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.
Planning For A Home Backup Power System
Emergency solar backup power is an excellent alternative to fossil fuel generators for short to long term utility outages. A few years ago the power companies were 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.
Zombie Apocalypse or Just A Few Days of Power? Where Here is Where You Start.
Sizing an emergency backup system for your home begins with a goal that is personal to your home, your lifestyle, motivation and budget. 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?
The BIG Questions You Need to Answer First
A load analysis, which is a detailed list of everything you expect to power in your home during a blackout, is a critical part of your backup design. For each load, the expected power consumption and hours of use are listed and totaled for one day. 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.
Find the Power Requirements (watts) For the Appliances that Need Power During a Black-out.
Make a list of the appliances that need power during a blackout that you need to keep running. Refrigerators, special lighting, etc. Only list the essential items, since the system size (and cost) will vary widely with power needed. The amps of individual appliances can usually be found on the back of the appliance, on the name plate or in the owner’s manual. If an appliance is rated in amps, multiply amps by the operating voltage (120 or 240) to find watts. Watts is the measure of power you are looking for. Add up the wattage of all the items on the list that may need to run simultaneously to arrive at the total amount of watts.
Energy Load Worksheet (Excel)
Energy Load Worksheet
IE: 5 - 13 watt light bulbs X 5 hours per day = 65 watts. 18 CF refrigerator @ 5 amps x 120VAC = 600 watts x 6 hours per day = 3,600 watts. Need Help? If you download the Excel worksheet you will only have to indicate how much of each piece of equipment you have and how long your run it.
Critical or essential loads needed during a utility outage are NOT based on a homes sq. ft. It is NOT based on how many people are living in the house. It is based on the equipment or appliances you want to run and how long each day during a blackout you want them to operate. It does not get more individual than that. The amount of energy you and your family want in reserve power will vary among individuals habits and personal choices.
Define How Long of An Outage the System Must Accommodate.
Power outages last from a few minutes, to a day or more. Again, this decision will greatly affect the system size and cost, so the desired length of time should be traded against the total loads supported. If the backup system needs to provide power for an indefinite period of time, you will need to use solar or a generator to recharge your battery bank. You should consider the systems on the off-grid living page (TABS ABOVE). The off-grid kits will work in a grid interactive capacity for backup.
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|
|10 kW Backup Kit||BP9344481||8,500W Surge / 4,400W CONT||10,752 wh||120/240||8/200 ah||Optional Add On||Grid & Or
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 4000||03304322||5,800W Surge / 4,000W CONT||19,920 Watts||120/240||8 - 415 aH||Existing or Optional Add On||Grid Tied w/ Solar
Off-Grid / Backup
|SMA AC-Coupled SI6048||03304321||11,000W Surge / 6,000W CONT||N/A||120VAC/56A||None||Existing or Optional Add On||Grid Tied w/ Solar
Off-Grid / AC Coupling
If you do not see a standard pre-engineered backup system that meets your needs we will custom design one for you. Simply fill out the "Contact Us" form (Top RH Tab), and tell us how many watts you want to backup per day and for how many days.• 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.
emergency solarliving off the grid during a utility blackout with backup power
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. We've been getting a flood of questions recently on the subject of battery backups on solar (PV (Photovoltaic)) systems. Is it possible? How do they work? How much do they cost? The short answer is, yes, we can add a fully automatic battery backup system to an existing conventional grid-tied solar system, or design it into a new one. The advantage of having a battery backup feature is that it provides a little more flexibility to the system, offering more options in sources of electric power even when the grid is down for days, or for weeks. 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. Emergency solar backup power provides an instant, automatic emergency backup for when things go wrong.
Is Battery Backup Really Necessary?
Just because something can be done doesn't necessarily mean that it needs to be done. A battery backup element is going to add to the cost of a solar system, so you should make sure that it's worth it. The cost for a modest (approximately 4kW) sealed battery pack that will keep a typical family home running in emergency mode for 2 or 3 days, plus an additional battery-based inverter and safety hardware, will start at about $7,800. That price quickly rises as the size increases. Also, keep in mind that AGM batteries (sealed) will typically only have a useful life of about 7 years before it has to be replaced, and new batteries are not cheap. The hard-nosed financial question, then, is if it is worth the cost of a battery backup to keep the lights on during an occasional garden-variety power outage that lasts just a few hours. If not, we heartily recommend the standard blackout kit: A candle, a bottle of wine and a friend. You'll be fine.
Designing a Size to Fit Your Needs
If your area experiences frequent power grid outages, particularly if it often takes days for electricity to be restored, a battery backup might be a useful feature to have. Some people are also concerned about disasters, hurricanes, tornadoes, earthquakes, societal collapse, which might leave them without access to a working electrical grid for weeks or even months. In those cases, it can be useful to have a battery backup to keep electricity generated by a solar array, over and above immediate needs, in reserve for nights and cloudy days.
To keep costs down, the battery backup capacity can be kept at a minimum (smaller is cheaper) by designing it to meet only the bare-bones electrical power needs, what is called the "critical load." This typically means the refrigerator/freezer, stove/oven, furnace, well and sump pumps, a few light circuits and perhaps a security system. This isn't a time to worry about the swimming pool pump, tennis court lights or air conditioning (But try telling that to folks in Florida or California). Depending upon conditions, however, it may be possible to add such extras as a clothes washer and drier to the critical load list, if their use is carefully scheduled.
The size of the required battery capacity can be estimated by adding up the power draw for each piece of equipment or circuit on the critical load, and then subtracting the average power input from the PV array,taking into account the hours of darkness and overcast skies.
Nuts and Bolts
A critical load AC breaker panel needs to be installed, usually near the existing main breaker panel. These are connected by a large conduit or gutter box, to allow for convenient switching over when going to emergency solar backup power mode. 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 good reasons why you have to do this. The inverter must be the type designed to work with a battery backup - not all inverters are compatible, and it must be able to handle the voltage and frequency required to meet the critical load. If that load consists only of 120V appliances and circuits, you'll only need a 120V inverter, which is less expensive, but if you require 240V for anything on the critical load, you will need a 120/240V inverter.
How It Works
When an 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. Under normal operating conditions, the inverter's built-in transfer switch is closed, so power from the PV array and the power grid passes through the inverter as if it isn't even there. In the event of loss of power from the grid, the inverter quickly (meaning 30 milliseconds or less) opens, isolating the critical load panel from the grid. This is important since it insures that no power feeds back into the grid, where it might injure or even kill a worker trying to repair the lines. This 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. Note, however, that even at 30msec the switch-over does not qualify the system as an uninterruptible power supply (UPS); critical data storage or medical equipment that requires that should have independent UPS backup.
In situations where your emergency backup is AC coupled to your solar array, in battery supply mode, power from the solar array will continue to be directed first to the critical load. If the solar supply falls below minimum needs, the additional power will be drawn from the battery pack. On the other hand, if the supply from the solar panels is greater than what is required for the critical load, the battery will be recharged. If the battery is fully charged and the critical load is being met and power from the solar array is still being produced, the inverter will shift the output frequency up or down a few hertz for a few seconds, causing it to go off-line for 5 minutes. When the inverter comes back on-line, if the conditions remain the same, available power is in excess of need, and then it will go off again, continuing the cycle until the power is needed. In this circumstance, larger demands on the critical load can be made, such as using a clothes washer and dryer.
A Backup to Your Backup
For systems in areas that may experience extended power outages (ice storms, super-volcanoes, zombie attacks or giant lizards spitting radioactive fire from their mouths come to mind), a modest-sized (5 to 10kW) propane-fired generator is an excellent addition to the system. If loads exceed sunny days for a few days, the generator can be used to top off the hungry battery bank. By using a generator as a third back-up, after the solar array and battery pack, it is possible to keep the power on without having to listen to the drone of a generator all day long.
Emergency Preparedness; Don't forget Your Pets
Emergencies can come in many different forms and circumstances. While it is vital for any home to have an emergency plan for its family members, it’s just as important to make sure your furry friends are protected as well. Planning the best way to care for your pet during an emergency either at home or on vacation will show all of your loved ones just how much you care for them.
Emergencies can come in the form of household fires, floods, earthquakes or power outages. Although power outages can be the least damaging of the group, they can be extremely deadly especially during the winter season. Having an emergency kit prepared for your pets can save precious time when needing to evacuate your home. Include a warm blanket, bowls, canned dog or cat food, bottled water, disposable cat litter for cats and a spare leash for your dog. Don’t forget to include a toy your pet can take comfort with. Remember, just like everyone else in your family, pets will be just as scared to be in a strange place away from their home.
It’s possible that an emergency could strike when you are not home, even if it’s just away for the day at work. Speak with neighbors who would be willing to take in your pet if you are not able to get to them when an emergency strikes. They should have a spare key to your home and be somewhat familiar with your pet so that they will trust them. Also, contact local animal shelters in your area to find out where you could temporarily store your pet in an emergency since many emergency recovery sites do not allow owners to bring their pets with them. Pets should be tagged or wearing collars so that they can find their way back to their owner if they get lost or separated.
Remember to keep your pets in mind when you are away on long trips. If you choose to leave your pet at home, have a neighbor check on them frequently, at least twice a day to make sure they and the house are doing well. In the summertime, remember to leave out plenty of water and have a nice warm place for them to cuddle in the cold months. You should never leave your pet alone for too long a duration, as they need companionship just as much as the other necessities of life. If you take your pet with you on your trip, don’t forget to pack an emergency kit in your trunk, just in case.
Preparation is the key to surviving any emergency situation. Practice evacuation drills with your family. Include bringing your pets as part of the drills so that it becomes routine.
So, yes, a battery backup for a grid-tied solar array system is entirely possible. It isn't cheap, and it requires planning and care to design, install and operate, but it can be done. If you believe that the potential for an extended period of time off the grid is greater than you feel comfortable about, and you are willing to invest in the additional hardware, you can be power autonomous for weeks and even months then having power during a utility blackout should be at the top of your priority. There is no better way to prepare for an emergency than with solar backup power.