cabin off grid questions

idiggplantsidiggplants Registered Users Posts: 27 ✭✭
hello everyone. so my dad and i are doing solar at our cabin in northeastern pa.

currently we have a 12v deep cycle(100ah, i think) which runs minimal lighting, a mini windup fm radio, and a 12v waterpump. and the occasional inverter usage to charge small batteries.

the battery lasts 2 trips generally before we take it home and charge it with a battery tender. so 4 days.

we are trying to decide on panel sizes, and charge controllers. im thinking we need 150-200w of panels, he is thinking 80-120w. considerable price difference.

and then, onto the charge controller... the mppt's look like a better option.. more efficient. but more expensive. ~$150 more, but 30% more efficient. so at 150w thats 45watts more we would be getting. 45w of panels would be more than 150.

problem is, the mppt only come in 15a or 60a. nothing in between. if we find out that 200w isnt enough, we have no more room to expand. and the 60a is way out of our price range.

also, i see that the mppt controllers can handle higher output panels? how much would we be saving on panels then? there are so many brands, it is hard to keep track of what's what.

for example.. bp's bp3140j 140w panel is $600
compared to Kyocera Solar KD-135GX 135 Watt for $325

and everything in between.

we want to do it right, but we dont want to spend more than we need to. while our current setup isnt too convenient, its pretty cheap.

also, do small inverters(modified sine wave) use juice when nothing is plugged in? we have one that we want to tie into a wall outlet for the clean look, but we are afraid we are going to forget to turn it off all the time.

finally, where are some good places to buy solar equipment online? we have found a few stores, but who knows if they are reputable, or their prices are good.

sorry for the hodgepodge of questions. we just have so much to get squared away before making a big(to us) purchase.

thanks!
wes

Comments

  • mike95490mike95490 Solar Expert Posts: 9,361 ✭✭✭✭✭
    Re: cabin off grid questions

    Rogue Solar http://www.roguepowertech.com/products/mpt3024.htm
    makes a 30A controller.

    I'd "guess" that a 200W panel will be enough to recharge and power small loads. No fridge !
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

  • BB.BB. Super Moderators, Administrators Posts: 32,007 admin
    Re: cabin off grid questions
    currently we have a 12v deep cycle(100ah, i think) which runs minimal lighting, a mini windup fm radio, and a 12v waterpump. and the occasional inverter usage to charge small batteries.

    the battery lasts 2 trips generally before we take it home and charge it with a battery tender. so 4 days.
    Sounds like a reasonable/small system. However, really need to know your daily Amps*Hours (or Watt*Hours) load and the size of your existing/proposed battery bank.
    we are trying to decide on panel sizes, and charge controllers. im thinking we need 150-200w of panels, he is thinking 80-120w. considerable price difference.
    Basically, conservation (low power devices); then measure/estimate daily power needs (Amp*Hour/Watt*Hour/etc.); then define battery size/rating; next size the solar array; and finally choose MPPT/PWM type controller.
    and then, onto the charge controller... the mppt's look like a better option.. more efficient. but more expensive. ~$150 more, but 30% more efficient. so at 150w thats 45watts more we would be getting. 45w of panels would be more than 150.
    PWM may be a better choice for you... Especially if the solar array is close to the battery bank/charge controller...

    If you have a larger system and/or longer distance between array and charge controller--A MPPT controller may be a better fit.
    problem is, the mppt only come in 15a or 60a. nothing in between. if we find out that 200w isnt enough, we have no more room to expand. and the 60a is way out of our price range.
    As Mike says, there is the Rogue 30 amp 12/24 volt MPPT controller. And MorningStar makes a TS 45 amp 12/24/48 volt MPPT controller. Any of those would be fine choices.
    also, i see that the mppt controllers can handle higher output panels? how much would we be saving on panels then? there are so many brands, it is hard to keep track of what's what.
    Yea--a big problem... Panels (and it seems, panel manufacturers) are lasting about about 2 years in production then the newer/bigger/cheaper panels come out.

    Generally, the >100 watt panels have a better $$$/Watt pricing--however, there are fewer and fewer that run at Vmp~17.5 volts (for 12 volt battery banks) but run at oddball Vmp voltage (oddball for PWM and 12/24/48 volt battery banks).

    The larger market for solar panels is Grid Tied Solar--which run at ~200-600 VDC. So higher voltage panels require less copper and work well with GT Inverter systems.
    for example.. bp's bp3140j 140w panel is $600
    compared to Kyocera Solar KD-135GX 135 Watt for $325
    Kyocera makes nice panels and stand behind them.

    Also, check your cost insured and delivered to your front door... Panels >~135 watts usually need to ship truck. And shipping costs for single/fractional pallets of solar panels can be pretty expensive.
    we want to do it right, but we dont want to spend more than we need to. while our current setup isnt too convenient, its pretty cheap.
    In general, conservation and measuring your loads--then doing a couple paper designs/costings will give you a system that should meet your needs without wasting money and tripping over common mistakes (such as a large battery bank and small solar array).
    also, do small inverters(modified sine wave) use juice when nothing is plugged in? we have one that we want to tie into a wall outlet for the clean look, but we are afraid we are going to forget to turn it off all the time.
    Yes--they do... For smaller solar systems, the idling current of the inverter running 24x7 can be 1/2 the total power collected by the solar panels (or more).

    For a small 12 volt system--I would highly suggest you look at the MorningStar 300 Watt TSW 12 VDC inverter... It has both a "search mode" (only comes out of standby when >6 watts of AC load is present) and a "remote on/off" input (use a simple 12 volt signal switch/wiring to turn inverter on/off). A very rugged and reliable True Sine Wave inverter (get a large/cheap MSW inverter to run your hand tools and water pump if you need more power).

    MSW does have problems running some loads.

    All About Inverters
    Choosing an inverter for water pumping
    finally, where are some good places to buy solar equipment online? we have found a few stores, but who knows if they are reputable, or their prices are good.
    Our host Northern Arizona Wind & Sun would be a good start (moderators and posters here are volunteers--we have no relationship with NAWS other than what you see here). The two Admins are from NAWS (Windsun and Rick).

    Hope we can help.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • simagicsimagic Solar Expert Posts: 100 ✭✭✭✭
    Re: cabin off grid questions

    I "personally" happen to like these panels.. They perform well for me and you might want to check it out.

    http://www.grapesolar.com/index.php/products/modulesandkits/gs-s-100-ts/
  • icarusicarus Solar Expert Posts: 5,433 ✭✭✭✭
    Re: cabin off grid questions

    Not much time to write the morning, but remember the cardinal rule of off grid solar when you make hardware choices: Loads always grow with time! When have power available for one. We,, y u will eventually succumb and use it for other uses.

    The second cardinal rule is,, people over estimate their solar potential, while at the same time they underestimate thier loads,

    Welcome to the forum,, good luck and keep in touch,

    Tony
  • Fe-WoodFe-Wood Solar Expert Posts: 96 ✭✭
    Re: cabin off grid questions

    That is how I started with solar- small system for my cabin. I started with a single Kyocera 135 (I think) this was about 10 years ago. 2 big box store deep cycle batteries and the smaller Morning Star Controller. I have a lot of sun in the summer so I ended up cooking my first set of batteries in about 3 years. My system runs 12VDC lights and a car radio. Fridge is Propane. I had a water pump to increase pressure that I ran off a lighted switch.

    As Icarus said, you will grow beyond the system fairly fast as you utilize the convenience of having power.

    My system has grown to 6 batteries and a wind turbine for the winter months. Seems pretty balanced as the batteries last longer. It also gets used everyday. It runs a cheepo 1000w inverter that is switched.

    I found this is a nice size system to learn with as the investment isn't that big and the learning possibility is huge.
  • westbranchwestbranch Solar Expert Posts: 5,183 ✭✭✭✭
    Re: cabin off grid questions

    Battery sulphation is the bugbear to watch out for, if you discharge too heavily. you may already have is going on in that battery.

    there is a rule of thumb: plan for 3 days use without recharging, to a 50% discharge ie 50Ah of use.
    NOTE that 50% DoD takes the battery to near death, too far beyond this point and you will not be able to recharge it...

    get the larger panel (s) as you will use more as Icarus says, voice of experience...

    HTH
     
    KID #51B  4s 140W to 24V 900Ah C&D AGM
    CL#29032 FW 2126/ 2073/ 2133 175A E-Panel WBjr, 3 x 4s 140W to 24V 900Ah C&D AGM 
    Cotek ST1500W 24V Inverter,OmniCharge 3024,
    2 x Cisco WRT54GL i/c DD-WRT Rtr & Bridge,
    Eu3/2/1000i Gens, 1680W & E-Panel/WBjr to come, CL #647 asleep
    West Chilcotin, BC, Canada
  • techntrektechntrek Solar Expert Posts: 1,372 ✭✭✭
    Re: cabin off grid questions

    Actually 50% DOD is normal, up to 70% DOD is OK once in a while, and anything beyond that is bad.
    4.5 kw APC UPS powered by a Prius, 12 kw Generac, Honda EU3000is
  • idiggplantsidiggplants Registered Users Posts: 27 ✭✭
    Re: cabin off grid questions

    wow! so much info! thanks everyone. ill try and address everything, in a somewhat logical way, and hopefully eliminate some questions, and narrow our options.

    first, a little more info on what we use. all the lights are 12v rv lights. some LED, some incandescent. our fridge and other appliances are all propane. other than lights, radio, and 12V water-pump, there is very little electric usage.
    BB. wrote: »
    Sounds like a reasonable/small system. However, really need to know your daily Amps*Hours (or Watt*Hours) load and the size of your existing/proposed battery bank.

    yeah. that seems to be our most difficult hurdle right now. currently we have 2 batteries. not sure what the size is, as they are deka factory seconds. and they are also 3-5 years old, so they certainly no longer have the full capacity. so we cant estimate based on how long they last.

    we can get a pretty good idea on what we use in lighting based on how much we use each light and what the draw is. but the pump is the difficult part. we looked on the box, got an amperage draw, and estimated our daily number of flushes, and chili days. :blush: we used to use an outhouse, and all of our water was brought in in jugs. so adding that amount and the amount we use in the toilet, we know how long the pump takes to pump one gallon. got our ah/day usage from that.
    and then we assumed that the radio and inverter were each another lightbulb running sunrise to sundown(though they arent), just to get an estimate.
    what we came up with is a VERY estimated 38ah used in a day.
    BB. wrote: »
    PWM may be a better choice for you... Especially if the solar array is close to the battery bank/charge controller...

    If you have a larger system and/or longer distance between array and charge controller--A MPPT controller may be a better fit.

    the distance between the panels and the batteries/charge controller will be 16'. 20' if we put them in our second location. more on that later. is 16-20' "long?"
    BB. wrote: »
    Yea--a big problem... Panels (and it seems, panel manufacturers) are lasting about about 2 years in production then the newer/bigger/cheaper panels come out.
    yeah. it seems like its similar to computers tho. even if you buy the best, in 2 years your going to wish you had the new one.
    BB. wrote: »
    Generally, the >100 watt panels have a better $$$/Watt pricing--however, there are fewer and fewer that run at Vmp~17.5 volts (for 12 volt battery banks) but run at oddball Vmp voltage (oddball for PWM and 12/24/48 volt battery banks).

    The larger market for solar panels is Grid Tied Solar--which run at ~200-600 VDC. So higher voltage panels require less copper and work well with GT Inverter systems.
    yeah. it seems like with what we are doing, that sticking with the 12v panels, and the pwm is what we should focus on now, unless the mppt and higher voltage is recommended for our 20' distance.
    BB. wrote: »
    Kyocera makes nice panels and stand behind them.

    Also, check your cost insured and delivered to your front door... Panels >~135 watts usually need to ship truck. And shipping costs for single/fractional pallets of solar panels can be pretty expensive.

    well, i was hesitant to say where we were shopping before in fear of being suspected as a spammer, but it seems relevant. we were looking at mr. solar because they have pre-made packages for off grid rv stuff, and they are reasonably close to us, so shipping or picking up would be reasonable. here is what ive discovered. the bp 135 watt from mrsolar is 500 bucks. plus unknown but probably small amount for shipping.

    the kyocera from http://www.solar-electric.com that you guys recommended is 325 plus 80 shipped. 100 bucks less at least. seems like the route to go. are the bp panels better in some way? mounting, efficiency, reliability, etc?
    I "personally" happen to like these panels.. They perform well for me and you might want to check it out.

    http://www.grapesolar.com/index.php/...s/gs-s-100-ts/
    wow. 300 bucks for a 100w. thats a good deal too. same question as above.. mounting, efficiency, reliability, etc all the same as the bp, and kyocera?
    BB. wrote: »
    Yes--they do... For smaller solar systems, the idling current of the inverter running 24x7 can be 1/2 the total power collected by the solar panels (or more).
    say no more. it was just a passing interest. using it only when needed isnt that much of a hassle.
    Not much time to write the morning, but remember the cardinal rule of off grid solar when you make hardware choices: Loads always grow with time! When have power available for one. We,, y u will eventually succumb and use it for other uses.
    well, a few of you are saying this, but with our setup, we dont really have any need to expand our loads. we have had essentially unlimited supply of power there with our current setup. 2 batteries are always there for a weekend, and we dont really go out of our way to conserve our usage, and we never use more than one. other than a few more showers, and lightening up on our yellow let it mellow rules, i dont think we are gonna get to crazy with the amount of power we use/need. ill be the first to admit you told me so in 5 years though. :D
    That is how I started with solar- small system for my cabin. I started with a single Kyocera 135 (I think) this was about 10 years ago. 2 big box store deep cycle batteries and the smaller Morning Star Controller. I have a lot of sun in the summer so I ended up cooking my first set of batteries in about 3 years. My system runs 12VDC lights and a car radio. Fridge is Propane. I had a water pump to increase pressure that I ran off a lighted switch.
    hmm. too much sun? i thought the charge controller would regulate the charging to avoid that. we sometimes dont use the cabin/batteries for a month or so. is that going to destroy them?

    sounds like our setup is pretty close to that. except our water pump is responsible for all the pressure.(5' of head)
    BB. wrote: »
    measure/estimate daily power needs (Amp*Hour/Watt*Hour/etc.); then define battery size/rating; next size the solar array; and finally choose MPPT/PWM type controller.
    westbranch wrote: »
    there is a rule of thumb: plan for 3 days use without recharging, to a 50% discharge ie 50Ah of use.
    NOTE that 50% DoD takes the battery to near death, too far beyond this point and you will not be able to recharge it...

    ok. so for sizing the battery bank.. assuming 38 ah per day, we need 38ahx3days=114ah. since we only want to drain 1/2, we need 230ah batteries? will 2x100ah do it since it is a "rule of thumb?"

    we were thinking of using our 2 deep cycle batteries to start with. and then when they eventually go, we would replace them with whatever would be ideal for our usage.
    BB. wrote: »
    In general, conservation and measuring your loads--then doing a couple paper designs/costings will give you a system that should meet your needs without wasting money and tripping over common mistakes (such as a large battery bank and small solar array).
    so, here is what my math is getting me right now..
    ASSUMING 38ah/day..
    read somewhere that a "100 watt panel produces an average of about 6 amps per peak sun hour, or about 30 amp-hours per day."
    so we need 38/30x100 or 127 watts per day.

    im sure im missing something here. could someone direct me to a good rule of thumb on energy used per day to watts needed?

    also.. to add to my confusion.. or hopefully lessen it.. with multiple batteries. in order to keep one bad one from killing the other(s) we would need an isolator. does that only isolate the charge side? or the usage side as well? because if not, we are going to have to split up our lights, pumps etc onto different batteries.

    finally(for now):
    we see 10 degree days pretty often up there. when we are at the cabin, the heat will be on and all will be good. but when we are not, how can we keep the batteries from getting so cold they go bad(sulfate?). we were thinking that 1, we could put them in the crawlspace/basement, where the ground temp keeps it closer to 50 degrees.. but its very moist down there. or we could have some sort of warming device that used the solar energy to warm the battery compartment(small incandescent light, etc) or maybe its not a concern since it is always hooked up to a charging source?

    phew. thanks!!!
  • BB.BB. Super Moderators, Administrators Posts: 32,007 admin
    Re: cabin off grid questions

    First, sulfating batteries... Batteries are "spec'ed" at ~77F or 25C... And, very roughly, there is an engineering rule of thumb. Basically 10C rule of 2...

    For every 10C (18F) increase in temperature, battery storage life will be cut by 1/2 and sulfation rate will double.

    On the other had, if you cut the temperature by 20C, then the storage life will:
    • 1/2 * 1/2 = 1/4 the suflation rate and 4x the storage life.
    Also, self discharge will be reduced too (should be a factor of 1/4).

    Of course, you have cycle life too... But even if you deep cycle the battery and reduce the life from ~1,000 to 2,000 cycles down to 500 cycle life, if it is a 9 month weekend cabin, that is:
    • 9 months * 4 weekends per month = 36 "cycles"
    • 500 cycle life / 36 cycles per year = 13.9 years
    So--realistically, a pair of "average" 6 volt 220 AH golf cart batteries (connected in series for 12 volts) will last you around 3-5 years with decent care.

    So, the only thing that cold temperature negatively affects is the apparent storage capacity of your battery bank. Near freezing, your bank will operate at about 85% of rated capacity... But if you heat up the cabin and the bank, everything will be fine for winter use (if you are there).

    Deep Cycle Battery FAQ
    www.batteryfaq.org

    Sizing your battery bank... Roughly 2-3 days of "no sun" and 50% maximum discharge. You found that ~230 AH battery bank at 12 volts will meet your needs--And that is about what a good quality "golf cart" battery is rated at.

    Put two 6 volt batteries in series, and you will have 12 volts at ~220 AH. Just about perfect for your application (note: some of us here recommend that you series connect battery banks--such as here, two large 6 volt batteries in series--Vs getting two 110 AH 12 volt batteries in parallel. Paralleling battery banks does have current sharing issues, more cells to check water levels, and more things that can go wrong and take down your bank; such as shorted/open cells/bad, bad cable connections, etc.).

    Now, a 12 volt 220 AH battery bank would want ~5% to 13% rate of charge... 10% is about the sweet spot. And assume solar panels+charge controllers are 77% efficient:
    • 220 AH * 14.5 volts charging * 0.10 rate of charge * 1/0.77 solar PV derating = 414 watts
    You could go down to 5% rate of charge (207 watts of panels), but would like to see you closer to 10%. Over 13% rate of charge gets pretty expensive for little extra energy return unless you have special needs (like lots of power needed while sun is up--such as water pumping, shop tools, etc.).

    And, how much power in a day will this harvest for you... Assuming you are in Allentown PA. Using PV Watts with fixed array, your hours of noon time equivalent sun per day would be:
    1      3.22     
    2      3.85     
    3      4.71     
    4      5.24     
    5      5.24     
    6      5.25     
    7      5.57     
    8      5.23     
    9      4.85     
    10      4.37     
    11      2.93     
    12      2.81     
    Year      4.44
    
    It looks like for 9 months of the year, you get 3.85 hours of sun (average) per day (February)... Assuming 77% PV eff; 80% flooded cell eff; and 85% inverter eff:
    • 0.77*0.80*0.85 = 0.52 = 52% end to end efficiency (yes, 1/2 your rated panel power)
    And 3.85 hours of sun will give you (February):
    • 3.85 hours of sun minimum * 414 Watts of solar panel * 0.52 eff = 828 Watt*Hours of power
    Or, if you are using mostly 12 volts for now... backing out the inverter losses:
    • 828 WH per day * 1/0.85 no inverter losses * 1/12 volts = 81 AH @ 12 volts
    So--This looks to supply more than enough power for you.

    It is your choice, you could go to 2 days of no sun and 50% maximum discharge (4x daily power usage)--that will reduce your solar array size.

    And you can go below 10% rate of charge and be closer to 5%... You probably will get OK results (especially if you are only there on weekends)... Note--unless you enjoy monitoring your system closely--you really only want to run the system around 50% to 75% of your system's ability to generate power. These are averages and sometimes you will get more and sometimes less (weather/clouds/etc.). If you have a genset and are OK using it--you can recharge the bank every couple days (morning recommended) to keep the bank "charged enough".

    If you will not have a genset or don't want to use one except in an emergency--then plan a little bit more headroom for solar power.

    So look at the hours of sun, what months you will be there, and if you will be packing a generator or not... And tune the proposed system to your needs.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • idiggplantsidiggplants Registered Users Posts: 27 ✭✭
    Re: cabin off grid questions

    holy crap. so 415 watts of panels, AND we need to get new batteries? no way my dad's going to be on board for that.

    with $1600 we could haul the batteries home and charge them for 15 years. going to be tough to convince him that its worth it. really bummed. was excited to get this plan into motion.

    our setup just isnt ideal for solar. though the batteries may last a while, the return on our investment will be even that much longer. if we are charging the battery back up within 1 day of leaving, we have expensive panels sitting there doing squat for a week to a month.

    so it really becomes a convenience decision. $700 is a semi justifiable expense for convenience. $1600, and essentially getting rid of our batteries, is not.

    bummer.

    thanks anyways though! sorry for taking your time. i truly appreciate the education.
  • idiggplantsidiggplants Registered Users Posts: 27 ✭✭
    Re: cabin off grid questions
    BB. wrote: »
    It is your choice, you could go to 2 days of no sun and 50% maximum discharge (4x daily power usage)--that will reduce your solar array size.

    And you can go below 10% rate of charge and be closer to 5%... You probably will get OK results (especially if you are only there on weekends)... Note--unless you enjoy monitoring your system closely--you really only want to run the system around 50% to 75% of your system's ability to generate power. These are averages and sometimes you will get more and sometimes less (weather/clouds/etc.). If you have a genset and are OK using it--you can recharge the bank every couple days (morning recommended) to keep the bank "charged enough".

    If you will not have a genset or don't want to use one except in an emergency--then plan a little bit more headroom for solar power.

    So look at the hours of sun, what months you will be there, and if you will be packing a generator or not... And tune the proposed system to your needs.

    -Bill

    just saw this. dont know how i missed it. probably cause i was disappointed.

    ok. so since we are just getting into this, i think we will probably adjust down a little bit. we do have a generator up there always for running our big power tools. and we also have the option of having our old batteries up there as backup in the beginning in case we start getting too low on the batteries hooked up to PV.

    in that case ill just have to convince my dad to get a monitor for the batteries.

    when you say 10% rate of charge, what does that mean? 10% of what?

    thanks again. hopefully this can happen. honestly, all i think i can convince him to do is install a 135w panel now with a charge controller rated to handle a second 135w panel. and keep the better battery that we have. which i know is going to kill the battery real quickly.
  • BB.BB. Super Moderators, Administrators Posts: 32,007 admin
    Re: cabin off grid questions

    10% of the battery bank's rated AH capacity (20 Hour Rating).

    Remember, we are trying to give you a rough ideal system for 9 months of the year. If you are there 6 months of summer/summer weekends, a smaller panel array with 5% rated charge may be fine.

    But yes, a solar power system makes more sense when used most of the year. When used only weekends for 3 to 6 months of the year, an efficient generator or hauling the batteries may make more sense.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • idiggplantsidiggplants Registered Users Posts: 27 ✭✭
    Re: cabin off grid questions

    We are generally up 2 times a month(may-aug), once a month in spring/fall, and maybe 3 times total (nov-march)
  • BB.BB. Super Moderators, Administrators Posts: 32,007 admin
    Re: cabin off grid questions

    Yea... That is difficult to spend that much money for so little power usage with solar.

    Problem is, the longer the batteries sit discharged (small solar array, or no solar array), the faster they sulfate.

    It is not a good idea to plan on using the system for a weekend, and then allow a small array to recharge over the next week or two back to full charge.

    Solar panels are getting much cheaper these days--$1-$2 per Watt of panel vs the $5-$10 a watt less than 10 years ago is amazing...

    However, leaving a bunch of expensive equipment in a remote, mostly unoccupied cabin, can be a big issue in itself.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • Fe-WoodFe-Wood Solar Expert Posts: 96 ✭✭
    Re: cabin off grid questions

    Hmm, This has been a helpful thread-

    I had always assumed I had trashed my batteries because they lasted only about 5 yrs. Sounds like I was wrong.

    In the summer my location sees about 7 hrs of good solid sun. My controller would sit at equalize and float for several days until the system was used again. I had always assumed that was killing the batteries.
  • BB.BB. Super Moderators, Administrators Posts: 32,007 admin
    Re: cabin off grid questions

    Sitting at Equalization Voltage (around 15+ volts for a 12 volt bank) is not a great thing... A different charge controller may be called for.

    However, 5-7 years for a "golf cart" type deep cycle battery is not a bad life.

    Spend 2x as much, and your batteries may last 10-15 years. :roll:

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: cabin off grid questions

    Our cabin went from "occasional" use to pretty much full time for half a year.

    The first electric installed was a 12 Volt battery to run the radiotelephone. It was recharged from a generator as needed (once per trip would do). Then it got a small 30 Watt panel and controller to keep it up between visits. That's how it starts.

    The next thing you know, there's 700 Watts of panel on the roof and 2.4 kW hours of consumption. :p
  • ggunnggunn Solar Expert Posts: 1,973 ✭✭✭
    Re: cabin off grid questions
    The first electric installed was a 12 Volt battery to run the radiotelephone.

    Radiotelephone? Now, there's a word you don't hear very much any more. ;)
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: cabin off grid questions
    ggunn wrote: »
    Radiotelephone? Now, there's a word you don't hear very much any more. ;)

    Telus has been trying to phase them out for years now. The CRTC forces them to maintain service so long as licenses are active. If you let it lapse, you can not get it renewed nor are any new licenses issued or old ones transferred. Eventually they will all be gone.
  • techntrektechntrek Solar Expert Posts: 1,372 ✭✭✭
    Re: cabin off grid questions

    Can you post a pic or two of your radiotelephone setup?
    4.5 kw APC UPS powered by a Prius, 12 kw Generac, Honda EU3000is
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