Best solar collector for shtf situation

System
System Posts: 2,511 admin
If, when, the shtf and the grid is either permanently down or only up occasionally, a few solar collectors to make electricity to store in back up batteries would be a valuable asset. With today's technologies and available products, either in kits to build or as a complete solar collector, what do you think is the best, most durable, option?
Thanks for helping, as I am researching this and am starting from the equivalent of a second grade student.

Comments

  • Urbandialect
    Urbandialect Solar Expert Posts: 107 ✭✭✭✭
    Re: Best solar collector for shtf situation

    Buy your own solar collectors aka Solar panels, that would be the most durable option.
  • techntrek
    techntrek Solar Expert Posts: 1,372 ✭✭✭
    Re: Best solar collector for shtf situation

    Anything offered by Wind Sun here, is a good option. They don't sell junk, and will answer your questions if you do your own installation.
    4.5 kw APC UPS powered by a Prius, 12 kw Generac, Honda EU3000is
  • The Only Sarge
    The Only Sarge Solar Expert Posts: 164 ✭✭✭✭✭
    Re: Best solar collector for shtf situation

    I do not know about SHTF scenario but can speak to the reliability statement.

    Buy a commercial UL approved panel(s). No homemade stuff.

    Buy a Trojan battery or equivalent Golf Cart batteries. Stay away from WalMart type "Marine Batteries"..

    Have at a minimum 5%-10% of your battery amp hours in solar panel amps.

    If you have a panel that makes 7.5 amps and you have 200 amp hours of batteries...you would need a minimum of 10 amps. MINIMUM to charge those batteries.

    Fuse everything.

    Manage your power expectations. Do the math.
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: Best solar collector for shtf situation
    Buy your own solar collectors aka Solar panels, that would be the most durable option.

    Correction: that would be the least durable option. It is very difficult to build your own panels and have them come out right. However, DIY panels do have the possibility of repair if they should be broken, whereas commercial panels are pretty much impossible to fix.

    Kits? Good way to throw your money away. Buy lottery tickets instead. :roll:

    Step #1: figure out what are your critical loads that must be supplied and determine how much power you'd need. That is maximum Watts at any one time (including allowances for start-up surge for things like refrigeration) and total daily Watt hours. Without those numbers you're just guessing and won't be able to choose intelligently from the many possible solutions.

    Step #2: pick from the available equipment that which best meets your needs. Many of us run off-grid all the time. If you're going to skip the back-up generator, know that you will be spending a lot more to cover those times when the sun does not shine brightly upon your patch of paradise.

    Step #3: know that nothing lasts forever. Batteries will have to be replaced and equipment does fail, sometimes unexpectedly. How severe of an armageddon do you plan for? That's up to you.
  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Re: Best solar collector for shtf situation

    From our Solar FAQ thread, we have some detailed threads on designing and installing your own emergency solar power system:


    Emergency Power

    Basically a very long thread that starts from the beginning with a few vague requirements through design and assembly for a "portable" solar RE off-grid power box.

    And here is another example by Mike90045 called the Solar Monolith:

    attachment.php?attachmentid=384&stc=1&thumb=1&d=1234752636

    attachment.php?attachmentid=385&stc=1&thumb=1&d=1234752653

    Update pictures/information here.

    Looking at a fridge designed for off-grid use (solar or propane) are usually very expensive and have few "features" (not frost free, smaller than a standard fridge, etc.). Can be difficult to get service.

    There are alternatives for many of the "power hungry" appliances out there... One of the neatest solutions is to take a chest freezer and change the thermostat over to one that will work in the "fridge" temperature range... Can get down to 0.25 kWhrs per day (instead of 1-2 kWhrs per day).

    Chest freezer as a chest refrigerator
    micro freezer

    Solar Thermal can be a nice source for space heating and hot water... And usually is "cheaper" per kWhr/BTU vs Solar PV Electric. Also, Solar Thermal lends itself very well to do it yourself projects. Note, these are plumbing projects and have their own issues (leaks, pump failures, installation issues trapping air, anti-freeze, storage, heat exchangers, etc.):

    Solar Shed and other Solar Thermal Links

    A good place to start reading is Home Power Magazine... They have a free past issue online--and have a lot of articles you can read for free. I don't always agree with them and their reviews--but they are a fun and enlightening read:

    Home Power Mag


    Otherwise, conservation is your friend... Reducing loads to the minimum needed... For example, I have LED flash lights and head lamps and a supply of CR123 lithium batteries and AA. I use the lights and batteries all the time--so they stay fresh and the batteries will still last 5-10 years in storage.

    In an urban setting--going more than a week without power is going to be a huge issue (water, sewage, food, public services, etc.)... Figuring out how long you will need to be self sufficient and have enough clean water/food/energy supplies to hold out (i.e., more like camping) and what you will need to power that (i.e., well pump, minimal lighting, perhaps A/C in one zone of the home) will define your power needs.

    Then it is pretty much a paper design of a solar power system to power that.

    Try to keep it small... Solar power is not very cost effective for emergency use, and building a large system for occasional or emergency use is expensive (plus batteries will need to be replaced every 3-8 years or so, new charge controllers/inverters every 10+ years or so, etc.).

    If you do need a large system... Then look a t Hybrid system (Grid Tied/Off Grid capable) so you can sell the power back to the utility through net metering (if your utility supports GT solar).... At least you get some use of your money to reduce the power bills.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • techntrek
    techntrek Solar Expert Posts: 1,372 ✭✭✭
    Re: Best solar collector for shtf situation
    Buy a Trojan battery or equivalent Golf Cart batteries. Stay away from WalMart type "Marine Batteries"..

    I disagree with this. First, as many others have said in the past, going with cheap batteries at first gives you the option of screwing them up at lower cost to you if your system design is wrong. Second, I have 16 deep cycle batteries from Wal-Mart currently over 3 years old in emergency backup service, and they still operate normally.
    4.5 kw APC UPS powered by a Prius, 12 kw Generac, Honda EU3000is
  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Re: Best solar collector for shtf situation

    In general, marine batteries do not deep cycle much better than car batteries. It is better to go with true deep cycle batteries like "golf cart" type. Still pretty inexpensive.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • Peter_V
    Peter_V Solar Expert Posts: 226 ✭✭✭
    Re: Best solar collector for shtf situation
    techntrek wrote: »
    I disagree with this. First, as many others have said in the past, going with cheap batteries at first gives you the option of screwing them up at lower cost to you if your system design is wrong. Second, I have 16 deep cycle batteries from Wal-Mart currently over 3 years old in emergency backup service, and they still operate normally.

    There is a significant difference between "emergency backup" and daily use.

    Even a car battery will last for 4-5 years as an emergency backup if it's hardly ever used.
    Try using it daily as a deep cycle battery and it will be shot in 2-3 months at best.

    Marine batteries might last 6 months or so as a daily use deep cycle, a year at the most. Properly sized golf cart batteries should last at least 5-6 years when cycled daily.
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: Best solar collector for shtf situation

    Whoa, boys and girls.
    Let's remember that places like Sam's Club and Costco not only sell the RV/Marine type "deep cycle" batteries but also at least some of these outlets carry the "golf cart" batteries - which some people have had quite good results with, especially considering the low price. Don't confuse "type" with "brand".

    The RV/Marine and even automotive batteries will run an inverter. But it's a mater of for how many cycles? So the "motive force" batteries are #1 choice, followed by RV/Marine, then automotive as a last resort. Buying inexpensive batteries of the right sort will be a better choice than buying expensive batteries when you don't know quite what you're doing or buying the wrong sort at any price.

    Your actual experience may vary. Hopefully it will be a good one. :D
  • 2manytoyz
    2manytoyz Solar Expert Posts: 373 ✭✭✭
    Re: Best solar collector for shtf situation

    My thought is if you're preparing for a SHTF scenario, there's a possibility the batteries WILL see a lot of use. Why bother buying them otherwise? So that said, get some decent batteries to begin with.

    I've done just that. I live in hurricane prone FL. Last major power outage was in 2004. Local area without power for 18 days. That includes grocery stores, and gas stations (so much for generators). This helped inspire me to buy batteries and solar panels.

    You don't have to spend big bucks to get good batteries. I've been buying golf cart batteries at BJ's Wholesale Club, and more recently, at Sam's club:

    photo2-1.jpg

    photo1-1.jpg

    6V 220AH golf cart batteries for $71. That's a GOOD deal. My oldest batteries were purchased Jan 2007. Still performing well. Go price a 12V ~200AH deep cycle battery... they are very expensive as compared to two $71 golf cart batts in series.

    You might end up as I did. I initially bought batteries and solar panels as a backup power source. I slowly started using the otherise wasted power. Each month I try to pull one more thing off the grid, and put it onto alt-power. Now when the power goes off for an hour or two, I hardly notice. Lights, fridges, TVs, computers, etc, all still running.
  • The Only Sarge
    The Only Sarge Solar Expert Posts: 164 ✭✭✭✭✭
    Re: Best solar collector for shtf situation
    techntrek wrote: »
    I disagree with this. First, as many others have said in the past, going with cheap batteries at first gives you the option of screwing them up at lower cost to you if your system design is wrong. Second, I have 16 deep cycle batteries from Wal-Mart currently over 3 years old in emergency backup service, and they still operate normally.
    LOL....I love the internet.
  • techntrek
    techntrek Solar Expert Posts: 1,372 ✭✭✭
    Re: Best solar collector for shtf situation
    LOL....I love the internet.

    Yup, because there is nothing like first-hand experience and the sharing of information and ideas, right Sarge? 8)
    4.5 kw APC UPS powered by a Prius, 12 kw Generac, Honda EU3000is
  • The Only Sarge
    The Only Sarge Solar Expert Posts: 164 ✭✭✭✭✭
    Re: Best solar collector for shtf situation
    techntrek wrote: »
    Yup, because there is nothing like first-hand experience and the sharing of information and ideas, right Sarge? 8)
    If you say so.
    Buy cheap stuff and learn from there.
    You betcha.;)
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: Best solar collector for shtf situation
    If you say so.
    Buy cheap stuff and learn from there.
    You betcha.;)

    Don't stub your toe: I can tell you before you do it that it's going to hurt. :p
  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Best solar collector for shtf situation
    Don't stub your toe: I can tell you before you do it that it's going to hurt. :p

    if he stubs his toe i won't feel a thing.:p