Solar panels are an excellent way to capture the free energy that comes from the sun. However, even solar panels have one major drawback: when the sun goes down, the power stops flowing. To prevent that happening, we can capture that energy, and store it in one of the best solar batteries.
These batteries can also harness energy generated by wind turbines, or any other form of sustainable electricity production. Depending on the size of the solar battery, you can then use them for anything from charging a cellphone, to heating an entire home.
Solar batteries come with a variety of specifications. Whole-house units from brands like Tesla, Generac, and LG cost thousands of dollars. Then there are smaller models that fit in anything from golf carts to motor yachts, plus compact units for hiking and camping. In this article, we’re focusing on the best solar batteries for vehicles, off-grid cabins, tiny houses, and marine use.
— Best AGM: VMaxTanks 12V, 125Ah
— Best Budget: Weize 12V, 75AH
— Best Lithium: ExpertPower 12V, 100Ah
— Best Hybrid Gel: Renogy 12V, 100Ah
— Best Portable Pack: Blavor Qi Portable Charger 10,000mAh
How We Chose the Best Solar Batteries
Methodology
We researched the products from more than a dozen manufacturers in order to find a selection of different solar batteries, and offer solutions for a variety of needs. The following were the key criteria:
Performance: All but one of the solar batteries we used produces 12 volts of power, so the Amp hour rating (Ah) is the major difference. Two batteries of the same Ah will deliver broadly similar performance, so we chose a variety of capacities in order to provide suitability for different tasks.
Chemistry: A number of different chemistries are used within solar batteries. While they all perform very much the same when new, some degrade more quickly than others. We have chosen one solar battery from each of the four main types in order to highlight how this impacts on performance and lifespan.
Brand and Price: Some brands are widely recognized as supplying quality products, and in the main we stuck with those who have a long-established reputation for durability — a key facet of any battery. That said, price is always important so we have also tried to highlight value for money. The best solar panels will help you save more money and energy.
Related: The Best Solar Generators
The Best Solar Batteries: Reviews and Recommendations
Best AGM Solar Battery: VMaxTanks 12V, 125Ah
VMax Tanks
Why It Made The Cut: The VMaxTanks 12V solar battery offers reliable, safe performance, and is frequently recommended both for RV use and for off-grid living.
Specs:
— Amp hours: 125Ah
— Cycles: 1,000 (see below)
— Weight: 75 pounds
Pros:
— Long lifespan
— Safe to use at any angle
— Maintenance free
Cons:
— A little pricey
— Heavy
If you’re looking for a solar battery you can depend on to start your vehicles, the VMaxTanks 12V solar battery is a good choice. It’s designed with AGM (Absorbent Glass Mat), a type of lead-acid battery chemistry that has long proven an effective way to store power. However, unlike the original liquid-filled lead-acid type, AGM batteries have the electrolyte stored in sealed plastic containers. They won’t spill if tipped over so they can be used on their side or stood on end. They also require no maintenance beyond recharging.
The VMaxTanks 12V solar battery’s 125 amp hours of output also makes it a good option for the higher demands of RV use. However, better value will be achieved when several units are wired together to provide higher output for off-grid use. It also performs well in cold weather, where lithium ion batteries are less effective.
While more expensive than some, the VMaxTanks solar battery can be expected to last 8 to 10 years, or around 1,000 cycles. VMaxTanks quote a lifespan of up to 3,600 cycles, but by then it will only take a 10 percent charge. A noticeable drop in performance usually occurs when AGM batteries have dropped to around 40 percent capacity, at which point they are frequently replaced. Hence our lower cycle rating. Another way to save energy is by investing in the best solar panels.
Best Budget Solar Battery: Weize 12V, 75AH
WEIZE
Why It Made The Cut: Weize has a reputation for producing affordable batteries that offer competitive performance. This 75Ah model offers proven reliability, and the versatility to power a number of small electric vehicles.
Specs:
— Amp hours: 75Ah
— Cycles: 600 (estimated)
— Weight: 46 pounds
Pros:
— Reliable power for small vehicles
— No maintenance requirement
— Competitive price
Cons:
— Shorter life than premium models
— Packaging offers minimal protection
The Weize solar battery is another popular AGM model. So it has proven reliability, and is safe to use in any position without risk of spilling acidic electrolyte. It is maintenance free, and works well at low temperatures.
The Weize’s compact design, and 75Ah capacity suits a wide variety of functions. It is relatively lightweight at 46 pounds, making it viable for campsite use, and in small boats with trolling motors. It is ideal as a backup for a sump pump in the event of a power failure. It will run a variety of electric vehicles such as golf carts, lawn equipment, and wheelchairs. It can also be used to power emergency lighting.
This battery’s lifespan is quoted at around 6 years. While we were unable to find a figure for cycles, it is likely to be around 600 to 700. While these figures are lower than some, the Weize solar battery still represents good value when the low price is taken into account.
That said, we can’t speak from direct experience, but we have seen several reports of batteries being damaged on arrival. Most felt this was due to packaging that doesn’t provide sufficient protection.
Best Lithium Solar Battery: ExpertPower 12V, 100Ah
ExpertPower
Why It Made The Cut: ExpertPower’s LiFePO4 uses active battery management to boost performance and extend operating life. It is among the most durable solar batteries on the market, delivering consistent power levels for many years.
Specs:
— Amp hours: 100Ah
— Cycles: Over 2,500
— Weight: 22.6 pounds
Pros:
— Consistently high performance
— Outstanding durability
— Very light
Cons:
— Expensive
— Not as efficient as AGM in cold weather
Lithium ion batteries typically provide more power than lead acid and AGM, and over a longer period. LiFePO4 (Lithium Iron Phosphate) is the latest chemistry, and provides superior performance. A typical AGM solar battery provides about 50 percent of its capacity before power drops off. The ExpertPower LiFePO4 solar battery delivers up to 80 percent. They also degrade by only around 1 percent per year. The ExpertPower LiFePO4 is quoted as having a minimum life of 2,500 cycles, but it may be as high as 7,000 cycles over a 10-year period. They recharge faster than AGM too.
The ExpertPower LiFePO4 uses no rare earth metals so it is more environmentally friendly than many competitors. There’s also no danger from accidental overcharging, as the cells are incombustible. This makes the ExpertPower solar battery popular in hazardous environments.
In fact there are few applications that don’t benefit from the ExpertPower solar battery including RVs, marine craft, and off-grid installations. The only minor drawback is a drop off in performance in extreme cold (below 0 degrees Fahrenheit). Additionally, although the cost of the ExpertPower 12V solar battery is competitive for its kind, the initial cost is two or three times that of AGM alternatives.
Best Hybrid Gel Solar Battery: Renogy 12V, 100Ah
Renogy
Why It Made The Cut: Renogy’s 12V solar battery comes from a company whose focus is on renewable energy. It uses proprietary plate technology to provide excellent service life with high safety levels.
Specs:
— Amp hours: 100Ah
— Cycles: 750
— Weight: 63.9 pounds
Pros:
— Outstanding durability
— Non-hazardous
— Useful carry strap
Cons:
— Slow recharging
— More expensive than AGM
Renogy’s hybrid gel solar battery uses another form of lead-acid chemistry. While less common than AGM, it has actually been around for longer. It combines pyrogenic silica (which is inert) with sulphuric acid, as found in other lead-acid batteries.
The result is a thick gel that allows the battery to be used at any angle. It is also highly resistant to vibration, and very tolerant of temperature extremes. These features make hybrid gel solar batteries a popular choice for marine, off-grid, and industrial applications. Hybrid gel batteries are also frequently paired with emergency generators and medical equipment due to their longevity and reliability.
Renogy’s 12V hybrid gel solar battery has a life expectancy that can reach 12 years. Self discharge is also relatively low at around 3 percent per month, so it can be shelved for long periods if necessary. Recharge cycles are comparable with AGM, but the Renogy solar battery discharges more thoroughly for extended time between charges. That said, it isn’t rated as highly as typical lithium alternatives.
Best Portable Solar Battery Pack: Blavor Qi Portable Charger 10,000mAh
Blavor
Why It Made The Cut: The Qi portable charger has its own solar panel, providing energy storage potential wherever you go. It can then charge a variety of mobile devices via USB or wirelessly.
Specs:
— Amp hours: 10Ah
— Cycles: Unavailable (see below)
— Weight: 10 ounces
Pros:
— Rugged construction
— Multiple charging options
— Great value
Cons:
— Solar charging slow
— Comparatively bulky
Our final choice is somewhat different, but the Blavor Qi portable charger is an efficient way to provide energy for people who need to charge their mobile devices while on the move. With a maximum of 10,000 mAh (10Ah) available it is theoretically capable of charging three devices simultaneously, though this does reduce charging speed. It will also depend on connectivity. The Blavor Qi offers wireless charging for suitably specified cellphones, plus 2 USB ports.
The rugged design is rated IPX5 waterproof. Technically that means it can sustain a consistent low-pressure spray. In real terms it can take more or less any weather conditions short of being submerged. It is also dustproof, and shock-resistant, though the level of protection does make it a little bulky when compared to some rivals. An LED flashlight is built in, as is a compass. These underline the Blavor Qi portable charger’s suitability for hiking and camping.
Blavor does not provide charge cycle information. Similar devices offer anywhere from 200 to 1,000 cycles but unfortunately there is no way to assess this without running the Qi portable charger for its entire lifespan. The relatively small size of the solar panel does mean battery recharging speed is quite slow. Hanging it from the outside of a pack to maximize exposure is recommended where practical.
Things to Consider Before Buying a Solar Battery
Solar battery chemistry is a key issue, and we have discussed this in detail with each of our top four picks. The following are other features that will have a major impact on finding the best solar battery for a particular function.
Power Rating
The voltage demands of any piece of equipment are fixed. So for example many golf carts use a 6-volt battery, most cars use a 12-volt battery, and large trucks might use a 24-volt battery. You can’t fit a 24-volt battery on a golf cart, or a 6-volt battery on that truck. It won’t work.
However, each battery can vary in terms of Amp hours (Ah). Strictly speaking, this is the number of amps the battery can supply in an hour. However, in real terms the figure is more about how long the battery will provide power before it needs recharging. So for example a 100Ah solar battery can provide 10 amps for 10 hours. A 200Ah solar battery will provide the same 10 amps for 20 hours, or 20 amps for 10 hours.
Both batteries will run the same 12-volt equipment, but one will do it for longer than the other. The tradeoff is cost. More Amp hours means higher prices, which is why a recommended Ah is often advised by buggy, car or RV manufacturers. A more powerful solar battery could be fitted, but performance gains may not be sufficiently noticeable to warrant the increased costs.
For off-grid use, in a cabin or small homestead for example, it is possible to connect 12-volt solar batteries together, in series or in parallel, in order to increase voltage and/or amp hours. How to do that goes beyond the scope of this article, and we suggest expert advice is sought. You can also take your energy saving to a new level by adding solar power to your home.
Battery Life
Most solar batteries are called ‘deep cycle’ because they provide (discharge) a higher percentage of their stored energy than standard lead acid models. This can vary from around 50 percent to more than 80 percent depending on chemistry.
Each time a solar battery goes through a discharge and recharging cycle, it loses a little of its capacity. For at least the first couple of hundred cycles, the difference will be negligible, but eventually it will impair performance to the point where the solar battery will not provide sufficient power to drive the required equipment. Whole-house models are rated in years, and frequently last more than a decade. While this is also true of smaller solar batteries, they may also be rated in cycles. Typically this will be upwards of 500 cycles, and it can be several thousand.
It is also worth checking self-discharge rates. The charge in any battery will trickle away if left unused. Figures are usually given as a percentage per month. Old-style lead acid batteries can have self discharge as high as 20 percent, whereas the best solar batteries can be as low as 1 percent.
Weight and Size
Most 12-volt solar batteries are fitted in vehicles or stationary equipment, so weight isn’t usually a problem. However, if you’re using backup batteries for camping for example, it’s a figure worth checking. They can vary from around 20 pounds, to upwards of 70 pounds.
Choosing the correct size can also be important. Physical dimensions shouldn’t be difficult to find, but there is also a figure called the ‘BCI Group Size’ (Battery Council International) which is an international standard often quoted by vehicle and equipment manufacturers.
FAQs
Q: What are the best batteries for solar power?
Lithium ion, and in particular lithium iron phosphate, are generally considered the best batteries for solar power because they are more compact, and have better discharge cycles. However, they tend to come with higher price tags.
Q: What size solar panel to charge 12v battery?
The size of a solar panel to charge a 12V battery can vary. Any panel with an output above 100 watts will do it, but could take 12 hours or more. A 200-watt solar panel might do it in 8 hours or less. For more accurate figures, you would need to look at the performance of a specific panel.
Q: How much does a solar battery cost?
Solar battery cost can be anywhere from around $70.00 for a 12-volt model to over $10,000 for a whole-house installation. Mostly it depends on power output, though battery chemistry also has an impact.
Q: Which solar batteries last longest?
The longest lasting solar batteries are lithium iron phosphate (also called LiFePO4), a type of lithium-ion battery.
Q: How many solar batteries are needed to power a house?
It isn’t really a question of how many solar batteries are needed to power a house, but rather the amount of power required. While smaller units can be daisy-chained for tiny homes and cabins, the usual approach to adding solar power to your home is to use just one or two high capacity units. And you can add more energy-efficiency to your life with the best rechargeable batteries.
Final Thoughts
Our top pick for best solar battery, the VMaxTanks 12V solar battery is a powerful all-around model that underlines the capabilities and versatility available. The Weize model is a more affordable option for those who need to power less demanding devices like mobility scooters or trolling motors. While both of these are likely to appeal for their competitive pricing, investing in a lithium solar battery like the ExpertPower LiFePO4 can actually work out as better value in the long term. Especially if the demand is for consistently high performance, and frequent charging cycles.
This post was created by a non-news editorial team at Recurrent Media, Futurism’s owner. Futurism may receive a portion of sales on products linked within this post.
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