The Benefits of Battery Banks

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Derrick Harper
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1 The Benefits of Battery Banks 1 Page

2 D I S C L A I M E R O F L I A B I L I T Y A N D W A R R A N T Y This publication describes the author s opinions regarding the subject matter herein. The author and publisher are not rendering advice or services pertaining to specific individuals or situations. For specific advice, or if expert assistance is required, the services of a qualified professional should be obtained. The author and publisher assume no responsibility whatsoever for the use of the information in this publication or for decisions made or actions taken based, in whole or in part, on the information in this publication. The author and publisher make no warranties, express or implied, regarding the information. Without limiting the foregoing, the author and publisher specifically disclaim and will not be responsible for any liability, loss, or risk incurred directly, indirectly or incidentally as a consequence of the use or misuse of any advice or information presented herein. Use this publication and information with good judgment and do the best you can in your particular situation. You agree to indemnify and hold the author and publisher, and their respective officers, directors, agents, employees, contractors and suppliers, harmless from any claim or demand, including reasonable attorneys fees, related to your use or misuse of this publication or the information contained therein. You further agree that you will cooperate fully in the defense of any such claims. Notice: As the purchaser of this electronic document you are permitted to store it and print it for your own personal use only. Otherwise, no part of this publication may be reproduced, stored in a retrieval system or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise without the prior written permission of the copyright owner and publisher. It is illegal to make a copy of all or part of this publication for someone else, even if you do not charge for the copy. If you have purchased this book from anywhere other than OffGrid-Independence.net, including ebay, please report it to david@offgrid-independence.net immediately. C O P Y R I G H T Those who have received or purchased the guide are neither authorized nor permitted to transmit copies of this guide to anyone without written permission. Giving away copies to people who haven t paid for them is illegal under international copyright laws and will submit you to possible legal action. Therefore, the utilization of this file is limited to personal use only. T E R M S A N D D I S C L A I M E R By using, viewing, and interacting with this guide or the OffGrid-Independence.net website, you agree to all terms of engagement, thus assuming complete responsibility for your own actions. The authors and publishers will not be held liable or claim accountability for any loss or injuries. Use, view, and interact with these resources at your own risk. All products from OffGrid-Independence.net and its related companies are strictly for informational purposes only. While all at-tempts have been made to verify the accuracy of information provided on our website and within the publications, neither the authors nor the publishers are responsible for assuming liability for possible inaccuracies. The authors and publishers disclaim any responsibility for the inaccuracy of the content, including but not limited to errors or omissions. Loss of property, injury to self or others, and even death could occur as a direct or indirect consequence of the use and application of any content found herein.

3 TABLE OF CONTENTS Introduction... 3 How a Battery Bank Works... 4 Do the Math... 4 Equations to Memorize... 7 Gather Supplies... 9 What Type of Batteries Should Be Used? Configurations Parallel Wiring Battery Banks for an Off-Grid Home Conclusion Page

4 introduction If you are an outdoor enthusiast who enjoys camping in remote areas without electricity, you may already be familiar with the benefits of a battery bank. If your cell phone battery goes low, you can use the battery bank to power your phone charger so you maintain the ability to use the phone for emergency purposes if needed. A battery bank can also be very beneficial if you live off the grid or experience power outages. The stored power of a battery bank can be used to operate some household appliances, computers, devices, electronics, or to charge smaller batteries for use in portable lights, medical equipment, and devices. Battery banks are widely-used in an array of applications. Any time you need to access stored power, such as solar or wind power, battery banks may be the perfect solution. 3 Page

5 How a Battery Bank Works It may be helpful to think of a battery bank as a storage box. The battery bank holds the energy so that it can be used as needed for various purposes. Battery banks can be wired in different ways. They can be wired to increase voltage while maintaining the same amperage; or they can be wired to increase amperage while maintaining the same voltage. Do the Math Before you build your battery bank, you need to determine what battery power is needed for your purposes. What appliances or devices will you power with the battery bank? Will it be used frequently or just for an occasional emergency? Is your battery bank part of your prepping plan? To determine your battery power needs, you ll need to do a little math. If you re one who cringes at the thought of doing a little math, don t worry. The 4 Page

6 formulas are simple, and you won t have any problem figuring it out if you use the information below. Here are a few basics that will help you: An amp is the amount of electrical current that flows through a circuit. Major appliances are on 20, 50, or 60 amp circuits; lighting and small appliance circuits are 15 or 20 amps. Volts flow through the wires and are a measure of the pressure that causes current to flow through a circuit. Typically, household wiring is 120 volts or 240 volts. You can multiply the circuit s amperage by the circuit s volts to determine the amount of wattage a branch circuit can handle. (As an example, a 20-amp, 120-volt circuit can handle 2,400 watts (20 x 120 = 2400). See the chart below to get an idea of the wattage of common household appliances and equipment. 5 Page

7 ITEM WATTAGE Clothes Dryer 4900 Dishwasher 1200 Frost-Free Refrigerator 615 Frost-Free Freezer 500 Oven Range Washing Machine 500 Furnace 500 Room Heater 1350 Water Heater Blender 300 Coffee Maker 1200 Iron 1100 Hair Dryer 600 Clock Radio 70 Electric Blanket 200 Microwave 1450 Vacuum Cleaner Page

8 Mixer 130 Two-Burner Hot Plate 1650 Toaster 1150 TV 150 Computer 300 Stereo 1200 Power Drill 360 Circular Saw 1200 Table Saw 4500 Wet-Dry Vacuum 1850 Equations to Memorize Remember these equations to help you determine what the voltage and amperage of a possible battery bank would be: Watts divided by Amps = Volts Volts multiplied by Amps = Watts Watts divided by Volts = Amps 7 Page

9 As an example, using the equations above, if you had a lamp with a 100-watt, 10-amp incandescent bulb, the requirements would be, at least, 10 volts and 10 amps to operate the bulb. You wouldn t need a battery bank with an auto battery to power a 100-watt bulb, but this example allows you to see how you can figure how much power you might need from your battery bank. Did you know that you can scale up your battery bank to power large appliances or even your entire home? As mentioned above, a battery bank can serve many purposes for outdoor use, for an emergency power outage during storms, or as preparation for when normal electricity supplies might not be available. Read ahead to learn how you can build a battery bank. 8 Page

10 Gather Supplies Once you determine the purpose of your battery bank and figure out what size and power requirements are best for you, you need to gather the supplies to build your battery bank. The supplies you need will depend on the size and power of the battery bank you want to build. For an example, you may want to use only two automotive batteries and create a small solar array that is a great portable choice for small devices or to run boating and camping equipment. On the other hand, you may want to build a large battery bank that consists of several automobile batteries to power your entire house. To assemble a battery bank, you will need the following supplies: A minimum of two batteries Insulated cables for connecting the battery terminals. If you re operating the battery bank from solar or wind power, you ll need a charge converter. The charge converter keeps the batteries from overcharging when the energy is not being drawn from the batteries. 9 Page

11 If you are going to power appliances or electronics from the battery bank, you will need an inverter to convert the power generated by the batteries from DC to AC, which is required to power electronics and appliances. Equipment to capture the power source, such as a solar panel array or a wind turbine; and the means to connect the array by cables to the charge converter. As you can see, the list is short in exchange for the power you need to operate a myriad of appliances and devices when traditional forms of electricity are not available. The costs for building your battery bank will vary, depending on the size of the bank and what components you need to purchase. Your largest investment will be the batteries. If you set up a small bank that consists of two 12-volt automobile batteries, you should be able to build the battery bank for around $200 or less, depending on where you acquire the batteries and necessary components. Keep in mind that you might be able to purchase some of your components second-hand. Obviously, if you re planning to build a larger battery bank that consists of several batteries, your costs will rise proportionately. 10 Page

12 What Type of Batteries Should Be Used? Technically, you can use any two or more automotive batteries that are in good condition to build your battery bank. But some batteries will yield better results and require less maintenance than others. Deep discharge or deep-cycle lead-acid batteries may be the best batteries for your battery bank. These batteries have the capacity to store a great amount of energy, which can be a huge advantage. Lead-acid batteries are available in two types: sealed or flooded (also known as wet cell). The flooded batteries are less expensive, but you must check the electrolyte level that covers the plates and make sure the electrolyte levels are maintained at the correct level. The flooded batteries can also create another level of troubleshooting with the electrolyte levels that must be monitored. When wiring batteries in series to create a battery bank, it s best to use batteries with the same voltage and amperage ratings. This 11 Page

13 will give you the best results with longevity of the battery bank and with energy output. Two or more 12-volt deep-cycle lead-acid automotive batteries may be a great choice for your battery bank. You can find them at automotive or big-box stores, and they are not expensive. For a minimum output, the 12-volt deep-cycle lead-acid battery will provide you with months of consistent power that suits your planned purposes. Configurations The batteries can be configured in two basic ways to create a battery bank: in series, and parallel. One method is to wire the batteries in series, which adds the voltage of the batteries but keeps the amperage the same. To connect batteries in series, you use a jumper cable to connect the positive terminal of the lead battery to the other battery s negative terminal. If more than two batteries are used in the series, you continue by wiring the positive terminal of the second 12 Page

14 battery to the third battery s negative terminal. You continue this connecting process until all the batteries are connected. One of the most important things to focus on is to never cross the remaining open terminals with each other. If you do this, you could be injured and the batteries could be damaged. Parallel Wiring There is another method for wiring batteries to form a battery bank: parallel wiring. With parallel wiring, the voltage stays the same, but the amperage doubles. Heavily insulated cables should be used with parallel wiring. For parallel wiring, use cables to connect the positive terminals of the lead battery to the next battery, and then the negative terminals of the lead and second batteries. Then connect the device you want to power to the lead battery. Having learned how to connect batteries using in series and parallel methods, you can combine the two methods for a 13 Page

15 series/parallel configuration. Here s how to do a series/parallel configuration: Start with two sets of batteries that are already connected in parallel (positive to positive and negative to negative terminals). Since electricity flows through a parallel connection in the exact same way that it flows through a single battery, you can connect two parallel connections in a series as you would two single batteries. If this seems confusing, just think of the first parallel connection as one large single battery and the second parallel connection as one large single battery. This will simplify the configuration in your mind. Using a cable, connect the positive terminal from one parallel bank to the negative terminal of the second bank. If you are building a large battery bank, you will need to use more than one cable. Knowing the methods for wiring battery bank configurations provides you with options for using the battery banks to meet your demands for stored power ranging from small banks of two 14 Page

16 batteries to provide portable back-up power if the electricity goes out to powering small recreational toys or a computer. Just think how nifty it would be if there is a big snow storm that causes a power outage, but you re still able to power-up your computer and get necessary work done! Or how much more comfortable would you be on a camping trip if you know you have backup power in the event of an emergency! You can also create a battery bank that can power your home if you want to go off-grid. Battery Banks for an Off-Grid Home Most home energy storage systems deliver power in 12-volt, 24- volt, and 48-volt outputs, which means you can combine batteries to reach the correct output needed. First, you must determine how much electricity in watt-hours the house requires each day. To determine this, use a recent bill from your electric company. On your bill, find the number of kilowatts used. Use the highest kilowatt month as your reference base. The highest 15 Page

17 energy days probably happen in the peak of winter and peak of summer when temperatures are extreme and either the heating system or air conditioning system is running frequently. It s better to have more stored energy than you would use than not have enough. Simply take the month s kilowatt usage and divide it by 30 (number of days in the month). To convert the kilowatts to watthours, simply multiply the number of kilowatts by 1,000. This is the electricity in watt-hours that you use daily in your house. Now, figure how many backup days of energy you need to have in storage for when you can t depend on wind or solar power to harness energy such as on days that are too cloudy for solar energy. It s smart to have three days of backup battery power for your battery bank. In that case, multiply your average daily watthour usage by three (if you have chosen to have three days of backup power or use the number for the days that you ve chosen to have backup power). Next, you ll determine the depth of discharge so that you don t always let your batteries discharge all their energy to power your 16 Page

18 house. Letting the batteries fully discharge frequently can wear out your batteries quickly. For this reason, limit your depth of discharge to 25% of the battery s energy. In other words, do not let the battery get lower than 25% charged. Now, convert this number to a decimal (0.25) and divide the number of the previous calculation (the daily watt-hours X number of days of backup). Write this number down! Now, put some thought into the ambient temperature effect. Keep in mind that lead-acid batteries are rated for mild temperatures in the 70-degrees Fahrenheit range. When it is considerably colder outside, the batteries will be less effective and their output is lowered. This can be a significant factor if you live where winters are frigid for several weeks at a time. It will be important for you to protect your battery bank from harsh weather conditions while making sure the batteries remain wellventilated. When the batteries are not well-ventilated, flammable gasses can build up and cause toxic fumes and possibly cause fires. Do not store your battery bank in your house. If you have a well-ventilated garage or out building, it may be the perfect location for storing your battery bank. 17 Page

19 Now, back to that amp-hour number that you wrote down make sure that you include the ambient temperature factor and then calculate your amp-hour capacity: Use your total calculated number and divide it by the total voltage of your battery bank 12-volt, 24-volt, or 48-volt. Use that number to set up your battery bank size accordingly so that it meets both your system voltage requirements and the amp-hour capacity that you calculated If you got lost in all that math, read back over the previous section to become more familiar. If you re not a math person, it might take a few minutes to grasp it all. Also, look at the following example to clarify the calculations in your mind. If you want to set up a solar energy system that you use a 48-volt battery bank as a backup for, and you ve calculated that you use 5,000 watt-hours of energy per day in your home, and you want to have backup energy for four days, your math would look like this: You want 20,000 watt-hours of backup (5,000 watt-hours per day X four days) 18 Page

20 You ll limit to 25% discharge of battery, so divide 20,000 watt-hours by.25. Now, you have 80,000 watt-hours. The lowest average temperature is in the 60s so you multiply 80,000 by 1.11, which equals 88,800 watt-hours. To figure the amp-hours, divide 88,800 by 48-volts (or whatever is the total voltage of your system). Now you have 1,850 amp-hours. So, the amp-hours and the voltage of the system will determine your battery bank setup. Your option could be 2-volt batteries with an amperage rating of 650 amp-hours. This means you could set up a series of three parallel battery strings, each containing eight batteries. This configuration would meet and exceed the minimum amperage and voltage requirements of the system. 19 Page

21 Conclusion As you have seen in this report, a battery bank can be extremely beneficial in many situations. Isn t it good to know that you can create a battery bank that can provide stored power for your needs as the needs arise? Simply do your math and determine your energy needs for your purposes. Gather your supplies and follow the step-by-step method for wiring your batteries together with the parallel or in series methods. Monitor your battery discharge levels and there you go you ve got efficient backup energy for a small investment of time and money. 20 Page

Solar-Powered Battery Bank

Solar-Powered Battery Bank 1 Page D I S C L A I M E R O F L I A B I L I T Y A N D W A R R A N T Y This publication describes the author s opinions regarding the subject matter herein. The author and publisher