Emergency Solar system

[S2man]

When I started prep'ing, for emergency lighting I went with led flashlights, head lamps, lots of NiCd's, lots of rechargeables with 110 & 12V chargers, and 10 solar yard lights. If the electricity went out permanently, a TEOTWAWKI situation, all we would have would be the yard lights charging AA's for flashlights and whatever else will run on them. And I'm *sure* the charging controls in the yard lights are top-of-the-line.

So I've been leaning toward a small emergency solar system. Once on 12V, I would have a lot more options, could charge a larger variety of batteries, and perhaps occasionally power a small appliance like a grinder or sewing machine. I've been buying 12V versions of small appliances whenever possible, like my propane detector. I got a solar security light. And I've got my eye on a nice little, Maha 12V smart AA/AAA charger and some of those Eneloop batteries ;)

I see 30, 45 & 60W systems with mounts, cables, charge controller, etc. for $160-290. Plug and play. In this SHTF scenario, I take the AGM batteries out of the cars, pull the system out of storage and set it all up. Now we're living up-town!

Another option, at this point, is to buy a better panel, a larger charge controller and accouterments, with an eye toward expanding the system in the future. That would put an emergency system in storage for a SHTF event. And we could purchase more panels, and perhaps a wind generator, as funds become available. Then, when the happy battery day comes, we can hook it all up.
...
I started this post several days ago, to ask your opinions on the options. But once the options were clearly laid out, it was time to talk to DW about it. She heartily agreed we wouldn't want to go to TEOTW with a flashlight and a CD player. So getting an emergency solar energy system put together is a go. But which one? The quick and easy kit, or lay a foundation for a larger sytem?

Then we discussed economic issues, hyperinflation, unemployment, mutant shrews, living off grid, you know, the normal stuff we discuss around here. We agreed that we want to work toward getting off-grid. If not completely, then largely. An exercise in self reliance. So welcome me to the club, at least in thought.

Now for the deed. My first purchase will be a Solar panel, a charge controller for wind and solar, and enough of the nuts, bolts and wires to assemble an emergency system. Any suggestions on pricing or brands, hints, tips, opinions, favorites, other options, or book recommendations would be appreciated. Especially a good book on the subject. I've got some learnin' to do.

[Aamylf]

[QUOTE=S2man;280202]and easy kit, or lay a foundation for a larger sytem?

Then we discussed economic issues, hyperinflation, unemployment, mutant shrews, living off grid, you know, the normal stuff we discuss around here. "


I am so glad DH and I aren't the only ones whose dinner table conversation usually includes the words zombies, cholera and bee boxes....:yes4: I don't feel so alone now.

[DavidOH]

Start with what you want to power.
What is it's current draw?
How many items? What are the daily watt hours usage?
How often, and for how long will you need this item/items to run?

Example:
I started with a radio. A base station Ham receiver.
It draws 1 amp @ 12v. I expect to use it about 4 hrs a day.
So for a panel to power it directly, the panel should produce at least 1amp at 12volts. If the radio is in use the panel should keep it going. With the radio off I can charge a battery or use other items.
With that estimate I should get about a 15 watt panel.
1 amp x 12 volts = 12 watts

Go through your list of items that you want to run. ( You probably have already)

Please don't get one on those cheap setups from Harbor Freight, or Northern tool, or somewhere else. I don't think they will hold up to being moved, or being used outside in all weather.

More to come....

[nadja]

Well, since you and your wife have decided to make it a go situation, why not buy small but correctly and start the foundation system in earnest ? Sure , it cost more, but in the long run it pays for itself many many times over. If you were to start with a Shucko solar panel about the 255 watt size in 24 volt which is about $585.00. Then, in a few weeks or so you buy a charge controller, which I would buy the Outback mppt 80. They are far more versital than anything else on the market at the moment . Costs vary , but by carefull shopping around, you can do fairly well. Now, the hard part, you will need an inverter to get your ac power from the starting system, and that will set you back. I would recomend the Outback 24v inverter with the mate which is actually the seperate led module which will have a total cost of just under 3k.

This is where you will need to sit down and both of you make a very large and expensive decision. Batteries. See, not only are they expensive, but like your car battery, they break down over the years. Good ones can last upwards of 10 years, but you will pay for them also. How many do you need ? Well, to many and you will never get a good charge on them and therefore wear them out long before their time. Too few means that you will run out of power early in the evening long before you should. batteries and solar panels are like socks and shoes, you need both, and in the correct compliment to work correctly. That is the science part I do not do. I do however live totally on solar , off the grid and have for a little over 16 years. So do almost all of my friends. We live kinda remote like ! LOL I suppose the point I am trying to make , is that if you go the cheap route on any of the above, when it comes time to go off grid or thrown off grid, it would not be the time to throw away the cheap stuff as it would no longer support your needs or system The components I have mentioned are easily "growable" to a much larger system. The weak link is the batteries, and also one of the most expensive parts of the system as they really all need to be put it service at the same time. That way the weaker or older ones are not pulling down the newer ones you keep adding. Shortens battery life by leaps and bounds.

[Teg]

A set up mounted on a small to mid sized cargo trailer (http://www.trailersplus.com/Georgia/Marietta/cargo_trailers.php) would seem to be a nice way to go if you want it to be mobile, have it all mounted rooftop and I am pretty sure you can find the inverters, batteries and such through an RV store, if it came down to it.

[nadja]

A set up mounted on a small to mid sized cargo trailer (http://www.trailersplus.com/Georgia/Marietta/cargo_trailers.php) would seem to be a nice way to go if you want it to be mobile, have it all mounted rooftop and I am pretty sure you can find the converters, batteries and such through an RV store, if it came down to it.

A CONVERTER changes ac power into dc power. An INVERTER changes dc power into AC power. Not the same animal

[Teg]

A CONVERTER changes ac power into dc power. An INVERTER changes dc power into AC power. Not the same animal

My apologies, I was typing fast. :) But sans my technical error, what do you think about the basic idea itself?

[nadja]

Hi, no problem on the mis-name, but you would be amazed at how many people really don't know the difference.

Now as far as the trailer goes, there are some around here. Full panel array on the top of a 12' cargo trailer, with all the support gear locked inside. They are owned by the local power co. and "rented out" to customers until they get their permanent systems installed. I imagine that if you were planned to bug out, then it would be ideal per se.

[S2man]

Sorry I haven't been around. I put in 72 hours at work last week, and am on track to do it again this week.

David, no, I haven't made the load list yet, as we just made the decision to go solar. But I see a new spreadsheet in my future... :) Not going cheap, here. I want a good panel and charger, a foundation for building a future system.

nadja, I was thinking of smaller panels, say ~100W. That would be a good size for the initial emergency setup. And it would be easier to squeeze another couple of panels into the budget ocassionally. I'll have to look at the $/W and compare panel sizes. Any other reasons to go with larger panels?

I hear good things about the Outback controllers. And I sure would like mppt. I've been focusing, in my little free time, on researching hybrid wind and solar controllers. Not much luck. I see some good solar OR wind OR other controllers, but only one solar AND wind version. The Sunforce. And I'm not impressed with it. Any hints in that direction would be appreciated.

If folks don't have an easy charge controller solution to combining wind and solar, how do they do it? I may have to just plan toward solar and see if wind fits in in the future...

Batteries. Ah, yes, batteries. I listed them last because of the issues you mentioned. I can't buy two of them per year, like the panels. I would expect to have everything else in place, or on hand, before ordering the batteries.

The inverter. My first inclination was to go 12V, like patience. But an inverter for those CFL light circuits would sure be easy to implement. I think it would be worth the inverter loss to avoid rewiring the entire house for 12V. Is inverter loss constant, or is it associated with the load? eg, would I want to turn the inverter off at night, or would turning off all the lights suffice?

[DavidOH]

I see some good solar OR wind OR other controllers, but only one solar AND wind version. The Sunforce. And I'm not impressed with it. Any hints in that direction would be appreciated.

If folks don't have an easy charge controller solution to combining wind and solar, how do they do it? I may have to just plan toward solar and see if wind fits in in the future...

go 12V, I think it would be worth the inverter loss to avoid rewiring the entire house for 12V. Is inverter loss constant, or is it associated with the load? eg, would I want to turn the inverter off at night, or would turning off all the lights suffice?

If I did not already have a charge controller I would go for the MPPT also.

Have a look at My Solar Project thread here:
http://www.backwoodshome.com/forum/vb/showthread.php?t=24490
or better yet, Go to my thread at Northern Arizona Wind and Sun forum:
http://www.wind-sun.com/ForumVB/showthread.php?t=10461
It's the same project and folks there were very helpful.

Sure, I think if you are doing the whole house it's better to use a large inverter than rewire for 12v. They will defiantly use power even if you are not running anything. It is your call if those losses are acceptable or not.

[nadja]

I would not even suggest rewiring your house for any 12v. Having lived on solar for so long, there are many pitfalls in doing that. One, is the size of the wiring required to carry the 12v current the distance. Even if you can afford the size and amount of wiring required, a long distance always requiring a much larger wire would soon get to the point of not being able to "fit" into normal plugs and switches, and fixtures etc.

Actually, I use 3- trace/xantrax C-60's at the moment , two for my two solar arrays, and one for my wind generator. I also have an outback mx-60 which is for my future use for more panels and/or a spare, along with two C-60's still new in the box. Back up. Hopefully, next year , although not really needing it for sure just yet, I will replace all of my batteries. Expensive , but so is not haveing any power for my fridge and chest freezer, not to mention my two desk top computers, lights, stereo, and older tube 27" tv. I am old and like my creature comforts.

[GentleLady]

Glad to hear someone is living totally off-grid on solar. You would't happen to be in Arizona............??

[nadja]

Glad to hear someone is living totally off-grid on solar. You would't happen to be in Arizona............??


LOL of course I am in Az. I listen to all the people back east talking about the killer heat wave and my wife and I chuckle all the time. How about living here in ariz. for about 30 years, with the last 16 on solar, which means NO AC ! Why does everyone only visit for the most part in the winters ? I know it is also about the same over there in Texas, as I framed houses there for about 6 months, and yes it was summer ! Arlington to be exact.

[12vman]

IF you are seriously considering wind as a source, PLEASE get a wind assessment of your area first. Not too many places within the interior of the U.S.A. is blessed with a good wind average. I had my bubble popped when I invested in two gennys. IF I would have done just a little research first, I could have saved myself a bunch of grief and labor. I'd been much better off just buying a few extra panels instead, which I did after I licked my wounds for a few years..

IMO, A good starting point would be around 200 watts. I've seen folks over the past buy a small, inexpensive set up less than 100 watts and become vey disappointed. 100 watts of panel isn't very much if you look at the potential real close..

Don't use "12" as your divisor! The average "working voltage" of a 12 volt panel is ~17 volts. Using 17 will give you more realistic numbers..

Take 100 watts.. Divide by 12.. 8.33 amps..

Take 100 watts.. Divide by 17.. 5.88 amps..

Small errors in a small system can make a huge difference! They use some fancy math so be careful! Check the specs carefully..

Realistically, 100 watts of panel during an average charge day (4 hrs.) can collect ~ 23-24 amp hours. That's really not enough to charge a set of golf cart batteries properly. And you're really limited to the things that you can operate within that range before running out of power, especially if you are using an inverter.

If you double that, (200 watts) now you have something to work with. 2 golf cart batteries have an average of 220 amp hour reserve. 1/4 of that is ~50 amp hours. (25% discharge limit) 200 watts of panel on a good day can replace this amount in a 4 hr. period. This is a good match with the golf cart batteries and you have ~50 amp hours to work with. Invest in a C-40 charge controller and you can expand up to near 650 watts of panel before you would need to replace the controller. Add panels and batteries as you can later. Add 200 watts, add 2 more golf cart batteries.. ect..

As for wiring..
If you plan to sell your home at a later date, by all means wire it normally and invert. If you plan to keep your system small and simple and never plan to sell, you might consider wiring for low voltage.

My system is totally 12 volt and I planned it from the get-go. I'm an 'ol fart livin' in the middle of nowhere with no intentions of ever selling out and I'm totally happy with a simple system and 512 watts of panel. I geared everything around 12 volts (lighting, tv, stereo, pumps, ect) and only use an inverter when there is no way around it. (small kitchen appliances) I can use an inverter in every room to run what I need, disconnect it and put it away. Of course I have some 2 ga. copper running up the center of my house to tap from but it's only a 1 time investment..

Your situation and your ultimate goal will designate what you choose to do. Just remember the "10 to 1 factor" when using an inverter. It takes 10 amps of 12 v.d.c. through an inverter to produce 1 amp at 120 v.a.c. (not including the inverter losses)

[S2man]

David, Thanks, I'll check out those links.

Actually, I use 3- trace/xantrax C-60's at the moment , two for my two solar arrays, and one for my wind generator. .

nadja, so how do you tie the three controllers together to charge one bank? Or do you have separate banks? This is where I'm stuck combining solar and wind. Nice prep's on the redundant controllers, BTW.

12vman, thanks for all the feedback. I lost the tabs I had open on my energy research, but I believe the official data said my avg wind is 13 or 14 mph here. I thought one of the low-wind-speed models, in the 400-500w range would be a good compliment to a 500W PV system.

On the 100W panel: I don't intend to build a 100w system. Sorry, I am talking about two projects here. First, an emergency, SHTF, hook it up to what ever batteries I can get my hands on, PV system. Second, assemble said emergency system with plans to expand it into a full blown system; So, even though the first panel and charge controller need to be purchased with a full system in mind, they will go on the shelf for several years, until enough components are acquired to assemble a complete system.

On the wiring: Yes, moving my existing lighting circuits from the grid box to an inverter-powered box sounds much easier than running new wires, connectors, adapters, receptacles, fixtures and lamps for 12V.

I'm thinking, perhaps, a smaller constant-on inverter for light loads like, well, lights. Then another, larger, inverter which would be turned on, on demand, for the occasional heavier load such as a kitchen appliance. All 12V work and rechargeables charging could take place in the battery bank room, on demand. A few dedicated 12V circuits could be run where they are justified.

[DavidOH]

I'm thinking, perhaps, a smaller constant-on inverter for light loads like, well, lights. Then another, larger, inverter which would be turned on, on demand, for the occasional heavier load such as a kitchen appliance. All 12V work and rechargeables charging could take place in the battery bank room, on demand. A few dedicated 12V circuits could be run where they are justified.

I am thinking the same thing.
I have a Trace 2000. It will put out 2000 watts. I do not foresee that I will ever need that much. If I ran a microwave, lights, fans, and my computer all at once I might get close.
I'm looking at something about 300 watts that will do true sine wave.
It should have much lower losses.

[nadja]

S2Man. You DON"T combine the three controllers together. Kinda sorta anyway,. I seperate my panels into banks and bring each bank into a seperate c-60 Now, you would want to set all your settings exactly the same. If using a xantrax or trace, you would use a voltage meter. Not just the little wheel's that are provide. I have my bulk loads set at 14.4 and my float loads set at 13.4 They (controllers) will simply stop bringing in power as they have reached your set levels. That is why they are called controllers.
Almost the same thing as the voltage regulater in your car. Just a little tiny bit more complicated and of course expensive !