higher-capacity batteries more quickly lose their ability to hold a charge over time. By 500 charge cycles, you might be down to 50% of their max charge. As a result, we generally recommend 1,000 – 1,500 mAh batteries. But if you’re powering brighter floodlights, you might need these. They also are decent options for holiday solar lights that need extra power but aren’t in use all year. For everyday path lights, stick with other options.

How About Amazon Basics Rechargeable Batteries?

Amazon Basics 2,000 mAh Rechargeable Batteries
    From a brand you can generally trust these 2,400 mAh batteries will get the job done.

      Pros:

      Cons:

What We Like: They do what they say, but they are high-capacity batteries with high self-discharge. Expect only to use 50% capacity at 12 months. If you like the Amazon brand and you need the high capacity, go for it. But it’s not our favorite option.

Who Should Buy It: People who want Amazon-backed products over a generic Chinese brand.

Types of Batteries for Solar Lights

Cropped view of man holding batteries among can, glass bottles, plastic bags, paper strips, paper and plastic tubes

The most important thing that you have to know before purchasing new batteries for your solar lighting is to acknowledge that there are different types of batteries, each with its own pros and cons:

  • Nickel-cadmium batteries (which are labeled NiCd) were very popular once upon a time. In fact, they were considered to be the best rechargeable batteries that the market had to offer back in the 90s. Because of their rather light weight, they were extremely popular for portable devices, but since portability isn’t your concern when it comes to solar light, this advantage isn’t something you’re interested in. Compared to alkaline batteries, these won’t have any noticeable voltage drop as they’re drained of power, and that is one major advantage. However, as you’ll come to learn, they aren’t the most popular choice when it comes to buying rechargeable batteries for solar lights.
  • Nickel-metal hybrid batteries (labeled NiMH) are a new(er) market entry (at least compared to alkaline batteries), but they have quickly taken over the throne. When it comes to NiCd or NiMH for solar lights I personally think NiMH is best. They can hold more electric charge and are more eco-friendly when it comes to disposing of them.
  • Lithium-ion batteries (Li-ion) are definitely a type that you’ve heard of in the past. They have been around for decades, but it wasn’t until the 1980s that they actually became popular. In fact, your laptop or your smartphone mostly get their power from this type of battery. The biggest advantage that these bring over NiMH batteries is that they take way less to charge (about half the time), but the major drawback is that they are quite expensive.

What Makes a Good Solar Light Battery?

Graph showing the self discharge of a good solar light battery versus conventional rechargeable batteries.
Image credits: EBL via Amazon

Naturally, not every type of battery is compatible with just any solar light. Type and size are very important if you want to avoid wasting money on batteries that aren’t going to serve their purpose.

The instruction manual and even the packaging of your solar lights will most likely mention what type of batteries they’re compatible with. Always read this information before you go battery-shopping, as there is still a huge number of people that buy batteries that simply don’t correspond to the type of device they’re looking to power.

If you can’t find the instruction manual for your solar lights, simply open the battery compartment and take one of the batteries from there. The safest way to shop for batteries has always been taking an old compatible battery to the store. If you’re shopping online, you’re going to need the manual or some manufacturer instruction to make sure you’re spending money on the right item. As a general note, solar lights use AA or AAA batteries (because of their size similarity, people often mistake one type for the other and end up buying the wrong thing).

I wanted to insist a little bit on the four types of batteries mentioned before, but analyze them strictly from a solar light-related benefits/cons point of view:

  • NiCd batteries may be the veterans of rechargeable batteries, but they experience problems with memory charge. That means that you have to discharge the battery completely before you can recharge it, which means that you can’t really plan ahead, battery-wise. Let’s explain that: If you want to charge a NiCd battery that still has about 30 percent of juice left in it, the battery’s memory will remember that you only charged it with 70 percent-worth of power. The next time you’ll want to charge the battery, it will only fill with 70 percent of its normal capacity.
  • NiMH batteries are very efficient in terms of the economy, but they have a shorter lifespan compared to other types of batteries. However, they are more affordable than others.
  • Li-ion batteries are the champions of rechargeable batteries, but they aren’t all that affordable. The best part about them is that their voltage output will never be affected by the amount of charge left. That means that a Li-ion battery will give a solar lamp the same power whether it’s 100 percent charged or has a mere 20 percent of battery power left. They also have a longer lifespan compared to the other two types of batteries mentioned above.

Important: If you buy NiCd or NiMH batteries, never use them in the same compartment. You should either use one or the other. Because of the discharge difference between the two, the batteries are more likely to leak.

How We Picked

We selected rechargeable batteries that best hold their performance over multiple charge cycles. We preferred NiMH batteries because they better maintain performance over multiple charge cycles and don’t contain heavy metals, making them easier to recycle and a greener choice. Beyond battery type and capacity, we primarily focused on longevity and value to make our final selections.

Replace Your Batteries the Right Way

When you’re considering buying new batteries for solar lighting, it’s best if you replace them all at once. But the most important piece of advice that you should remember is that not all batteries for these lights are the same, and knowing the differences, pros, and cons of each might save you some money in the long run. Finally, after adding the new batteries, make sure to fully charge your solar lights; this will increase their efficiency.

We chose the BONAI branded lights as our favorites because they are reasonably priced, will last for at least three years, and will reliably power your solar LEDs.

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