- Drafting and Permit Document Service.
- Our Solar permit service is available along with our home and business solar packages to help you with the process of obtaining a building permit to install your solar kit. The permit service is custom tailored for your solar system for your local jurisdiction. We guarantee the documents will be approved by your local permit officials or your money back.
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Emergency Solar Backup; AC Coupling, Home Power
Battery Based Backup Kits
During power outages our backup power systems will keep essential loads running automatically. We can custom design a system to handle any residential or small business load. If you do not see what you want, just let us know what you want to keep running and for how long, and we will design a system that’s right for you.
- Backup Power Solutions:
- Sizing A Backup System:
- Essential Loads; Energy Conservation:
- Resource Documents:
Planning For A Home Backup Power System
Emergency solar backup power is an excellent alternative to fossil fuel generators for short as well as long term power outages. A few years ago the utility was quite reliable and blackouts were few and far between. Thanks to an aging infrastructure in America and severe weather that is on the rise this is no longer the case. These days it is not unusual to hear stories from New Jersey to San Diego about power outage durations lasting from a day to a couple of weeks. If you live on the end of a utility line, grid failures can be both frequent lasting a long time because the power company is not going to prioritize restoring service to a few dozen homes when it has to be concerned about the thousands in an concentrated district.
At Blue Pacific Solar we believe that with the improvements in modern on-grid inverters, energy efficient lighting, cheap price of quality solar panels and careful design considerations means home emergency backup power need not rely on fossil fuel generators.
Sizing an emergency backup system for your home begins with a goal that is personal to your home and your lifestyle. Start by asking yourself a few simple questions. How often does the utility power go down at my home and how long do the power outages last. For my lifestyle, what is important for my family to have access to when the grid goes down? Refrigerator? Well pump? Sump Pump? Lighting? Now ask yourself what is my budget for accomplishing my goals? Got some general ideas what you want to power and how much you want to spend?
A load analysis, which is a detailed list of everything you expect to power in your home, has always been an critical part of home power system design. For each load, the expected power consumption and hours of use are listed. (For detailed information on completing your detailed load analysis click on the tabs above) There are no one-size-fits-all solution for backup power systems. Each emergency solar backup system is uniquely designed to its site, loads, budget, and the personal lifestyle of the homes occupants. OK, with that out of the way, we have some work to do before you can select the right emergency solar backup power system.
Here are some questions your will need to answer to get started choosing the right backup power system for you:
- List your loads. How many watts per day do you expect your appliances and lights to consume? The most important challenge in an backup power system is to balance your energy consumption with your solar power generation or pacing your energy draw from your battery bank.
- TIP: No easy way around this so get out a pencil and start listing everything you want to run and how long you usually run it. IE: 5 - 13 watt light bulbs X 5 hours per day = 65 watts. THIS IS IMPORTANT: When we say "list your loads", we mean all your loads from the cell phone chargers to a hair dryer. Energy Load Worksheet
- How many days without utility power do you want to be able to run?
- What is the largest load you expect to operate (Watts / Amps / Volts IE: 240V Well Pump = 9.5 Amps But You Might Need up to 30 Amps to Turn over the Locked Rotor on the Motor to Start the Well Pump.)
- What is your budget?
- TIP; The use of energy-efficient appliances and lighting, as well as non-electric alternatives such as a propane or wood stove should be considered first. Every watt you save will help to lower the cost of your emergency solar backup power system.
• Off-Grid – Utility Grid Power is not available for use.
• On-Grid – Utility Grid power is available for use. Does not imply the ability to sell power back to the utility grid.
• Grid-tie, Grid-interactive, Grid-intertie, Bimodal – Utility Grid Power is available for use and the system is capable of returning (selling) electricity back to the utility grid.
Midsized Battery Based Home Backup Systems
Backup emergency power kits delivered to your home assembled and tested by experience factory trained technicians. Kits include all internal cables and come pre-wired with clearly labeled connecting points for AC and DC input connections. You will not find a better value or more flexible backup power systems on the market today. Pure sine wave power that will power nearly any typical home energy load.
|Item #||INV OutPut||Battery Watt Hours||AC Volts||# of Batteries||Solar Panels||Power Source||Price|
|4.8 kW Backup Kit||BP9101000||1,750W Surge / 1,000W CONT||4,800 wh||120||4 /200 ah||2 /235 Watt||Grid & Or
|2000W Power System||BP9102000||3,100W Surge / 2,000W CONT||4,800 wh||120/240||4/200 ah||Optional Add On||Grid & Or
|10 kW Backup Kit||BP9344481||8,500W Surge / 4,400W CONT||10,752 wh||120/240||8/200 ah||Optional Add On||Grid & Or
|19 kW Solar Generator||BP958615||8,500W Surge / 4,400W CONT||19,200wh||120/240||16/200 ah||8 / 250 Watt||Grid &
If you do knot see a standard pre-engineered backup kit that meets your needs we will custom design one for you. Simply fill out the "Contact Us" form (Top RH Tab), and tell us what you want to power and how may days off grid you would like to run.
AC Coupling Grid Tied Battery Based Backup Systems / AC Mini-Grid
Are Enphase microinverters grid tie only? No, not when you add any of these AC coupled backup systems. AC coupling allows your grid-tie solar investment to be grid independent when the grid goes down. AC coupling uses your grid-tied solar inverter combined with a on-grid backup inverter with battery bank to provide the electricity you need to keep the lights on and run loads that are important to your family during a utility blackout or storm.
AC coupling uses grid tied inverters networked to one or more centralized on-grid battery-based inverters. This configuration allows AC electricity to either go directly to AC home loads, bypassing the batteries, or to charge the batteries via the battery-based inverter. Regulation is done on the AC side of the system by limiting the output of the grid tied inverter (s) when the batteries are fully charged or consuming the excess AC power not used with a diversion load or by using a relay driver to turn on and off the Enphase microinverters or central inverter.
|Item #||INV OutPut||Battery Watt Hours||AC Volts||# of Batteries||Solar Panels||Power Source||Price|
|3.0kW AC Backup||BP9344487||8,500W Surge / 4,400W CONT||10,752 Watts||120/240||8 - 224 aH||Existing or Optional Add On||Grid Tied Solar Array / Grid / Generator|
|AC Coupling 3300||BP9344488||8,000W Surge / 4,400W CONT||20,544 Watts||120/240||8 - 428 aH||Existing or Optional Add On||Grid Tied w/ Solar
Off-Grid / Backup
|Sunny Island MNSMA1AC||MNSMA1AC||11,000W Surge / 6,000W CONT||12,228 Watts||120VAC/56A||4 - 260 aH||Existing or Optional Add On||Grid Tied w/ Solar
Off-Grid / AC Coupling
|AC Coupling 6600||BP3600105||16,000W Surge / 8,800W CONT||20,544 Watts||120/240||8 - 428 aH||Existing or Optional Add On||Grid Tied w/ Solar
Off-Grid / Backup
SMA Grid-Tied Inverters With Stand Alone Secure Power Supply Capability
Daytime power when the grid goes down without batteries. The Sunny Boy 3000TL-US / 4000TL-US / 5000TL-US represents the next step in performance for UL certified inverters. One of many unique features of the TL-US residential series is its innovative Secure Power Supply ability. With most grid-tied inverters, when the grid goes down, so does the solar-powered home. SMA’s solution provides daytime energy to a dedicated power outlet during prolonged grid outages, providing homeowners with access to power as long as the sun shines. UL Certified, 10 Year Inverter Warranty Standard, 20 Year Available.
|SMA Secure Power Inverters||Part Number||Maximum DC Power||Output Voltage||Type||Price|
|SMA SB3000TLUS||3100441||3200 Watts||240 VAC||Grid-Tied
|SMA SB4000TLUS||3100442||4200 Watts||240 VAC||Grid-Tied
|SMA SB5000TLUS||3100443||5300 Watts||240 VAC||Grid-Tied
*STC - To learn more about solar panels and how they are measured you need to know what STC stands for. STC in an acronym for "Standard Test Conditions". All solar panels are rated in Watts. The watt rating is how much power (amps times volts) the panel will produce in full sunlight at 25 degrees C (77F). This is the industry standard (STC) for all PV panel ratings (PV means Photovoltaics which is a fancy word for solar). Solar panel manufactures have long used this test standard which is 1,000 watts per square meter solar irradiance, 1.5 Air Mass and a 25 degrees C. cell temperature.
PTC is an acronym for "PV-USA". The PV-USA test conditions were developed at the PV USA test site at the University of Davis, California for standards established by the California Energy Commission that are considered closer to real world conditions (Real World Vs STC factory test conditions). The PTC rating test is 1,000 watts per square meter solar irradiance, 1.5 Air Mass, and 20 degrees C. ambient temperature at 10 meters above ground level and wind speed of 1 meter per second. In California, solar panels manufactures must be tested and rated independently at the PV USA test facility at the University of Davis (CA) to be considered for rebates.
The ambient temperature rating (PTC) is generally considered a better real world standard than factory conditions because silicon solar cells average about 20 degrees C. above ambient temperature in the real world, cell voltage drops as temperature increases. A module's power output in real life conditions is lower than the power measured at the panel manufacturing factory where cell temperature is maintained at a controlled 77 degrees F. (25 C).
STC Vs PTC Cell voltage drops about 0.08 volts per degree C. in environments which exceed 25 degrees C. That means an STC rating of 17 volts can actually become a PTC (PV-USA) rating of 15 or 16 volts. Using Ohm's Law, volts times amps is equal to watts which equals power, so a reduced voltage, means reduced watts.
Neither PTC nor STC account for all "real-world" losses. Actual solar systems will produce lower outputs due to soiling, shading, module mismatch, wire losses, inverter and transformer losses, shortfalls in actual nameplate ratings, panel degradation over time, and high-temperature losses for arrays mounted close to or integrated within a roofline.
**Freight Shipping (Freight Delivery is Dock to Dock)
Item that are too large or heavy to ship UPS are shipped by ground freight. In circumstances where we offer freight shipping, free or otherwise, that means dock to commercial dock (not residential) to any of the lower 48 states. If the customer does not specify a local commercial dock that is available, we will ship to the nearest terminal where the shipment will be held for will call pick up by the customer. If you choose to have your order shipped to your residence, most orders require special handling for unloading and the pallet has to be transferred to a truck with a lift gate. In most cases, truck freight companies do NOT require their drivers to unload shipments. An additional "Residential" as well as a "Lift Gate" special handling fee will apply if the driver unloads the merchandise to the curb at your residence. The special handling fee is $89.00 and is available at checkout. If you have selected this add on service, the shipping carrier will call and schedule delivery of your solar kit, (provided the weight and dimensions of the product fits the criteria for lift gate service). You can avoid the residential and lift gate fees by arranging a "Will Call" pickup at the closest freight company terminal. In that case, you will need a pickup truck, a copy of the bill of laden, and a photo ID. When you arrive at the freight company terminal, the freight company will load your order into the bed of the truck with their forklift. The most common pallet size = 65" X 44" (Height depends on Product). Be sure and check for hidden damage.
Estimate Your Loads and Select a Voltage
Appliance & Equipment Load List: List and add up your daily electrical equipment load demand in watt hours (wh):
Watt hours (wh) and amp-hours (AH); Watts = Amps X Volts. Watt hours are the most common measure of electricity usage and are the easiest to understand. Amp Hours = Watt hours / System Voltage. Many professional system designers will use amp hours to size a system because amp hours takes into account real world behavior of solar panels and battery banks. Either method will arrive at the same conclusion if done properly. For our purposes here, we will primarily use watt hours (wh) when sizing the number of solar panels (and inverter) and amp hours (AH) for our battery selection.
- TIP; What's the difference between watts and watt hours? One joule "per second" and is a measurement of the rate of power flowing. 1 watt is a unit of energy equal to the power of one watt operating for one hour (3,600 joule's). Watt and watt hours are often interchanged and misused. 1 watt hour (wh) = 1 watt of power supplied for 1 hour. Think of watts (w) as the speed you’re running and watt-hours (wh) as the distance you ran. A light bulb rated at 20 watts, in 1 hour it will consume 20 wh, and in 5 hours it will consume 100 wh.
TIP; Higher voltage means less resistance which allows equipment to run cooler. Cooler electrical equipment = longer life.
Your system voltage means the nominal voltage you select for your battery bank, charge controller and inverter (if you are planning to use one). Here are some things to consider when choosing your systems voltage:
- The DC system voltage is established by the battery bank in backup power systems. A major factor in making this decision is how much power will be required from the batteries. As power demands increase it is advisable to raise the battery voltage. This voltage is important because establishes the type of charge controller and inverter that will be selected. The selection of the battery bank voltage affects the currents. A 1200 watt backup power system operating at 12 volts draws 100 amps. (1200w / 12v = 100A). The same system draws only 25A at 48 volts. Lower amps reduces the size of conductors, over current protection devices, disconnects and charge controllers. Additionally, since voltage drop and power losses are smaller at lower amps, higher voltage backup power systems are more efficient. As a rule of thumb, backup power systems up to 1000 watts use a minimum 12 volt battery bank which limits DC currents to less than 84 amps. For 2000 watt systems, 24 volt battery banks are used. For 5000 watt system a 48 volt battery bank should be selected.
- TIP; How long each day does a refrigerator run? 120VAC Refrigerators can be a large load for backup power systems or they can be no draw. How often a refrigerator will run during a 24 hour day depends on many factors and will vary from home to home for the same refrigerator. Some of the variables include; the room temperature throughout the day, how full your refrigerator is (Full refrigerators run less often once the contents are cooled), and how often you open the door throughout the day. You can lower the run time of your refrigerator by turning off the automatic defrost function and keeping your refrigerator full. One off the grid living tricks is to keep full jugs of water in a 1/2 full refrigerator. Once the contents of the refrigerator are cooled, an energy efficient model in your home that is full might be expected to run 24% - 35% of the time with a room temperature of 70 degrees or about 6 hours out of 24.
Daily backup power System Charge Requirement in Amp Hours:
- Since the energy output to the loads must be balanced by the energy input from your solar panels, we need to calculate your daily charge requirement in amp hours as that number will come in handy later. Take your total daily watt hours x 20% (rule of thumb) to account for losses in inverter, circuits and wire transfer. Now divide by the system voltage you chose based on the previous section and write this number down. This is the charge in amp hours your solar panels will have to provide each day to meet your load requirements you have set. Example 5,000 watts daily load total X 20% = 6,000 watts / 48 volt system = 125 amp hours that will need to be generated in this example of a emergency solar backup power.
Size Your Solar Panel Array
Input Must Equal Output.
(A) The size and or number of solar panels is calculated from the total energy requirements + allowing for wire and inverter transmission loss (20% rule of thumb) less the lowest solar irradiance available in the area of the system which is usually the shortest daylight month of the year (December).
(2) Next look at the solar irradiance near your area from our lowest peak sun hour resource map. Find the nearest city to your home and write down the lowest daily sun hours. Divide your daily load calculation (+ 20%) use by lowest sun hours per day. For example, if the daily average electricity load demand is 5,000 watts, and the site is in Salt Lake City UT, you would take 5,000 watts X 20% / 4 sun hours = 1,500 watt solar array. That means if you choose 235 watt panels you would need 6.39 rounded up = 7 - 235W solar panels. Especially for backup power systems its a good idea to always round up, but this is where your budget comes into play and a personal choice to aggressively manage your daily energy usage.
TIP; Match the Number of Solar panels to the Battery Capacity: After you finish sizing the number of solar panels you need to off-set your load requirements, you will need to consider whether the panels power and your battery bank's capacity are sized to work together, or are matched, within reason. You will want the solar panel array to have the capacity to ideally fully charge your battery bank on the shortest day of the year or be prepared to lower your power needs during the wintertime. If the backup power array is too large, you waste money and power because your charge controller will not send all the current the solar panels produce because your battery bank will not be capable accepting too much power too quickly. If the solar array is too small, it will not be able to fully charge your battery bank.
Evaluating your emergency solar backup power site is similar in many ways to grid interactive site evaluations. Key Considerations:
- Check out areas available to install your solar kit. A few things to consider; array dimensions, orientation, tilt and obstructions. For backup power installations, ground mount systems are the most popular. (Top-of-Pole or Rack Mounted)
- Shading of array location. This is important in any solar installation but a must in backup power systems.
- TIP; If you do have some shading issues and your system is less than 3kW, we do have an backup power Enphase system you may want to consider.
- Roof type and age.
- TIP; If you plan on re-roofing within 5 years but are not ready yet, some homeowners will replace only the shingles located under the solar array when the panels are installed and leave the rest for later.
- Battery Bank and Inverter Location.
- TIP; Solar cells are activated by visible light not ultra-violet or infra-red. Solar panels produce electricity when exposed to sun light, but plan to keep your inverter and battery bank in the shade and or indoors. Inverter and charge controllers should be located as close to the battery bank as possible.
Battery Sizing and Selection
Choosing your battery:
Battery bank sizing is the part of the backup power system that has a higher probability of causing you problems that other parts of your system. Use the battery sizing worksheet to help you through this critical stage. Factors such as your budget may tempt you to look to cheaper battery alternatives, but a quality battery will pay off over the years. We recommend you choose a 2V or 6V battery and connect them in series so that the total equals the system voltage you initially selected.
To properly design a emergency solar backup power battery bank, you need to account for the storage capacity required, the maximum discharge rate (the sum of all the loads which might be run simultaneously), the maximum charge rate (the current output from the solar array or wind turbine though the charge controller), and the minimum ambient temperature at which the batteries will be used. Whichever of these factors requires the largest capacity will dictate the size of the battery bank. The storage capacity of a battery the amount of electrical energy it can hold is usually expressed in amp-hours (Ah). Using one amp for 100 hours means 100 Ah have been used. A battery bank in a backup power solar power system should have sufficient capacity to supply needed power during the longest expected period of cloudy weather. A lead-acid (vented or sealed AGM) battery should be sized 20% to 50% larger than this amount.
TIP; Only similar batteries should be connected together in one bank. Do not connect old and new batteries or wet and gel cell batteries together.
Battery Sizing Worksheet
Use this worksheet to determine what size battery bank is required for your system. Battery size, or capacity, is measured in amp-hours. Battery voltage is determined by the number of "cells" in series. All lead-acid battery cells have a nominal output of 2 VDC. Actual cell voltage varies from about 1.7 VDC at full discharge to 2.4 VDC at full charge. 12 VDC lead-acid batteries are made of 6 separate cells in one case. 6 VDC batteries are made of 3 cells in one case. Putting battery cells in parallel increases amp-hour capacity, but does not change voltage.
Battery state-of-charge (SOC) can be measured by an amp-hour meter, voltage or by specific gravity. Some care and knowledge is required to interpret state-of-charge from voltage or specific gravity readings. We recommend amp-hour meters for all systems with batteries. An amp-hour meter is like a fuel gauge for batteries and provides all the information needed to keep batteries charged. At a glance, the user can see system voltage, current, and battery condition.
Charge Controller & Inverter
Choosing your charge controller:
A charge controller is an electronic voltage regulator used in backup power solar and wind systems with battery banks to properly control the charge from the solar panels or wind turbine keep the voltage to the battery bank within acceptable limits. The charge controller automatically tapers, stops, or diverts power when batteries become fully charged. Without a charge controller your solar panels or wind generator would continue to send electricity to the battery bank and eventually destroy your batteries.
Your charge controller will:
- Provide an optimum charge to the batteries.
- Prevent your battery bank for being overcharged from your solar panels or wind turbine.
- Prevent unwanted discharging.
- Provide information on the state of charge of the battery bank.
|Modified Sine Wave Inverters(Sometimes Called Square Wave)|
|You can save a few dollars by purchasing a modified sine wave over a pure sine wave inverter but consider this first before you buy. Modified sine wave inverters may not run:|
|• Laser printers, photocopiers, and anything with an electrical component called a thyristor|
|• Anything with a silicon-controlled rectifier (SCR), like those used in some washing machine controls|
|• Some laptop computers (Apple Products can be particularly fussy about their energy source)|
|• Some fluorescent lights|
|• Some new furnaces and pellet heaters with microprocessor controls|
|• Digital clocks with radios|
|• Appliances having speed controls|
|• Medical equipment should not be power with modified sine wave inverters.|
|Because the total harmonic distortion is higher in modified sine wave inverters, motors will run hotter and not last as long. You may hear a buzzing from your stereo system and you might see lines on your TV screen.|
The simplest charge controllers cut the power when the battery reaches a set voltage, and turn it on when a low voltage set point is reached. Pulse width modulated (PWM) charge controllers turn on and off very rapidly, maintaining the batteries at full charge with whatever power is available. Maximum power point tracking (MPPT) charge controllers optimize the voltage of the solar panels or wind turbine to maximize total power output then convert that to the correct voltage to charge the battery. This process significantly increases the power from a solar array, particularly in low temperatures when battery voltage is significantly below the solar array voltage. Most MPPT charge controllers work with higher array voltages, enabling the use of larger solar panels, which can be more economical on a cost per watt basis. A higher voltage solar array also minimizes the required wire size between the array and the charge controller. While more expensive than PWM controllers, MPPT charge controllers can boost system performance significantly by up to 30%.
Blue Pacific Solar sells Midnite Solar, Outback Xantrex and Morningstar charge controllers. All these companies have take much of the work out of the technical calculations required for properly sizing a charge controller for emergency solar backup power systems with their string calculators. On all our backup power pre-engineered packages, we have matched the right sized charge controller with the package for you.
Choosing your backup power Inverter:
Living off the grid means you will be generating, storing and processing every watt your backup power home or cabin sucks up. If your cabin is going to need AC power, then an backup power AC inverter is going to be of particular interest to you because you will be depending on it day in and day out.
Backup power inverters are sold either sine wave or modified sine wave. Sine wave output, which has low total harmonic distortion, will power virtually any type of load, even sensitive audio electronics. Modified sine wave inverters may not run some types of equipment satisfactorily, and some loads won’t run at all.
An backup power inverter must supply enough power to meet the needs of all the appliances running simultaneously. Before selecting an inverter, you must know the watts your appliances will require and their amp and surge needs. Sizing an inverter for an backup power system, which is based on instantaneous load, is very different from sizing a grid tied inverter, which is determined by the solar panel array size. A grid tied inverter’s job is simply to convert all the DC electricity from the solar array into AC power, which is fed back into the house electrical system then onto the grid if production exceeds the homes energy consumption. In a grid tied system, the inverter is not responsible for meeting the AC loads, since practically unlimited utility power is available. In the case of an backup power inverter, the inverter has to provide enough energy to all the AC loads, sometimes at the same time. Say you need to simultaneously power 3,000 Watts from various appliances. For an backup power system, you’d need an inverter that could supply at least that amount. Note that the solar array size does not enter into this inverter sizing since the inverter pulls its power from the battery bank.
Blue Pacific Solar only sells inverters that meet Underwriters Laboratories (UL) 1741 standards. So if you are on the fence between two choices of inverters, you might ask and find out if it is UL listed and is it an inverter specifically made for backup power solar or wind applications.
Electrical Distribution Parts
Electrical Distribution Parts:
Wire size and breakers are the final items in your backup power design to consider. The amount of current (amps) traveling through any electrical circuit depends on the size of the wire (AWG), the voltage of the array or battery bank, and the one way distance of the wire run. Lower AWG gauge wire has less resistance than larger gauge wire. The longer the distance of your wire run while using lower voltage the larger gauge wire you are going to need. If your solar array consists of 4 or more 90 watt panels and is more than 50' from your battery bank, you should consider using 24V as a minimum with 48V being a better choice. You can check out the wire size you need here for your wire run.
TIP; Proper wire and connector sizing is important. Utility voltage: The utility strives to maintain voltage at the point of common connection at a home within +/- 5% of nominal. The protective functions of the inverters are set to +10% / -12% by default. The high voltage end of the tolerance is of most concern because the inverters are a SOURCE and not a LOAD. If the utility is consistently 5% high, that leaves less than 5% for all wiring and interconnection losses and inverter measurement accuracy. If you are concerned about the utility’s voltage, you may request that your utility place a data logger at the PCC and make a record of the voltages available to you at the site. This is true of all inverters, but especially true of MicroInverters which are located at the array, the distance to the PCC could be substantial. Undersized conductors can cause the voltage measured at the MicroInverter to be outside of the IEEE limits, which then causes the MicroInverter to enter an AC Voltage Out Of Range (ACVOOR) condition at which point it ceases to export power.
Emergency Essential Backup Loads; Appliances and Energy Conservation
Life during extended power blackouts from storms or just an aging grid is not mystical or difficult. It just requires you to pay careful attention to a few basic principles.
TIP; Shift as many high wattage loads to other forms of power such as propane. Reduce excess waste through household education promoting efficiency and increased energy conservation. Use the energy you do have in proportions to what is available.
These power consumption numbers are approximate representations that can be used in calculating your backup power requirements. The actual electrical consumption of your appliances or electronics may vary substantially from these figures. Check the name plate tags, or better yet, measure the watts using a electronic gadget on the market called Kill-A-Watts meter. Multiply the hours used on the average day by the wattage listed below. This will give you the watt hours consumed per day Remember that some items, such as well pumps, are used only for a fraction of an hour per day. A 600 watt item used for 5 minutes per day will only consume 50 watt hours per day.
Cooking, Heating and Cooling
Each burner on an electric range uses about 1,500 watts per hour. A microwave oven has about the same power draw, but since food cooks more quickly in a microwave, the amount of watts consumed is usually lower. Propane, wood or solar hot water are generally better alternatives for space heating. Good passive solar design and proper insulation can also reduce the need for winter heating. Swamp coolers are a more reasonable load than air conditioning and in locations with low humidity such as the SW, they are a great alternative.
Lighting requires careful study since type, size, voltage and placement can all significantly impact the power required. Compact fluorescent lights are common and efficient, but it is a good idea to have a DC-powered light in the room where the inverter and batteries are in case of an inverter fault. Also, AC light dimmers and overhead fan speed controlls will only function properly on AC power from inverters that have pure sine wave output.
Refrigerators are a double edge sword. Look at the name plate inside the door for the amps then multiply times the volts to get the watt hours consumed. How long a refrigerator runs each day can vary from home to home even with the same size refrigerator. Personal habits like how full your refrigerator is and how often you open the door have a major effect on duty hours each day when calculating your emergency backup power requirements.
Televisions, Washing Machines and Other Appliances
Televisions; look for an efficient DC TV. Power in your television set can vary widely depending on the type. Standard AC electric motors in washing machines, larger shop machinery and tools, swamp coolers, pumps, etc. (usually 1/4 to 3/4 horsepower) consume relatively large amounts of electricity and require a large inverter. Often, a 2,000 watt or larger inverter will be required. These electric motors can also be hard to start on inverter power, due to large surge loads at start-up, and they are very wasteful compared to high-efficiency motors, which use 50% to 75% less electricity.
TIP; Surge is the amount of short term power needed to turn over the locked rotor on an electrical motor.
A standard washing machine uses between 300 and 500 watt-hours per load, but new front-loading models use less than 1/2 as much power. If the appliance is used more than a few hours per week, it is often more economical to pay more for a high-efficiency appliance rather than make the backup power system larger to support a low efficiency load. Vacuum cleaners usually consume 600 to 1,000 watts, depending on how powerful they are, but most vacuum cleaners will operate on inverters as small as 1,000 watts since they have low-surge motors.
Many small appliances with heating elements such as irons, toasters and hair dryers consume a very large amount of power when they are used but, by their nature, require only short or infrequent use. With a sufficiently large system inverter and batteries, they will operate, but the user may need to schedule those activities with respect to the battery charging cycle for example, ironing in the morning so that the emergency solar backup power system can recharge the battery bank during the day. Electronic equipment, such as stereos, televisions, VCRs and computers, draw less power than appliances with heating elements, but these loads can add up as well, so opt for more efficient models, such as an LCD TV instead of a plasma or CRT design.
Computers, Music Systems and Cell Phone Chargers
Laptop computers us about 25% of the power a desktop computer uses. You should try and avoid desktop computers altogether. Music systems should be powered using pure sine wave power instead of a modified sine wave inverter. There is nothing that can kill the Zen faster in the evening living off the grid than static from a modified or cheap pure sine wave inverter. Cell phone chargers from the manufacture are usually more efficient than cell phone chargers you buy elsewhere. Every watt you consume by inefficient electrical equipment matters not only to your wallet but also your piece of mind living backup power.
Power Consumption Tables
|Central Air Conditioner||5,000||Electric blanket||200||Hedge trimmer||510|
|Electric Clothes Dryer||3,500||Shaver||15||Weed eater||500|
|Oven||3,000||Water pik||100||1/4” drill||250|
|Hair Dryer||1,538||Well Pump (1/3-1 HP)||480-1200||1/2” drill||750|
|Coffee Machine||1,300||Plasma TV||350||9” disc sander||1200|
||213||3” belt sander||1000|
|Popcorn Popper||1,400||25” color TV||150||12” chain saw||1100|
|Toaster oven||1,200||19” color TV||70||14” band saw||1100|
|Hot Plate||1200||14” color TV||80||7-1/4” circular saw||900|
|Iron||450||Stereo||40||8-1/4” circular saw||1400|
|Toaster||1,100||Satellite dish||30||Refrigerator / Freezer|
|Microwave||1200||Radiotelephone - Receive||5||20 cu. ft. (AC)||1,080|
|Room Air Conditioner NA||1,200||Radiotelephone - Transmit||40-150||16 cu. ft. (AC)||720|
|Water heater (240VAC)||5,500||100 watt incandescent bulb||100||15 cu. ft. (Upright)||500|
|Sink Waste Disposal||450||25 watt CFL||28||15 cu. ft. (Chest)||500|
|Espresso Machine||360||50 watt DC incandescent||50||Cell Phone - recharge||2-4 watts|
|Dehumidifier||350||40 watt DC halogen||40||MP3 Player - recharge||.25-.40 watts|
|Blender||300||20 watt DC CF Light||22|
|Video Game Player||195|
|Portable Fan||60||Engine Block Heater||150-1000|
|Ceiling Fan||100||Portable Heater||1500|
|Can Opener||100||Waterbed Heater||400|
|Curling Iron||90||Stock Tank Heater||100|
|Cable Box||20||Clothes Dryer - Gas Heated||300-400|
|Clock Radio||30||Well Pump (1/3-1HP)||500 - 1200|
Solar Kits Documents & Instructional Manuals
emergency solar backup powerliving off the grid during a utility blackout
Emergency Solar Backup Power for your home or small business can come in handy when bad weather or other conditions interrupt the utility electrical service. Home or business owners can find themselves unable to power critical load appliances and lights. This situation can be serious if critical applications such as medical devices, telephone, home office computers, sump pumps, or refrigeration are threatened. This emergency backup power systems is one of the best values currently available on the market.
When a emergency blackout happens at your home or business, the AC pure sine wave inverter instantly starts powering critical loads from the batteries until the power comes back on. (If you have the unit hardwired to a critical load subpanel. Otherwise, you use the AC wall plugs in the cabinet with an extension cord) The backup power unit will then automatically re-charge its batteries and go into a standby mode. When the power goes out, lights, refrigerator, computers, television, alarm systems, automatic gate or garage openers, all continue working during a emergency blackout. When the power comes back up, the unit switches over and starts recharging the batteries for the next time. The home backup power kit comes with an easy-to-use monitoring system so you can check your power supply anytime of day.
Hardwiring Your Backup Power System to Your Home or Business. Here is how it works. When you are working out the details of how your backup power kit is going to work in your home or business, the first step is to decide what loads are critical to you during a blackout. If you choose to hard-wired your backup power kit, the power needs to be sent to a critical load sub-panel that is not directly connected to your home or businesses main AC utility service panel. The two panels may be connected only by using the AC inverter that comes pre-wired with the backup power battery cabinet. The way it works is you will have an AC power in conduit coming from your main service panel that is connected to the "AC" in-port on the backup power cabinet. You then connect an "AC" out-port that is connected to your critical load sub-panel box only which is not connected to your home or business main service panel. What happens during a utility blackout is power will only be supplied to the critical load subpanel from the backup power unit which is wired to several important independent outlets or switches in your home or business. To make this happen in this scenario, you either need to relocate specific critical load circuits or install new ones near where you need the power during an emergency power outage. There are some very goods reasons why you have to do this. The first is called islanding, which is a bad thing. (Illegal and dangerous) Islanding means you are sending power back to the grid. Imagine, if you will, a utility worker responding to the power outage in your neighborhood. He or she thinks the power is down and starts working on the line and is injured because power is back flowing from your home. The second very good reason this backup power system needs to be wired this way is when the grid is up, power will be flowing to the AC out-port connected to the backup power center. This creates a condition where the state of charge on the bank of batteries is not regulated and you will fry the batteries. Wired correctly, when the utility power is working, electricity will flow from your main power panel through the backup power kit to power the critical circuits that you moved to your sub-panel. Keep in mind you must limit the continuous power to your critical load circuits to no more than 80% of the output of the inverter. If you need more continuous power we can parallel multiple inverters to increase the current flow. But if you choose to do that without increasing your battery bank you will simply drain the batteries faster. Better to just decide on a few "have-to-have" loads and stretch the draw down on the batteries in the backup power center.
AC Coupling of Existing Grid Tied Solar Systems
Grid connected solar systems do not require batteries to operate because the excess energy produced is in effect stored with the utility company in the form of NET metering. What many homeowners fail to realize when they purchase a standard grid tied system is when the grid goes down, so does the power being produced by the solar panels. Why? The IEEE-1547 standard requires that utility interactive inverters cease to export power (Means your meter spinning backwards) if the voltage measured at the Point of Common Coupling (PCC) (That mean your homes electric service meter) exceeds +10% or -12% of nominal. If that were not the case, the result would be an unintentional island of power generation that would energize a portion of the utility power grid that the local utility has de-energized. The importance of grid connected home solar systems is clearly recognized, but as home systems continue to make inroads into America's utility grid, national guidelines were needed to stipulate how homes and businesses could connect to the grid. To this end, the Institute of Electrical and Electronic Engineers (IEEE) worked with the United States Department of Energy (DOE) to develop the IEEE 1547 standard, which provided in 2003 a set of requirements in America for the interconnection of home solar systems into the utility power grid. When the grid goes down, most homeowners with an existing solar system quickly become frustrated because the potential power that is readily available nearby is useless. MidNite solar, Magnum Energy, SMA and Outback have long recognized this void in the market place that will allow existing solar customers and new customers to utilize the AC energy that is normally back fed through to the utility company to now be used to in a home or business and still be in compliance with the IEEE-1547 standard.
AC coupling kits for existing grid tied and emergency power battery based applications during utility blackout's. In ac-coupled backup solar systems, these on grid systems are integrated with battery-based on grid inverter systems. AC coupling uses grid tied inverters networked to one or more centralized battery-based inverters. This configuration allows AC electricity to either go directly to AC home loads, bypassing the batteries, or to charge the batteries via the battery-based inverter. Regulation is controlled on the AC side of the system by limiting the output of the grid tied inverter (Enphase(inverters) or SMA Central Inverter) when the batteries are fully charged or bleeding off the unused AC electricity created by the solar panel AC inverters via a relay driver. The Relay Driver is a logic module which provides high level system control functions such as high / low voltage alarms, load control and generator start. The product controls AC relay driver outputs by reading digital data inputs by reading battery voltage.
When the utility power goes down during a storm or blackout, the on-grid inverter and utility interactive SMA central inverter or Enphase (inverters) stop exporting power to the grid. Once this occurs, in less than a 60th of a second the on-grid inverter automatically starts pulling power from the battery bank to continue to power the homes backup loads. Since the utility based AC inverter is connected on the home side of the on-grid inverter, the utility inverter will have a frequency synchronization with he on grid inverter and begin to produce power. The cycle time for the utility AC inverter to begin operating again is about 5 minutes with most inverters.
The utility AC inverter is now operating again using the on-grid battery based inverter and is producing as much power that is available through the homes solar system. This electricity is used by all the loads in the home with the excess electricity being used by the on-grid inverter/charger to recharge the home's battery bank. The amount of power that is allowed to be produced is regulated by either an high voltage AC relay which senses the voltage of the battery bank interrupting the AC electricity being produced by the AC utility inverter or a diversion load.
AC-coupled backup solar systems can also be equipped with a diversion load. Diversion controllers do not cut off the current like a relay will but simply divert it or "dump it" into a ceramic air heating resistor or hot water tank through a heating element. An ac-coupled backup system using a diversion controller will adjust the battery charge by redirecting the electricity coming from the AC central inverter or MicroInverters. Often times diversion loads are used in conjunction with a wind turbine where the blade cannot be stopped and the power has to go somewhere. The primary issue with diversion loads or dump load systems is the extra expense and space needed to mount the ceramic air heating resistor.
Storage batteries are when an emergency solar backup system gets really interesting. The term battery is a reference to a row of electro-chemical cells connected in series. These are sometimes simply called cells or battery cells. Several batteries connected together are called a battery bank. Another term for a rechargeable battery is an accumulator but that term will not normally be found in most off-grid designers vocabulary. In emergency solar backup systems when the grid is down, the home is a slave to the batteries. What that means is the electricity produced by the emergency solar backup system is stored in the battery system. Whether or not there is electricity flowing into the home depends on the state of charge (SOS) of the battery bank. No power in the batteries, no lights in the home when the grid is down.
|Marine||Gelled Electrolyte||Absorbed Glass Mat (AGM) Deep Cycle Battery||Flooded Lead Acid Deep Cycle|
|Construction||Thicker plates than automotive, but not as thick as deep cycle. Considered a hybrid battery.||Electrolyte is gelled by adding silicon dioxide to the electrolyte.||Electrolyte is in an absorbed glass mat which means the liquid is absorbed into a fiberglass mat that is sandwiched between the plates.||The liquid electrolyte is sulfuric acid and water solution.|
|Properties||Moderate to low water loss, low self-discharge rate.||No Maintenance. Spill Proof. Must be charged at a lower rate to prevent excess gas from damaging the cells||Low maintenance. Spill Proof. Can withstand deep discharge. Highly efficient, no water loss. Low self discharge rate. An additional benefit of AGM batteries is they can be shipped as normal freight.||Low maintenance, robust charges well with low current, can withstand deep discharge. (Safety WARNING: Extreme caution should be used when storing and filling lead acid batteries. Additionally, flooded lead acid batteries have to be shipped marked hazardous material and require special handling by the trucking company.|
Range in aH
|60 - 260 aH||10 - 130 aH||100 - 3300 aH||400 - 2430 aH|
Life Cycle (Approximate)
| 20% - 1000
40% - 500
| 30% - 800
50% - 300
| 30% - 3000
50% - 1000
| 30% - 4500
50% - 1200
Note: This battery comparisons shown here are for the purposes of general considerations regarding the characteristics of batteries often used in backup power designs. You should always compare specific battery manufactures specifications for detailed comparisons.
The type of batteries used in emergency solar backup system often times flooded lead-acid or AGM batteries. Though there has been a lot of progress in the technology of battery designs being driven by computer and electric vehicles, cost and or low maintenance is ultimately the reason you will see lead-acid batteries in most large backup power homes or cabins. A lead-acid battery is made up of electrochemical cells that usually have a nominal voltage of 2 volts DC. Six of these electrochemical cells connected by series will provide a 12 volt battery. Lead-acid batteries used in backup power solar systems are available as 2 volt, 6 volt or 12 volt batteries. By connecting these different types of batteries together, you can produce a variety of increasingly stronger battery banks that will store more energy. Additionally, by connecting the batteries in series and or parallel, you can pump up the power to 12, 24 or the more popular 48 volt systems that are sometimes needed for larger emergency solar backup AC inverters. Lead acid battery technology has improved over the years but the fundamental electro-chemical reaction in all flooded lead-acid batteries is basically the same. As the flooded lead-acid deep cycle battery is discharged the lead dioxide positive active material and the sponge lead negative plates creates a chemical reaction with the dilute sulfuric acid electrolyte to form lead sulphate and water, during charging this process is reversed. The efficiency of the charge and discharge process is less than one-hundred percent because during the charge process the voltage from the charge controller and solar panels has to be increased (over the discharge voltage) by about 7.5 to 10.5% to overcome inherent electro-chemical inefficiency and the battery cells internal resistance. Deep cycle lead-acid batteries are widely used in emergency solar backup system because they are readily available nearly everywhere at a lower initial cost. The life cycle of all lead-acid batteries (flooded, sealed gel cell and AGM) is substantially shortened if operated at high temperatures or the depth of discharge (DOD) is consistently low both of which can be prevented with a properly designed emergency solar backup system. Deep cycle batteries fail through degradation of the plates via sulfation. Elevated temperatures and over charging both create sulfation and becomes the primary reason battery life is shortened which is the primary reason Blue Pacific Solar only will specify Midnite solar, OutBack, MorningStar and other UL listed charge controllers in our backup power systems.
The last critical piece of electronic equipment in your emergency solar backup system is the AC on-grid inverter. There are a number of things to consider when choosing an emergency solar backup on-grid inverter the first of which is tare losses or the energy consumed to operate the inverter itself in standby mode. In each backup power design, every watt wasted means a larger battery bank and or more solar panels. The second big specification in an backup power inverter is surge capacity. The ability of an inverter to surge to a higher burst of electricity than its rated output for a short duration to turn over the locked rotors of equipment like well pumps is critical. The specifications that should be looked at are the are the maximum output current (Amps) and the AC surge watt capability. If there are large loads a good number to look for is a five second surge capability of at least 3 times the rated output of the emergency solar backup power AC on-grid inverter.