? for wind and solar power users

Discussion in 'Homesteading Questions' started by gobug, Nov 13, 2004.

  1. gobug

    gobug Well-Known Member Supporter

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    How long do your batteries last.

    My nephew just attended a conference and was told to figure on only two years!

    What kind do you use?
     
  2. fordy

    fordy Well-Known Member

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    ...................gobug , Everything I've read says that , even the 6 volt , deepcycle , golfcart batt's are supposed to last around 10 years or so . Several folks on the Rv forums are putting 2-6 volts in series to get 12 vdc and they typically will have (2) sets of these for a 12vdc source of power for their 12vdc to 120vac power source to their inverter . There are lots of different deep cycle battery choices available for remote locations and the more expensive the better the efficiency and the service life I would think , fordy :)
     

  3. 12vman

    12vman Offgridkindaguy

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    I used 6 volt golf cart batteries made by Interstate. I used them for 5 yrs. but I could tell in the last year they were getting tired. I would say 4 yrs. with no problems. I just replaced my whole battery this year with some batteries I bought at Sam's Club for $47 each with no core charge. These batteries are built by Exide which is a good name in storage batteries. They are the golf cart style also. I'll tell you in a few years if they are any good...
     
  4. gobug

    gobug Well-Known Member Supporter

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    My BIL, an electrician, also suggested golf cart batteries from Walmart, but he thought they would last like 25 years. I guess the constant use a solar system puts on them wears them down faster. At 47 each, that seems to be a major expense. Thats a lot more than panels over an extended period of time.

    Does it make sense to dedicate some panels to things like pumping water where you can fill a cistern during daylight and not use batteries at all? Unfortunately, I cannot think of many daytime only uses.
     
  5. blanknoone

    blanknoone Member

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    This is a little off the topic, but I had a conversation with a marine electrician about expected battery life on boats (the ones for power, not the engines). He said you should expect between 8 and 12 years for good batteries. However, he said the best investment you can make is in a good 'charge management' system. He said normal use puts very little wear and tear on batteries, but if you either run them all the way down or keep putting a charge to them when they are fully charged, you will pay with your battery life. He strongly suggested that the best way to save money in the long run was in the charge management system, that a good one will keep your batteries in good shape far longer than a poor one. I asked what made a 'good one' and he said a cheaper one will run a continuous trickle charge, but the better ones will turn completely off when the batteries are fully charged. He said there are generally other features that can make a difference, but that was the easiest way to tell.

    Things may be different fot boats, especially as they often connect to shore power for long periods or run a big generator to charge quickly. I don't have experience with green power, but I wouldn't be too surprised if the systems were on the side of trying to push as much as possible into the batteries while the sun/wind is available...possibly at the expense of battery life.

    I personally trust and believe him. But he could have been trying to sell my father (with the boat) something.
     
  6. aaatraker

    aaatraker Well-Known Member

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    Backwoodshome magazine is running a series on solar, covers all aspects, give it a look maybe it will help. Homepower magazine is all
    about alterative power, try them both on the internet. The link below should answer all your questions.


    http://www.marine-electronics.net/techarticle/battery_faq/b_faq.htm
     
  7. BobBoyce

    BobBoyce Well-Known Member

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    gobug, there is no simple answer for that. It all depends on how you treat your battery bank. Ignore the needs and limits of the batteries, and they won't even last 2 years.

    I use a combination of different types of batteries for different purposes. On the battery bank for my home, I use regular deep cycle wet cells (like golf cart batteries). On my electric vehicle however, I use sealed valve regulated AGM batteries. These SVR AGM batteries cost nearly $200 each, but they have the ability to deliver higher peak demand current than the normal golf cart type battery.

    noone, the marine electrician was correct. Good charge controllers are very important for extending battery life. Proper battery maintenance, and abiding by the limits of discharge, just as important.

    As lead acid batteries discharge, sulfur from the electrolyte, combines with lead on the plates, to form lead sulphates. Sulphation covers plate area, preventing electrical contact of the plate with the electrolyte. The deeper the state of discharge, the more rapid the sulphation formation. Leaving a battery in a discharged state allows sulphation formation at the greatest rate. Recharging reverses sulphation to a degree, but once hard sulphate crystals have formed, regular charging has little effect. More than 90% of all lead acid battery failures are due to sulphation buildup.

    There are pulse chargers and desulphators available that can reverse sulphation, dissolve the crystals, and return the electrolyte back to normal. With the use of a good charge controller, a desulphation system, and proper battery maintenance, the greatest amount of battery life can be acheived, like 10-15 years or more.

    I built a homebrew desulphator that I run on batteries for a few days at a time as preventative maintenance. I have used it to fully recover batteries that were thrown away because they would not take a charge.

    Bob
     
  8. mightybooboo

    mightybooboo Well-Known Member

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    For wet acid batteries the shallower the discharge the more recharge cycles it will take.A good 4 step charger with an equalizing charge option will help keep the electrolyte mixed aiding in charging all the batteries equally and help eliminate sulfation.Bil has about 10 years on his Trojan L-16 battery bank(8 batts),does only 20% discharges.He doesnt equalize at all,doesnt like the strain aspect of equalization(up to 16.5 volts).My standby batteries,also L-16(8 batteries also)is 5 years old,rarely used,are in great shape.I charge up monthly and equalize every 4 months or so.So the load placed on the size of bank,and rate and depth and length of discharge,and mode and level of charge are all factors that determine battery life.If you only get 2 years use,you arent treating them right. :no:
    BooBoo
     
  9. 12vman

    12vman Offgridkindaguy

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    I'll admit I was rough on my battery. I let it go way too low quite a few times. I undersized my panel array for the conditions of winter in Ohio. I had to fire-up the back up genset too many times..

    I just rebuilt my system this fall. I doubled the solar array but kept the same amount of battery. I only use (4) golf cart batteries in series-parallel for a 12 volt system. My demands aren't too big. I've noticed that the charge level now never goes below 12.4 volts after a very cloudy day. The charge controller will float out after 3-4 hours of full sunlight so I believe I'll get longer service from the battery. During full sunlight, the array produces around 30 amps. I've seen 6-8 amps on a very cloudy day. I just conserve during cloudy periods..

    I've had no need to use the genset since the rebuild. I watch the battery level daily. Usually in the morning before the next charge cycle. So far I'm impressed..

    This is my first whole house system. I have found that the design figures needed to be changed some for Ohio. We have a lot of short, cloudy days in the winter.. :no:
     
  10. tkrabec

    tkrabec Well-Known Member

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    I've been doing research for a solar system(mostly because my wife won't let me spend the money) but everything I have read about batteries is summed up pretty simply.
    1. Do the proper maintainence water them, check for corrosion, float them as necessary

    2. the more you discharget them the faster they die. ie If you discharge a battery so it has 10% life left it will last for say 100charges, to 30% left 250 charges 50% 1000, 80% 15,000 charges.

    3. Keep the whole battery at the same temperature, don't set it on a cold concrete slab, the bottom will stay cooler than the top (or warmer in the winter) and that will destroy the battery life.

    4. Don't charge the battery too fast. "Dead" batteries can take lots of charge initially, but if they stay at that rate they heat up too much and boil off the electrolite.

    5. keep your batteries matches as best as possible buy all the batteries at the same time, from the same batch and lot(if possibly)

    -- Tim
     
  11. mightybooboo

    mightybooboo Well-Known Member

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    Very nice 12vman.Looks like 600 watts of panels,and a full charge in 3-4 hours,may as well toss in a couple more batteries,but you seem well balanced as it is now,not too shabby,Im impressed too.What controller are you using,I would guess a Trace?Would like to hear more details on your system.What panels,etc.BTW,just saw 10 (multi-crystalline) 95 watt panels go for 2650.00 on ebay,wouldnt that be nice to pick up,WOOHOO!
    I have (2) SP-275 (monocrystalline) 75 watters on my Motorhome with an RV Power Products 20 amp controller.Good stuff.Im adding to the MH array so we can use it while building the new home.Will then plug its array into the L-16s onsite.The house will use unisolar(amorphous) panels,while 50% larger in size for given output,you can put a bullet thru em and they still function,plus the power output actually increases with heat,unlike most panels.Thats a great property only amorphous panels really supply.Im using monocrystallines for size per output and fair resistence to heat loss of power output because size is the issue on MH roof.
    The new Sanyo HIT panels are crystalline and amorphous in one.They may be a real winner with the best of both,but not Unisolars ability to shrug off damage.Lots of good stuff happening in panels these days,lots of options.
    Sure do love this stuff.
    BooBoo
     
  12. 12vman

    12vman Offgridkindaguy

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    What I ended up with is (8) Unisolar 64's connected in parallel for 12 volt charging. You can see them on the link at the bottom of my post. I use a C-40 Trace charge controller. I have 2ga. copper wire from the panel array to my battery area. Of course, the 2ga. wire is too big to connect to the controller so I spliced some 6ga. for a short distance to connect with. The battery is within 4ft. of the controller so I used 6ga. again to the battery. Everything seems to work well..

    As for my home, I operate almost everything on 12 v.d.c. The only time I use an inverter is when I use this laptop computer with printer of if I want to use a blender or the vacume cleaner. Beyond that, my lighting,tv, stereo, water pumps, small battery charger (aaa,aa,c,d,9volt) operates on 12 volt direct. All of my power tools are battery operated but I use an inverter for the chargers of them. I have several small inverters (400 watt) scattered around the house. I use them the most. I also have one big one (1200 watt) connected to the battery that is switched on-off via switches and a relay. I can turn the big boy on at 3 different locations in the house. (bedroom,bathroom,kitchen) I have 12 volt-120vac outlets togather throughout. The a.c. outlets have a neon lamp in them so I know the big boy is on. The a.c. outlets are standard and the 12 volt outlets are cigar lighter outlets with a 15amp breaker built in. It's all my design and works very well..
     
  13. BobBoyce

    BobBoyce Well-Known Member

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    My home battery bank is comprised of 16 golf cart type batteries in series parallel for 24 VDC. The main inverters (primary and backup) are 24 VDC. I'm not sure about the brand of charge controller. I bought it used a number of years ago, and it's not mounted in any kind of box. It's just a large PC board mounted to a metal plate with a couple of huge mercury relays. Each relay has a 50 amp capacity.

    My array is over 1 KW of mixed and matched panels. I have 8 that are 75 watt, and 5 that are 150 watt. All but one 150 watt panel are wired in series parallel. The primary load cables for the array to the equiptment closet are 000 guage copper to reduce losses. I have a 4 guage copper cable that brings in +12 VDC from that single 150 watt panel to a small 12 VDC battery bank in my ham shack.

    I still have 5 more 150 watt panels in storage that I have not set up yet. I was concerned about too much wind loading on the support pipe for the array so I did not add them to it at the time I assembled the array. This is one of the pictures taken of the array being assembled.

    [​IMG]

    Bob
     
  14. mightybooboo

    mightybooboo Well-Known Member

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    Very nice,I didnt recognize the unisolars,thought they were Kyocera multi-crystalline.
    Very nice indeed.
    BooBoo
     
  15. fordy

    fordy Well-Known Member

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    ...............This thread is really getting interesting . I'm in the initial planning stages of trying to figureout what size of system (wattage) I'm going to need and then decide on the composition of the individual components that will make up a complete off-grid system . Between a Wind charger and a grouping of solar panels the wind charger would seem to be the Most Vulnerable . Also , the higher end panels are advertised to have a 25 year life span . The more I read and study the various components I'm coming to the conclusion that a group of long life batt's , solar panels and a diesel genset all tied together with a Xanatrex inverter\charger is the best way to go . I'm figuring it's going to run around 10k or so for a really adequate and long lived system . But , I maybe singing a different Tune when it comes down to actually spending that much money , we'll just have to see . Atleast now , I know , that , I can live a comfortable lifestyle without a direct hookup to the Power company . You'll keep posting all this great pic's and information cause it is really helping me to understand how these systems all come together , thanks , fordy... :)
     
  16. 12vman

    12vman Offgridkindaguy

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    WOW,Bob.. That's what I'm talkin' about!! I was curious on who had what out here. If I had all that power I could build another house.. :haha:

    How far from your home is your array? That's some huge wire! I'm only roughly 20' away. The poles the panels are mounted on are right aginst the house..

    Great set-up.. :worship:
     
  17. mightybooboo

    mightybooboo Well-Known Member

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    If it didnt have a 20-25 year warranty I wouldnt even consider the panel,the quality is obviously lacking somewhere.Its been claimed that folks have had mono-crystalline panels for over 25 years with no notable loss of efficiency.The thin film amorphous like the unisolars have 20 years I believe,but the verdict isnt in on them yet that Ive seen re:durability beyond that point.I hear they are very popular in the hotter areas in Australia.Really starting to sound like mono-crystalline(the ones with the individual cells like Bobs)really shouldnt wear out at all ,so the headman at
    www.homepower.com
    magazine is saying,and he sure is THE Guru in this.He is thinking they should last a lifetime.Amazing isnt it?

    Bob,is your controller an MPPT style,if not you are losing 10-20% of your power,on a bright day my little controller ups my amps in by 15%.Though there are folks who will argue this.

    BooBoo
     
  18. mightybooboo

    mightybooboo Well-Known Member

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    Fordy,when talking solar power,the gurus discuss amps,not watts,why I dont know,but they do.
    BTW,to keep on topic,Im doing an equalizing charge right now,thanks for the reminder. :D
    BooBoo
     
  19. BobBoyce

    BobBoyce Well-Known Member

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    12vman, the pole that the array is on is about 20 feet from the home near the center, but the equiptment closet is at the west end. It's about 80 feet from the equiptment closet to the pole, through an underground 4" PVC that goes up the side of the pole.

    mightybooboo, my charge controller is just the cutoff type that opens circuit when the battery bank reaches full charge. I really don't need any more current. I don't want to cook my batteries, and I don't have any more room in the equiptment closet to add more unless I were to build a new battery rack.

    Bob
     
  20. BobBoyce

    BobBoyce Well-Known Member

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    mightyboo, almost forgot. I gave thin film amorphous a try, never again!

    I wasted a lot of money buying panels that tapered off production rather rapidly compared to the mono or poly-crystalline.

    I was just lucky to find a buyer and disposed of most of them while they were still new enough to sell.

    They suffered from reliability problems with the cell connections as well. In hot climates they don't have as much trouble. Temperature variations cause the glass substrate to expand and contract at a different rate than the frame, which stresses the contacts points, causing the thin film to seperate from the glass.

    The few thin film amorphous panels that I had kept, all failed within 5 years. The warranty was worthless, factory went out of business years ago. I still see their panels on the surplus market for way too much money.

    I used to be a dealer for a name brand of solar panel, so I managed to buy some trade-in panels at decent prices, and bought some new at wholesale as well.

    Bob