Off Grid Power, Batteries, PV Panels, Generators...

Discussion in 'Energy & Electricity' started by JeepHammer, Oct 31, 2008.

  1. JeepHammer

    JeepHammer Well-Known Member

    Battery Basics,
    Things you MUST know if you are going to use Batteries!

    1. Batteries Discharge Faster When Sitting On Concrete.

    This was true when Thomas Edison was making 'Radio' batteries, but they are no longer made in metal cases.
    Modern batteries will actually benefit by being in contact with a concrete floor, helping to stabilize the temprature better.

    Batteries WILL discharge if you let the tops collect dust and moisture! Dust and moisture will actually 'Short' the terminals out and discharge the battery!


    2. Batteries Work Better When They Are Hot.

    Batteries will give optimum output around 62°F to 68°F.
    Warmer will shorten the life of the batteries,
    Colder will reduce effective output of the batteries.


    3. Any Water Will Do.

    EVERYTHING in that water will adversly effect your battery!
    Chlorine will neutralize the acid,
    Fluoride will build up on plates,
    Calcium will cause scale on the plates,
    Metals will cause corrosion and shorting between plates,
    The list goes on!

    Distilled water will NOT adversely effect your battery and will readily mix with the acid in the cell.

    DO NOT USE 'DRINKING' WATER that might have salts or other things added for 'Taste', just plain old Distilled water!


    4. You should add 'Acid' to the cells.

    Your battery comes with all the acid it should ever need!
    As the water evaporates away, the acid simply concentrates in the cell.
    You should add DISTILLED WATER to the cell to dilute the acid/water electrolyte mixture back to a proper concentration.

    Don't panic!
    And DO NOT suck the water out because you will be taking acid out with it!
    Simply skip over that cell until the excess water evaporates naturally, then maintain the proper electrolyte level from that point on.


    5. You can check a batteries' health by testing for voltage.

    You can check a batteries' health by one of two methods,

    A. With a hydrometer.
    Check the specific gravity of the individual cells to see if they are 'Fully Charged' or not.
    This is easily accomplished with the battery/cells still hooked up in the battery set or bank.
    You simply sample the liquid from each cell with a 'Hydrometer'.
    Hydrometer - Wikipedia, the free encyclopedia

    B. By doing a 'Load Test'.
    Take the battery out of it's battery 'set' and check it's state of charge,
    Then load that battery over a period of time to see if it will carry the specific load for a designated period of time.



    The larger the amperage, the larger the cables have to be to carry that amperage,
    The farther apart the terminals have to be to keep arcing from happening, and generally the more expensive everything will be to install Parallel battery systems.
    Last edited: Oct 31, 2008
  2. JeepHammer

    JeepHammer Well-Known Member

    Basic PV array & connections.

    There are a lot of things you should consider when installing PV arrays.
    Again, The golden rule is,

    If you intend to charge batteries directly from a PV array, then you will only need enough batteries to reach the charging voltage limit... Or use a 'Charge Controller'.

    Small PV panels have been used for years to directly 'Trickle Charge' batteries in seldom used vehicles or for seldom used appliances.
    For us country folk, we use PV panels to charge batteries for electric fence 'Chargers'.
    I use one to keep the two deep cycle batteries on my car trailer winch charged for the weeks/months I might not use the car trailer for anything...
    Many people use small PV panels to keep boats, RV's, or what ever charged up when not in use...

    The next step in direct PV solar battery charging is larger scale...
    I use two large (but wrong voltage for my home system) to charge batteries in an electric vehicle.
    Lots of batteries make up a 'Battery Bank', and since there are plenty of batteries, I need a larger solar panels to charge them up.
    In my case, the two panels make up 24 volts, and I use a small charge controller to keep them from Over Charging the vehicle's battery bank.


    The next step would be batteries for an 'INVERTER'.
    Emergency batteries, like an emergency battery backup for computers, or for your refrigerator, freezer, maybe a low current consumption light or two, would be handled in this same way.
    An inverter would convert the battery power from DC (Direct Current) to AC (Alternating Current) so your household appliances will function from battery power.

    Now, we are up to having several Solar Panels, Charge Controller, Batteries & Inverter.
    I will cover 'Inverters' in a later post...
    This is a basic, Modern, Solar PV system!

    Your PV array should be as many panels as you can afford!
    You can mix and match panels if you have the correct inverter (Multiple Inputs for DC).
    There is no such thing as 'Too Much' production capacity, since larger panels are $500 to $1,500 each, it's a self limiting proposition!

    You CAN start with just two or three, and buy & add on as you go!
    I suggest you do this!
    This allows you to size your system to your needs as you go, so you aren't 'Too Big' and waste money.

    In my particular case, we have 'Net Metering', which means when I'm not using the current I produce, I send it back to the electrical 'Grid', and turn my meter backwards...
    Building credits for when it's dark, or an appliance too big for my panels kicks on and I have to buy electricity...
    My bill usually reads "Amount due $0.00" and I REALLY like that part!

    I DO NOT get money for overproduction!
    Any extra production I made at the end of the year is NOT paid to me,
    That means I'm right about where I need to be, with a 'NET' of $0.00 cost to me.

    Some states require the electric utility PAY YOU for the extra production,
    And some states even require they pay you EXTRA, above the 'Consumer' rate, for the 'Carbon Free' production! A GREAT IDEA!

    In my case, When the air conditioner runs long and hard, I have to pay a little in, and I can live with that...
    If I had electric stove, electric heat, or electric hot water heater, I'm sure that bill would be MUCH more, and I'd add extra panels to recover some of that money!
    But, as it stands, I come out about even if the summers aren't too hot for too long, and that is about all a guy can ask for!


    Doesn't matter if you have Grid Intertie Synchronous Inverter, or just a stand alone DC to AC Inverter!
    You DO NOT want to overpower your inverter and burn it up!

    Inverters USUALLY have a WIDE RANGE of input voltages, and you need to know the limits before you start sizing the PV arrays for them!

    SERIES, one wired into the next one, will raise voltage.

    Series Strings wired in PARALLEL will raise the AMPERAGE while keeping voltage constant.

    Last edited: Oct 31, 2008

  3. JeepHammer

    JeepHammer Well-Known Member

    PV Panels, Grid Intertie and Non Grid Wiring

    Grid Intertie Systems.
    Depending on the number of PV Panels,
    (Photo-Voltaic Panels)
    You can significantly reduce or eliminate your electric bills.

    Small PV systems will power about everything in the house as long as you keep a eye towards energy efficiency.
    Compact Florescent light bulbs,
    Energy efficient refrigerators, freezers, ect.
    Turning of the power to parasitic loads like 'Stand-by' on TV's, VCR's, DVD's, Stereo Equipment, Computers, ect.

    You will need a MASSIVE PV array to power things like,
    Electric Hot Water Heaters,
    Electric Cloths Dryers,
    Electric Furnaces,
    Electric Stoves,
    Air Conditioning Units,

    That is were a grid 'Intertie' system comes in,
    With small panels, you power the 'Normal' running loads of the house in the day time.
    If nothing is on, then you turn the meter backwards and gain credits.
    If a heavy load comes on, like the Air Conditioner or Furnace, then the grid takes over and runs the appliances until that large drain device kicks off.

    You can easily accumulate enough credit through the day to run the heavy drain devices and still maintain a credit.

    In my state, you don't get paid back the 'Excess' current you return to the grid, but you CAN cancel your bill out by turning the meter backwards.
    It's called 'NET METERING'.

    In some, more 'Enlightened' states, the Electric company not only has to pay you for your extra production, but they have to buy the 'Carbon Free' current at a premium price!

    Anyway, this shows a typical Grid Intertie system,
    With, and Without Batteries.


    Batteries WASTE about 70% of the electricity you throw at them!
    They waste it as resistance in the terminals,
    They waste it as heat both charging & discharging,
    They waste it in the electrical to chemical storage process,
    They waste it in the chemical to electrical discharge process...

    Batteries just aren't very efficient, but if you intend to live 'Off Grid' they ARE a 'Necessary Evil'.
    You simply can't afford to run a generator every time you want to use the microwave or watch TV!...

    SO, With that said,


    I DID NOT include the battery charger you will need to recharge the batteries from the generator when there has been clouds for several days, or if you don't have very many batteries or very many PV Panels...

    With a generator supplied Battery Charger (Consider A Generator With Starter/Alternator the same voltage as your battery banks... In this case, 24 Volts.
  4. JeepHammer

    JeepHammer Well-Known Member

    Just saving space for next variation.
  5. Erika123

    Erika123 Guest

    About off grid energy

    If you would like to make good use of the sun, it is very doable without costing a lots amount of money. See this Solar Panels and System. Hardy Solar Home Stezader 4 kW off grid energy generator system.1,500 Watt off grid Solar Panel System.
    off grid
  6. Iron_Bran

    Iron_Bran New Member

    This is impressive

    I really like this forum - y'all clearly know what you are talking about. I appreciate your conclusions that batteries are really inefficient - people get so hung up on one little spec, and decide one size battery will work perfectly and another is total garbage.

    In reality, batteries need to be sized to the system, but there are more inefficiencies throughout the system that you could ever imagine accounting for.
  7. MrSfstk8d

    MrSfstk8d Well-Known Member

    This is a really great primer on PV and intertie Jeep Hammer. Great set of posts, and good visuals, especially for those who may not be at all familiar.
  8. ZoomZoom

    ZoomZoom Rookie Prepper

    Great series of posts.

    I will toss something out though. When connecting DC batteries, particularly in parallel, it's best to match their size, age, output. If you connect 2 mismatched batteries, the weak battery will draw from the strong and generally make a mess of things. Think of when you connect jumper cables from a good to a dead battery. The bad battery will draw from the good until they're equal. Basically, you end up with 2 half-dead batteries when now renders both of them inadequate.
  9. Great job!

    This is a GREAT post! Well Done!
  10. rhrobert

    rhrobert Happy in the hills

    Build your own battery

    Don't know if any of you will find this useful, however it might make for some good experiments:

    Attached Files:

  11. UncleJoe

    UncleJoe Well-Known Member

    Very cool. Well worth saving. :thankyou:
  12. YouNeedBatteries

    YouNeedBatteries ExCommunicated

    You can also buy a sealed, maintenance free, factory activated battery. It has less of a shelf life, but you won't have to deal with constantly refilling the acid.
  13. GaryS

    GaryS Member

    Just want to share a thought about being independent of the power grid.

    Last spring I installed a 20kw whole house generator that automatically starts and takes over supplying power if commercial power is out for a couple of minutes.

    We recently had a power failure when a car hit a transformer. My generator did exactly what it was supposed to, and within minutes my house was the only one in our development that was brightly lit. That's the rub. I stood out like a sore thumb, and even though I went to the neighbors and told them they could run an extention cord if power was off for long, I sensed some resentment that I had something they didn't.

    I turned all the lights off and sat in the dark while the generator was burning propane at the rate of two gallons an hour. If power had been off for days, as it sometimes is, I would have been the most hated person in the development.

    I guess what I'm saying is that if you prepare, you might not be very popular when your preparations become the center attraction.
  14. LincTex

    LincTex Jack of all trades?

    There have already in this country cases of people getting killed over a generator dispute. In that one case it was the noise, but others will very easily want your power as well.
  15. Nadja

    Nadja Well-Known Member

    I live so remote, that running a gennie doesn't count. But 99% of my off grid house power comes from my solar system. But, living in the city, if you flaunt it, you may just lose it. Like driving a rolls royce to the really bad part of town. Not good
  16. GaryS

    GaryS Member

    That's what is really bothersome. I live in a small, rural development four miles from a very small town and a hundred miles from a city. Even rural folks don't have the same mindset that prevailed when I was young. Sad to think that being prepared puts a target on your back no matter where you live. Apparently the only difference between living in a city or in the boonies is the number of people drawing a bead.
  17. oldvet

    oldvet Well-Known Member

    This may sound completely cold hearted but, they could have done the same as you or at least purchased a smaller gas powered gennie for emergency power. I would not loose a seconds worth of sleep worrying about them resenting or hating me just because I had some foresight and planned for the worst.

    Don't get me wrong I have compassion and show it when it is needed or warrented, but the folks that get bent out of shape just because you are taking care of your own can BITE MY SHORTS!
  18. Nadja

    Nadja Well-Known Member

    Old Vet, I am an old vet myself and agree with you. But, not everyone would be set up with the type of mindset's we have. Plus, although he says he is mostly rural, having neighbors tells me he is not as rural as I am for instance. Everyone has different circumstances in life and they all need to be delt with differently.
  19. How remote is remote enough?

    Like Nadja, I live in a very remote part of Az, and all my power comes from solar and wind. I see my neighbor drive by about once-a-week (yes, just one neighbour in about a 3 mile radius, maybe 5 in 10 miles, etc). Town is about a 20 minute drive down a dirt road, with the city being about another 15 past that.

    that said, if my better-looking-half has the lights on before I drive in, I can spot our ranch about 1/2 a mile away. Being the only light in a remote area can be just as bad as being the only light in the 'burbs.

    Food for thought.