Connecting Batteries Together For Battery Storage
For either off-grid or grid-connected reneable energy systems that use batteries for their energy storage, connecting batteries together to produce larger battery arrays of the desired operating voltage or 24 hour current demand is an important part of any solar power energy storage system.
Most alternative energy generating systems fall into two main categories, a “grid-connected system”, and an “off-grid system”. Grid-connected systems are so named because they connect directly to the electrical utility grid and if the electrical generating device, solar panels, wind turbines, hydro generator, etc, is producing more electricity than is needed, the excess is fed onto the grid.
But grid-connected systems with battery backup (Hybrid Systems) are also possible. Battery based grid-connected systems require a different type of inverter as well as a battery charge controller to monitor the flow of electricity into and out of the battery bank.
Off-grid or stand alone systems use batteries to store their electrical energy. Off-grid systems are ideal for remote rural areas and applications where the connection to a utility grid is either impractical or unavailable. In these cases, it is more cost effective to install a single stand alone off-grid system than pay the costs of having the local electricity company extend their power lines and cables directly to the home.
All stand-alone and battery backup alternative energy systems whether wind, solar or hydro powered all require some form of battery storage so its important that connecting batteries together is done correctly.
An electrical generator charges the batteries, usually during daylight hours for solar and the batteries supply the power when it is needed, often at night and during cloudy weather, so connecting batteries together to store this free solar energy is and important part of any off-grid renewable system.
The two most common types of rechargeable batteries in use today are lead-acid and alkaline. Lead acid batteries have plates made of lead, mixed with other materials and submerged in a sulphuric acid electrolyte solution. The lead acid battery is an integral part of any off-grid alternative energy electrical system and the fundamental lead-acid technology has not changed since its invention.
Lead-acid batteries are the most common in renewable energy charging systems because their initial cost is lower and because they are readily available nearly everywhere in the world. Deep cycle lead acid batteries are called a secondary battery, as it may be recharged by applying current. A primary battery is one that is not rechargeable. All deep cycle batteries are, therefore, secondary batteries.
Deep cycle batteries are a form of lead-acid battery that is specially designed to provide a steady current over a long period of time. There are many different sizes and designs of deep cycle lead-acid batteries available, all designed to be repeatedly discharged by as much as 80% of their capacity so they are a good choice for off-grid systems. Even though they are designed to withstand deep cycling, these batteries will have a longer life if the cycles are shallower.
Connecting Deep Cycle Batteries
Batteries are generally wired or connected together to produce a specific voltage and amp-hour storage capacity. The batteries of small renewable energy systems, for example, those used to power cabins, RV’s and boats, etc, are typically wired to produce 12-volt electricity.
Off-grid systems used to power homes and businesses, etc, are typically wired to produce 24 or 48 volt DC electricity. This low-voltage DC electricity can also be converted to mains AC electricity by an inverter which boosts the voltage to 120 volts or 240 volts, commonly used to power larger electrical devices.
When more than one deep cycle battery is connected together the resulting battery bank will have either a different voltage or a different amp-hour capacity (or both) when compared to a single battery.
Batteries can be wired or connected together in either series or parallel combinations, or both to increase the voltage or current capacity of the battery bank. Then connecting batteries together allows for more battery storage.
Batteries Connected Together in Series
A battery bank is built up by connecting two or more deep cycle batteries together. Battery banks made from batteries that are connected in series have the same current capacity as the individual batteries, but the voltage is multiplied by the number of batteries in the series string.
In a series connected battery bank the positive terminal of one battery is connected to the negative terminal of the next, and so on. Connecting batteries together in a series combination means a higher voltage for the same current.
Batteries Connected Together in Parallel
Battery banks made from deep cycle batteries that are connected in parallel have the same voltage as the individual batteries, but the current capacity is multiplied by the number of batteries. In a parallel connected battery bank the positive terminal of one battery is connected to the positive terminal of the next with the negative terminal connected to the negative terminal. Connecting batteries together in parallel branches means a higher current for the same terminal voltage.
Series and parallel combinations of batteries within a battery bank increase both the voltage based on the numbers of batteries in the series strings and the current capacity based on the number of series strings connected in parallel. Connecting batteries together in both series and parallel combinations allows for more battery storage at a higher voltage.
Lets look at some of the ways we can connect batteries together to produce higher voltages and current configurations.
Connecting Batteries Together For 12 Volt Wiring
All combinations of series and parallel battery connections will produce an array of 12 volts.
Connecting Batteries Together For 24 Volt Wiring
All combinations of series and parallel battery connections will produce an array of 24 volts.
Connecting Batteries Together For 48 Volt Wiring
Finally, these combinations of series and parallel battery connections will produce an array of 48 volts.
In off-grid stand-alone alternative energy systems, the electrical energy produced by the generating device can not always be used when it is produced. Because the demand for energy does not always coincide with its production, electrical storage batteries are commonly used in many off-grid and grid-tied systems.
The battery bank voltage selection, either 12, 24 or 48 volts often depends on the load voltage requirements of the system, the storage capacity required and the type of batteries available. For larger loads it is sometimes better to connect deep cycle batteries together to produce higher voltages in order to lower the system currents.
For example, a 240 watt DC load operating from a 12 volt battery draws about 20 amps, where as a 240 watt DC load operating from a 48 volt battery only draws 5 amperes, a quarter of the current. This lower system current has many advantages by reducing the size of the cabling, isolation switches and fuses used thereby saving you money.
One final safety point in understanding batteries and connecting together lead-acid batteries for greater energy storage. Lead acid deep cycle batteries are the most dangerous part of any solar or wind power system. Gloves, eye protection such as goggles and masks as well as old clothes must be worn when handling lead acid batteries and electrolyte as “battery acid” both burns and irritates skin and eyes.
To find out more about “connecting batteries together” and how you can use them as part of a Home Solar system, or to explore the advantages and disadvantages of connecting batteries together for more battery storage and how you can use Deep Cycle Batteries as an alternative to automotive batteries, then why not Click Here and get your copy of one of the top battery builders guide from Amazon today and learn how to build, rebuild and recondition deep cycle lead-acid batteries
Can Solar and Batteries Outlast an Extended Power Outage?
It depends, experts say. Just expect to make a few sacrifices.
Even by the standards of the generally well-informed clean-energy customers in California’s Bay Area, Todd Karin is a savvy one.
Karin works as a postdoctoral researcher in the energy storage and distributed resources division at Lawrence Berkeley National Laboratory. Last year, he chose to add solar and storage to his home, first buying an array of Panasonic panels and then adding a Tesla Powerwall a few months later.
Karin said the decision to go solar was an environmental and economic one, but the energy storage he had installed was in preparation for an uptick in power outages. He lives in a part of rural Solano County situated between San Francisco and the Central Valley. Though power outages roiled the Bay Area last week — with Pacific Gas Electric reporting a peak of 738,000 impacted customers — Karin and many of his neighbors were prepared.
“Almost all of our neighbors have generators. You can hear it when you go outside,” Karin said. “One of our neighbors got a generator from a hospital that they were throwing away. They could light up the whole town if PGE would let them.”
The outage was the first extended test for Karin’s backup system. PGE cut electricity to his house for a little over two days. Without power, the well and pump system supplying water to his home can’t function. But the Powerwall largely worked, allowing the house to use water, the fridge and even a table saw for a bit of woodworking.
California’s outages come at a time when many residential solar sellers are rushing battery products to market or working to expand attachment rates for new sales. Sunnova, Sunrun, SunPower and Tesla all offer in-house storage products for home solar customers. Those products join a growing crowd of storage vendors including Simpliphi, LG Chem and the latest entrant, Generac, a company formerly focused solely on backup generators.
Not quite full resilience
PGE’s public safety power shutoffs could mean a windfall of business for residential storage providers. Outage areas ringing the Bay Area align with the home base of some of the most likely clean-energy buyers. And though fire is a natural part of California’s landscape, extreme weather worsened by climate change is making wildfires more severe, compelling more customers to look for resilient energy solutions. On Monday, the California Department of Forestry and Fire Protection was managing several fires burning throughout the state.
California also remains the top state for residential solar installations. In January a state mandate goes into effect requiring all new homes to include solar. California’s storage market is also the biggest in the U.S. and grew 70 percent from Q2 to Q3, according to Wood Mackenzie Power Renewables.
In a market flush with options, though, it can be unclear how they all stack up — especially in the event of an extended power outage.
No solar-plus-storage system currently on the market can completely support average U.S. electricity usage during a days-long blackout. But customers can rely on them for some of the basics, analysts say.
Depending on the size of the battery, these home solar-plus-storage systems can add a certain level of resilience: keeping the lights on, the internet running, food from spoiling, etc. It’s definitely valuable,” said Michelle Davis, a senior solar analyst at WoodMac.
“But the average solar and battery sizes being installed today couldn’t support an HVAC system, standard hot water heater and other loads in a typical home for more than a few hours. So is it full resilience during a blackout? No, definitely not.”
Karin said he used an electric burner for most cooking to try to conserve power. Mild temperatures meant no need for climate control, but that would have sucked up too much electricity anyway. However, lack of access to HVAC can be dangerous for many people during an outage.
Karin’s system also didn’t perform seamlessly. For reasons unknown to him, his SMA string inverter repeatedly tripped off. Though it didn’t interrupt his power, it did likely put added wear on the system. Tesla did not respond to request for comment about whether other customers had reported issues.
How long will my battery system last?
Some batteries will also provide longer backup than others. The 13.5-kilowatt-hour capacity of Tesla’s Powerwall, for instance, outranks Sunrun’s Brightbox at 10 kilowatt-hours. But those systems have the same power rating, at 5 kilowatts, which means they offer the same “maximum load coverage,” according to WoodMac’s director of solar, Ravi Manghani.
“Typically, during a power outage, one wouldn’t aim to draw at the maximum 5 kilowatts, a load roughly equivalent to running a clothes dryer, microwave and hair dryer all at once, Manghani said.
“An average homeowner typically will draw 2 kilowatts maximum during an outage, and an average of 750 to 1,000 watts during the course of the outage, he said. This means a Brightbox will last for 10 to 12 hours, while a Powerwall will last for 12 to 15 hours.”
Certain applications and programs already on the market, such as Sense and Powerley, can also give homeowners an idea of their usage. But in a Catch-22, the apps might require power to function, though data on past power usage could help homeowners identify which appliances to prioritize.
Recent data suggests that many homeowners installing energy storage systems are opting for two batteries instead of one for greater backup capacity.
John Berger, CEO at residential solar and storage company Sunnova, told Greentech Media that the company has seen an influx in demand for storage from existing customers looking to update their systems, as well as new customers asking for batteries from the start. In terms of how long the system can last, however, Berger offers what he called “a rather unsatisfying answer.”
“It depends on how much power your home uses, how big it is, what the weather is in your particular area,” he said. “Some of our customers may be able to have a whole home backup with one or two batteries, and then in other cases that may still not be enough.”
Coming soon: Your personal nanogrid
Sunnova is working on integrating traditional generators and demand-side management alongside its storage-plus-solar system to create a “nanogrid” that the company will then manage as a service provider.
Because conventional generators use fossil fuels, that solution isn’t as clean as solar-and-storage alone, but it could offer higher reliability during extended outages.
Whatever solution customers choose, Berger said most recognize that climate change is worsening the impact of natural disasters, whether or not they live in California.
“We see it all around the country and around the world,” said Berger. “This seems permanent; this is not going to go away. It’s not a one-time event, or two times. It’s not just the wildfires; it’s the hurricanes as well.”
“There’s no reason to sit in your house and wonder when the utility is going to shut off the power or when the power lines are going to go down. Frankly, that’s a bit archaic,” he added.
“We should, as a society — and not just in the United States, but globally — be demanding better service. […] Right now, an increasing number of folks are able to go out there and get that better service.”
Now in its fifth year, the Energy Storage Summit will bring together utilities, financiers, regulators, technology innovators, and storage practitioners for two full days of data-intensive presentations, analyst-led panel sessions with industry leaders, and extensive, high-level networking.
Kohler enCUBE 1.8 KW Solar Recharging Generator
The Kohler enCube was on the edge of innovation when it first came out, but its lead-acid power source is making way for more popular lithium-ion units.
Do a Google search for “solar generator” and you’ll be in prepper heaven with all kinds of choices from instruction on building your own DIY kit to legit-looking systems that are awfully tempting. There are questions left on the table though, especially if you’re not a prepper but the idea of a solar charging generator sounds appealing. The big one for most of us (and I’m included in that group) is the reputation of the company building an rather expensive generator. When I saw the Kohler enCUBE 1.8 KW Solar Recharging Generator at World of Concrete earlier this year, I finally had an option where the reputation was already proven.
With reputation established, the next question is all about capability. A typical gas-powered jobsite generator has to pull 5000 watts in order to get the attention of many professionals. That’s not a surprise with a suite of tools that includes everything from drills to miter saws. However, this golden age of cordless tools might make us reconsider what we actually need. The Kohler enCUBE and I are going to address that end of the question in future article. For now, let’s see what the enCUBE has to offer.
First Impressions
There are only two reasons to mention the packaging for a tool – either it’s terrible or it’s excellent. For Kohler, it’s outstanding. I was nervous about having a generator of this weight shipped, but it turns out there was nothing to worry about. A custom molded high density foam ensured any bumps were absorbed while extra rigidity was added to reinforce the corners of the box.
Even on paper, the power to weight ratio stands out like a sore thumb. 109 pounds is a lot to haul around. In the Kohler enCUBE’s defense, it has an integrated wheel base and telescoping handle to make moving it around easier. The weight comes from using a 12 volt, 100 amp hour AGM lead acid battery. This isn’t your standard car battery. It’s designed as a deep cycle power source that won’t suffer the negative effects that typical lead acid batteries encounter when discharging too far before recharging.
A total of six power outlets come on the unit to give you a variety of options. For standard devices, like corded tools and battery chargers, you have two 120 volt power outlets. Tech devices can be recharged on a pair of 5 volt USB outlets. Finally, two 12 volt vehicle outlets are also available.
Battery terminals on the back allow for vehicle jumpstarting. I’ve been told by an insider that it can also be used to daisy chain an extra battery as a power source, but that’s outside the scope of what the enCUBE has been designed to do.
The battery is accessible by removing the screws under the top lid. This means that you’ll be able to replace the AGM battery yourself when the time comes and leaves the door open for potential improvements.
Sunlight: Gatorade for the Kohler enCUBE
Solar charging is one of the major draws for this system, but those new to the idea need to be sure and understand the expectations. Solar power is efficient and clean. However, it also tends to be slow. I received the enCUBE with the optional 60 watt solar panels. This puts my complete charging cycle time at somewhere around 20 hours in perfect conditions.
The reality is you’ll only experience those conditions for short periods of time. Even in Florida, peak charging on a good day is only going to be in the neighborhood of 4 – 6 hours.
Whether recharging via AC power or solar, the Kohler enCUBE gives you a charge status indicator. It uses a 5 bar indicator along with a digital readout of your current charging power. I went out at high noon (high, hot, bright sun at 92 degrees) to see what I could pull for input power. I maxed out at 45 watts of input power and averaged close to 30 watts. That means my peak charge time is just under 27 hours and my realistic charge time is closer to 40 hours from completely depleted to full.
You can reduce the charge time greatly by going with Kohler’s 150 watt solar panel option or by combining up to 240 watts of panels. With the real world charging I saw, this would make your average charge time between 10 (240 watts) and 16 hours (150 watts).
While it’s billed as a solar recharging generator, using the wall charger will be your go-to option overnight between jobs. The manual states that it may take as many as 24 hours to fully recharge the battery. Even though I was pulling 85 watts from the wall (14 hour charge time), the system is going to reduce the charge rate as it gets closer to full to protect the battery.
Why Not Use Lithium-Ion?
If you’re reading this as a professional tool user, you’ve probably wondered why the Kohler enCUBE wouldn’t just utilize a big lithium-ion battery. It’s a great question – lithium-ion is lighter, has a smaller footprint, longer life cycle, charges faster, and doesn’t lose the ability to deliver full power as it drains. With all those benefits, you’d think a lithium-ion power source would be a no-brainer.
The big reality at this stage of the game is price. The enCUBE starts at just under 1100 and runs about 1400 for the package I received. To make a lithium-ion package at the same price point, we’d be looking at 25 – 30 amp hours, not 100. Lithium-ion is certainly somewhere down the line for serious consideration. However, with a battery-powered generator having to balance capacity, power, and price point compared to gas powered generators, it just doesn’t make much sense.
Using the Kohler enCUBE
The Kohler enCUBE is listed as a 1.8 kilowatt (1800 watt) generator. It is capable of drawing 20 amps (3600 watts) for the quick surge required by tools and devices. In high stress applications, it can produce 15 amps (1800) watts for 10 minutes. However, for sustained power, you’re looking at 12.5 amps (1440 watts). The battery certainly holds more capacity than the two high-draw scenarios, but Kohler has designed protections into the system to extend the battery life.
When you’re powering smaller items through the USB and vehicle chargers, you can pull power without turning the system on. You only need to power it up when you’re using the outlets and all three will operate normally with the power on. You’re able to run the generator while it is charging as well. As the unit reaches the last 20% or so charging, it reduces the energy flow. It continues to slow down the draw until it reaches a maintenance trickle charge to protect the battery.
Aside from the information you’re given during charging, a couple other useful bits of data are displayed during use. Similar to the input wattage displayed during charging, you’ll now see the output wattage. The computer takes this and calculates the amount of time you can continue to run at that output – an outstanding feature for any kind of sustained tasks.
Living in the golden age of lithium-ion power, we need to get back to our more careful roots when using an AGM lead acid battery. These have a battery memory. If you constantly charge with only 20% or 40% of the capacity used, you’re going to limit the future capacity. You also need to avoid going too deep into the discharge. A low battery alarm and automatic shutoff will occur when the voltage drops too low, but you also want to keep an eye out to avoid dropping below 20% remaining capacity to avoid damage.
Properly maintained, an typical AGM lead acid battery can last up to 8 years and more than 4000 cycles. Less careful use should still net 2 – 3 years and 700 – 800 cycles. You’ll want to extend the life as best you can considering the 150 – 250 replacement price tag.
A Note About Value
If you’re comparing the enCUBE to gas powered generators, there’s going to be a gap. Even on the high end of the scale, generators in this wattage class are going to be several hundred dollars cheaper than the package we reviewed (though the generator on its own is in the high-end range). You can easily get triple the power or more for the same price with gas power, but you lose all the benefits that battery brings with it.
When you’re looking at the 1800 watt battery powered generator class by itself, things get more interesting. Goal Zero and Earthtech are the main competition – they’re going to start at 2000 and go north from there. Additionally, Kohler has been around for a long time and their name is synonymous with quality small engines, including those found on generators. Kohler offers a longer track record and reputation along with savings of more than 600 by the time it’s all said and done.
Conclusions
There are lingering questions about what we can realistically run and should expect to get out of the Kohler enCUBE in terms of work. I’m going to leave those dangling out there for another week or two and tackle them in another article. At this stage, we simply wanted to get to know the enCUBE and see what it was all about compared to other small generators out there.
There are trade-offs between gas and battery powered generators. The Kohler enCUBE has no emissions, no gas and oil to worry about, no small engine maintenance concerns, is nearly silent, and can be used indoors. The downside is the weight, price, and recharge rate.
Where the enCUBE shines is in its ability to deliver power across three platforms with a brain that helps maintain the battery for a longer lifespan. It enjoys the Kohler name and reputation while tackling a price point that’s hundreds of dollars less than their battery-powered competition. Whether you’re preparing for a loss of electricity or looking for a more environmentally friendly way to get the job done, the Kohler enCUBE is at the top of this generator class.
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Japan Power Rental Market Assessment Report 2023-2029: Market to Reach a Value of 263.8 Million. Infrastructure Investments by the Japanese Government Stimulates Demand
DUBLIN. June 27, 2023 /PRNewswire/.- The Japan Power Rental Market. Strategic Assessment Forecast 2023-2029 report has been added to ResearchAndMarkets.com’s offering.
Japanese Power Rental Market is forecast to reach a value of 263.8 million by 2029 from 206.1 million in 2022, growing at a CAGR of 3.6%
Government measures to prevent and mitigate natural disasters will accelerate rental power equipment demand. In 2021, the government launched a five-year plan to accelerate emergency measures for national resilience, contributing to the prevention and mitigation of disasters to have a project budget of USD 117.2 billion.
In March 2022. Japan’s Ministry of Economy, Trade and Industry (METI) allotted its first Power Crunch alert after an earthquake hit in Tokyo Region. In June 2022. Mitsubishi and Japanese Utility Kyushu Electric Power Co collaboration stated that they teamed up to use grid-scale battery storage to reduce the impact of solar curtailment on the island of Kyushu in southern Japan.
The government is taking necessary actions for disaster management, which prompts the demand for power equipment in the Japan power rental market. According to Japan Meteorological Agency (JMA), in 2022, Japan witnessed eight earthquakes of five or more magnitude.
Since the country is prone to frequent natural disasters such as earthquakes, storms, and floods, power equipment is necessary to regain access to power during a blackout or an outage in those disaster-prone areas in the country. This will likely create demand for rental power equipment in Japan.
Mining Exploration Program Along With Clean Energy Strategies in Japan to Push the Demand for Leasing Power Equipment
Amazon will purchase green energy from Clean Energy Connect via the Japanese trading business Itochu for its operations. For this reason, Itochu will build renewable energy supply networks in America and Japan. Corporate power purchase agreements (CPPAs) have been signed with Clean Energy Connect (CEC), a member of the Itochu group, to supply Amazon with renewable energy for 20 years.
CEC will spend over 10 billion yen in the grand scheme to build Amazon’s modest solar power installations. By 2024, there will be roughly 700 solar projects in Japan. producing about 38,000 kilowatts of green energy. One of the largest CPPAs in Japan is anticipated to be the one with Amazon.
In addition to the former general electricity utilities, electricity retailers include telecommunications carriers, trading companies, gas and petroleum companies, steel manufacturers, and subsidiaries of former general electricity utilities. Currently, 730 entities have attained retail licenses as of August 2021 in the retail electricity sector, per METI’s Agency for Natural Resources and Energy data. In 2020 the net system energy demand was 821 TWh, of which former general electricity utilities accounted for 81%.
Japan Gold Corp announced in February 2023 the 2023 Exploration Program over its 2,920 sq km Japanese portfolio of mineral rights. Six projects have been chosen for development with geophysical surveying and drilling proposed in 2023 outside of the Barrick Alliance. Seven additional projects have been selected for work programs to provide a pipeline of targets to drill in 2024.
Infrastructure Investments by the Japanese Government Stimulate Demand for Rental Power Equipment
The government increased its FOCUS on upgrading the public infrastructure, including developing airports and railway stations. The government invested USD 470 million and USD 490 million in renovating the Kansai International Airport Shinjuku Station in 2022. The Kansai International Airport expansion project started in May 2021 and is expected to complete by 2025.
The Japanese government started maintenance and renovation projects in 2022. It planned to renovate 24,458 bridges, 3,761 tunnels, and road renovation projects at 5,296 locations nationwide. Therefore, the increasing concern about renovating roads, bridges, and tunnel renovation maintenance projects expects to support renting of power generation equipment in the Japan power rental market.
- The key players in the Japan power rental market are Kanamoto, Nishio, Aggreko, Caterpillar, Atlas Copco, Cummins Inc., and KOHLER Power.
- In July 2021. Kanamoto signed and expressed its support of the Task Force on Climate-Related Financial Disclosure (TCFD) and joined the TCFD Consortium.
- Kanamoto
- Nishio
- Aggreko
- Caterpillar
- Atlas Copco
- Cummins Inc.,
- KOHLER Power
Other Prominent Vendors
- Yanmar
- Akashi Rental Co., Ltd
- U-MAC VIETNAM
- ORIX
- NIKKEN CORPORATION
Segmentation By Power Rating
Segmentation By Equipment
Segmentation By End-User
- Construction
- Retail
- Oil Gas
- Mining
- Events
- Utilities
- IT Data Center
- Manufacturing
- Others
Segmentation By Application
For more information about this report visit https://www.researchandmarkets.com/r/q743d3
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