If you’re in a hurry and want to know which are the overall best solar batteries we found, check out the Battle Born Lithium Iron Phosphate (LiFePO4).
This post contains affiliate links. We may get paid an affiliate commission if you buy something or take an action after clicking one of the links on this web page. This does not affect your purchases or the price you may pay, but helps support our team continue to provide you with the best and most up to date information.
Finding the best solar batteries to store the solar power you generate can be overwhelming. But with a few pieces of information, you can build the best solar battery bank specific to your needs at an affordable price.
The first step to simplify the job is to figure out what type of solar battery you need and how many.
Not having enough capacity can burn up your system. Have too much and you’ll waste money on things you don’t need.
A single solar battery may not seem too expensive. But the cost adds up when you realize how many solar batteries you will actually need to have enough power for days when you can’t charge your battery bank.
To begin, we need to understand how much power you use over a period of time, described in the unit of measure called Kilo-watt Hours (kWh).
Don’t worry, we’re going to try and keep this in as plain of English as possible. But you will need to learn some basic terms to read the labels on what you’re buying.
Once we know how much power over time you will need it will tell us how to get away with the fewest batteries necessary.
By learning the volts, or the force of the current your devices demand, and amps, or total electricity going through the wire, we’ll know which are the best solar batteries you need to keep your devices up and running for the longest period of time at the best price.
In this article we will review the following solar batteries:
- Universal Power Group 12V 100Ah AGM SLA Deep Cycle Battery
- Renogy Deep Cycle Hybrid Gel 12 Volt 100Ah Battery
- Weize 12V 100AH Pure Gel Deep Cycle Battery
- Battle Born LiFePO4 12V 100Ah Deep Cycle Battery with Built-in Battery Management System (BMS)
- VMAXTANKS 6 Volt 225Ah AGM Battery
If you would like to read each of the reviews on how we came to our decision, you can jump to them using the table of contents below.
Or read on to understand how you can determine which are the best solar batteries for yourself.
Why A Solar Battery May Be Right For You
Do you live connected to the grid and use solar panels to reduce your electric bill? Without a way to store the excess energy you produce, you may be leaving money on the table.
While you sell your power back to the grid at one rate during the day, you have to buy it back at four times that rate at night.
If you want to live completely off-grid, there’s no other way to power your electronic devices when there is no sun without a battery.
There are many benefits to storing your own power, including autonomy, convenience, and cost.
Yes, a battery bank will be an investment but, with the savings you make from not having to pay for an electric bill you will soon see the savings after you earn back your initial investment.
How Does A Solar Battery Bank Work?
If you have a solar panel system without a battery, you sell back the excess energy your panels produce to the grid at a reduced rate.
While this may lower your electric bill, you are actually losing money by not storing that extra energy for yourself.
A solar battery bank allows you to save that excess energy for later use instead of selling it cheap and buying it back at premium.
The way the system works is you route your solar panels to the batteries, then route the batteries to your electrical box.
Your appliances pull energy from the batteries, and the solar panels recharge the batteries.
The most ideal situation is when you store enough power in your battery bank and still produce enough to sell back to the grid.
In some cases you can end up with an electric bill net positive at the end of each month.
Wouldn’t it be nice for the electric company to owe you money for a change?
Now how many solar batteries you need will depend on how much power you use on average and the type of battery you get.
You should also consider how much power you will need in the event you have a few days when there is no sun; for example, in the winter when the sun is lower and it’s cloudy, or you must endure a storm.
How long you’re able to power your home without power from the grid we refer to as “autonomy.”
How autonomous you need to be is relative. For example, if you live in the southwestern United States where you get 8 hours of sun even in the winter, then maybe you only need one or two days of autonomy, or enough power stored in your batteries to survive without sun or the grid for up to two days.
But, if you live in the northeast, where you may not see the sun for a week during the winter, well you may need to increase your autonomy to up to seven days.
You know your situation best and will need to be the judge when it comes to determining your needs.
Doing this exercise will also make you more aware of your consumption and how you can reduce it to allow for a more affordable solar battery bank.
Depending on the type of battery you have will limit you on how low you can discharge, or drain, them before they will no longer recharge.
This limitation will also reduce the total power you have available to use and will thus increase the number of batteries you need.
For example, for lead-acid batteries you should not discharge your batteries more than 50% of its rated capacity at most.
Some even refrain to discharge below 70% capacity before charging again to maintain the battery for the longest period of time.
Lithium solar batteries don’t have this problem and you can drain them to their entire rated capacity and they will still come back to their full charge.
For example, let’s look at if you have a 12 Volt (V) 100 Amp hour (Ah) Lead-acid battery and a 12V 100Ah Lithium battery.
If you need 100 amps over the period of 1 hour, then you will need at least two lead-acid batteries, because you can only discharge them to a maximum of 50% of their rated capacity.
Whereas, you would only need one lithium ion solar battery that can discharge to its full rated capacity.
Let’s look a little deeper into this phenomena.
What To Look For In The Best Solar Batteries
There are three components we need to keep in mind when buying a battery: the voltage (V), the “amp” hours (Ah), and the composition of the battery i.e. lead-acid, gel or Lithium.
I know we’re introducing some new technical terms here, so let’s review.
Voltage
The voltage is the force, or volts, of current your appliances or devices need. If you want to visualize it think of the pressure at which water goes through a hose.
Depending on how you intend to use your solar power, you will need to determine if a 12V, 24V or a 48V system will be more efficient for you.
Understanding how much voltage your system should have is beyond this article. But you can learn more about building systems with different voltages in this article here.
Amperage
The number of amperes, or amps for short, will tell you how much electricity, or the total capacity, your appliances need to operate.
Imagine trying to water your garden with a kink in the hose.
If you don’t get enough power to the device, it can damage the inner workings and cause it to fail.
The battery’s Amp hour rate will tell you the capacity over a given time.
Composition
You’ll want to consider the chemical composition of the battery, whether it is a lead-acid, gel or lithium composition.
There are various factors that differentiate one type from another and we will get into detail about each below.
But for a quick example,a lead-acid battery is your least efficient battery, but the most affordable. It’s a very old technology, but it gets the job done.
Yet, with lead acid batteries you will need more of them to reach the same capacity that a gel or lithium battery provides.
This is because you can only discharge a lead acid battery to 50% of its capacity before you damage it.
So how many 12V 100 amp hour (Ah) lead-acid batteries would you need to draw a load of 100amps for one hour? You would actually need two to run that load to prevent a single battery from discharging to 100%, and maintain that 50% depth of discharge (DoD).
Round Trip Efficiency
This term refers to how much power you get back from the battery, and how long it takes to charge the battery. The better the battery, the higher this efficiency. But it’s important to note that no system is 100% efficient.
There will always be an inevitable loss of energy due to heat. It’s rare for battery manufacturers to disclose the actual efficiency, because it will also depend on how well you build your system. For this reason we have to overestimate our needs when using lead-acid batteries.
Battery Life and Warranty
Don’t buy a battery without a warranty! Most manufacturers will have at least a one year warranty, and some of the better ones will go up to ten years. Choose at your own risk.
Calculating Your Total Amperage Needs
It’s math time! To know how many batteries you need, you will need to know how much power you use.
We measure power in Watts (W). You may notice the electric company charges by the hours of Kilo (or 1000) Watts you use each month.
You can use that number and divide it by 30.3 (the average number of days in a month) and then by 24 to understand your daily Kilo-Watt hour (kWh) usage.
Or if you are building a system to only run specific appliances, then you can calculate the kWh by taking the most power required from each device and multiplying it by the number of hours you expect to use it.
We can find the power (aka Watts) on the tags of the power cable for the device, on the box, or sometimes it’s printed on the device itself near the battery or power port.
If the label does not say the wattage, then you can calculate it. They should at least give you the Volts and the Amps. We can then calculate the Watts by multiplying the Volts by the Amps.
For example a device with a 12V and 100Amp rating will have a total power need of 1200 Watts (12V x 100A = 1200W).
If you want to use that device at max power for one hour then it will run at 1200 watt hours or 1.2 kilowatt hours ((1200W / 1000) x 1 hour).
Thus you will need a battery with enough juice to power that device.
To calculate how much power a battery can provide you multiply the battery’s voltage by the amp hour rating to get the watt hours available.
So if you have a 12V battery with 100 amp hours, then it can provide 1200 watt hours.
Please keep in mind the composition of the battery when making this calculation.
If you remember you can only discharge a lead-acid battery to 50% capacity. So, you will actually only get half, or 600 watt hours, from one battery with a 12V and 100A rating, and will need to get two to power the device needing 1200 watts.
More Questions To Find The Best Solar Batteries
What Is A Deep Cycle Battery?
A deep cycle battery is a battery designed to discharge near its full capacity and to power devices for longer periods of time,hereas, a starter battery, i.e. a car battery, provides short high-current bursts of power.
You would use this to “start” a large motor for example, and discharge very little of its capacity.
Can I Use A Car Battery For My Solar System?
Car batteries are the worst option when it comes to storing the solar power you generate.
As we said, car batteries deliver massive amounts of energy quickly, and then recharge slowly.
Whereas deep cycle batteries deliver a lower amount of power over a longer period of time and recharge quickly.
What’s The Difference Between Sealed Lead-Acid Batteries (SLA) vs Flooded Lead Acid Batteries (FLA)?
Both are lead-acid batteries. Lead-acid are the most common batteries, and the oldest technology.
They are both similar in performance, depth of discharge (DoD) and cycle life.
The main difference between them is the work needed to maintain the flooded battery compared to the sealed battery.
A flooded lead-acid battery requires maintenance. You need to water the cells every so often, perform periodic equalizations, and control the electrolytes.
Also when charged under certain conditions it can produce hydrogen gas.
Thus, you would need to house the battery in a sealed enclosure and ventilate it to remove the hydrogen gases and prevent explosions.
A sealed lead-acid battery, as it’s name suggests, is already sealed, and does not need this maintenance.
Some argue that because of this inability to maintain the sealed battery, you may not be able to keep it as long as a flooded lead-acid.
But the way we see it, you’re more likely to forget to maintain a flooded lead-acid battery and kill it sooner.
Can I Mix My Batteries?
You don’t want to mix different chemistries or ages of batteries. The charge settings are different for different types of batteries.
If you replace an older battery and mix it with a new battery of the same type, the charge output will most likely be different and cause a problem.
You’ll need to equalize most batteries first before introducing a new battery into a bank of batteries that is a year or older.
Do I Need A Battery Or Can I Run My Appliances Directly From My Solar Panels?
If you are still connected to the grid, the solar panels alone can provide power for your devices to use when there is sun. You can then switch back to using power from the grid when there is no sun.
If you are planning to live off-grid you will need a battery to store power to use when there is no sun.
What Is The Peukert Effect?
The Peukert Effect describes how if you use a lot of electricity all at once you will diminish the battery’s capacity.
We won’t go into the details as to why this happens, but know that this only applies to lead-acid batteries.
For example, take a 12V lead-acid battery with a standard 100 Amp Hours (Ah) rated at 20 hours. This means the battery has the ability to provide 100amps of power over 20 hours of use.
But if you draw a heavy load and need to discharge 100 amps in 1 hour, you will actually receive a fraction of the labeled capacity.
This is a result of the Peukert Effect.
The 100 amp hours is only promised over a 20 hour period, or a slower more constant use of power rather than a quick burst.
This is important to keep in mind when calculating the total amperage you use and thus how many batteries you will need to support your usage.
To compensate for this effect you will need to increase the total amps of your system if you intend to use high loads often.
Common things that draw high loads are power tools, microwaves or fancy coffee machines. The higher the load, the greater the effect.
Most batteries will come with a scale that will help you calculate the actual capacity it’s rated for a given period.
If you are going to use high loads it’s important that you pay attention and don’t over discharge your batteries .
The Peukert Effect does not apply to Lithium batteries, and you will get the full rated capacity no matter how high the load.
If you have a large bank of lead-acid batteries and run small loads, then you will have a less pronounced Peukert Effect.
What’s The Difference Between A 12V, 24V, And 48V Battery?
When you hear talks of higher voltages what they’re referring to is how much force the battery is able to deliver.
Why you would need more force depends on the intended use. If you need a small system to keep a few devices on while the power is out, a 12V system should be more than enough.
If you’re trying to power a sailboat or an RV then a 24V system may be better suited.
But if you’re trying to power an entire house, then a 48V system would be a better use of your money.
The higher the voltage the smaller the gauge of wire you can use.
Again, we won’t get into the details of why, but it’s important to know when determining the cost of your entire system.
If you do go with a higher voltage system, you will need a converter to step it down for your 12V devices. This extra cost is negligible compared to the savings you will get from the lower gauged wiring alone.
Should I Connect My Batteries In Series Or Parallel?
You can increase the voltage of your system by connecting lower voltage batteries in series if necessary.
If you intend to run a system with higher voltage for a longer period of time, you may find it makes more sense to buy higher voltage batteries.
Trying to connect too many lower voltage batteries in series and parallel to increase the capacity will overload the system.
Remember, batteries do not like to be in parallel as it will lead to quicker degradation. Avoid connecting more than two batteries in parallel for the best performance.
How Much Do The Best Solar Batteries Cost And How Many Do I Need?
Ok, sit back and grab a candy bar or something, because this is going to take a minute.
The short answer is it depends on three things:
- The total load you need to power.
- The number of days of autonomy you would like as backup when you can’t charge your batteries.
- The type of battery you’re using to understand how many batteries you will need.
Let’s do a simple exercise to show you how you can calculate your budget.
Say, during a power outage, you want to have enough power for just the essentials, i.e. a refrigerator and your microwave, for up to three days of use.
First, let’s see how much power each device needs to run.
You can check the specs on each device or use a power meter to see the refrigerator needs 120W and the microwave 1000W.
Now we know you’re not going to be running these items for 24 hours each day, so we will use averages.
The average fridge runs 4-5 hours a day.
So 120W at 5 hours per day will give you 600 Watt hours (Wh).
For three days of autonomy, you will need to have 1800 Wh available.
And let’s say you run the microwave three times a day for breakfast, lunch and dinner, for a total use of 1 hour per day.
We’re going to do the same math and show 1000W for 1 hour per day is 1000 Wh.
For three days of use we will need 3000 Wh stored.
So now we add 1800 Wh and 3000 Wh to know that our total power needed for three days of autonomy will be around 4800 Wh.
So how many batteries do you need? Let’s say you decide to use the lower priced lead-acid batteries with 12V and 100 Amp hours.
If you multiply 12V by 100Ah, then you get 1200 Watt hours.
But if you remember lead-acid batteries can only discharge 50% of its total capacity.
So you really only have 50 Amp hours available.
So we divide 1200Wh by 2 to get 600Wh per battery.
Now we know we will need enough batteries to store up to 4800Wh.
So if we divide the 4800Wh we need by 600Wh each battery provides we get 8 batteries.
Now it’s not recommended to connect 8 batteries in parallel, so you will need to configure them correctly.
You can see how to do that here. But in the end you will need 8 batteries worth of capacity to get the job done.
Maybe 2 more for safety. You always want to overcompensate.
You can reduce the total use of the devices to not max out the system, but for this example, we’ll stick with the round number.
Now your average lead-acid battery goes for around $200, thus 8 multiplied by $200 will call for a $1600 investment.
That does not include the other components that are needed to charge the batteries and deliver the power to your devices.
More on that later.
Are Sealed Lead-Acid Batteries Really Cheaper Than Lithium Or Gel Batteries?
Well, that’s a common myth that we should bust. If you do the math, you will find the batteries with a higher price tag are actually cheaper for you in the long run.
Let’s continue with the same example above and see what happens when we swap out the lead-acid battery for the higher priced lithium battery.
The average lithium battery costs around $1,000. Now before you have a heart-attack, let’s do some more math.
First a lithium battery can be fully discharged. So you’ve just cut the number of batteries you need to store the same amount of available power in half, or 4 batteries.
Now let’s consider that you can only cycle a lead-acid battery around 300 times, where a lithium battery can cycle up to 3000 times.
To deliver as much power over the same amount of time as a lithium battery, you would need to replace your lead-acid batteries 10 times.
So let’s look at the 4 lithium batteries you need at $1000 each, for a total investment of $4,000 for 3000 cycles at full discharge, compared to the eight lead-acid batteries at $1600 you would need to replace ten times for a total cost of $16,000 over the same 3000 cycle period.
Now you can have your heart attack.
We won’t go into the fact that you would actually need more lead-acid batteries due to the loss of efficiency due to the Peukert Effect that we talked about before…
Are All Lithium Batteries The Same?
No. There are six different compositions of lithium batteries.
You can read about the various types of lithium batteries if it interests you.
But the type of lithium battery you choose will depend on the application.
For our analysis we’re sticking to the function of storing energy generated by solar panels, which the Lithium Iron Phosphate (LiFePO4) handles best.
You can read more about it below.
Our Choices Of The Best Solar Batteries
The Best Solar Battery | 12 Volt Sealed Lead Acid (SLA)
Universal Power Group 12V 100Ah AGM SLA Deep Cycle Battery
Check Price On Amazon
For the record, lead acid batteries are not our favorite. But they are the most economical (in the short term) if you need something quick and don’t want to fork out a lot of cash.
If we had to choose one, the Universal Power Group provides a stand-up no frills deep cycle sealed lead acid absorbed glass mat (AGM) battery that will get the job done. (Say that ten times fast).
All the acid is in the glass, making the battery spill-proof, even if the seal breaks, and thus much safer.
Moreover since there is no free liquid present, the battery is nearly immune to freezing.
The low internal resistance also eliminates overheating even under heavy use.
This makes them a great option for those who need a solution for very cold or hot environments.
Because they are sealed you do not have to maintain or ventilate them like you would a flooded battery.
We use “maintain” carefully because that doesn’t mean you don’t need to take care of them. It’s very important to keep them charged properly.
Although with the AGM material the battery has a low self-discharge rate and can sit longer in storage between charging.
Because it’s sealed you can mount it in any position.
Its durable casing helps make it more resistant to shock and vibrations under harder conditions.
This 12 Volt has a capacity of 100 Amp hours and can connect in series if you want to increase the voltage to 24V or 48V. You can also connect them in parallel if you want to have a higher capacity battery bank.
You may want a friend to help you get them into position, as each battery weighs in at over 60lbs.
Lead acid batteries are able to last between 200 to 300 cycles at 50% discharge.
UPG provides a one year limited warranty for all their batteries, assuming of course that you don’t discharge it below 50% of its rated capacity.
Keep that max discharge rate in mind when determining how many you will need for your power storage.
For example let’s say you need 100 amps to run your appliances. This battery is rated for 100 amps, but you can only discharge it to 50%, or 50 amps of usable electricity under normal conditions.
That means you actually want two batteries to get the full 100 amps your appliances need.
Be sure not to overcharge your AGM battery otherwise you will “gas” the battery and lose conductivity.
Make sure to update your charger settings so that it will not charge over 14.4V.
PROs
- Sealed Absorbent Glass Mat construction makes for a safer, longer lasting battery
- Lead Acid Batteries are more affordable (individually and in the short term)
- AGM technology makes it immune to freezing and overheating
- Because it’s sealed you can mount it in any position, and not worry about spilling.
- Maintenance free.
- Low self-discharge rate allows it to hold its charge longer between recharging.
- Can be wired in series or parallel
- 1 year limited warranty.
CONs
- Cannot discharge more than 50%, meaning you need more batteries to get the job done.
- Lead-acid batteries do not last as long as other types of batteries, i.e. lithium, and are required to be replaced more often.
Check Price On Amazon
The Best Solar Battery | 12 Volt Hybrid Gel
Renogy Deep Cycle Hybrid Gel 12 Volt 100Ah Battery
Check Price On Amazon
Renogy is a renown solar technology manufacturer, and they set the bar high when it comes to batteries for solar use.
They offer a variety of battery types including AGM lead-acid batteries, Lithium Iron Phosphate batteries, and Pure or Hybrid Gel batteries.
If you’re not familiar with gel batteries, they are like AGM batteries in that there is no liquid, but instead of glass, they use a gelified acid.
This also makes it leak proof, maintenance free, and thus safer to handle compared to a low-cost flooded lead-acid battery.
A hybrid gel battery is an absorbent glass lead-acid battery but they use a gel instead of a mat. This gives it the advantage of an increased cycle life in comparison to that of a standard AGM battery.
Renogy provides both hybrid and pure gel batteries in both 100 Ah and 200 Ah options.
We find the 12 V 100 Ah Deep Cycle Hybrid Gel battery is the best middle-of-the-road choice.
The hybrid gel battery is ideal for those who want an affordable battery like the standard AGM but are willing to pay for a longer life.
It is still a lead-acid battery, and so it’s not recommended to discharge it more than 50%. Keep that in mind when planning how many batteries you will need.
Gel batteries are also idyllic for use in very hot climates.
Renogy constructs their battery with corrosion resistant grids that enable a life of more than 750 cycles at 50% depth of discharge.
You can also connect them in series or parallel to customize your voltage and amperage needs.
And because of it’s similar construction to that of a standard AGM battery it too weighs in around 60lbs.
Do not charge at a voltage higher than 14.4V to avoid drying out the gel and rendering it non-conductive.
PROs
- A gel hybrid allows for slower deeper discharges and quicker and more reliable recharging to full capacity compared to a standard AGM battery.
- Ideal for those who need a battery in hot climates.
- Non-hazardous, leak proof.
- Maintenance Free.
- Can be wired in series or parallel
- Lasts twice as long as a standard AGM battery
- 3 year material warranty
CONs
- More expensive than a standard AGM battery.
Check Price On Amazon
The Best Solar Battery | 12v Pure Gel Battery
Weize 12V 100AH Pure Gel Deep Cycle Battery
Check Price On Amazon
A pure gel battery is similar to an AGM battery in that it is a sealed lead-acid. This means that it too is spill-proof and requires no maintenance.
But, as its name suggests, it uses a thick gel to hold the acid together in place of absorbent glass fibers.
The benefit of this is that it operates extremely well in hot climates, but does poorly in cold climates.
An easy way to remember which battery does what is to think of an AGM battery being a great option for a snowmobile. While a pure gel battery would be great for a jet-ski in the Bahamas in the summer.
The gel battery is better suited for use in hotter climates because they have less internal resistance.
They will also recover and recharge much better and have a longer life cycle compared to an AGM battery.
They are designed for daily use and can live up to 350 cycles under optimal discharge conditions of up to 50%.
You will have to take extra care to make sure to recharge the gel batteries correctly. Meaning you should have a charger that will not charge at a rate higher than 14.4V which would render the gel dry and no longer conductive.
As we mentioned before Renogy provides a great selection of Gel batteries, but their pure gel batteries tend to be out of stock.
So the lesser known Weize will do just as well, if not perform a little better, and they’re a little less expensive then Renogy.
The Weize 12V is rated for 100 amp hours, but again because it is still a lead acid battery you will not want to discharge it below 50% of its rating.
They weigh in at 67lbs.
And Weize provides a 1 year warranty for its batteries.
One thing that’s important to note before you consider the Weize is that they use M6 (1/4″) ring connectors as opposed to M8 (5/16″) that Renogy 12V 100AH gels use.
So you will need to make sure the cables you have will fit, or get new cables.
PROs
- Ideal for hot climates
- Designed for daily use, with deep discharge and quick recovery
- Low self-discharge, meaning it can sit on the shelf without losing a charge for longer periods of time between being recharged.
- Longer lifespan than other lead-acid batteries
- Can be wired in series or parallel
CONs
- Not suited for cold climates
- More delicate internal composition requires extra care not to overcharge
- Heavy
Check Price On Amazon
The Best Solar Battery | 12V Lithium Iron Phosphate (LiFePO4)
Battle Born LiFePO4 12V 100Ah Deep Cycle Battery with Built-in Battery Management System (BMS)
Check Price On Amazon
Finally, the moment we’ve all been waiting for. The Lithium Iron Phosphate battery or LiFePO4 for short.
If you’re looking for the best battery for your solar power storage needs, you will not find a better performing battery than the Battle Born LiFePO4 12v 100Ah deep cycle battery.
Why is it so good? First, a LiFePO4 battery will outperform any lead-acid or gel battery.
Lead-acid batteries suffer from the Peukert Effect, or loss of efficiency due to heat. This in turn affects the amount of power you get for the money you spend.
But, LiFePO4 batteries do not suffer from this effect, and you get all the power you pay for.
The next problem with lead-acid that the LiFePO4 batteries resolve is the allowable depth of discharge.
If you have a 100Ah lead-acid battery, you still can only discharge it to 50% of its total capacity.
Which again means if you need 100 amps for one hour, you would actually need to buy two batteries!
Whereas with the lithium battery, all things remaining equal, you will get all the amps without a problem discharging it below 50%.
The cherry on top is they also recharge faster than any other battery technology.
Now we’ll get right to it, these batteries are not cheap upfront.
You could get five lead-acid batteries for the price of one LiFePO4 battery.
But, it’s foolish to judge the price tag without thinking about the lifespan and use of the battery to calculate total cost.
A lead-acid battery when maintained correctly, could last around 200 to 300 cycles at 50% discharge.
But, one LiFePO4 battery can fully discharge for up to 3000 cycles under normal use, or up to 6000 cycles at the same 50% discharge rate.
So let’s do a little math before we judge price tags. Bear with us, we’ll do the arithmetic for you if you missed our first example above.
If the average price of a 12V lead-acid battery with 100Ah rating is around $200, and the average price of LiFePO4 battery with the same 12V 100Ah rating is around $1,000, how much are you actually spending to build a system to deliver 100amps over 1 hour at 12V?
We know this is not a practical situation, but we’re trying to make the math easier to follow.
First we have to remember that you can only discharge the lead-acid battery up to 50%. So right off the bat, you’re going to need two, whereas the LiFePO4 can do the job on its own.
So that’s now $400 for the lead-acid compared to the $1000 for the LiFePO4.
Then we have to consider the Peukert Effect if we’re discharging a high-load which can reduce the performance of the lead-acid battery by up to 25-30%.
This would call for a third lead-acid battery to give you the same consistent power load the LiFePO4 can provide.
So now that’s $600 for the three lead-acid battery bank compared to $1,000 for the single LiFePO4.
Then you have to take into consideration the lifespan of the batteries.
The lead-acid batteries last an average of 200 to 300 charge cycles. While the average LiFePO4 can last around 3000, or at least ten times longer at full discharge.
So you will have to replace your lead-acid batteries ten times to get the same performance over the same period. Which amounts to a total investment of a whopping $6,000 compared to a $1,000 investment in just one LiFePO4.
When we compare the two types of batteries in dollars and cents, the difference becomes night and day.
Furthermore, the LiFePO4 batteries are safer than the sealed lead-acid batteries. And they need no maintenance above making sure to charge them correctly.
If you then consider that each lead acid battery weighs around 60 pounds, or 180 pounds for three, where the single LiFePO4 battery weighs 30 pounds, you’re not only going to avoid breaking the bank, but you won’t break your back either.
Now we understand that there are some times where a cheap lead-acid battery would be perfectly acceptable. And you just don’t want to swing the high upfront cost for LiFePO4.
But keep in mind that today, especially when buying through Amazon, there are 0% financing options that really make this a no brainer.
When it comes to which brand of LiFePO4 battery you should buy, Battle Born out shines the rest with their superior products, customer service and warranty of up to 10 years.
Their LiFePO4 also includes a Battery Management System (BMS) that automatically shuts off the battery to protect it from common causes of failure like temperature problems or grounding issues.
This will save you some money as well as time from having to buy and install a separate BMS.
They’re also made from 100% safe and nontoxic renewable energy sources for all you survival hippies out there like us who care about not contributing to the end of the world.
PROs
- Does not suffer from loss of efficiency due to heat (Peukert Effect)
- Can discharge fully without danger of damaging the battery
- Nontoxic
- No acid to leak out if damaged or dropped
- Safely mounts in any position
- Maintenance-free
- Recharges much faster than other types of batteries
- Built-in battery management system (BMS)
- Protected from ground faults
- Lightweight (30lbs) – ½ the weight of lead-acid batteries
- Can be wired in series or parallel
- Lasts 10 times longer than a lead-acid battery
- 10-year warranty
CONs
- High per unit upfront cost
Check Price On Amazon
The Best Solar Battery | 6V Absorbed Glass Matte (AGM)
VMAXTANKS 6 Volt 225Ah AGM Battery
Check Price On Amazon
Ok. So we didn’t convince you that the LiFePO4 batteries were worth the investment and you want a low-cost battery that’s “good enough” to get the job done.
Well then we have one more recommendation for you to consider, and that is to use 6V deep-cycle batteries instead of the standard 12V batteries.
Now you may be wondering how you’re going to use a 6V battery to provide the 12V your devices need.
The trick is to pair two 6V batteries in series to double the voltage and give you those 12V.
While you do have to buy two to get the same voltage as one 12V battery, you benefit from gaining twice the capacity as your standard 12V battery.
Were you to get two 12V 100AH batteries and connect them in parallel, you would double the capacity, and thus have a battery bank of 12V with 200Ah.
If you take two 6V 225Ah batteries and connect them in series you would double the voltage and have a batter bank of 12V and 225Ah.
So what’s the difference if you get two 12V or to 6V if the outcome is the same?
The 6V batteries have three lead cells compared to the 12V six cells and packs more lead per cell.
The 6V batteries are lead-acid and it’s not recommended to discharge them more than 50%. But you can go up to 80% in an emergency and still recover, where this may not be the case with a 12V.
They also will last longer.
A 6V battery at 50% discharge can last around 600 to 700 life cycles whereas we mentioned before that the 12V can last just around 200 to 300 cycles.
They also recharge much faster than the 12V battery.
With a deeper discharge cycle, a longer lifespan and a faster recharge capability using 6V batteries for your solar power storage system is a superior and more affordable solution despite their slightly higher price tag.
PROs
- Same footprint (slightly taller) as a 12V but with twice the capacity and lifespan
- Safer to discharge with a higher ability to recover from discharges below 50%
- Sealed and therefore safer to handle and position
- Maintenance-free
- Low self-discharge rate allows it to hold its charge longer between recharging
- Can be wired in series or parallel.
- 1-year limited warranty
CONs
- Not recommended to discharge more than 50%, meaning you need more batteries to get the job done
- Lead-acid batteries do not last as long as other types of batteries, i.e. Lithium and require to be replaced more often
- Heavy – Weighs near 70lbs
Check Price On Amazon
Other Considerations
If you need help understanding how to build your entire solar power setup you can read about the other components below.
Before you checkout, be sure you have all the components you will need to make sure you maintain your battery life.
Battery Monitors & Temperature Sensors
You wouldn’t buy a car without a dashboard telling you the fuel, oil and temperature levels would you?
Not running your batteries down past their limit is critical to protect their performance and your investment.
Check your monitors often to make sure you’re not overusing them.
The monitor will also help you see if there are any “phantom loads.” These are devices that draw a charge that you are unaware of that could drain your batteries past their limits.
To know the battery’s state of charge (SOC) you will need a voltmeter.
The voltmeter will tell you the voltage, and you can determine the state of charge with this simple table:
| State Of Charge | Voltage |
|---|---|
| 100% | 12.7 – 13.2 |
| 75% | 12.4 |
| 50% | 12.2 |
| 25% | 12.0 |
| Discharged / Flat / 0% | 11.8 |
Do not let your lead-acid batteries get below 12.2 V!
Keep your battery charged when not in use, and recharge it as soon as you can to keep it running as long as possible.
If your Battery Monitor does not come with a temperature sensor, then you will need to buy one appropriate for the type of battery you have.
It’s important to know if your battery runs too hot and you need to decrease the load before you damage it.
Doing so would critically reduce its charging capacity, or kill it all together.
The Victron BMV-712 Battery Monitor comes with voltmeter and battery temperature sensor.
It’s a great all-in-one solution that also comes with built-in bluetooth so you can keep track of your battery from your smartphone.
The Victron is by far the best battery monitor, but it is expensive. There are more affordable options like the AiLi Battery Monitor that will work just as well if you’re on a budget. But you will need to get your own battery temperature sensor.
Battery Management System (BMS)
A battery management system is a device that monitors, equalizes, and shuts down your batteries to protect them from failure due to grounding faults or temperature volatility. Sometimes they come built into the battery or you need to buy it separately.
If you’re building a lithium iron phosphate battery bank and need a BMS you can check this one out here, or find one appropriate for the type of battery bank you’re building, i.e. lead-acid, lithium, etc.
Some lithium batteries like the Battle Born come with a BMS already built-in to save you the trouble.
Power Inverter
The power inverter will take the direct current (DC) stored in your battery and convert it to alternating current (AC) that is safe to use for your devices. There are some cases where you may want to use DC current, and some charge controllers will give you that option.
The type of inverter right for you will depend on the number of amps you need it to handle. Here is an affordable inverter that comes with everything you need to hook it up you can check out. There are different options to choose from based on the number of watts you need for your system.
Charge Controllers
A charge controller keeps you from overcharging your batteries by controlling the amount of power your battery receives from the solar panel.
This is especially important with Lithium batteries.
Without going into too many details, after you’ve determined the voltage for your system, 12V, 24V, or 48V, you’re going to want a charge controller that can handle that voltage.
Check out this article on the best solar charge controllers for an in depth review, or you can check out our top choice the Victron SmartSolar MPPT 100V/30A Charge Controller. Victron makes charge controllers with different amp ratings specific to your needs.
Fuses & Circuit Breakers
When running higher voltage systems it’s important to use fuses to prevent overload and fire. When choosing a fuse you will need one that’s at least 125% of the amps that the device will carry.
Here’s a list of fuses you can use to find the one that you need for your system:
Main Fuses from Battery Bank to Inverter.
Be sure to choose the size fuse that matches your inverter. You can use the table below to determine what size fuse your inverter needs.
Connect multiple 12V devices in one hub using this Blue Sea Systems ST Blade ATO/ATC 12V Fuse Blocks
We like to use Bussman circuit breakers. Search for the one that meets your amp rating needs.
Wire
Again the wire you need to connect your components will depend on the amps carried. Too small and they’ll burn up. Too big you’ll be spending more money than you need.
Connector Cables for Series/Parallel Setup
You will most likely be getting more than one battery to have enough power, and thus will need a way to connect them together. There are connector cables designed for that job and come in colors to help you identify positive and negative to prevent crossing wires. Be sure to check the gauge of the wire to make sure they will work with your setup.
Lug Assembly Types
Battery lug assemblies come in bare copper and tinned copper.
Bare copper is itself resistant to corrosion and more efficient.
But if the battery is going to be working in wetter or humid areas, then getting tinned copper will help it be more resistant to corrosion.
Battery Charger
If you’re not going to have your battery connected to solar panels all the time, then you’ll want to have a deep cycle battery charger to make sure they stay topped off, and do not self-discharge below their recommended depth.
Debrief
You’ve made it to the end! We apologize for the length of this article. We know you were just looking for a battery.
But hopefully you understand now that it’s not so easy to provide an accurate answer without considering all the factors.
If we had to choose just one as the best solar battery it should be clear that it would be the Battle Born Lithium Iron Phosphate (LiFePO4).
These lithium solar batteries are far superior to any other battery, lithium or otherwise, on the market.
And if it disappoints you for any reason, Battle Born’s excellent customer service will help you resolve the issue.
Some final thoughts before we go is to keep in mind that there is no perfect battery. There’s only a battery that is perfect for the job you need it to do.
Do not overcharge your batteries with a voltage charger that is too high.
Make sure you read the instructions carefully before getting started hooking up your system.
Keep batteries in a cool place between 65-70 deg F.
If you live in especially cold or hot climates consider the battery composition that’s appropriate for your situation.
Use a battery heater pad for cold temperatures near freezing to prevent damage.
Keep your batteries in a cool ventilated place in hotter climates.
If you’re going to introduce a new battery into an existing system, be sure to bottom balance them to equalize the voltage of the battery bank.
Connect them in parallel for a day for them to balance out, and then configure them how you wish.
And finally, don’t mix battery compositions or introduce batteries that are older than one year into your bank.
If you have any questions or concerns please drop them in the comments below.
We appreciate any value you can add to the community that would help us better understand which are the best solar batteries.
–Team AppliedSurvial
