What Are Solar Batteries Used For? See What They Can and Cannot Do
There’s some confusion and misunderstanding of what solar batteries can actually do. Yes, they can achieve quite a lot in your bid for energy independence and freedom from the power company. But there are limitations, and some of those limitations depend on the brand of battery.
So before you start comparing solar batteries, you would be wise to take a moment and be sure you know what you’re looking for, and that your expectations are realistic. Solar batteries are used for several purposes. Be sure those align with your needs.
Here are a few things solar batteries can and cannot do.
5 things solar batteries are used for
1. Increasing solar efficiency
For grid-connected solar panels, any excess energy you produce goes to the grid. Even if you have a good net metering policy that gives you full or nearly full credit for that excess power, you still lose some in the transmission process. It’s more efficient to use it all yourself, and batteries help make that possible.
2. Overcoming weak net metering policies
If you live in an area with weak or non-existent net metering, then any excess power produced by your solar panels gets taken by the grid, and you get nothing for it. To make better use of your investment, solar batteries enable you to keep your excess energy and use all or almost all of it. By using more of your energy, your investment pays off sooner.
3. Avoiding high peak power bills
Some utilities charge extra high rates during times of peak usage, such as in the evenings. During those times, your solar panels often can’t produce energy because the sun is down.
With solar batteries, you can continue to power your home during these times of peak usage, and thus avoid paying the higher power rates.
4. Powering your home at night with solar energy
With enough solar battery capacity, you can power your home with solar energy even at night. By morning, most likely you’ll have depleted all your stored solar energy, but you didn’t need to use the grid nearly as much as you would have, and your batteries will recharge the next day. This again is a huge financial savings.
5. Sustaining Your Basic Power Needs During an Outage (for certain brands)
Certain brands of solar batteries, such as Tesla, don’t function during a power outage. If continuing to have power during an outage is one of the main reasons you want solar batteries, make sure you buy a brand that will kick in during an outage and provide power to your home’s most essential systems.
This is far more important than price!
Solar batteries are fairly costly in most cases, but the most important thing is to get your needs and priorities met first, and look at price second. And to be clear, you will find some pretty wide variations in price. Coastal Solar offers several solar power battery options to meet a variety of needs and price points.
Solar batteries that work during a power outage are often called hybrid batteries. A solar consultant can help you be sure the kind of battery you’re looking at will work with your solar array.
4 Things Solar Batteries Cannot Do
You can see that solar batteries are used for quite a lot. But there are some things they cannot do, or that they can only do in certain situations. Know ahead of time what is and isn’t possible before you get too far into choosing battery brands.
Here are four things solar batteries cannot deliver.
1. They don’t work with every solar array
Different batteries have been designed for different purposes. You’ve already seen one example with regard to power outages. Some batteries, like hybrids, are designed to store and use solar energy regardless of whether the power is on or off. Others are not.
Here are a few other situations where only certain types of solar batteries will work:
Certain solar panel brands
Some solar batteries are only compatible with certain brands or types of solar panels. If you have an existing solar array, make sure the batteries you’re looking at are compatible with your brand of panels.
Existing solar arrays
Likewise, some solar batteries can only be installed at the same time as the solar panels, whereas others can be added on to an existing solar array. If you have an existing array and want to upgrade it with batteries, you’ll be limited to particular solar battery brands.
If you are considering installing solar for the first time, you will have more options for batteries – but if you want a brand that must be installed at the same time as the panels, you’ll have to decide at the time of installation.
Certain sizes of solar arrays
Some solar batteries are designed for specific sizes of solar arrays. Some batteries work with smaller arrays like those used by a residence. Other batteries were designed for larger systems like industrial plants and large warehouses, businesses, and farms.
If you have or are interested in an off-grid solar array, you’ll have a whole host of additional challenges compared to a grid-connected system. And with off-grid solar, it is practically essential to get batteries. Otherwise you’re assured of having no power at night, ever.
There are particular brands of batteries designed to work with off-grid solar arrays. So if you’re going off-grid, look for brands that specialize in that.
Outdoor solar situations
Finally, some solar batteries are designed to work outside in small scale situations, such as with boats and RVs. Sometimes you’ll see very low prices for batteries and wonder why they’re so much lower. Often, this is why, because a boat or an RV doesn’t need as much solar battery capacity to power all the systems on board. You’d need dozens of these kinds of batteries to power a home, and it would be impractical and would not save you money over the larger battery options.
2. Disconnect you from the grid – in most cases
Again, this part is complicated.
An off-grid solar array can be disconnected from the grid…obviously. And so can its batteries, as mentioned earlier.
But an on-grid system will remain on the grid after you buy solar batteries. If your batteries become fully charged, then any excess power will again be sent back into the grid, and will be subject to net metering policies. During an outage, you would need hybrid solar batteries to keep your lights on. But you’ll still be connected to the grid.
3. Sustain all your home’s energy systems in a power outage
It’s almost impossible for a solar array to power all your home’s energy needs during a power outage. For outages lasting several days, it becomes even more unlikely.
That’s why, if keeping your power on during an outage is one of your main reasons for wanting batteries, your best approach is to also install a new subpanel connected with the solar batteries. With that, you can specify which systems you want the batteries to supply power to during an outage.
For example, you would want your freezer and refrigerator to stay on. But your hot water heater, which guzzles energy that you don’t necessarily need for a few days, could be left off. You could also select certain lights, certain outlets for charging phones, and things of this nature.
Your heater and air conditioning are a tough question, because if you lose power for days in the middle of the winter like what happened in Texas a few years back, the whole point of having solar batteries in that situation would be to use your heater. But, your heater will use up that stored energy pretty fast.
So if you leave that connected to your batteries, you would want to use it in spurts. Warm up the house, then turn the heat off and let it get cold again. Your panels would recharge your hybrid batteries during the day even in the power outage to some degree. But still, running the heat all the time won’t be practical.
4. Recharge forever
Just like the rechargeable batteries in your phone and laptop, solar batteries slowly lose the ability to fully recharge. In technical terms, their depth of discharge for solar batteries decreases a little bit with each cycle of storing and using energy.
So when you buy a solar battery, it will not last forever. This is a price differentiator. Often, the more expensive batteries will last much longer than the less expensive ones. So you have to decide how many years you want to invest into your solar batteries.
Speak with a Solar Consultant
As you can see, solar batteries are complicated. They can work wonders in your quest to own your power and liberate yourself from the utility. They help you beat peak power rates and lousy net metering policies.
But certain brands only work in certain situations, and the power outage issue is quite a bit more complicated than you may have realized before reading this.
If you are interested in batteries, ask your solar consultant for options and possibilities while you’re discussing your new solar array if you don’t have one already. Or, if you do already have a solar array but are interested in upgrading it with solar batteries, talk to a solar consultant and get a quote on batteries. If you want to keep learning on your own, you may be interested in our full guide to solar power battery storage.
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