How to Choose the Right Battery for Your Solar System

The batteries that we often come into contact with in life are lead-acid batteries and lithium batteries. But not everyone has a certain understanding of batteries. We all know that sudden power outages caused by extreme weather conditions are often encountered in our lives. It has a great impact on our daily work and life. If you have a backup energy storage battery at home, combined with a solar power generation system, it is simply perfect. But many people do not know the characteristics of lead-acid batteries and lithium batteries, and it is difficult to make the right choice. After all, the performance and price difference between the two are relatively large.

Lead-acid batteries cost much less up front, but they have a shorter life-span as well as call for regular upkeep to maintain them running properly. Lithium batteries are much more expensive up front, but they are maintenance-free and have a longer lifespan to match their greater cost. This write-up provides a side-by-side comparison of both choices.

This write-up looks at a choice you’ll need to make if you acquire a battery-based planetary system, either to relocate off the grid or to include power storage to your grid-connected house.

Particularly, we’re mosting likely to consider lead-acid vs. lithium-ion batteries– both primary battery types used for solar. Below’s the recap:

Lead-acid is a tried-and-true technology that costs less, but calls for regular maintenance and does not last as long.

Lithium is a premium battery modern technology with a much longer life expectancy and also greater performance, however you’ll pay even more cash for the boost in efficiency.

Where can I find lithium batteries for sale? I think it would be more reliable to buy on Amazon and some websites that specialize in selling lithium batteries.

Let’s review the advantages and disadvantages of each option in extra detail, and also describe why you could select one over the other for your system.

Lead-acid vs. Lithium Solar Batteries: The Basics
When you build a planetary system, you have 3 primary battery options:

Flooded Lead-Acid (FLA)
The differentiating attribute of FLA batteries is that home plates are submerged in water. These should be examined consistently as well as filled up every 1-3 months to keep them functioning appropriately.

Falling behind on upkeep can reduce the life of the batteries and invalidate the service warranty. FLA batteries likewise need to be mounted in an aerated enclosure to enable battery gases to escape.

Secured Lead-Acid (SLA)
SLA batteries can be found in two types, AGM (Absorbent Glass Mat) as well as Gel, which have several similar residential properties. They require little to no upkeep as well as are spill-proof.

The key difference in AGM vs. gel batteries is that gel batteries often tend to have lower cost rates as well as outcome. Gel batteries normally can’t deal with as much fee present, which suggests they take longer to charge and also output much less power.

Lithium batteries
The very best lithium battery chemistry for solar applications is Lithium Iron Phosphate, shorted to LiFePO4 battery or LFP batteries. This new innovation lasts longer and can be put through much deeper cycles. They likewise require no maintenance or venting, unlike lead-acid batteries.

Lithium batteries cost even more in advance, but the added effectiveness implies you can potentially spend less per kilowatt-hour of capability over the lifespan of the battery.

Lead-acid vs. Lithium Batteries: Pricing Breakdown
Let’s consider just how much it would certainly cost to develop a battery bank with all 3 alternatives.

We’re not just curious about the up-front cost, but likewise the cost of possession over the life of the system. As an example, we’ll check out how much the batteries would set you back to power this 5.13 kW off grid solar system, which we sell for $12,899 at the time of magazine.

In an off-grid environment, you want to take a look at the estimated cycle life considering that you are cycling your batteries every day. This system would certainly produce an estimated 23.08 kWh each day in the summer as well as 11.54 kWh daily in the winter season.

Right here’s just how much it would cost to purchase batteries for that system over the first 10 years.

Solar System 2

 

5 Key Differences Between Lead-acid and also Lithium Batteries

  1. Cycle life
    When you release a battery (usage it to power your appliances), after that charge it support with your panels, that is referred to as one fee cycle. We measure the life expectancy of batteries not in regards to years, yet instead the amount of cycles they can take care of before they expire.

Consider it like putting gas mileage on an auto. When you review the problem of a made use of vehicle, gas mileage matters a great deal more than the year it was produced.

Exact same chooses batteries and the variety of times they’ve been cycled. A covered lead-acid battery at a vacation home might go through 100 cycles in 4 years, whereas the same battery could undergo 300+ cycles in one year at a full time home. The one that has actually experienced 100 cycles is in far better shape.

Cycle life is also a function of depth of discharge (just how much capability you make use of prior to recharging a battery). Deeper discharges put a lot more tension on the battery, which shortens its cycle life.

  1. Deepness of Discharge
    Discharge deepness describes how much total ability is utilized prior to recharging the battery. As an example, if you use a quarter of your battery’s capacity, the deepness of discharge would certainly be 25%.

Batteries don’t release fully when you use them. Instead, they have a suggested depth of discharge: how much can be used prior to they should be re-filled.

Lead-acid batteries need to only be run to 50% depth of discharge. Past that point, you run the risk of adversely influencing their lifespan.

In contrast, lithium batteries can deal with deep discharges of 80% or more. This basically suggests they feature a greater useful capability.

  1. Efficiency
    Lithium batteries are more reliable. This suggests that more of your solar power is kept as well as utilized.

As an example, lead acid batteries are just 80-85% efficient depending upon the version as well as condition. That means if you have 1,000 watts of solar entering the batteries, there are only 800-850 watts offered after the charging and discharging procedure.

Deep cycle lithium batteries(Can be frequently used as our daily rv batteries, marine batteries, cabin use batteries) are greater than 95% effective. In the same example, you ‘d have over 950 watts of power available.

Higher performance implies your batteries charge faster. Relying on the arrangement of your system, it can additionally indicate you acquiring less solar panels, less battery capacity as well as a smaller sized back-up generator.

Solar System 3

  1. Cost Rate
    With greater effectiveness also comes a much faster rate of charge for lithium batteries. They can deal with a higher amperage from the charger, which indicates they can be replenished a lot faster than lead-acid.

We share fee rate as a fraction, such as C/5, where C = the ability of the battery in amp hrs (Ah). So a 430 Ah battery billing at a price of C/5 would get 86 charging amps (430/5).

Lead-acid batteries are restricted in just how much charge existing they can manage, mainly since they will certainly overheat if you bill them also promptly. Additionally, the charge rate gets substantially slower as you approach full capacity.

Lead acid batteries can bill around C/5 during the bulk stage (up to 85% capability). Afterwards, the battery charger immediately slows down to complete the batteries. This suggests lead acid batteries take longer to bill, in some cases greater than 2x as long as a Lithium choice.

  1. Power Density
    The lead-acid batteries included in the contrast above both weigh around 125 pounds. The lithium battery checks in at 192 pounds.

A lot of installers can take care of the additional weight, but DIYers could locate the lithium batteries extra difficult to mount. It’s smart to enlist some help training and relocating them into place.

But that features a tradeoff: the power density of lithium batteries is much more than lead-acid, indicating they fit more storage capacity right into much less room.

As you can see in the example, it takes two lithium batteries to power a 5.13 kW system, yet you would certainly need 8 lead-acid batteries to do the exact same task. When you take the size of the entire battery bank right into account, lithium evaluates much less than fifty percent as a lot.
This can be a real benefit if you require to get creative with just how you mount your battery bank. If you are hanging an enclosure on the wall or concealing it in a storage room, the boosted energy density helps your solar power battery box fit into tighter rooms.

Lithium vs. Lead-Acid: Which Should You Choose?
Lithium as well as lead-acid grade out at equivalent costs over the life of possession, but lithium is a much steeper financial investment in advance. We would not suggest it unless you use your system every day.

Right here are the battery kinds we ‘d recommend for a selection of applications:

Full Time Off-Grid Residence
Flooded Lead-Acid or Lithium.
If you live off the grid permanent, your best choice is FLA (if you don’t mind routine maintenance) or the premium Lithium alternative for hefty usage.

Off-Grid Cabin/ Vacation Home
Sealed Lead-Acid.
If you own something like a hunting cabin or a villa, you’ll only be there a couple of times a year. That means you will not have the ability to stay on par with the upkeep needed of FLA batteries.

Invest a bit extra on SLA instead. They’re zero-maintenance, so they won’t pass away if they sit still for a couple of months.

Battery Backup System
Secured Lead-Acid. 

Let’s state you are developing a system with battery back-up for emergency situation power failures. Preferably, you will just make use of those batteries once a year (a couple of times if you live in a location with an undependable power grid). They won’t see adequate usage for you to spend right into lithium, and also you do not want to execute upkeep on FLA batteries you use yearly.

Select SLA, which (once more) don’t need upkeep.

Remote Industrial Use
Sealed lead-acid or lithium.

The decision-making procedure is practically the same here. Lithium can be worth it to power a commercial website that sees heavy use. If you are powering basic tracking tools at a remote outpost, SLA will do the job more affordable, and also you still won’t need to bother with maintenance visits.

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