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If you’re thinking about investing in solar panels for portable off-grid power or to generate electricity for your home, you may be wondering if you need a solar battery.
If you’re looking for a system you can take on the road, the answer is yes.
Solar generators and portable power stations that can produce electricity from sunlight require a solar battery — and other essential components — to operate and have one built-in.
Strictly speaking, you don’t need a solar battery to power your home if you connect to the National Grid with a solar inverter and a bidirectional smart meter.
However, there are many reasons why a system that offers solar + storage is a vastly more beneficial solution than being tied to the grid.
Learn everything you need to know about solar battery storage, how it cuts your electricity bills, and how it protects your home.
How Do Solar Batteries Work?
Like all rechargeable batteries, solar batteries store direct current (DC) for use when alternating current (AC) or “household” is insufficient to power connected devices or appliances or when using stored energy is preferable to alternatives, such as on-grid power.
In most instances, DC stored in solar batteries is converted by an inverter into AC electricity before consumption, although DC-to-DC applications — such as charging a portable power station with a car battery — exist.
A solar battery is essential for off-grid and hybrid photovoltaic systems that generate and store electricity from sunlight.
Other off-grid and hybrid balance of system (BoS) components include photovoltaic (PV) modules — like solar panels — solar inverters, charge controllers, and battery management systems.
Some of the above parts are optional in grid-tied solar power systems — more on that soon.
The technical specifics of how a solar battery works vary considerably based on chemistry and the battery type.
However, without getting into electrolytes and cathodes, here are the basics of how all types of solar batteries work.
(Source: EIA)
- PV modules — usually solar panels comprised of monocrystalline or polycrystalline silicon solar cells — capture photons from visible light using the photovoltaic effect.
- The n-type and p-type semiconductors in PV cells physically convert solar energy into direct current electricity.
- The combined DC output of the solar panel array is transmitted through cables or wiring to the next BoS component in the chain, typically a solar inverter or charge controller.
- Most solar generators and hybrid PV systems send DC power to an MPPT or PWM charge controller first. Once conditioned, direct current electricity is then stored in a solar battery.
- In grid-tied (and a minority of hybrid systems), DC from the PV modules is first transmitted to the solar inverter. The inverter converts DC into AC electricity for household use. In systems with solar battery storage, this leads to reduced energy efficiency because AC electricity must be converted to DC and back to AC repeatedly, resulting in power loss.
- Once DC is converted to alternating current by an inverter, the solar battery powers household systems and appliances. Solar generators — which have all the necessary BoS components built in — are standalone units that you plug appliances and devices into directly. The photovoltaic system often integrates with home circuitry and wiring via an automatic or manual transfer switch for home backup applications.
- A solar battery provides power at night or other times when electricity generation from PV modules is insufficient to meet your household electricity needs. Portable power stations with PV inputs typically provide multiple charging methods in addition to solar power.
- PV modules recharge solar batteries during the day, or anytime there’s enough sunlight. Streetlamps, the moon, and other ambient light sources are insufficient to recharge a solar battery — unless it’s for a pocket calculator or similar low-wattage device.
- Once the solar battery is at full storage capacity, any additional power your PV array generates may go to waste. Consider expandable systems that give you room to grow, both in terms of electricity generation and consumption potential.
- Solar battery systems with intelligent remote control and monitoring software—such as EcoFlow’s DELTA series of generators and portable power stations—can easily be configured to avoid Time-of-Use (ToU) tariffs and only charge during off-peak hours, which is the cheapest time to use electricity.
Grid Tied vs. Off-Grid Solar Battery Systems
Intermittency is one of the primary challenges facing all clean, renewable energy systems designed for residential use.
Wind, solar, and hydropower are intermittent by nature.
Wind turbines don’t generate electricity on still days.
Solar panels don’t work at night.
There are currently three viable solutions to the problem of intermittency for residential photovoltaic (PV) systems that generate electricity from solar energy.
On-Grid Solar (Without Storage)
Grid-connected residential solar power systems toggle between electricity from the National Grid and electricity generated by PV modules during the day.
Grid-tied systems don’t produce electricity at night, and generation potential is reduced on cloudy days.
Whenever your electricity consumption exceeds the supply from your solar panel array, your solar inverter and a special meter from your utility provider will work together to help ensure a reliable supply of power to your home.
The Smart Export Guarantee (SEG) is a government scheme that allows homeowners and businesses to install a bidirectional (or smart) meter to sell electricity that renewable energy systems produce in excess of self-consumption back to a participating utility provider.
Learn more about eligibility for the SEG and how it works.
If you don’t “feed-in” to a registered Smart Export Licensee (utility or power company), any additional electricity your solar panel array generates over your household consumption simply goes to waste…
Unless you install solar battery storage.
Feeding-in by participating in the SEG scheme is rarely a profitable endeavour for homeowners.
Most power companies pay you less for any electricity you can sell than the rate for the energy you consume from the grid.
Increasing self-consumption of solar power typically offers a better return on investment over the mid-to-long term than selling electricity back to the National Grid.
And it’s essential to note…
Grid-tied solar power systems without solar battery storage automatically shut down in a blackout.
All on-grid systems are designed to go offline immediately and for the duration of a power outage to ensure the safety of utility workers and avoid additional damage to the grid infrastructure.
If you want to achieve power independence and home energy security against extreme weather events and grid failures due to ageing infrastructure — off-grid or hybrid solar + storage solutions are a vastly superior choice.
Off-Grid
You may be surprised by how many people in the UK currently live off-grid.
And not just in motorhomes, campervans or caravans.
Technically, living off-grid means forgoing indoor plumbing and at least when it comes to electricity.
More and more homeowners are choosing to generate all of their electricity off-grid.
The government does not track exactly how many households generate all of their electricity from renewable sources, and estimates vary depending on the source.
According to the Federation of Master Builders (FMB), “the figure [is] at anywhere from 25,000 to 150,000 homes.”
The increasing accessibility and decreasing cost of residential solar power and whole home backup battery systems have led to more and more homeowners generating a significant portion (or all) of their household electricity.
Solar battery storage is a must if you want to cut your power bills by going at least partially off-grid.
Without it, you’ll remain dependent on National Grid power — or a natural gas, diesel, petrol, or propane (LPG) inverter generator with ongoing fuel costs.
Hybrid (Solar + Storage)
If your goal is to reduce your electricity bills and your dependence on the grid, a hybrid solar + storage system gives you the convenience of utility power plus the home energy security and cost savings of off-grid.
For example, EcoFlow’s DELTA Pro 3 is a modular hybrid solar panel + battery solution with multiple charging options and flexible expandability.
With up to 36kWh of solar battery storage and 12kW of AC output (24kW surge), it’s more than powerful enough to back up most homes.
Even if you don’t have the budget or space to install enough solar panels to meet all your household electricity needs, solar battery storage can slash your bills in creative ways.
For example, many energy suppliers offer Time-of-Use (ToU) tariffs or multi-rate pricing, which means you pay a lower rate for electricity at specific times of day.
By integrating a hybrid solar generator with your home circuitry using EcoFlow Smart Home Panel 2, you’ll have uninterrupted access to power (~20ms auto-switchover) that you can easily program to kick in during on-peak demand hours when you’re charged a higher rate for electricity per kWh.
Avoiding ToU on-peak rates can lead to significant energy savings — and you can stop wondering why your energy bill is so high.
EcoFlow DELTA Pro 3 isn’t a bidirectional solar power system, so it’s not eligible for the SEG scheme.
However, the energy bill savings you can achieve with solar battery storage will outweigh whatever compensation you’re likely to receive from being an SEG generator — Ofgem’s term for scheme participants.
Not only that, multiple government solar incentives and grants besides the SEG are available — including 0% VAT — for consumers who purchase eligible solar panels and home battery systems, which can save thousands of pounds on purchase and installation costs.
Take advantage of any available opportunity to reduce your initial investment and shorten your solar payback period.
Here is a current list of programs.
| UK Solar Grants | Run Time | Potential Savings | Eligibility |
| 0% VAT | April 2022 to March 2027 | £2,300 (4kW solar panels + battery) | All UK buyers |
| Energy Company Obligation 4 (ECO4) | April 2022 to March 2026 | Partially or fully FREE solar panels | Low-income households |
| Smart Export Guarantee (SEG) | January 2020 to indefinite | Additional £45 to £80 (£440 to £660 total savings) | Any solar panel owner |
| Home Energy Scotland Grant and Loan | June 2023 to indefinite | £6,000 (£1,250 grant + £4,750 optional loan) | Means-tested for low-income or home energy performance |
| Home Upgrade Grant (HUG) | September 2023 to March 2025 | Up to £10,000 dependent on region or property type | Homes with an energy performance rating of D to G |
| Public Sector Decarbonisation Scheme (PSDS) | April 2023 to April 2025 | Regionally dependent | Companies and institutions looking to decarbonise |
It’s worth doing your research as new schemes are frequently announced.
Once your equipment is paid off, the cash you save on electricity bills is your solar ROI.
After all, money saved is money earned.
Solar Battery Capacity
Solar battery capacity measures how much electricity a rechargeable battery pack can store between charges.
Storage capacity for large rechargeable batteries, such as those used in hybrid and off-grid photovoltaic (solar) and/or home backup applications, is typically measured in watt-hours (Wh) or kilowatt-hours (kWh) — the same unit of measure used on your electricity bill.
Like most smartphones or laptops, very small batteries — like those used in power banks — may measure capacity in amp-hours (Ah) or milli-amp-hours (mAh).
Some large solar generators, like EcoFlow’s Power Kits, measure storage capacity in volt-amps (VA) or kilovolt-amps (kVA), which includes electrical efficiency — known as the power factor — in the equation.
However, most residential solar panel systems with battery storage use watt-hours (Wh) and kilowatt-hours (kWh), so we’ll focus on that here.
Storage capacity is a relatively easy concept to understand.
Capacity in Wh/kWh indicates how long you can operate appliances with a fully-charged solar battery before the battery must be recharged.
For example, if you have a 60-inch LCD television that requires 200W of power to operate, a solar battery with 4000Wh (4kWh) capacity — like EcoFlow DELTA Pro 3 — can keep your TV running for about 20 hours before the battery goes flat.
4000W (Capacity) / 200W (Load) = 20 hours (Run time)
Not all appliances consume electricity at a constant rate, making it trickier to calculate how much solar battery capacity they require to run for a given period.
For example, most refrigerators vary in consumption constantly based on a thermostat that measures internal temperature.
Only using the minimum amount of electricity to maintain the desired temperature makes modern fridges much more energy efficient, but variable consumption also makes battery backup requirements harder to gauge.
The same goes for home heating and cooling systems (HVAC), water heaters, and many other appliances.
Learn how to calculate kWh usage for your home.
Storage capacity is arguably the most crucial factor in evaluating whether a solar or home backup battery will meet your needs…
But it’s far from the only thing to consider.
Here is a summary of other terms to help you make an informed purchase decision and meet your electricity storage needs.
AC Output
The household electricity (AC) output of a solar generator or residential photovoltaic (PV) system with battery storage isn’t determined by the battery itself…
But it’s still an essential consideration when purchasing solar panels and a balance of system.
PV modules — like solar panels or shingles — don’t generate household electricity independently.
Depending on whether you’re opting for an on-grid, off-grid, or hybrid solar + storage system, you’ll need the following components in addition to PV modules like solar panels that generate direct current (DC) electricity using photovoltaic cells.
- Solar inverter
- Solar battery*
- Charge controller*
- Battery management system*
- Cables and wiring
- Transfer switch**
* Not required for grid-tied PV systems
** For home wiring integration (Optional)
AC output (typically measured in watts or kilowatts) is an essential consideration for generators, solar energy systems, and portable power stations because it determines what appliances you can start and run simultaneously.
It’s crucial to note the difference between starting and running watts for appliances, particularly ones with motors such as refrigerators and HVAC systems.
Many such devices require a short burst of surge power to turn on.
Starting wattage is rarely a concern when running appliances on grid electricity.
However, if a generator or PV system doesn’t provide enough starting wattage, the devices you’re trying to power won’t even turn on.
Fossil fuel and inverter generators typically offer 10% or less above their running wattage as surge power.
Thanks to proprietary X-Boost technology, most of EcoFlow’s solar generators and portable power stations deliver double their running wattage as surge power.
For example, EcoFlow DELTA Pro 3 provides 4kW of continuous AC output per unit.
Thanks to proprietary X-Boost technology, it can power up to 6000W of high-wattage home appliances simultaneously, and it provides 8000W for starting refrigerators and other devices that require a surge of power to turn on.
If that’s not enough, you can double or triple your AC output and solar charge capacity by connecting up to 3 x DELTA Pro 3s together for a maximum of 12kW continuous power (18kW X-Boost/24kW surge).
Each EcoFlow DELTA Pro 3 is expandable up to 12kWh of storage with Smart Extra Batteries (up to 36kWh maximum capacity with 3 units connected in parallel).
Charging Methods
Many dedicated solar batteries only charge using DC electricity generated by PV modules like solar panels.
If your goal is to live completely off-grid, having solar power as the only charging method may not be a concern.
However, if you’re seeking a hybrid solar + storage solution that allows you the convenience of using utility grid electricity as needed or charging using other sources such as a portable petrol or propane generator, EV pile, or 800W alternator charger, you’ll need a portable power station with multiple charging options.
For example, EcoFlow DELTA Pro 3 offers dual-PV (solar panel), AC wall outlet, fossil fuel generator, EV pile or Alternator charging, plus fast multi-charging combinations.
EcoFlow’s current range of solar generators provide multiple methods to recharge the LFP solar battery built into the unit.
Solar Charge Input
No matter how much viable installation space you have — for example, a rooftop that routinely receives peak sunlight — your solar battery and other essential components like the charge controller and solar inverter limit the number of PV modules you can connect.
The combined wattage, amperage, and voltage of your solar panel array MUST NOT exceed the solar charge input capacity of your balance of system components.
Depending on the system, connecting too many PV modules in series or parallel can cause permanent damage or worse.
Here are the essential specs to consider when determining the number of solar panels you can connect to your system.
- Number of input ports
- Maximum wattage, voltage, and amperage per port
For example, EcoFlow DELTA 3 Pro has 2 solar input ports with the following specs:
- High Voltage Port:30-150V/15A, 1600W Max
- Low Voltage Port:11-60V/20A, 1000W Max
Most solar panel manufacturers market PV modules based on their maximum rated power wattage.
For example, EcoFlow’s 400W rigid solar panel can generate a maximum of 400 watts under ideal laboratory conditions.
All reputable PV module manufacturers use Standard Test Conditions (STCs) to measure performance.
Standard Test Conditions for Solar Panels
| Condition Type | Standard Test Condition | Real-World Conditions |
| Solar Incident Angle | Always zero, irradiation beam always normal to the PV panel* | Variable, and depends on time, date, and site latitude. In the case of rooftop systems, roof orientation, and inclination govern system capacity. |
| Solar Irradiation | Always equal to 1000 Watts/m²* | Variable and depends on the time, date, and site latitude. Limited sunshine hours bound system capacity. |
| Ambient Temperature | Always 25°C* | Variable and depends on the time, date, weather condition, and site latitude. Higher ambient temperature degrades PV panel efficiency and reduces system output. |
| Air Mass Coefficient (AM) | Always equal to 1.5* | Variable and depends on the time, date, and site latitude. Higher AM with higher latitudes. |
| System Losses (e.g., Wiring, Inverter) | Always Zero* | Variable and depends on the design and location of PV panels, inverter, and grid meter. |
*Cannot be achieved in real-world operation (Source: ResearchGate)
Because rated power and other specs like efficiency are determined in a lab, solar panels don’t always generate their maximum wattage in real-world conditions.
However, you should always assume that the combined maximum power output of the PV modules in your array will meet the manufacturer’s specs during periods of high solar irradiance, i.e., in direct afternoon sunlight.
So, if a portable power station, solar battery, charge controller, or solar inverter has a maximum PV input of 2600W, does that mean you can safely connect 6 or 7 400W solar panels?
Not necessarily…
(Source: Electrical Technology)
Series, Parallel, and Hybrid Solar Panel Wiring
How you connect or wire solar panels together and to the balance of system changes the combined voltage and/or amperage of the combined power output of the array.
There are three ways to connect or wire solar panels together.
- Series: Increases current (in amps)
- Parallel: Increases voltage (in volts)
- Hybrid: Increases current and voltage by combining series and parallel wiring
There are benefits and disadvantages to each method of wiring solar panels in series or parallel.
For large-scale PV arrays, a hybrid wiring configuration is likely the best method, but it must be undertaken carefully, typically with a reputable installer.
Bottom line — it’s essential not to exceed your system’s solar charge capacity in watts, amps, or volts.
Cycle Life (Lifespan)
Unlike lead-acid rechargeable batteries, lithium-ion batteries do not degrade significantly over time but rather with use.
All rechargeable batteries diminish in performance based on the number of times the battery is charged and discharged.
Each full charge/discharge of a battery is called a cycle.
For solar batteries that are in regular use, cycle life is the best measure of lifespan or longevity.
For example, the average lead-acid solar battery has a cycle life of about 500 charges/discharges before the unit must be replaced.
SLA or non-lithium-ion deep-cycle solar batteries may last for 1000-1500 cycles.
The LFP batteries in EcoFlow DELTA Pro 3 have a cycle life of 4000 Cycles to +/-80% Capacity (11+ years of regular use).
Depth of Discharge
Depth of discharge (DoD) measures how much of a battery’s total storage capacity has been consumed and expresses it as a percentage.
A fully charged battery nominally has 100% DoD, but the reality is more complicated.
For example, a 1000W battery that’s used up half of its charge technically has a DoD of 50%…
However, if you continue to discharge a traditional lead acid battery below 50%, you will significantly decrease its cycle life and cause permanent damage to the battery cells.
Even VRLA or Sealed Lead Acid deep cycle batteries often have a recommended DoD rate of less than 80%, and using more than 50% of the total storage capacity on a regular basis will significantly shorten cycle life.
“Depth of Discharge” — when used as a manufacturer’s spec — is better described as the maximum percentage of total storage capacity that can be consumed without causing permanent damage and severely curtailing the battery’s lifespan.
In other words, DoD reflects a battery’s “usable” storage more accurately than total storage capacity.
Lithium-ion batteries typically have a DoD of 80%, and LFP batteries can reach 100% DoD without significantly impacting performance or shortening cycle life.
Continually running a solar battery from full to flat and back is never optimal…
But LFP solar batteries offer far more usable storage than flooded or sealed lead-acid batteries with the same total storage capacity — up to 50% or more.
State of Charge
State of Charge (SoC) is essentially Depth of Discharge in reverse.
SoC indicates how much of a battery’s total capacity is stored at a given time, measured as a percentage.
For example, when a solar battery is half full, both its DoD and SoC are 50%.
Think of it as similar to a fuel gauge in a conventional car or truck.
Your battery’s SoC tells you roughly how much petrol is left in the tank.
Here’s the formula:
Capacity Remaining / Total Storage Capacity x 100 – State of Charge Percentage
So, if you have a 4kWh solar battery and you’ve used 1kWh of its total capacity, the remaining capacity is 3kWh, and the SoC is 75%
(3kWh/4kWh) x 100 = 75% SoC
Because SoC is variable, it isn’t typically used as a manufacturer’s spec.
However, it’s helpful to understand its relationship to depth of discharge and that flooded lead acid batteries, gel cell, and AGM solar batteries are far more sensitive to SoC variability than Li-ion or LFP models.
Temperature
As anyone who’s tried to start a car on a subzero day will know, outdoor temperature can significantly affect battery performance.
Lead-acid solar batteries will operate at high and low temperatures but perform optimally at 15ºC – 25ºC.
Even a 5-degree increase in temperature to 30ºC results is 25% reduction in cycle life.
Frequently charging and discharging lead-acid and deep-cycle SLA solar batteries above 30ºC or below 10ºC will cut their lifespan roughly in half, meaning more frequent replacement is required.
Li-ion and LFP solar batteries have a wider operating temperature range without negatively impacting cycle life or performance.
Unlike lead-acid batteries, they can also be safely operated indoors without ventilation, making maintaining an ideal temperature at the installation site easier.
If you wish to install solar batteries sheltered outdoors or in a space like a garage that may not have an ideal temperature range, heating and cooling or temperature compensation systems are also an option.
Li-ion and LFP batteries are far less sensitive to temperature than lead-acid, but all batteries perform best at around room temperature or slightly warmer or colder.
Effect of Ambient Temperature on Solar Battery Performance
(Temperatures indicate a safe operating range without decreased longevity or performance)
| Battery Type | Ideal Temperature & Charging Advisory | Charge Temperature Range | Discharge Temperature Range | Storage TemperatureRange |
| Flooded Lead Acid | 25ºC (77ºF) Expected cycle life reduction of ~25% for every 5°C increase above 25°V. SoC must be maintained at 60% at temperatures below 0ºC | 10°C to 30°C (50°F to 85°F) | 10°C to 30°C (50°F to 85°F) | 20°C to 25°C(68°F to 77°F) |
| Sealed Lead Acid (SLA/VRLA/Deep Cycle | 25ºC (77ºF) Expected cycle life reduction of ~50% per 10ºC rise in temperature above 25ºC. SLA batteries discharge faster in subzero temperatures — approximately 40% faster at -20ºC than at 0ºC | 10°C to 30°C (50°F to 85°F) | 10°C to 30°C (50°F to 85°F) | 20°C to 25°C(68°F to 77°F) |
| Lithium-ion (Li-ion) | 20°C to 30°C (68°F to 86°F) | 0°C to 45°C (32°F to 113°F} | –20°C to 60°C (-4°F to 140°F) | 5°C to 20°C (-4°F to 77°F) |
| Lithium Iron Phosphate (LFP/LiFePO4) | 20°C to 30°C (68°F to 86°F) | 5°C to 45°C (41°F to 113°F) | -20°C to 60°C (-4°F to 140°F) | 10°C to 25°C (50°C – 77°F) |
Solar Battery Types
For most applications, solar battery chemistry determines the type.
But it can get confusing.
“Deep cycle” is more of a marketing term than an actual type of battery and is generally applied to sealed lead acid (SLA) or lithium-ion (Li-ion) battery cell chemistries.
There are at least 12 unique subtypes of Li-ion battery technology — including lithium iron phosphate (LiFePO4/LFP) and lithium nickel manganese cobalt oxides (NCM) — with more constantly in development.
Let’s focus on the most commonly used solar battery types.
1. Lead Acid
Lead-acid is the oldest form of rechargeable battery chemistry, dating all the way back to 1859.
Despite the underlying technology being over 160 years old, lead-acid batteries remain common in everyday use.
One example of a traditional lead acid battery that everyone is familiar with is starter batteries for internal combustion engine-powered vehicles like cars and trucks that run on petrol or diesel fuel.
Lead-acid batteries are cheap but ill-suited for use in photovoltaic or home backup applications, primarily due to the following factors:
- Short cycle life (500 cycles or less)
- Requires extensive routine maintenance
- Recommended depth of discharge (DoD) of 50%
- Sensitivity to extreme cold and heat
2. Sealed Lead Acid (SLA) & Valve Regulated Lead Acid (VRLA) Deep-Cycle Batteries
SLA and VRLA are interchangeable terms for lead-acid “deep-cycle” or “dry” batteries that improve on flooded lead-acid batteries for solar applications in multiple ways, primarily
- Greater recommended depth of discharge
- Routine maintenance-free – no refilling or watering required
- Ventilation is not mandatory
- Increased cycle life
- Faster charging
As with lithium-ion batteries, there are multiple subtypes. The most common are
- Gel Cell
- Absorbent Glass Mat (AGM)
Each is similar in components and performance, with gel cell getting a slight edge in most solar applications.
The main difference is the method used to immobilise the electrolyte solution (sulfuric acid) required in all lead acid batteries.
SLA batteries offer significant benefits over flooded lead-acid for solar applications and tend to be relatively affordable compared to Li-ion batteries.
However, they don’t come close in terms of lifespan and performance to advanced subtypes like LiFePO4/LFP.
3. Nickel Cadmium (NiCd/NiCad)
Once the sole competitor to lead-acid, NiCd batteries are no longer in widespread use, and manufacturing except for specialised applications is banned in many places, including the EU.
4. Lithium Ion (Li-ion)
Li-ion batteries have only been commercially available since the 1990s…
Today, they’re now found in virtually every precision electronic device or appliance that requires energy storage, including cell phones, laptops, and smart home appliances.
In fact, there’s a good chance you’re reading this on a laptop, tablet, or smartphone that relies on Li-ion battery chemistry right now.
Conventional lithium-ion chemistry is still used in many applications, including solar batteries.
However, new subtypes of lithium-ion batteries have emerged in recent years for high-wattage applications that demand regular use, such as electric vehicles and solar generators.
5. Nickel Manganese Cobalt (NMC)
Primarily used in EVs, NCM batteries are falling behind LFP when it comes to affordability and performance and are infrequently used in residential solar applications.
Even Tesla and other EV manufacturers are rapidly switching from NMC to cobalt-free lithium-iron phosphate batteries.
6. Lithium Iron Phosphate (LFP/LiFe PO4)
LFP solar batteries are currently the gold standard for portable and residential PV applications, and the technology is still improving rapidly.
EcoFlow is the industry leader in developing and manufacturing LFP batteries for portable off-grid power, solar generators, and home backup solutions that are cutting-edge and affordable to consumers.
All of EcoFlow’s most current range of DELTA and RIVER Series portable power stations use LiFePO4 batteries that last up to 4,000 cycles before storage capacity diminishes to +/-80%…
That’s over a decade of daily use.
7. Emerging Technologies
The hunt for ever-more efficient battery chemistries with longer lifespans and better performance never stops.
Decarbonisation of the environment is a global priority, and governments, corporations, and institutions like universities pour billions of dollars a year into researching new electricity storage methods.
Some emerging technologies show promise, but it will likely be years, if not decades, before any become viable for home solar battery use.
Here’s a sampling of possibilities on the (likely distant) horizon.
Using Solar Batteries
Aside from the basic functionality of storing DC electricity generated by solar power for later use, how you choose to operate a solar battery depends entirely on your balance of system components, battery type, and individual use case.
Here are a few examples.
Grid-Tied Systems
You can add solar battery storage to a grid-connected system with PV modules and a solar inverter, but then it technically becomes a hybrid system.
Solar battery storage is not required in grid-tied systems.
Once homeowners discover the benefits of battery storage, they may opt to purchase a relatively inexpensive deep-cycle solar battery for home backup use.
This option can be viable for power cuts and blackouts since they occur infrequently in the UK.
However, simply adding a solar battery won’t give you intelligent energy management options that will save you money on electric bills.
Not only will manual switching likely be required daily, but deep-cycle batteries also have short lifespans compared to Li-ion types when put to regular use.
Depending on your current system configuration, you may also have to reapply for permits to remain connected to the National Grid and/or participate in the Smart Export Guarantee.
EcoFlow PowerOcean DC Fit is a comprehensive retrofit solution that allows you to upgrade from grid-tied to industry-best home battery storage while sidestepping the pitfalls above.
Off-Grid
Many off-grid systems — like EcoFlow’s DELTA 3 — come with all the necessary balance of system components built-in, including the LFP solar battery.
EcoFlow solar generators provide portable power for everything from hiking to road trips to whole-home backup.
The EcoFlow RIVER 3 Series is ideal for camping and backing up home office equipment at home.
For example, EcoFlow RIVER 3 + 45W Solar Panel weighs only 3.5kg, which is light enough for a child to carry.
With 110W of solar charge input, you can recharge from 0 to 100% in as little as 2.6 hours of direct sunlight.
Or charge up before you hit the road…
Plugging RIVER 3 into a home wall outlet allows you to charge from 0 to 100% in just 60 minutes.
EcoFlow RIVER 3’s solar battery couldn’t be easier to use.
Just plug your appliances and personal electronic devices directly into the unit with multiple AC, DC, USB-C, and USB-A ports.
If you need an uninterrupted power supply for your desktop computer, external hard drives, or WiFi router, EcoFlow RIVER 3 Plus offers <10ms true-UPS battery backup.
Hybrid Solar + Battery Storage
Maintaining Solar Batteries
Routine maintenance can be extremely inconvenient or non-existent, depending on the type of solar battery you choose.
Here’s a summary of basic maintenance requirements for solar batteries by type in order of difficulty, from most demanding to effortless.
Flooded Lead-Acid
FLA solar batteries may be the cheapest option available, but their short cycle life and extensive maintenance requirements mean that you’ll pay a steep cost to replace the battery regularly…
Not to mention the aggravation of keeping it operational in the meantime.
Here are the basic steps to maintaining FLA solar batteries.
- Watering the battery: Flooded lead-acid batteries are often referred to as “wet” because liquid levels must be routinely monitored and the battery refilled with distilled water. Care must be taken not to overfill the battery or to let it run dry.
The method for checking your water levels varies by model, but you should never use tap water and ensure the battery is fully charged before adding water.
- Wear eye and hand protection during handling: Watering and maintenance puts you at risk of exposure to sulfuric acid — the electrolyte solution that lead-acid batteries rely on to function.
Acid splashes can result in serious chemical burns, eye damage, and blindness. It’s essential to play it safe. Always wear protection when maintaining a lead-acid solar battery.
- Corrosion prevention: Many inexpensive “wet” solar batteries look (and perform) like old-school car batteries. You may have to apply a sealant to all metal parts of the battery terminals to prevent rust and deteriorating performance.
Wires must not be exposed where they connect to the battery. Any exposed cable should be covered with adhesive-lined heat-shrink tubing. Battery tops should be rinsed at least twice a year — if not more.
- Cooling and heating: Lead-acid batteries perform optimally at 25°C. Routinely charging, discharging, or storing the battery at temperatures less than 15°C or greater than 30°C will significantly diminish cycle life and performance.
Temperature compensation methods, such as heating or cooling systems, can help extend lead-acid and deep-cycle solar battery cycle life and improve performance. - Restore to a full state-of-charge at least every 3 weeks.
- Avoid undercharging and overcharging to avoid potential damage and fire risks.
- Install in a well-ventilated area to prevent exposure to harmful fumes
Sealed & Valve Regulated Lead Acid
SLA deep cycle batteries are often called dry or maintenance-free.
One of the primary benefits of AGM or gel cell batteries is that the electrolyte solution is immobilised, and the unit requires no watering.
If battery terminals are exposed, follow the steps outlined above for FLA batteries.
If using a charger other than PV modules, make sure it’s the one recommended or provided by the manufacturer.
Follow the manual as closely as possible regarding the recommended state of charge. Most VRLA batteries require regular charges/discharges to a specific SoC to optimise cycle life and performance.
Lithium-ion & LiFePO4
Lithium-ion batteries require no routine maintenance or monitoring.
Li-ion solar batteries perform best when a SoC of 50% – 80% is maintained during regular use.
Be particularly vigilant about overcharging if you use a system with separate components — such as a battery, charge controller, and BMS from different manufacturers.
Unregulated charging of Li-ion batteries can lead to thermal runaway, which can cause explosions or fires in rare circumstances.
EcoFlow solar generators have an Advanced Battery Management System to prevent over and undercharging and maximise safety and performance.
Because of the differing chemistry, LFP batteries are not susceptible to thermal runaway.
Benefits of Solar Batteries
- Lower electricity bills
- Power your house at night and when your consumption exceeds the supply from your solar panels
- Provides power during blackouts (unlike grid-tied systems without storage)
- Home energy security
- Reduced on-grid electricity consumption and reliance
- Higher return on your solar investment
- Eligibility for government incentives
- Reduce electricity bills by avoiding Time-of-Use rates and with smart home energy management
- Achieve home energy security
- Low-to-no maintenance (depending on type)
- Quiet operation — especially compared to petrol, natural gas, and diesel standby generators
- Safe for indoor installation (flooded lead acid batteries require ventilation per manufacturer specs)
- Reduced carbon footprint
- Unlike fossil fuel generators, there are no ongoing fuel costs
Frequently Asked Questions
The answer is one or many. It depends on numerous factors, including storage capacity (in kWh), AC output (in watts), how many appliances you want to operate simultaneously, and electricity consumption and usage patterns in your home. The storage capacity offered by high-quality lithium iron phosphate (LFP/LiFePO4) solar batteries means that one or two should be enough to power most homes.
Final Thoughts
You may not NEED solar battery storage for your home, but if you’re looking to maximise your return on investment in renewable energy and protect your family from power cuts, it’s the right choice.
For off-grid adventures like camping and fishing where you want electricity, a solar generator has battery storage and empowers you to generate electricity anywhere there’s sunlight.
EcoFlow’s DELTA Pro 3 lets you do both by providing 4 kilowatts of AC output (expandable to 12kW) and up to 12kWh of solar battery storage while being compact enough to take on the road.
It’s just one of EcoFlow’s wide selection of portable power stations and solar generators for home and off-grid use.
Check out our selection today.
