My new system.

gomangogomango Registered Users Posts: 24
ok, so I am now to the point where I am brave enough to post my system layout after reading that other here are about as lost as I am. Here goes.

My Goal... To run the lights, a small fridge, and the TV.

Starting with the load.

I will require about 4500 watts per day off grid. More depending on what fridge I purchase.

Here is what I have on hand as of now.
  • Two 1182 amp hour batteries at 12 volt each in series. (GB 6-125-13)
  • One Outback FX2024 sealed inverter
  • One remote temp sensor
  • One FM60 charge controller
  • Twelve Kaneka 60 watt panels
  • Lots of acreage for more panels budget permitting
  • 4.5 hours peak sun per day
  • One 300 watt micro hydro system

Can anyone tell me if I will run into issues at this point? I am still shopping for a good diesel genset that will fit my needs, but am still broke from the rest of it all.

This will replace the current over taxed system currently in use. Am running off two L16 Batteries at the moment and a cheap 1000w inverter.

Comments

  • icarusicarus Solar Expert Posts: 5,436 ✭✭✭✭
    Re: My new system.

    First, I assume that you are calling for 4500 watt/hours Watts mean nothing with out a time component.

    The rule of thumb is, take the name plate rating of the PV divide by 2 to account for all system loses, multiply that number by 4 to represent the average number of hours one can expect.

    So your 720 watts of PV might yield 720/2=360*4=~1440 wh/day

    So, not including your water power which I can't comment on, you are going to be able to harvest only ~1/3 of your needs on an average. So without any reserve you need 3 times the PV, make that ~5 times to add in some reserve.

    Assuming 24 vdc. 1182 ah of battery yields ~28 kwh worth of power if you were to draw them down to zero. 14kw drawn to 50% SOC, ~5 kwh drawn down 20%, so your battery seems to be in the proper range. (for the loads)

    That said, your PV is too small for the battery (not just in the previous sense) but there won't be enough amps to properly charge it. It is recommended that batteries get charged between 5-13% of ah capacity (for a fla) so you battery (24 vdc) would like ~60 amps minimum. Your panels are likely to produce at best ~25 amps,, less than 1/2 of the recommended minimum.

    Your controller is plenty big for the PV

    Welcome to the forum, There are some very smart folks here who can answer nearly any question you can throw at them.

    Tony

    Just a comment on the water, assuming 80% 24/7 you might get 5.7kwh/day,, but I would be surprised if you get that.
  • AntronXAntronX Solar Expert Posts: 462 ✭✭
    Re: My new system.

    Don't get FM-60, get this controlelr instead. FM-60 is outdated. How much are you paying for those batteries. Can you afford AGM instead? The Kaneka panels is great choice for most Watts per Dollar, but they also take up twice the amount of space and may not last as long as polysilicon panels. You can get non-UL polysilicon for $1.82 per Watt from here.
  • icarusicarus Solar Expert Posts: 5,436 ✭✭✭✭
    Re: My new system.
    AntronX wrote: »
    Don't get FM-60, get this controlelr instead. FM-60 is outdated. How much are you paying for those batteries. Can you afford AGM instead? The Kaneka panels is great choice for most Watts per Dollar, but they also take up twice the amount of space and may not last as long as polysilicon panels. You can get non-UL polysilicon for $1.82 per Watt from here.

    He's already got the Panels and the controller. Too late to avoid Ready, fire, aim on that hardware.
  • AntronXAntronX Solar Expert Posts: 462 ✭✭
    Re: My new system.

    Eh, I need to read slower. FM-60 is still a fine piece of gear, and will serve it's purpose. The other one is a little better for almost same price.
  • gomangogomango Registered Users Posts: 24
    Re: My new system.

    I figured that I didn't have enough PV from what I read on other posts. I will be adding more as time goes on, but for now, it is a start.

    Getting back to the "Not enough amps to properly charge it"

    Will charging at to low of a rate damage the battery? Will it cause harm to pull the battery down to 50% and then do a full charge with the generator?

    My current loads are much lower than the goal simply because I am still building my house. Currently we have a few cfl lights, and a TV. The Fridge is propane but I will change that out when I have the system properly sized.
  • AntronXAntronX Solar Expert Posts: 462 ✭✭
    Re: My new system.
    gomango wrote: »
    ...Will charging at to low of a rate damage the battery? Will it cause harm to pull the battery down to 50% and then do a full charge with the generator?...

    As of now, your charging rate is 1182A/30A = 2.5%. Recommended range is 5% - 13% if I recall right. The acid inside needs to bubble and swirl around during charging to stay well mixed. Otherwise, battery will degrade faster. Charging your batteries fully with generator help once a week should be good.
  • mike95490mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    Re: My new system.
    Will it cause harm to pull the battery down to 50% and then do a full charge with the generator?...

    Only if your battery stays below 70% charged for more than 24 hours. The lead sulphate crystals will harden, and not dissolve during discharge. This is called sulphation.
    Say you loose 1% capacity each episode, and one episode a week. In a year, you have 50% degradation of your battery. That's what insufficient charging gets you.

    See attached battery file for in depth explanation.

    Attached DoE_BatteryHdbk1084.pdf 1995

    Sulfation - Formation of lead sulfate crystals on the plates of a lead-acid
    battery.
    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: 32,800 admin
    Re: My new system.

    Also, the longer you leave the battery sit/operate at a low state of charge (typical recommendation is below ~75% SoC)--the faster it will sulfate (sulfate crystallizes over time and will not return to the electrolyte during the next charging charging).

    Do not let the battery bank operate for days/weeks/months at low state of charge.

    Read the battery FAQ's for a better idea of how to keep your bank happy:

    Deep Cycle Battery FAQ
    www.batteryfaq.org

    5% is the recommended minimum charging rate for equalizing a flooded cell battery bank by several battery manufacturers. In theory, you only equalize every month or three--so you could use a genset/AC Charger to do the equalization when needed.

    However, the other issue is that batteries have self discharge--And with low charge rate, old (about to fail) flooded cell batteries can self discharge at 1% per day--Which would take pretty much the whole output from your array and leave nothing behind for daily power needs (why over sizing a battery bank to the array is problematic). Also, for example fork lift batteries, tend to have higher self discharge rates.

    AGM type batteries do have lower self discharge and live with less than 5% minimum rate of charge...

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • icarusicarus Solar Expert Posts: 5,436 ✭✭✭✭
    Re: My new system.

    Here are a couple of links that I think you must read and understand, if you are going to live off grid with batteries:

    http://www.batteryfaq.org/

    http://www.windsun.com/Batteries/Battery_FAQ.htm#Lifespan%20of%20Batteries

    A 50% routine discharge "won't hurt" the battery, but it will shorten it's total life span. It should be noted that battery longevity is very much related to depth of discharge and cycles. For example, a battery that may last 1000 cycles discharged to 50% might last 5,000 cycles discharged to only 80% SOC. (Numbers just made up, follow the link for real numbers!)

    So one can make an economic calculation to determine whether one should pay $X for a battery bank that will be discharged to 50% and will then last 3 years. Or one could spend ~$2.5X for a bank that will only be discharged ~20% but will last 8 years. What makes better sense?

    The biggest single mistake that people make with off grid solar systems is over drawing coupled with under charging. Most people prematurely kill a set of batteries as they learn how to charge/load them.

    Tony

    PS You beat me Bill!
  • gomangogomango Registered Users Posts: 24
    Re: My new system.

    Thanks for the links. I have read the wind sun faq, however I had not seen the other.
  • gomangogomango Registered Users Posts: 24
    Re: My new system.

    Moving on to the inverter now.

    This inverter was purchased used and did not come with a book. I looked at outback power website and the only pdf I could find was for the export version.

    Does anyone know of where I can find the fx2024 manual?
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭✭
    Re: My new system.

    Outback Power has just about every manual for anything they ever made at their web site:

    http://www.outbackpower.com/pdf/manuals/fx_vfx.pdf

    That should be the right one for the FX - all models.
  • gomangogomango Registered Users Posts: 24
    Re: My new system.

    Just and update on how its working out.

    I have been running the system for three weeks now, and the performance seems to be good for what I have. The batteries charge at 20 amps during peak times, and the controller goes into float for about 5-1/2 hours each day. Everything seems to run better on this inverter than the Xantrex modified sign wave inverter I was running. All the signal noise on the AV equipment seems to have disappeared.


    I checked the controller in heavy cloud cover this morning, and it appears to charge at just under 4 amps. Where this is adequate now, I will be adding an electric fridge in the near future, and this will change everything. As a remedy to this situation I have began to pay myself a power bill of $100 per month, and will dedicate these funds to system upgrades in the future. I know this is not much, but I plan to increase these contributions when I finish paying for the sheet rock and floors in my house. I realize that as my house is completed and the service load is increased... I will need to grow the system to accommodate. Thanks to everyone who answered my questions. I will have lots more when I decide to upgrade.
  • BB.BB. Super Moderators, Administrators Posts: 32,800 admin
    Re: My new system.

    If you just need refrigeration, a converted chest freezer is not a bad way to go (significant other may not appreciate the vertical access of a chest freezer though).

    Chest freezer as a chest refrigerator

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • gomangogomango Registered Users Posts: 24
    Re: My new system.

    Thanks for the heads up. I totally like this idea.


    A note on solar production I stated earlier... 20 amps during peak times was incorrect. Is more like 28 amps.
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