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This is one of the most common questions that newcomers to solar energy ask. Do solar panels come with batteries? Are they really necessary? Can you go solar without them? We have a lot to cover so let’s get started.
Solar panels use batteries to store the energy they produce. After the panels generate electricity, it is kept in the battery for use by appliances and devices in residential, commercial and industrial centers.
How Solar Batteries Work
To answer the question “do solar panels have batteries?”, no they do not. Batteries are not built into solar panels and they are sold separately.
But if you are going to invest in solar energy, it’s a good idea to get solar batteries. Here’s why.
Solar panels harness the sun to generate electricity. But it needs a battery to store this power.
Without a battery, you won’t be able to use solar power when it’s dark, snowing or raining. A solar battery serves as storage for solar power so you can use it anytime.
After your solar panels transmit the electricity into the battery, an inverter turns it into AC (alternating current) and is ready for your appliances, devices and gadgets.
If you need 20kwh a day for instance, solar batteries are a must. Solar panels can only produce energy in ideal conditions, i.e. when the sun is out.
With a solar battery you can harness the power of solar energy anytime regardless of the weather.
Types of Solar Batteries
There are many kinds of solar batteries, but these are the most suitable for homes, RVs and off the grid setups.
Lithium ion / LiFePO4
Lithium batteries are the best option for solar power. They are newer than lead acid and provide several advantages.
Lithium solar batteries weigh less, a big factor if you need to install several for your home or RV. More importantly, they are more efficient than lead acid.
Lithium solar batteries have an 85-100% depth discharge so you can use all (or almost all) of the solar power in it. I find lithium batteries ideal for running power hungry appliances and devices.
I strongly recommend lithium solar batteries because they last a long time, need zero maintenance and very reliable. My personal choice is the Eco Worthy 100ah LiFePO4 batteries because it provides deep discharges without sacrificing lifespan.
Lead acid batteries are the cheapest option available. There are two variants, flooded lead acid (FLA) and sealed lead acid (SLA).
FLA batteries are the most affordable but have several limitations. They require constant maintenance and only 50% depth discharge. Meaning you can only use 50% of the stored energy before it requires a recharge.
There are two types of SLA batteries, AGM and gel. Gel and AGM have similarities, but the bottom line is AGM offers better performance than gel.
If you are on a budget, AGM deep cycle batteries are a good alternative to lithium. My pick is the Renogy AGM 100ah batteries as it offers a nice balance of power and cost efficiency.
What to Look For in Solar Batteries
Before you buy a solar battery, there are many factors you have to consider.
Why do you want to buy a solar battery? What do you intend to do with it?
Do you want to minimize or eliminate your dependence on energy companies? Would you like to run appliances on solar power? Do you want to live in an RV and have access to energy anytime, anywhere?
How you answer these questions determines what solar battery to buy, how many and what capacity.
There are basically two options: lithium or lead acid batteries. Which is right for you depends on your requirements.
Lithium solar batteries are for you if:
- You want long lasting batteries
- Little to no maintenance
- Want to use as much stored solar power as possible
- Need to run energy intensive appliances and devices
Lead acid batteries are for you if:
- On a budget
- Willing to perform regular maintenance
Performance wise a lithium battery is better than lead acid. But if you are looking for an affordable option, I would buy AGM batteries. They’re not as good as lithium but much better than FLA batteries.
Depth of Discharge (DOD)
Depth discharge indicates how much of the solar power stored you can use before it has to be recharged.
The deeper the discharge, the shorter the battery lifespan. But lithium batteries can handle deep discharges better than lead acid.
Lithium solar batteries typically have an 85% depth discharge rate. Some models even have a 100% DOD. Even at 85% you can still use a lot of the power your solar panels produce.
Lead acid batteries have a 50% DOD, while AGM has around 70-75%. After that you have to recharge it.
Lithium batteries have a deeper depth of discharge than lead acid, but their superior design means it lasts longer. A lithium battery with an 85% DOD has a longer lifespan than a lead acid with a 50% DOD.
Again we see that lithium batteries have the edge over lead acid. But lead acid is more affordable and ideal if you are on a budget.
Solar panels are not 100% efficient and neither are solar batteries. Some of the electricity gets lost during the transmission and conversion process.
Solar panels, batteries and inverters have different efficiency rates, Check the specs of each product so you’ll know what to expect.
More expensive solar batteries have greater efficiency rates. While they cost more, I like to think of it as a long term investment.
Batteries with high efficiency rates store more solar power. This lets you use more solar energy and cut down on energy costs. The higher purchase gets offset by your savings, so you have to think long term.
How long do solar batteries last? This is a difficult question to answer because so many factors are involved. Depth discharge, usage, design, type etc. all of them affect battery lifespan.
In general, lithium solar batteries last 8-16 years or more. Lead acid batteries are good for 10 years minimum.
I want to add how you use the battery greatly affects its lifespan. Always follow the manufacturer instructions and the battery is going to last years.
Are Solar Batteries Worth It?
At first glance, buying solar batteries is expensive. But as I said you have to think of the long term. When you consider all the benefits it becomes clear that it is a good investment. It will literally change the way you live.
Reduce or Eliminate Electricity Bills
If you are on the grid, solar panels and batteries can significantly cut down your power bill.
There’s a reason why these batteries last 15 years or more. And that’s because going solar requires long term commitment.
The high initial cost of a solar system is going to pay for itself in the years ahead. Once the system has paid for itself, you can recover the cost through your energy bill savings.
If you are on the grid and the power goes out, there’s nothing you can do. Unless you have a generator you can only hope the utility company restores power soon.
If you have a solar system, there is backup power available. By calculating how much power you consume in a month, you can determine how many batteries are needed.
RV owners who have solar systems installed can attest to this. You can go anywhere you want and you’ll always have power available even at night.
You can do the same with your home. Solar batteries can store energy for emergency power. You can run appliances on solar power regardless of the time or weather.
Energy independence means not having to pay utility bills. It also means having electricity even during a power outage.
Good for the Environment
Going solar cuts down your carbon footprint. Not only do you cut down on energy costs, but you also help preserve a cleaner, better environment, which also benefits you.
Frequently Asked Questions
How many solar batteries do I need to run my house?
If you are only going to use solar during a power outage, list all the appliances you want to run. Add their total watts and you get an idea of how many solar panels and batteries are needed.
If you want to go off grid and run everything on solar 24/7, check your monthly power consumption. This will be indicated in your monthly bill.
Use that as a guide only. If you consume 900 kwh a month, better get a 1000 kwh solar system (remember, solar power is not 100% efficient).
If you aren’t sure how to proceed, consult a solar installer. They will tell you how many batteries are required to power your home.
What brands sell the best solar batteries?
Among the most popular brands are Renogy, Tesla, Solar Edge, Generac, Panasonic and SunVault.
Buying from a reputable brand is important. But consider your specific requirements. As I explained earlier, some homes might benefit from a lithium battery while others are better off with AGM.
Are solar batteries safe?
All batteries carry a degree of risk (overheating, overcharging, leaks). A lot of the danger comes from incorrect installation and lack of maintenance.
If you’re not sure how to install batteries on a solar system, hire a professional to do it. If you buy a solar system for your home, the company will likely install everything for you.
How do I make solar batteries last longer?
Use batteries only as directed. Follow all maintenance tasks and safety guidelines. Based on my own experience, doing these will make batteries last years.
I am an advocate of solar power. Through portablesolarexpert.com I want to share with all of you what I have learned and cotinue to learn about renewable energy.