How Long Can Solar Battery Power a House During an Outage?
When you install a home battery, what you are really doing is providing your home with a backup energy reserve in the case of an outage.
Whether you have a solar panel system at your home or not, a home battery can be used to store electricity and deliver it to your home appliances and devices. The benefits of a home battery are clear, especially during short or long-term outages, or in areas with Time-of-Use (TOU) rates that make electricity more expensive during peak use hours.
In this article, we’ll show you how to calculate how long a battery paired with solar can power your house during a power outage, and give you some tips for maximizing your battery usage.
How long can a solar battery power a house?
Without running AC or electric heat, a 10 kWh battery alone can power the basic operations of a house for at least 24 hours, and longer with careful budgeting. When paired with solar, battery storage can power more electrical systems and provide backup electricity for even longer.
In fact, a recent study by the Lawrence Berkeley National Laboratory found that when heating and cooling are excluded:
“(A) small PVESS with just 10 kWh of storage (at the lower end of sizes currently observed in the market) can fully meet backup needs over a 3-day outage in virtually all U.S. counties and any month of the year.”
PVESS stands for photovoltaics and energy storage system.
But exactly how long you can power your home with solar battery storage varies for each home and depends on three main things:
- Your battery storage capacity
- The output of your solar system
- Your electricity needs during an outage
We’ll show you how to budget your electricity to meet your solar and battery capacity below. First, let’s start with identifying your battery storage capacity.
Home battery capacity
Capacity — the amount of energy a battery can story — is one of the main features that influence how long a battery can power a house during a power outage.
Battery storage capacity is measured in kilowatt hours (kWh) and can vary from as little as 1 kWh to over 10 kWh. Multiple batteries can be combined together to add even more capacity, but a 10 kWh home battery is typical for most homes.
Check out this video to know more about Kilowatt hours (kWh).
During a power outage, assuming you have a fully charged home battery, you will be able to use most of the 10 kWh of stored energy. You’ll want to leave a minimum charge of 5-10% on your battery for a couple main reasons:
- To maintain the health of your battery
- To start your solar inverters in the morning so you can recharge your battery with solar power
For a 10 kWh battery, you’ll want to leave at least 0.5 kWh of capacity in reserve at all times. That leaves you with 9.5 kWh to power your home during a power outage.
On it’s own, 9.5 kWh of battery storage can power essential electrical systems for a day or two. But central air conditioning uses around 3 kWh per hour, which would eat up the entire battery in just over three hours. Let’s see pairing battery with solar can expand your options during a power outage.
Solar system output
The beauty of pairing battery storage with solar is that you essentially create your own miniature utility to power your home. This is especially useful during prolonged power outages because unless you have battery storage, your solar system will be turned off by the local utility to prevent the backflow of electricity from injuring workers trying to repair the grid.
But if you have battery storage, your system can operate independently when the grid is down. This is called “islanding.”
How electricity does a solar system produce?
Solar panel systems are measured in kilowatts (kW) that represent the amount of energy the system can produce in an hour of peak sunlight. So a 5 kW solar system can produce 5 kWh of electricity per hour in ideal conditions. But since conditions aren’t always ideal, we typically assume a performance ratio of 75%.
The average number of peak sunlight hours per day varies from 3.5 to 5.5 in the US. Multiple the system capacity by sunlight hours and 0.75 to find the daily output of a solar system.
For example, here’s how you would find the daily output of a 5 kW solar system getting 4.5 peak sunlight hours per day equals:
5 kW solar system x 4.5 sunlight hours per day x 0.75 performance rating = 16.875 kWh per day
In many cases, that’s more than enough to power essential electrical systems and recharge a 10 kW battery to use overnight. But electricity needs vary from home to home, so let’s run through a some common appliances and how much energy they use.
Your electricity needs during a power outage
How long solar battery storage can run your home depends how much electricity you use. And how much electricity you use depends on which appliances and systems you’re running.
During a power outage, it’s recommended to budget electricity for the most necessary things first and then make a plan for the remainder capacity. For many homeowners, the list of priorities includes:
- Kitchen and cooking
- Water heating
- TV and device charging
- Heating and cooling
Now, heating and cooling is last on the list not because it isn’t important, but because these operations take so much electricity they’ll likely have to be limited regardless of your battery capacity. So the wise move here is to budget your essentials first, and then get a sense of how much battery capacity is left for heating and cooling.
Note: If you have a gas furnace, you won’t need much electricity to keep the heat on.
Let’s run through an example scenario of powering essential systems during a 24-hour power outage to get an idea of how much solar and battery capacity you’ll need.
Use the tables below as an a la carte menu to create your own battery storage budget.
Refrigerator: 1.5 kWh per day
|“>Older 15-cubic foot unit (1996)
|“>5 kWh per day
|“>Newer ENERGY STAR 17-cubic foot unit
|“>1.16 kWh per day
A refrigerator is among most important things to power during an outage so that you can avoid having your food and drink go to waste.
If you have a modern, energy star approved model, your refrigerator is using around 1-2 kWh of electricity a day. If your fridge lived through Y2K, you might be looking at closer to 5 kWh per day.
Refrigerator electricity usage can be minimized by opening the door less and raising the temperature slightly. If you are preparing for a planned Public Safety Power Shutoff (PSPS), set the temperature very low before the shutoff event, and then set it to a higher temperature once the grid power goes out. That way the fridge starts cold and you can devote less battery capacity to power it during the outage.
Let’s say you have a relatively modern ENERGY STAR certified fridge that uses 1.5 kWh per day.
Running total: 1.5 kWh
Kitchen and cooking: 1 kWh per day
|“>2.3 kWh per hour
|“>1.1.5 kWh per hour
|“>0.12 kWh per 5 minutes
Even during a power outage, people gotta eat. And in a large enough outage, it may not be practical to eat out or order delivery.
Let’s say you make a pot of coffee and toast in the morning (0.2 kWh), microwaved some leftovers for lunch (.12 kWh), and baked a frozen pizza for dinner (0.75 kWh) because your trying to clear out the freezer. That amounts to just over 1 kWh throughout the day.
Running total: 2.5 kWh
Electric water heating: 2.5 kWh a day
|“>Electric water heater
|“>4-5 kWh per day (running 2-3 hours)
|“>Heat pump water heater (50-75 gallon)
|“>~2.5 kWh per day
Water heating accounts for an average of 18% of the total energy used in the household. or around 162 kWh per month. On a normal day, a water heater runs for around 2 to 3 hours a day, which means that it will consume roughly 4-5 kWh of electricity a day. Heat pump water heaters are more efficient and can run on around 2.5 kWh per day.
But power outages are not normal days. To save electricity, you may want to skip or shorten your shower, wash your hands and rise your dishes with cold water, and hold off on laundry for a day or two.
And if you have a gas-powered water heater, water heating is a non-issue in terms of battery use.
But for the sake of argument, let’s say you put on some extra deodorant and limit your water heating use to 2.5 kWh per day.
Running total: 5 kWh
Lights: 1 kWh per day
|CFL/LED (8 W) equivalent to 25 W incandescent
|0.008 kWh per hour
|CFL/LED (15 W) equivalent to 60 W incandescent
|0.015 kWh per hour
|CFL/LED (27 W) equivalent to 100 W incandescent
|0.027 kWh per hour
|CFL/LED (38 W) equivalent to 150 W incandescent
|0.038 kWh per hour
Compared to larger appliances, lights require very little electricity, especially if you have compact fluorescent (CFL) or LED bulbs. Even at the high end, a 38W LED bulb or 150 W incandescent bulb uses just 0.038 kWh per hour.
So if you budget 1 kWh of battery storage per day to lighting, you could run 26 bulbs for 1 hour each — more than enough to provide light for trips to the bathroom, closet, and getting ready for bed.
Remaining battery budget: 6 kWh
TV and device charging: 2 kWh
|0.024 kWh per day
|“>Modern TV: LED/OLED 4k or 1080P HDTV (20″ to 70″)
|“>0.014 to 0.18 kWh per hour
|“>TV: Plasma (40″ to 50″)
|“>0.4 to 0.48 kWh per hour
|“>0.06 kWh per hour
|“>0.02-0.05 kWh per hour
|“>0.032 kWh per day
Let’s be honest, one of the worst parts of power outages is going without internet and TV. Sure, you try to read a book for an hour or two, but that familiar glow is calling your name.
To keep the Wi-Fi on, you’ll need about 0.024 kWh. If you work from home, you can run your laptop for 8 hours for another 0.4 kWh. And if you want to wind-down with a movie or 3-hour Netflix binge, you’ll need another 0.54 kWh.
That adds up to 1.18 kWh, but we’ll round up to 2 kWh to account for phone charging and multiple devices running at once.
Remaining battery budget: 8 kWh
Air Heating and Cooling: Variable
|“>Electric furnace (with fan)
|“>10.5 kWh per hour
|“>1.5 kWh per hour
|“>Baseboard heater (6-foot unit)
|“>1.5 kWh per hour
|“>Window/Wall AC (8k to 18k BTU)
|“>0.73 to 1.8 kWh per hour
|“>Central AC (3 ton – 12 SEER)
|“>3.0 kWh per hour
|“>0.03 kWh per hour
|“>0.025-0.075 kWh per hour
As you can see from the table, heating and cooling take a lot of electricity. So if you only had a 10 kWh battery and no solar, you’d have maybe 2 kWh to budget for running fans or space heaters.
But with a battery charged by solar, you would have much more electricity to spare for fans and space heaters — perhaps even enough to run central AC for a few hours, depending on your equipment.
|“>1 kWh per hour
|“>0.46 kWh per hour
|“>Sleep apnea machine (CPAP)
|“>0.2 kWh per hour
Another thing to consider is powering medical equipment during a power outage. Certain equipment, like a nebulizer, requires a significant amount of electricity and could eat through 10kWh of battery very quickly.
Is getting a solar battery worth it?
Weather-related power outages in the US increased roughly 78% from 2011 to 2021, and are becoming a reality for more homeowners. If you like clean, quiet, and hands-free backup energy that can power your home for several days during outages, then solar and battery are totally worth it. Not only can battery keep your home powered, it can keep your local grid running, as we saw in California in September 2022.
In addition to providing backup power during outages, solar and battery can reduce your energy costs by shifting your power usage to off-peak hours when electricity is much cheaper (up to 20 cents per kWh!)
And, of course, there are the local and global impacts of reducing fossil fuel that pollute the air and contribute to climate change.
Click here or enter your zipcode above to see how much you can save with solar and battery.
.0 kW Solar Kit with Enphase Microinverters and 20 kWh Encharge Lithium Battery
Connect this solar kit with Enphase Energy microinverters to the grid for an easy home battery backup solution. Or, install it as a fully independent system to deliver power to remote off-grid locations.
The Enphase Ensemble inverter and battery technology works in any solar application (grid-tie, off-grid or battery backup systems). Plus, it can automatically detect connection to the grid and switch between on-grid and off-grid applications seamlessly.
This pre-designed 10.0 kW solar kit contains the core components you need to go solar on your own terms, including solar panels, microinverters, racking and batteries. Whether you install your own solar panels or hire a local contractor to assemble your system, GoGreenSolar’s kits give enterprising DIYers a way to save money on their solar project vs. outsourcing it to a turnkey solar provider.
What Will This Kit Power:
With South-facing exposure, this kit will produce 10,900 – 17,200 kwh per year and can deliver 7.86 kw of instantaneous power with no sun and up to 14.9 kW of instantaneous power in full sunlight.
When operating without the grid, this kit will power light electrical loads like:
- Washing Machine
- Small Well Pump
- Mini Split or Small Air Conditioner for a few hours when the sun is out
At GoGreenSolar, we’re here to provide guidance throughout the entire process of going solar:
- Design your dream system with sizing layout recommendations from our seasoned solar advisors.
- Skip the paperwork with our hassle-free permitting and interconnection services.
- On-demand tech support to help navigate installation and accommodate any questions/concerns you may have.
Every system we sell is backed by our 100% money-back guarantee. If for some reason your permit doesn’t get approved, we’ll refund your purchase in full. (See terms and conditions)
Build your custom solar kit
Are you interested in these solar panels for your home system? Request a quote for a complete DIY solar panel kit today.
- Solar made easy with complete solar kits
- Permitting and tech support designed for DIYers
- Step by step installation support
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kWh 48V 200 ah LiFePO4 Plug-N-Play Solar Battery storage system
Coremax is a leading Power wall Home Battery Manufacturer in Shenzhe China, We FOCUS on lithium iron phosphate battery packs, known as lifepo4 battery, which is the longest lifecycles and safest chemistry of all kinds of lithium battery. Our Whole House Battery Backup reach 8000cycles at 100%DOD. We offer 0.28 per wh price with top quality. Coremax 10kwh 48 volt 200ah powerwall home battery come with 15years design life. our battery compatible with nearly all kinds of Inverters, SMA, Solar edge, Sunny island, Deye,Growatt, Goodwe, Outback etc. look for distributors from USA market.
- Power energy: 10 kwh (10.24kwh)
- Voltage: Nominal voltage 51.2v for 48 volt solar system
- Battery installation: Wall mount or ground mount installation
- Battery pack capacity: 200Ah
- Protection: in house Solar energy storage BMS
- Battery cell type: Lithium iron phosphate cell (LiFePo4).
If you’re looking for a reliable and affordable solar battery storage system, the 10kWh 48V 200 ah LiFePO4 Plug-N-Play Solar Battery storage might be the solution you need. This system offers a range of benefits for residential and commercial solar PV installations, providing a convenient and cost-effective way to store excess solar energy for later use.
At just 28 per Wh, the 10kWh 48V 200 ah LiFePO4 Plug-N-Play Solar Battery storage is an affordable energy storage solution that can help reduce your reliance on grid power and lower your energy bills. This system is designed to be easy to install and use, with a plug-and-play design that makes it simple to integrate into your existing solar PV system.
The LiFePO4 battery technology used in this system is known for its long cycle life and high safety, providing a reliable and durable energy storage solution for your home or business. This technology is also known for its fast charging capabilities, allowing you to quickly and efficiently store excess solar energy for later use.
With a capacity of 10kWh and a voltage of 48V, this solar battery storage system is ideal for residential and commercial solar PV installations. It offers a high level of energy storage capacity, allowing you to store enough energy to power your home or business for several hours during a grid outage or peak demand period.
This 48v (51.2V) 10KWh 200Ah LiFePO4 lithium battery solar energy storage system designed for house owner residential usage. 48v lithium battery 200ah energy is normally big enough capacity for a small house solar energy storage. With Coremax 51.2v 200Ah 10kwh, you don’t have to parallal small 5kwh powerwall anymore.
Coremax 48v lithium battery 200ah designed by experienced engineers come directly from BYD. With rich experience and advanced techniques, it features stable and fashionable design, high energy, high power density, long service life, and easy installation and expansion, all of which reflect the real requirements of the end users and the strongest technical capability. Thanks to BYD prismatic large capacity cells and also BYD battery pack designer.
Lithium iron phosphate batteries is a kind of environmentally friendly backup power system. We use LiFePo4 rather than NCM to avoid safety concerns by lowering the possibility of thermal runaway because of improper disposal and save the production cost as well. Compared with other products in the market now, LiFePo4 experiences a lower rate of capacity loss. With state-of-the-art power conversion and energy storage technologies, our 10kwh wall mount Energy Storage System (ESS) offers high-efficiency power conditioning capabilities for demand management, power dispatch, renewable energy smoothing, etc. Coremax 10kwh LiFePo4 powerwall can provide comprehensive energy storage for residential, commercial and utility applications. Our solar energy storage system is now cover racked installation, wall mounted installation. and more will coming soon.
- Manufactured based on High quality BYD/CATL cells prismatic LiFePo4 cells inside.
- Build in with large capacity prismatic cells, high power, and excellent charge and discharge performance.
- Strictly controls the raw materials selection and the whole production process to ensure that the ESS has stable performance and excellent quality.
- Tested by relevant national departments in the aspects of quality and performance indicators.
- Ensured to be a high-quality battery with excellent performance.
- High integration with less installation space.
- Long life cycle, 5000 times at 80% DOD.
- Free of heavy metals and environment friendly.
- Maintenance free, no memory effect.
- Internal BMS with full protection, high voltage protection with higher reliability.
- Clean and safety internal design by BYD oringinal designer.
- Solar-Wind Power System / City Grid (On/Off) / Community and Family
- Back-up System and UPS
- Telcom Base / CATV system / Computer Server Center / Medical Instrument / Military Equipment
- Security and Electronics / Mobile POS, Mining Light / Torch / LED Light / Emergency Light
- RV Motorhome /Golf Carts Battery / Boat Marine Yachts / Electric Skateboard
- LED Backup / Engine Starting Battery, etc.
|Standard discharge after Standard charge(package)
|Mean Operation Voltage
|Voltage at end of Discharge
|Mean Operation Voltage
|Internal resistance measured at AC 1KH Z after 50% charge The measure must uses the new batteries that within one week after shipment and cycles less than 5 times
|Constant Current 100A
|Charge time : Approx 4.5h
|Maximum Continuous Discharge Current
|Maximum Discharge Current
|Operation Temperature Range
|Storage Temperature Range
|Less than 12 months :.10~35℃
|60±25%R.H.at the shipment state
|Less than 3 months:.10~45℃
|Less than 7 day :.20~65℃
|(LWH) 769 580 235mm
Inquiry or want to be the distributor
10Kwh is heavy and large capacity battery system. Normally we suggest buying 5kwh model. Because our BMS system is designed for use in parallel. 16pcs is no problem. In this way, it is more easy to shipping and installation. As a 5kwh model is about 48kg.
If you’re interested in becoming a distributor of the 10kWh 48V 200 ah LiFePO4 Plug-N-Play Solar Battery storage, you’ll be glad to know that this product is produced by a China-based factory. China is well-known for its manufacturing capabilities and expertise in the renewable energy sector, making it a reliable source of high-quality solar energy products.
As a distributor, you can benefit from the growing demand for affordable and reliable solar energy solutions, and the popularity of energy storage systems for residential and commercial use. By partnering with a reputable manufacturer like the one that produces this battery system, you can ensure that you’re offering your customers a high-quality product that meets their energy storage needs.
The 10kWh 48V 200 ah LiFePO4 Plug-N-Play Solar Battery storage is an ideal product for distributors, as it offers a range of benefits for homeowners and businesses looking to reduce their energy bills and increase their energy independence. With its affordable price point and plug-and-play design, this system is easy to install and use, making it a popular choice for customers.
As a distributor, you’ll also benefit from the manufacturer’s expertise and support, including technical assistance, training, and marketing materials. This can help you to promote and sell the product more effectively, and build a strong reputation as a reliable supplier of high-quality solar energy products.
In summary, the 10kWh 48V 200 ah LiFePO4 Plug-N-Play Solar Battery storage is an excellent product for distributors looking to enter the growing solar energy market. Produced by a reputable China-based factory, this system offers a range of benefits for customers, and can help you to build a successful business as a distributor of renewable energy products.
V 200Ah Power Wall Lithium iron battery 10kWh solar battery 6000 cycle times
48V 200Ah Power Wall Lithium iron battery 9.6kWh solar battery 6000 cycle times.
48V 200Ah Power Wall Lithium iron battery 9.6kWh solar battery 6000 cycle times
Perfect Compatible Easy Installation
Compatible to Both Residential Fast and simple installation
Single Three Phase Inverter
Safe Reliable Flexible Expansion
Lithium Iron Phosphate(LFP) cell Scalable from 5 to 30kWh CE,ISO9001,UN38.3,FCC
Smart BMS Long Life and safety
Advanced BMS system control power Ensure more than 5000 cycles tiems
output smartly and effectively
VOLTAGE 48 V
ENERGY 9600 Watts(Wh)
Dimension 650 L 520 W 240 H mm
WEIGHT 96 kg
Compatible inverters Growatt,Deye,Goodwe,Sofar,Sorotec,Pylontech and ect.
Warranty 5 Years
Cycle Times 6000 cyclt times 80%DOD
MAX CHARGING CURRENT 100A
INTERNAL RESISTANCE 30≤mΩ
DISCHARGE 100A max continuous. Month self discharge 2%(20℃)
LIFE CYCLES(BATTERY LIFESPAN) DEEP CYCLES
Up to 100% DOD capacity for 4,000 cycles in recommended conditions. 25℃ is better.
OPERATING TEMPERATURE RANGE
Ideal for rugged harsh environments.
Charging: 0 to 45 ℃(32℉ to 113℉）@60±25% Relative Humidity
Discharge:.20 to 60℃(-4℉ to 140℉）@60±25% Relative Humidity
Storage: 0℃ to 45℃（32℉ to 113℉）@60±25% Relative Humidity
Installation Floor stand(standard)
Scalability Max 4 pieces in parallel operation
【Cell Balancing 】 Series cells can lose capacity over time if not properly managed. The BMS keeps the cells balanced, which optimizes the battery for maximum available capacity and lifetime.
【Heat Management 】Extreme high or low temperatures can damage lithium batteries. The BMS continuously measures termperature and protects the battery from becoming unsafe or damaged.
【Short Circuit Protection 】The internal Battery Monitor System(BMS)will detect dangerous short circuits and protect the battery from damage.
【Copper Bus Bars】The connections between cells are made from 100% copper bus bars, which results in a very low internal resistance. Less internal resistance means less heat when the battery is under load resulting in better performance.
【UN DOT Certification】Tested and approved for UNDOT means Junlee! LiFePO4 Batteries can handle vibration and shock experienced in mobile applications.
【Prismatic Cell Enclosures】The metal, prismatic cell enclosure in Junlee. LiFEPO4 Batteries are super durable and perfect for mobile application.
【LiFePO4 Chemistry】LiFePO4 batteries have stronger chemical bonds than traditional lithium batteries. This makes them less vulnerable to things like short circuits, even if the BMS somehow Failed.
【Battery Management System】(BMS) The BMS inside. LiFePO4 Batteries manages various aspects of the battery to make it extremely safe providing better performance and longer life.
- 【Automotive Grade Lithium Battery】 Junlee lithium iron batteries have exceptional quality since they are manufactured by Automotive Grade LiFePO4 Cells with higher energy density, more stable performance greater power. Highest-level safety based on UL Testing Certificate for the cell inside the battery. With no acid in the battery, you’re able to safely mount in any position. This makes li-iron batteries perfect for solar home, RV, campers, golf cart, motor homes, off-grid applications.
- 【10 Years lifetime】Junlee LiFePO4 battery provides 4000 cycles, which is more than 10 times to Lead Acid with 200~500 cycles. Junlee LiFePO4 battery has a 10-year service life, three times longer than the Lead Acid’s 3-year lifetime.
- 【1/3 Lightweight】 Junlee LiFePO4 Battery weighs only only 1/3 the weight of lead acid batteries, which makes it an easy choice for RVs, Marine and Off-Grid Applications when mounting or mobility is in the consideration.
- 【95% Efficiency】 Junlee LiFePO4 battery’s flat discharge curve holds above 51.2V for up to 95% of its capacity usage, providing astronomical boosts in run-time compared to only 50% in Lead Acid. This product is your best choice for outdoor camping power and indoor easy installation.
- 【100% Protection】 Junlee LiFePO4 battery has built-in BMS (Battery Management System) to protect it from overcharge, over-discharge, over-current, and short circuit with excellent self-discharge rate. Built-in high-temp cut off prevents charging over 167 °F (75 °C). Without memory effect, no matter what state the battery is, it can be used as soon as it is charged. JunleeLiFePO4 battery is IP65 level waterproof, which set you free from worrying to install indoors or outdoors.
Q:What is special about lithium batteries?
A: With high energy density, it has reached 460-600Wh/kg, which is about 6-7 times that of lead-acid batteries. Long service life, life span can reach more than 6 years. Light weight, the weight is about 1/5-6 of the lead-acid product under the same volume.
Q:What is a lithium battery used for? A:Lithium battery use for power and energy storage. Like emergency power backup or UPS. Dependable electric and recreational vehicle power, golf cart,reliable and light-weight marine,solar power storage, surveillance or alarm systems in remote locations.
Q:What is the difference between a lithium battery and a lithium-ion battery? A:It mostly comes down to the fact that lithium-ion batteries are rechargeable while lithium batteries are single-use. Lithium battery have a higher energy density than lithium ion batteries.
Q:Are your batteries safe? A:Our batteries are safe. All Junlee batteries use the safest and most stable components, including a LiFePO4 cathode and a built-in Battery Management System (BMS).The BMS protects the cells against excessively high or low voltages, high currents, short circuits, and excessive heat or cold. These are the most common causes of battery failures, and we have taken every precaution to mitigate these risks in all of our batteries.
Q:What is an advantages of lithium batteries? A:Compared to lead-acid and other lithium batteries, lithium iron phosphate batteries offer significant advantages, including improved discharge and charge efficiency, longer life span and the ability to deep cycle while maintaining power LifePO4 batteries often come with a higher price tag, but a much better cost over the life of the product. No maintenance and super long life make them a worthwhile investment and a Smart long-term solution.
Q:How do I choose the correct lithium deep cycle battery for my application? In most standard 12, 24, or 48 volt systems the best choice of lithium battery is LiFePO4 (Lithium Iron Phosphate). The voltage of this type of battery is very similar to an AGM and will work great with readily available system components for your RV, boat, or off-grid power system.
Is a 10kW Solar Energy System Enough to Power a Home?
When asked to recommend a properly sized solar energy system for an average-sized home, many installation experts will suggest a 10-kilowatt (kW) system as their default answer.
But is a solar array with this capacity really good enough for the typical home? Or is it perhaps a little too potent?
A closer examination should reveal whether a 10kW system is the best option for the typical homeowner, and possibly whether it’s the best option for you.
Can a 10kW solar energy system power an average-sized home?
The United States Energy Information Administration (EIA) reports that in 2021, the average American residential consumer used 10,632 kilowatt hours (kWh) of electricity to power their homes .
Realistically, a well-maintained 10kW solar panel array in the prime of its life can be expected to generate between 10,800 and 14,400 kWh of electricity annually in most locations, given the amount of sunshine they receive .
The good news is that this is clearly enough to meet the needs of the average homeowner. The better news is that there is a list of sun-drenched states where a 10kW system could produce a whopping 18,000 kWh of electricity annually, at minimum .
These lucky localities include:
- New Mexico
Unsurprisingly, five of these seven are among the top ten states for solar energy consumption per capita .
How much electricity does a 10kW solar energy system produce on a daily basis?
The amount of electrical power a single solar panel can produce is directly proportional to the number of peak sun hours it is exposed to over the course of a day.
A peak sun hour is defined as 60 minutes of time in which a solar panel on your rooftop would be bombarded with 1,000 watts of energy per square meter of sunlight . In real-world conditions, a solar panel would only be exposed to one full peak hour of sunlight if it were around midday and there were no clouds in the sky. When this takes place solar panels function at 100-percent efficiency, meaning a 400-watt solar panel would produce 400 watt-hours of energy over the course of one peak sun hour.
During most of the day the sun’s irradiance will be less. In those instances what hits a panel’s surface will be measured as a fraction of a peak sun hour. So, if the sun were shining at half of its potential intensity between five and six o’clock in the evening, that would be calculated as 0.5 peak sun hours of exposure for each solar panel in a rooftop array.
Peak sun hours are generally charted on a daily basis, which means all of these fractions are added up to cover a single 24-hour time period. The final number represents the peak sun hours experienced on a particular day, and it can be used to determine how much energy a solar panel array would have produced on that day.
The mathematics of this is simple, requiring just basic multiplication. If five peak sun hours were experienced on a certain day, it would mean that a 10kW solar array produced 50 kilowatt-hours (kWh) of electricity over the course of that day (5h x 10kW = 50 kWh).
According to the latest estimates, an average American home will use around 30 kilowatt-hours of electricity a day . This means that a 10kW solar array would require just three peak sun hours a day to guarantee an adequate supply of electricity to the owner of an average-sized residence.
For a detailed information about your area, check the Global Solar Atlas. It is a detailed database, enabling you to access data on annual solar irradiation in any location around the world. It is a very useful tool to go through when considering investing in photovoltaic solar panels.
How many solar panels make up a 10kW solar system?
Solar panels in 2023 are more efficient than those manufactured in the past. Over the last few years average panel conversion efficiency has risen from 15 percent to above 20 percent, and as a result the typical power rating of a standard-size home solar panel has increased from 250 watts up to 400 watts .
This is great news for homeowners, because it means you’ll need to purchase fewer solar panels to reach the 10kW plateau than would have been necessary in the past. If you purchased solar panels rated at 400W, you’d need exactly 25 to achieve 10kW of capacity.
You could of course choose to purchase lower- or higher-capacity panels, which would alter that number in one direction or the other.
You might be interested in lower-capacity models, if the discounts on price were enough to make that your overall cheapest option. And in fact, as of 2023 solar panels in the 300 to 350-watt range are still the best sellers. Conversely, you might prefer upper-range 440W—480W panels if you were a bit short on roof space.
Monocrystalline solar panels would be your high-efficiency but higher-priced option, while less-efficient polycrystalline panels would occupy the opposite end of the solar cost spectrum .
How much roof or ground space will be required for a 10kW solar system?
The standard solar panel is 5.5 feet long and 3.25 feet wide. This means each one will cover 17.875 square feet of space once it has been installed.
Should you decide to install 25 400W panels, you would need at least 446.875 square feet of open roof or lawn space to make your solar array fit. However, industry professions often recommend that you keep up to 25 percent of your roof space clear when you install solar panels, for safety purposes and to ensure easy access .
If you follow this advice, you would need 594. 34 square feet of roof space for your solar panels, instead of 446.875. This would be the equivalent of a roof or ground area that was approximately 30 feet long by 20 feet wide, if that helps you visualize this more easily.
How much can you save on your electric bill with a 10kW solar power system?
The average price of electricity in the United States in December 2023 was 14.96 cents per kilowatt-hour . Meanwhile, a recent study cited by the U.S. Environmental Protection Agency (EPA) showed that the average American household consumed 10,715 kWh of electricity on an annual basis, which is an average of 893 kWh per month .
Performing the appropriate calculations, we can then determine that a homeowner in the United States who installs a 10kW solar power system could save as much as 1,603 each year on electricity bills, if they were consuming electricity at an exactly average rate.
This entire amount could be saved if the homeowner went off grid and used solar to meet 100 percent of their electrical power needs. They could accomplish the same with a grid-connected system, if net metering practices in their state allowed them to sell enough excess solar back to the utility company during peak production hours to make up for what they were taking from the grid after sundown.
The total potential for savings will vary significantly by location. Consumers living in states with higher electricity rates and/or above-average annual energy consumption levels would pay more for grid-produced power, which means they would enjoy even more savings by going solar.
How much does an average 10kW solar energy system cost?
As of February 2023, the average cost of solar panels in the United States was 2.86 per watt of capacity . At this price a 10kW solar panel array would cost you 28,600 to purchase and install, if tax credits and rebates are not included.
But they should be included. All new solar homeowners in the United States can now deduct 30 percent of the cost of their solar installations from their federal taxes, thanks to a new law passed by Congress in August of this year that increased the Federal Renewable Energy Investment Tax Credit from its previous level of 26 percent .
That would amount to a savings of 8,580 based on the average cost of a 10kW solar array, which would drop the total price to 20,020.
In some states, including California, New Mexico, Rhode Island, New Hampshire, and a few others, you can receive additional tax credits of between 1,000 and 6,000 for installing solar panels, reducing your costs even further . In the most generous states you could literally cut the purchase and installation price of your solar energy system in half.
How long does it take for a 10kW solar photovoltaic system to pay for itself in energy savings?
As established during a previous calculation, the average homeowner could conceivably save more than 1,603 each year by installing 10kW worth of solar panels on their rooftop. Putting the numbers together, it would take you, as the embodiment of that average homeowner, 12 years to pay off the price of your solar photovoltaic system in full.
This assumes you’ll be investing in the neighborhood of 20,000 to cover the total cost of your solar equipment installation project, as would be expected if you were taking your federal tax credit. If you live in a state where energy are higher, or are using more than the typical 893 kWh per month, your payoff time could be faster, possibly dropping below the magic 10-year mark if your savings were significant enough.
Even if it took you the full 12 years to pass the payback threshold, it should be noted that this period is less than half the lifespan of the typical solar panel array, which can be expected to last from 25 to 30 years with proper maintenance .
What size battery storage do I need for a 10kW solar system?
With a 10kW solar energy system, you might very well have the opportunity to go completely off-grid to power your home. To do so, however, you’ll need to connect your system to a battery bank, so you can store energy for use during those times when sunshine is unavailable or weak (at night and on cloudy or rainy days).
To determine your battery needs, you have to first divide the amount of energy you plan to store (in watt-hours) by the voltage of the battery (48 or 24 volt batteries would be standard). The answer to this equation will be expressed in amp-hours, which quantifies the amount of energy a battery would be able to discharge while in use. This will tell you how many batteries you need to include in your battery bank .
If you want to store enough energy to cover your electricity needs for three full days (a decent standard for a fully off-the-grid system), and you use 30 kilowatt-hours of energy each day (a typical amount for the average homeowner), you’d need a battery backup system capable of storing 90kWh worth of energy. This translates to 90,000 watt-hours, and it is this number you would divide by the voltage of your battery (to generate an answer in amp-hours).
So if you planned to purchase either 48-volt or 24-volt solar batteries, you would perform one of the following calculations:
90000/48V = 1875 amp-hours, or 90000/24 = 2750 amp-hours
In the first instance, you could meet your storage needs by purchasing five 48-volt solar batteries with a 400 amp-hour capacity (2000 amp-hours provided in total), or eight of these batteries with a 250 amp-hour capacity (multiple amp-hour options are available).
If you wanted to install a battery bank of 24-volt batteries, you’d need 10 batteries if they had an amp-hour production potential of 300 amp-hours each (300 x 10 = 3000, which is greater than 2750).
If you stay connected to the grid, you won’t need a battery bank. But some solar homeowners will add a battery or two to their solar energy system anyway, as a hedge against power outages or as a way to avoid using grid-produced electricity during more expensive peak hours.
With solar power, personalized solutions offer the best value
When you install solar panels on your rooftop, you should do so with a clear idea of what you’re hoping to accomplish.
If you’re interested in lighting, healing, and cooling a garage, studio or work shed, your equipment requirements will be fairly limited. If you plan to install a grid-tied system that will meet only 40 to 50 percent of your electricity needs, with the grid taking care of the rest, your solar array can be of modest size, and if it ends up performing either better or worse than you expected, it won’t have that much of an impact on your bank account.
But if your goal is to meet 100 percent of your electricity needs through solar, the stakes will be higher and your needs more precise. You’ll have to make a significant investment in solar panels in order to achieve that goal, and that’s why you’ll want to get it right the first time.
If your rooftop panels come up short, you may be forced to spend extra on expensive and time-consuming upgrades. On the other hand, if your solar array features notably more capacity than you really need, your upfront investment will have caused you unnecessary financial pain.
To avoid costly miscalculations, you should consult with solar installation professionals who can give you an accurate and detailed estimate of your home’s year-round energy requirements. They may very well tell you that a 10kW system is the perfect size for residence, but whatever they say you should rely on their expertise to guide your decision-making processes.