What Should I Do?

Portable Solar Generators & Hybrid Emergency Backup Systems

Saturday, February 11, 2012, 12:53 AM
What do you do when the power goes out?

In the past two decades, non-disaster-related electricity blackouts have increased by 124% in the US. These numbers are further compounded by the increasing incidence of large disasters that knock out power for extended periods of time in the US and longer wait times before you see your electricity back on. Furthermore, lots of folks have been in situations where grid power is either not available or impractical at the location in need.

Portable solar generators and hybrid emergency backup systems can be solutions to the increasing power reliability issues. However, there are some key points that must be addressed for the success and efficiency of such products. These critical ideas include the current state of fuel-based generators, trends in solar, understanding kwh and electricity terminology, the benefits of solar power, rethinking your power usage, measuring that usage, incorporating hybrid systems for prolonged activity, and utilizing knowledge to make informed buying decisions.

As members of the Chris Martenson community, we are all becoming educated and aware of the trends in energy pricing and availability, especially in regards to traditional fossil fuel choices. Many of us are witnessing climate change results and extreme weather and their impact on the increasingly fragile nature of our infrastructure, including grid supplied power and liquid fuel supplies. 

Traditional Generator Solutions

As a safeguard to these extreme weather events, many people have purchased and used a gasoline, diesel, or propane (liquid fuel) portable or fixed generator to deal with events and blackouts.  

There have been many choices and refinements in generator design, and costs have tended to stay down on the lower end products because of Asian imports. Also, gas fuel prices have remained relatively low, compared to overseas and non-subsidized costs per gallon. 

When the power goes out or you need some off-grid power, the easy and entry level choice has been to grab a generator, throw it in your truck or RV with some fuel cans, and fire it up when you need to run your electric applications. You can get 5 to 7 Kw generators that are still relatively portable, and, when bigger than that is needed, you can put them on a trailer for portability. However, because fuel costs have been low, there has not been much consideration for efficiency or long-term costs to running a gas powered generator for extended periods of time. 

When gas prices shot up to nearly $5 per gallon in 2008, people started to feel a little pain with this approach, as you only have power when the generator is running, and all generators have some “gallon per hour” consumption figure based on a full or 50% load, which needs to be taken into consideration. Generally, that means you need to keep pouring in the fuel. If you need to run electricity 24/7, that really starts adding up. Plus you have to ensure you have enough fuel to last you through the duration of your emergency or situation. That can sometimes be a lot of fuel. You also have to figure in the oil changes and scheduled maintenance by hours run, as well as having to listen to it and smell the fumes coming out all the time. 

Moving to Renewal Energy Options

With the price of fuel costs rising and the other factors that make traditional backup energy generation annoying, many people, specifically off-grid residents, started becoming interested in alternative energy systems, especially using solar panels. We have had tremendous upgrades in the technology, design, and usability of components over the last 30 years. This corresponded with drops in pricing, so that there are now many applications of solar energy production installed and in use with the proverbial “price per watt” starting to approach traditional grid power choices.  

The main approach that people in the off-grid world have done is set up their house with a fixed solar array, a battery, controller, and inverter setup. Either you are handy with electrical stuff and figure it out yourself, or you hire a contractor do the installation. Very typically, an off-grid power setup will include a second charging source or more; in most cases, a liquid fuel generator and charger. Some locations will also include a wind turbine and/or a micro hydro turbine for charge input to the batteries. 

The arrival of large scale grid–tie solar systems into the mainstream of US households and businesses over the last seven or so years has been facilitated by cheap, easy grid-tie inverters, net metering, regulatory and utility pricing decisions, and federal and state renewable tax credits and incentives. Unfortunately, there was not much long-term thinking in a lot of the large-scale design and redundancy issues, with a very large percentage of newer grid-tie solar installs NOT including an onsite battery backup. The thinking was that the grid is the battery, so do away with customer onsite battery storage issues. But if the grid goes down for any reason, the customer will not have power, even if they have a roof full of solar panels! (Read about a complete solar setup in the WSID Article: Installing a Solar Energy System)

There are many situations that have called for a smaller, personal-sized solar power system that is ready to go, plug-and-play, and portable. These would be used anywhere one would need power without a grid outlet nearby, where it is not appropriate/desirable to run a gas generator because of noise, fumes, or constant refilling of fuel. Any mobile solar generator device would include PV panel input, charge controller, inverter, and batteries.

The best way to understand how much power and storage you need for emergency backup or temporary use is to collect the wattage of everything that you want to run individually. Then consider for how long it needs to run and add everything up into the “watt-hours”. This basically boils down to “How many watts, for how many hours.” All consideration of solar input and battery storage comes out of that figure. 

Here are some practical scenarios to see how this works:

If you are handy and have done a little mechanical and electrical work before, it's not that hard to put together a small off-grid system yourself, or at least be in the know about how much power you really use or need in a grid failure situation.

The basics:    

electric theory 101   >   volts x amps = watts        

With watts being your power draw, watt-hours represent how many watts you need for how long.      

You cannot have a consistent power draw with a stand-alone system without at least double the amount of solar watts coming in. If an application or tool doesn't list watts but shows amps, you can still figure watts by the formula above. Most AC electric uses are at 120 volts.

Here is a simple example of how the math works, for a possible bare-bones emergency backup situation at a small home:

Refrigerator (Energy Star) - 250 watts

Lights - 75 watts

TV/Radio - 75 watts

----------------------------------------------------

TOTAL - 400 watts

Next, figure out how long your appliances will be on. Refrigerators and freezers will cycle on and off depending on their efficiency, the surrounding temperature, and how many times you open the door. You can get refrigerators and freezers to use less by keeping both of these on a back porch during times when the temperature is consistently low, and also putting them on a timer or switch that you turn off at night, as they really don't need to cycle all night to keep the food cold or frozen, especially if you don't open the door. With the rest of your appliances, you are in control of when they are on. 

For this example, let's say they run for six hours per day.  

400 watts x 6 hours =   2400 watt hrs

So we need 2400 watt-hrs worth of power to run our set up for a day. Next, let's take a look at our solar panels. Solar PV power for charging must be in the best south-facing exposure, with a minimum of 5 to 6 hours of direct sun, and 8 hrs is even better. If you have 5 hours of full sun on one 200 watt panel, you will have 1000 watt-hrs (5 hrs x 200 watts) of power available. If you have cloudy, snowy, or rainy days, you will get half or even 1/4 of that. As you can see, one typical PV panel is not enough to run our basic example. You need an absolute minimum of 3 panels, each being 140 to 200 watt PVs.     

Next in the setup are the batteries. A single 100 amp-hr battery @ 12 volts will seem to give you 1200 watt-hrs of stored power when you run it through the inverter, but it's not that simple. To optimize the life of your batteries, they shouldn't be drained more than 50%-60%. So that one battery will give you 600 watt-hrs. Which means that at night, running off-battery, you will get 600 watts for one hour, or 300 watts for two hours. 4 - 100 amp-hour batteries should give you just enough storage for the samples above. 

When it comes to batteries, the more, the better. If you ran the loads listed above all night, your batteries would be much depleted, and you would need to charge them up immediately back to full. Hopefully, the sun would be shining, and with 5 or 6 hours of 400 to 600 watts of PV input, your batteries would be charged back up. You also would need a good solar controller between the PV panels and the batteries, and a good inverter to take 12 volt DC from the battery and turn it into AC. It is always a good idea to get an inverter/charger, so if you have some grid power available, or a gas or diesel generator, you can run that for a while, charge your batteries up, then turn that off and run on batteries for awhile.  

Solar power and batteries are no different than gas in a car, as you cannot take more power out of the batteries than you can put back in with solar charging OR liquid fuel generator power. Having a good voltage meter, PV input meter, and watt-hour meter and paying attention to their readings are highly recommended.

Making sure your battery voltage does not go below 11 volts (for a 12-volt battery setup) for any consistent time will also help prolong battery life. 

There is a good rule of thumb for off-grid that is very simple and uses averages: Figure one solar panel + one battery, two PV panels + two batteries, etc. And whatever you think you will use in wattage, double it. And whatever you think your need in PV panels and batteries, better double that too.

Hybrid Systems

The solar backup system + a gas or diesel generator ( HYBRID system ) is really the best way to go, as there WILL be times when your batteries get low and there is no sun to charge it up with. Therefore, you need supplemental power from something else, possibly a small hydro system or windmill, but if you have the generator equipment already, and good fuel storage, then you only need to run it occasionally, and you can make your fuel last much longer that way. Also, good management of a HYBRID system would be to fire up the genny when you need the short, higher bursts of power, like water pumping or bigger tool use. If you plan your solar system accordingly, practice aware power management and efficient use, you can have the free energy from the sun powering most of your critical needs maybe 2/3 or 3/4 of the year.  

More complex, expensive and well-designed hybrid systems are setup with the solar, inverter, generator and batteries all inter-tied and on an auto monitor system. This will then remote start the generator whenever battery voltage OR wattage load exceeds certain set thresholds. In most cases, an electrical contractor is called in for these design and installation jobs.

One advantage of the portable style solar generator systems versus a fixed system (besides being able to take it with you) is that you can position the mobile solar unit in the best sun in your location, then run power cords to your needs. You can also turn the unit to do solar tracking through the day (morning view east, noon view south, afternoon view west) that can increase your daily PV watts output up to 30 % (from 5 hours a day up to 10, if you have the sun exposure).

Considerations and Advice

When considering the economic choices between energy efficiency and energy production, ALWAYS look closely, take action and spend money first on energy efficiency.  There is a fairly well tested formula in this business that says for every dollar you spend on energy efficiency, 3 to 4 dollars would be spent on energy creation to match the resulting output or savings.   

That means:

  • insulate your house
  • weather-strip and stop drafts
  • upgrade all appliances to Energy Star or better
  • use LED light bulbs
  • super efficient pumps and motors
  • make a wise choice of energy for the job at hand
  • practice power management and awareness
  • make lifestyle modifications
  • get a Kill-A-Watt meter and start measuring exactly what each activity uses
  • look at your electric bill and calculate what you use on average every day. 

These activities, and the time and dollars you spend to bring your daily use down, will ALWAYS cost less than spending that money on more oil or coal power plants, big massive solar farms or onsite solar PV systems, wind mills, diesel or gas generators, hydro dams, nuclear plants, etc.  

Granted, some of that upgrade is costly.  The best energy-efficient equipment seems to always cost more, but it will generally save you more money AND last longer in the bigger picture. Certainly the LED lighting story is that way, as the bulbs are extremely expensive right now, compared to incandescent or CFLs. But the energy savings and longevity will more than offset the upfront cost. We have ROI charts for a number of situations that will prove this. Many trends are going in that direction too, including the recurring cost of power. Most economic charts do not have a $$ slot for what it costs you, if you have no power.........

Conclusion

By doing the work of becoming extremely energy efficient, you can open up a whole new window of feasibility to having an independent or localized power source that is reliable and affordable. This is especially the case with solar and hybrid power generation systems. When looking at a backup/portable power system, keep these points in mind:

  •  Any solar sales person, consultant, or company that is really doing you a service needs to start with energy efficiency first, to get your average daily power needs down, BEFORE they even start calculating how much solar you need.
  • I would advise, in these times, to ALWAYS get a battery backup component to a home solar system if you are considering getting one, or adding that in if you already have a grid-tie system. While the grid-tie systems are great, if the grid goes down, for any length of time, you will be without power, even with a roof full of solar panels (we are seeing more and more consistently longer times to power restoration after storms).
  • There are a lot of cheap, plastic so-called solar battery or device chargers or "my solar backup," etc., being sold and pushed through TV, catalogs, and on the web. Buyer Beware!  Many of these are a joke, and will not really work in real life situations to actually and consistently charge your device or back up your critical needs at home, nor will they last more than a year before they break or stop working altogether, and then you will throw them away. We have looked at and tested a lot of them and talked to a lot of other folks using various brands, and the old saying "you get what you pay for" is never truer. If the solar surface is under 3 square inches, they simply will not put out enough electric to really charge your device in a timely fashion. Sure, if you leave your device plugged into them and in the sun for 10 hours or more, maybe they will start to get close to full charge. How real is that? 
  • If the battery is 50 amp/hrs or under for a home backup system, you will not get more than an hour or two of critical power usage before the battery is drained and will be ruined. When you really need it, will it fail? 
  • The same goes for the "solar LED flashlights." There is some real junk out there. Don't depend on them. Sift carefully to find quality and "actual value" -- a tool or product that will really work and last, time in and time out.    
  • There are some good NmH battery chargers, for your AA, C, D, etc, cells that will charge off AC AND a 12 volt DC cigarette lighter plug, which makes them very versatile for having in your car for all of your flashlights, radios, cameras, etc. If you get the 8 or 12-bay models, and fill them up with the main type of NmH batteries that you use, you will always have fresh batteries that can be cycled in for use and charge. These can also be made to charge off a small solar panel, which would make them even more versatile and power-outage-proof.

I hope this has been worth it to read through and get a new understanding of how you use power and how to create some of your own.

The Boy Scout Motto: “Be Prepared!”

~ Chaz Peling


Chaz Peling owns and runs SolSolutions LLC, in Santa Rosa, California. He’s also lived off-grid with alternative energy and micro solar setups for years.

SolSolutions designs, builds and sells alternative energy, solar electric, and battery backup equipment, and efficient applications, including the SolMan mobile solar generator.

Find us on the web at:    www.sol-solutions.com




This What Should I Do? blog series is intended to surface knowledge and perspective useful to preparing for a future defined by Peak Oil.  The content is written by PeakProsperity.com readers and is based in their own experiences in putting into practice many of the ideas exchanged on this site.  If there are topics you'd like to see featured here, or if you have interest in contributing a post in a relevant area of your expertise, please indicate so in our What Should I Do? series feedback forum.

If you have not yet seen the other articles in this series, you can find them here:

This series is a companion to this site's free What Should I Do? Guide, which provides guidance from Chris and the PeakProsperity.com staff on specific strategies, products, and services that individuals should consider in their preparations.

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31 Comments

txgirl69's picture
txgirl69
Status: Bronze Member (Offline)
Joined: Apr 21 2009
Posts: 96
Good Stuff

Wow, nice article.... I've been wanting to investigate solar/hybrid energy and I have done a little research - but since math was never my forte, the topic becomes overwhelming! Thank you for taking time to put it all together in layman's terms.

I need to learn more about the "small hydro" aspect of a hybrid set-up. We have a small stream that runs almost year-round. It's especially strong in the winter months, when our sun is at its weakest.

Again, thank you!

gmeader3's picture
gmeader3
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Joined: Jan 13 2009
Posts: 13
Recommend actual brands and models?
  • Which "solar LED flashlights" are good?. What brands an models will really work and last, time in and time out.    
  • What brand and model is a good NmH battery charger?, that will charge off AC AND a 12 volt DC cigarette lighter plug,  8 or 12 bay models?. 
joemanc's picture
joemanc
Status: Martenson Brigade Member (Offline)
Joined: Aug 16 2008
Posts: 834
Good Read

I've stocked up on rechargable batteries and a charger that will charge AA, AA and 9V batteries all in 1 unit.

As far as solar/battery - what a fiasco that has been for me. You are right about people finding out that grid tied means nothing when the grid goes down. We had a lot of that in CT during the October snowstorm. Before the storm, I had already gone down the road of doing just a grid tie solar setup, but that storm got me to want to do a battery backup. It's been impossible to find an installer. The installer I was working with heed and hawed about doing a battery backup for me, then his company decided I was not worth it. He did refer me to another installer who specializes in this battery backups, and now of course, has stopped returning my phone calls. It's unbelievable. So much for a push to go renewable! In the meantime, I keep trying to recuce my power use. I only used 105kwh last month, which may be why no installer wants to bother with me!

markf57's picture
markf57
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Joined: Aug 25 2008
Posts: 62
Prius as an option

If any in this group have a Prius, it can be made into a backup generator. The Prius makes for a nice hybrid option. Here are a few links:

hiwaay.net/~bzwilson/prius/priups.html - up to 2000 watts

www.priups.com/riddle/answer-1.htm Higher end options

Boomer41's picture
Boomer41
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Joined: Nov 30 2008
Posts: 67
Battery Backup Power for Home

Living in a condo in a densely populated suburb, running even a quiet generator 24 hrs a day is not an option for many reasons. Nor do I have the space to erect even a modest solar array. My approach was to build a battery powered backup system based on a  fork truck battery and an inverter.

I first did an energy budget for my home. This is a spreadsheet with the power consumed by every light and appliance listed along with the time, in hours, that it is on each day. From that I calculated the total energy consumed per day in watt.hours.

Lighting was the largest energy hog followed by the fridge-freezer and the gas furnace. Because they run for very short periods, some high power appliances such as a microwave oven or a hairdryer consume very little. Air conditioning is out of the question.

Lighting actually represented 40% of my historic energy consumption which made changing to LED and fluorescent bulbs almost essential. Another surprise was that two computers running continuously consume almost 8% of the total. The energy budget spreadsheet was extremely useful to see where the energy was being consumed and enable appropriate economy measures to be applied.

I was able to easily reduce my daily consumption to 9 kWH, of which lighting represented 28% in normal times with the utility power available. Clearly, once the power goes out, one can and should be much more frugal with lighting and other discretionary loads.

As chazp points out, totally discharging a battery will quickly destroy it. Also once the battery is 2/3 charged, replacing the final 1/3 of the energy takes a disproportionately long time. Accordingly, for a practical daily charge/discharge cycle, only the 'middle third' of the stored energy is useful. In other words, you ideally need a battery with a total energy storage capacity three times your daily consumption. i.e. in my case 27 kWH.

Since commonly available inverters only come in 12 volt and 24 volt versions it makes sense to go for the higher voltage to keep the battery current as low as possible. The calculation for the battery capacity required in my case was: 27000 watt.hours divided by 24 volts = 1125 Ampere hours (at the 20 hr rate). This translates into a 24 volt 13 plate lead acid forklift battery which measures 12"w x 31"l x 31"h, weighs 1500 lb and cost new about $3000.

The 24 volt DC power from the battery is transformed into 120 volt AC power for the house by a 3 kW sine wave inverter. A transfer switch to change over from utlity to standby power is essential and must be installed by a licensed electrician.

The battery is always on float charge when the utility power is present. If the power goes out I switch over to the battery backup. A fully charged battery will run the house for 48 hours using only 2/3 of its capacity. If the power stays out for more than 48 hours, I fire up a 2.8 kW Yamaha generator which makes only 70 dB of noise, a level which will pass unnoticed during the day, and recharge the battery to 66% in about 5 - 6 hours. Repeat daily, your consumption might vary. Small gasoline generators are easily converted to run on propane or natural gas.

120 VAC input chargers are typically limited to 60 amp DC output at 24 volts nominal, because of the power limitation of the standard wall outlet. To shorten charging time and better utilise the generator output, I used two 40 amp chargers which happily work in tandem.

Disclaimer: I am a retired electrical engineer with experience in the fork lift and mining industries. If you understand the above, I hope you find it useful. If not, you definitely need a professional to design and build your system for you. Doing all of the work myself, my system cost just under $8k which includes battery, chargers, inverter, generator, transfer switch, battery charge monitor and all cables.

Woodman's picture
Woodman
Status: Diamond Member (Offline)
Joined: Sep 26 2008
Posts: 1027
Small batteries and chargers

Nice introduction to this subject.

Using a smart charger for your AA, AAA, C, D etc. rechargeable batteries, rather than those simple plug in the wall socket units, will prolong the life of your batteries much more and keep from overcharging them.  One nice feature of these units is they tell you whether the battery is good or not and if it is charged.  I use a Lacrosse similar to this for AAA and AA batteries, including those for LED headlamps and handheld lights:

www.amazon.com/Crosse-Technology-BC-700-Battery-Charger/dp/B000RSOV50/ref=sr_1_1

I also have a Maha charger similar to this which will do up to 8 AA, AAA, C or D size:

www.amazon.com/Maha-PowerEx-MH-C801D-Rechargeable-Batteries/dp/B0042IOQPG/ref=sr_1_7

For power outages, my night biking light systems double as emergency lighting.  There some great LED  systems out there now that are incredibally bright.  I use one for a headlamp for working outside or running at night all the time.  My systems are made by Dinotte lighting and use Lithium ion batteries.  Expensive but high performance and very durable.

dinottelighting.com/

If I need to recharge and there is an extended outage, I can plug a small inverter into my car than converts 12VDC to 120VAC.  My truck also has a built-in 400 W inverter.  A small solar panel setup that would serve this function in the event gasoline is scarce seems a like a good idea, if anyone has recommendations.

Once you look at larger battery based systems though, the capital and maintenance costs seem too high to be worth it for the rare power outage unless you are dependent 100% of the time or live off grid.

Woodman's picture
Woodman
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Posts: 1027
Backup power from vehicle

Reducing your electrical dependence and usage is the most important step.  With wood heat, town water, and fuel cooking I have no critical needs for large amounts of electricity except perhaps refrigeration.  A solar/battery system to run my refridgerator would be very expensive.  A generator is one more piece of mechanical equipment I just didn't want sitting around unused 99% of the time, and fuel is a potential issue.  Cheaper generators are noisy and the nice honda inverter types are very expensive.

My solution was to get a very small freezer with a low starting wattage and a 1000W pure sine wave inverter I can run off a vehicle.    The freezer I wanted/needed anyway, and the inverter has no maintenance issues.    Bumming some 2 gauge DC wire off my father, the total cost so far is less than a generator.

I have yet to test this, but the intention is to run it off my Prius.  Although I think any vehicle with enough  alternator/battery power could be used, the Prius should save gas because the engine should automatically cycle on an off only as needed to keep the Prius batteries charged up.  More info in the first link in Post #4 above.  I have no intentions or time to mess with the high voltage battery though.  Anyone else with experience on this I'd appreciate any lessons learned.

Tom

Dscott's picture
Dscott
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Posts: 10
Energy saving

Another way to save alot of energy for people living in temperate and colder climates is improved heating controls. A single house thermostat will respond to the temperature in one room only so some rooms are too hot and others may be too cold. With digital thermostats controlling the radiator valves in each room you can control the temperature in each room and program different temperatures for different times of day and days of the week. This sounds complicated and therefore vulnerable but the system is modular and if it fails it can be disconnected allowing the boiler to run on its integral timer. 

www.housetechsolutions.co.uk

Dscott's picture
Dscott
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Posts: 10
Energy saving

Another way to save alot of energy for people living in temperate and colder climates is improved heating controls. A single house thermostat will respond to the temperature in one room only so some rooms are too hot and others may be too cold. With digital thermostats controlling the radiator valves in each room you can control the temperature in each room and program different temperatures for different times of day and days of the week. This sounds complicated and therefore vulnerable but the system is modular and if it fails it can be disconnected allowing the boiler to run on its integral timer. 

www.housetechsolutions.co.uk

Judd's picture
Judd
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Joined: Dec 12 2008
Posts: 20
solar generator

Has anyone tried the solar generators on the market? Thoughts? 

Woodman's picture
Woodman
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Posts: 1027
Excess solar power off grid

I understand when a grid-tied solar PV system generates excess power it is sent to the Grid. 

What happens with a non grid-tied system when loads are less than power generated, and batteries are charged up if you have them?

Mirv's picture
Mirv
Status: Silver Member (Offline)
Joined: Sep 30 2008
Posts: 105
what happens when available solar power is less than load

If the load is smaller than the available power, the solar panel will simply supply the load and no more.  You end up operating at less than optimum conditions with less than optimum power output.  if you want to do something about this and are  handy with a soldering iron, I can supply a circuit for you to use (this  is an interesting topic to me and I have a solution), or depending on which type of controller you have, you can get more out but you need additional load............

Boomer41's picture
Boomer41
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Joined: Nov 30 2008
Posts: 67
Solar Generator?

Judd,

I have not tried a "solar generator" (frankly I had never heard of such a thing) but I checked out the Phono Solar 1800 watt generator sold by Home Depot for $1500.

IMHO this will seriously disappoint anyone who buys it. The price does NOT include the battery and the battery box will hold a maximum of 400 AH batteries.  A 12 volt 400 AH battery as the storage device  is woefully inadequate to supply an 1800 watt inverter. If the inverter is run at full load the battery will be 50% discharged in only 80 minutes. (Discharging it fully will cause permanent damage to the battery). Even at only 10% of rated output  (180 watts) the battery will only run the "generator" about 12 hours.

Also the 140 watt solar panel will not fully recharge the battery in one day's worth of sunlight. I estimate about five good sunny days to recharge, so this might be OK for very short power outages, but it will be useless if the power is out for a day or more.

Hope this helps.

GregGGH's picture
GregGGH
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Posts: 10
 Hi Boomer 41  I seem lost

Hi Boomer 41 

I seem lost on the math required .....   you said ....."A 12 volt 400 AH battery as the storage device  is woefully inadequate to supply an 1800 watt inverter. If the inverter is run at full load the battery will be 50% discharged in only 80 minutes. (Discharging it fully will cause permanent damage to the battery). Even at only 10% of rated output  (180 watts) the battery will only run the "generator" about 12 hours........"

Can you explain the formula here ...sorry if it is obvious ...  but would appreciate understanding thispart better

Regards

Greg H

Woodman's picture
Woodman
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Posts: 1027
solar math

I'll take a stab, for my own education as well:

400 amp-hr batter x 12 volts x 50% discharge = 2400 watt hrs available from the battery.

2400 watt hrs / 1800 watt full load = 1.33 hrs = 80 minutes at full inverter load.

To re-charge, 2400 watt-hrs / 140 watts solar panel power = 15 hours at rated panel output, assuming the battery can be charged at that rate without overheating.

Say the panel gets 5 hours of full sunlight per day; it takes 3 days to fully recharge.  Probably longer since the charging rate should not be too great as the battery nears full charge.

Of course, these are very simplified calculations which neglect factors of inefficiency through every part of the process.

Boomer41's picture
Boomer41
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Posts: 67
More Solar Math

Hi Greg,

Woodman beat me to it and did a good job of explaining the math. As he mentioned, these calculations are simplified and don't take into account such things as efficiencies of the various components. For example, whereas Woodman calculated 3 days to recharge, assuming 100% efficiency, I estimated 5 days because solar panels only produce full output when facing directly into the midday sun.

Batteries, too, have more effective capacity when discharged slowly. Ratings of 'deep discharge' batteries are typically given at the '20 Hour Rate' which is the amount of energy which can be stored if it is consumed steadily over a period of at least 20 hours. If discharged faster (e.g. in our example above, the 80 minutes that the solar generator will run at full load) the amount of energy available will be less. In fact the calculated 80 minutes would be more like 60 minutes if the reduced capacity at the higher rate is factored in.

Hope this helps.

worrid's picture
worrid
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Posts: 1
Portable Solar Power Systems

other benefits to a portable Solar Power systems are for those living in apartments or condos and are not allowed to put a solar panel on their balcony, these could be very useful if you follow the guidelines for choosing one. yourgogreensource.com

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chazp
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micro hydro

Hello Txgirl69;

There are a number of "micro-hydro" type generating equipment packages you can get.

If you have the enough "Fall"  or "Head"   ( distance that the water needs to go vertical to get good pressure )

and enough volume of water steady, then maybe you can make something feasible.  

Basically you need larger diameter plumbing to move the water to a small turbine, that connects to a generator.

The pressure of the water turns the turbine and the generator, and that outputs electric, usually higher voltage,

so you can move it to where you need.   

We can source a number of suppliers of equipment in this area, if you are interested.

It will take some more detail on the proper design, and onsite installation is crucial also.

Hope that helps.

Chaz

SolSolutions

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chazp
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Solar LED flashlights and Nmh battery chargers

Hello Glenn;

 
Thanks for your interest in personal energy preparedness. 
 
I have had great luck with my Solar Goose Ultimate LED flashlight.
 
It is well built, high quality, strong LED chip, strong battery, and good charge potential with the solar input.
 
Brushed Aluminum design, not plastic.  Just feels and performs more like a good tool you want to keep around for awhile.  
 
SolSolutions will be featuring a special offer to the Chris Martenson community for these flashlights very shortly.
 
I will email a discount code to you when we have it up.   ( Next few days ) 
and post it on our website. 
 
 
For the Best Nmh Battery charger, I have had great luck with the Enercell Family Model 8-Bay Universal Battery Charger, from Radio Shack.
 
These units do all rechargeable battery styles, AA, AAA, C, D, and 9 volt Nmh.  
 
And they can do up to 8 at a time, which means you always can have a second set ready and charged.
 
What makes this very versatile is that it will plug into either 120 VAC with the wall adapter, or into a 12 VDC cigarette light plug, so you can have it in your car, ready to go.  And it has a USB port for electronics charging.  
 
We have sold these as a bonus, and the recommended small battery charger to go with the SolMan mobile solar generator.  
I am working on a special deal also for Chris Martenson web community members.
You can get them at any Radio Shack store also. 
 
Hope this helps for your energy readiness.
 
 
Chaz Peling
 
SolSolutions
 
www.sol-solutions.com
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chazp
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excess power off solar

In a non-grid solar PV system, when you have alot of solar input, 

and that has already charged the batteries to full,  ( not that common, if you are running an entire household 100% off-grid on solar),

then the solar controller throttles down the PV input to "float" mode on the batteries. 

Realty good design, and the more sophisticated controllers will shunt the extra PV watts over to a water heating or pumping application,

that essentially uses that power to store in another way, for later use.  

Chazp

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chazp
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solar generator reviews

Yes, we have seen alot of bundled "Emergency power" or "solar generators" 

by various companies, that have actually got into larger store and online presence.

The problem with much of them is how they are marketed, where they highlight the top wattage

of the inverter ( 1800 watts ) but down play, or don't mention that there is hardly any battery storage,

and generally undersized on the PV solar input also.  

These units will not last very long, if you are thinking you can plug in your fridge and some lights in a power outage.

Many of them won't last more than a half hour with any decent wattage pull.

Then you will drain the battery dead, and likely be frustrated and want to throw it out.

Many of them are based on a Chinese contract low bid manufacture design from Xantrex,

that also sold off it's previous good name to the low ball chinese bidders.  

Many of them are really poor quality components, and junky plastic boxes that will barely get you thru the 90 day warranty before the fall apart,

Buyer beware.      

Do your homework your watt-hours per day need at home, with the grid down, 

look at battery size and PV input as critical important  details when you purchase a solar generator.

Any decent sized solar generator or backup systems needs at least 3 full size batteries, and 3 full size solar panels to work reliably. 

When you really need it, will it fail? 

Chaz 
 

SolSolutions LLC

www.sol-solutions.com

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Damnthematrix
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Posts: 3998
micro hydro

chazp wrote:
There are a number of "micro-hydro" type generating equipment packages you can get.

If you have the enough "Fall"  or "Head"   ( distance that the water needs to go vertical to get good pressure )

I first learned about MH in the 1990's when I did my Diploma in Renewable Energy.....  Great idea, but there are very few sites in flat Australia that work, especially in the hotter climes such as where we are right now.  The evaporation rate is so high that even creeks in flood after a deluge are dry within a couple of weeks.

HOWEVER, as I actively pursue our move to Tasmania, and finding quite a few blocks of land with permanent creeks, I am now seriously narrowing my land searches for somewhere that has an appropriate MH site (and I've found a beauty!)

The main reason is that a 1kW MH setup working 24/7 will generate 24kWh every day.  I have sourced such a setup in Australia for just $2900, whereas a solar system to generate this much energy with PVs would easily cost five times as much, or more.......  especially in Tassie where the sun's probably only about 60% the strength we have here in Queensland.

THEN, my thinking started stretching further..... with such a reliable energy source, you could use your EV as the battery storage, and sell any excess to the grid through a Feed in Tariff for income....

Mike

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fogril121
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Diesel Generators

Just to tell you the right thing, my wife had been cribbing for the set-up of a power generator in the house for almost three years. Every time we would suffer power outage, the patience outage was sure to follow. Since I’m not a very high-on technology husband, I used to take her requirement for instant electricity even during a power outage very lightly. Her constant request for power-back up that will help the kids to read, play or lead a normal life when the power went off, r Cherry’s desire of not missing out on her favorite TV show kept falling on deaf ears till one day.

Thanks

Power GeneratorsDiesel GeneratorsElectric Generators

chazp's picture
chazp
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Posts: 15
Special offer on great LED-Solar Flashlights

To the CS community;

As I mentioned in the article and following posts, we were able to put together a special offer 

for solar-LED flashlights.   

Here it is:         http://www.peakprosperity.com/blog/special-offer/71970

Enjoy,

Chazp and SolSolutions

-----------------------------------------------------

Special Offer from SolSolutions and Solar Goose - LED-Solar flashlights

 

We are pleased to announce that SolSolutions is offering PeakProsperity.com members a special discount of 25% off all Solar Goose LED-Solar Flashlights and other associated lighting and charging devices. 



SolSolutions designs and builds portable solar generators.  They also use their industry expertise to recommend and sell the best in solar components, energy efficient appliances, LED lights, and off-grid energy options.

The Solar Goose Ultimate LED-Solar Flashlight is one of the best on the market. Solidly built of brushed aluminum, not plastic, the Ultimate Flashlight contains a strong solar charger, bright high-quality LED chip, and versatile design.

Solar Goose also has an Ultimate Survival Kit for lighting, communication and small backup power needs.  This kit can be an excellent addition to your car or mobile emergency preparedness package (Read the EDC Article).  Other back up solar charging and lighting products are available at Solar Goose as well. 



Specifically, SolSolutions and Solar Goose are offering:

  • A 25% additional discount on all Solar Goose products
  • Free shipping
  • A free mini solar/led flashlight with every order.  

Click Here to go directly to the Solar Goose online store, to take advantage of this offer, and use Coupon Code: SolMan, exclusive to PeakProsperity.com readers.  Offer will be valid through the end of March 2012.

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sammathew
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Backup Power

There are several options for backup power equipments when we face power failure e.g. generators, renewal energy resources or hybrid system. The most easily available and operative backup equipment is generator. Generators basically use diesel or gas as the fuel.

 

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Damnthematrix
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Posts: 3998
97% of Americans overestimate cost of installing solar

Ninety-seven percent American homeowners overestimate the cost of installing solar, according to a recent Harris interactive poll that illustrates public perception remains a major obstacle to adding more residential renewable energy to the grid.

The online poll, conducted on behalf of residential solar power company SunRun, found folks want to go solar. Nearly eight out of 10 of those who don’t already have solar panels say they would install a rooftop array if cost were not factor.  But according to the survey, the perceived costs are wildly out of whack with the real expense of installing solar. (See new note below)

Forty percent of the 2,200 adults surveyed think installing solar requires $20,000 or more in upfront costs. Only three percent accurately understand that installing solar can cost less than $1,000 upfront, which is possible because companies like SunRun, SolarCity and Sungevity all offer solar financing that allow homeowners to lease the panels without putting any money down. SunRun’s solar power service, also known as third-party-owned solar, is structured similarly to its rivals. The company owns, insures, monitors and maintains solar panels on the homeowner’s roof. In return, the homeowner pays a monthly rate over a 20-year period.

Market share for third-party solar has grown, particularly in California where it reached 75 percent of the home solar market in February of this year. In Massachusetts, the share for third-party solar is more than 80 percent.

Note: Based on some comments, I thought I’d add more information about solar leases. A solar lease is essentially a power purchase agreement or PPA. Utilities often enter into PPAs to buy power generated from large-scale solar and wind farms.

How it works

Generally, homeowners sign a long-term agreement between 10 and 20 years. Customers agree to pay a monthly fee for the solar electricity. That fee should be at a lower rate (on average over a year) than what the customer is currently paying their utility. In return, the solar provider takes on the responsibility and cost of installation and maintenance of the panels.

Solar leasing experiment

Out of curiosity, I recently went through the process of getting a quote for a solar system. Here’s what I found out:

The solar provider suggested I install a 6 kilowatt system (the average residential is 5 KW). If I skipped the lease option and bought the system outright it would cost roughly $38,000. State and local rebates and federal tax credit would cut $13,000 off the price. In the end, I would spend $25,000.

If signed up for the lease, those state, local and federal incentives would go to the solar provider and my fees would be lower as a result.

If I put $0 down, my lease payment would average $115 a month and my electricity bill would average $17, for a total cost of $132 a month. Without solar (this information is based on eight months of my utility bills), I would pay an average of $91 a month. So, under that scenario, I’m actually spending about $500 more a year. The lease payments would be subject to annual increase of 2.9 percent.

To be clear, since I’ve lived in my current house for less than a year, I’m missing the most important months (summer) of utility bills.  With a full year of my own electricity consumption information, I’d expect those numbers to shake out a little differently. I wouldn’t expect massive savings, but I would probably break even or see a small reduction in my energy bill.

Leasing would be a good option for folks who consume a lot of power, have high electricity bills (I’m an energy efficiency nut and thereby my bills are below average) and live in areas where there are local and state incentives.

So what happens if you move? According to the solar provider I checked out, you can assign the lease to the new homeowner, if they pass a credit check, you can prepay the remaining lease payments and assign the benefits and non-financial obligations to the new owner; purchase the system; or prepay the remaining lease payments and have the panels removed for no additional fee.

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Powersource 180...
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Powersource 1800 Solar Generator

The Power Source 1800 is the world’s first solar powered generator that is portable, powerful and can charge many important home appliances. The Powersource 1800 Solar Generator comes with a compact solar generator that fits anywhere in your home or truck and includes 4 plug outlets so you can charge more than one device at the same time for your convenience.

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mamunmizi
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Posts: 1
Solar Generator

Powersource 1800 Solar Generator wrote:

The Power Source 1800 is the world’s first solar powered generator that is portable, powerful and can charge many important home appliances. The Powersource 1800 Solar Generator comes with a compact solar generator that fits anywhere in your home or truck and includes 4 plug outlets so you can charge more than one device at the same time for your convenience.

A good point re cost of transmission. Also, I noticed that the map of solar installations vs available solar energy is rather misleading. It makes a lot more sense if you mentally overlay a map of California population density, ’cause the solar installations are – surprise! – where the people are. You may get more solar out in the Mojave Desert, but (except for that cluster around Palm Springs) there aren’t a lot of people living there. No people, no roofs, no rooftop solar.

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Jordin
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Posts: 1
U.S. Renewable Energy Slacking

Right now over 77% of our energy in America comes from fossil fuels, about 10% from nuclear, and only around 13% from renewable energy sources.

http://intellihub.com/2013/04/09/us-lags-far-behind-with-renewable-energ...

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sheilagonzalez
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Posts: 1
Solar 250kW Mobile Power Station

Do you know the unique powering features of our 250kW Mobile‬ Solar‬ Power‬ Station‬???

Eco‬ Nav‬'s UHE Solar Panels are the unique feature powering our 250kW Mobile Solar Power Station made of a Carbon‬ Fiber‬ Composite construction making them super strong and are super lightweight...
https://www.indiegogo.com/projects/solar-250kw-mobile-power-station.

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sherrizahir
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Loadbanks

Really good article and best information could be provided. Load banks are essential in today life for better life in case of blackouts. With more than thirty years of experience these buddies are providing load bank solutions across the world, Crestchic are the world’s leading specialist in load banks and have become the trusted name for load testing.

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