Help filling out my schematic

System
System Posts: 2,511 admin
Hello, I am planning on installing a solar system for a remote summer cabin and I need help filling out how everything goes together.

Right now I am getting a 85w solar panel, 10A charge controller (to accommodate a possible future upgrade), a 104A/hr AGM battery, and a 1500 watt inverter (to run a 1100w AC sump-pump for 5 min a day). But, just 12-13 amps a day total needed, so I have a nice 4 day buffer on the battery before I go below 50%.

So here is my diagram so far. I have 1 breaker box that everything goes through to save space/money but I am not sure what kind of breakers to put in them. Also, I have seen other people put extra fuses in their wiring - where and why?

Is there a standard way to split off DC loads before the AC inverter?

Any other advice is appreciated.

EDIT: And I also have a generator that puts out DC 8.5A@12v. that I would like to be able to attach to charge extra if needed - where would that go?




solar_diagram.jpg

Comments

  • icarus
    icarus Solar Expert Posts: 5,436 ✭✭✭✭
    Re: Help filling out my schematic

    1100 watt ac pump is a huge draw @ 12vdc,,, ~92amps! Consider a different pump with a much smaller amperage draw, over a longer time. Also be advised that Square D QO series is the only breaker that I know that is rated for dc (up to 48vdc)

    Using a dc breaker box is a fine way to split the dc loads, including the inverter IMHO. Also be advised that if you wish to power the 1500 watt ac inverter it will need a fuse/breaker of 125amps! Plus the large size wiring.

    Tony
  • System2
    System2 Posts: 6,290 admin
    Re: Help filling out my schematic

    This is the pump, it is for a pumping septic effluent up a hill to a drain field (we are very limited where we can build things). I might be able to use the 4/10 HP one that uses less power, but would need to run longer.

    http://www.lgpc.com/Product/ItemDetail.aspx?ProductID=476#

    But it is AC pushed through an inverter, running at 115v at 11.4 A = 1,311 Watts. It doesn't give me the watt rating, just amp. (11.4).


    EDIT: According to my calculations, the smaller pump running at 8.9A pumping 20 GPM would take 2.66 Amps/week, while the larger 11.4A pump moves 50 GPM and thus only need to use 2.6A a week!

    Also, I can not find any DC submersible effluent pumps, and that is what is required. Thus the AC.
  • quid_non
    quid_non Solar Expert Posts: 48
    Re: Help filling out my schematic

    Fom my small PV system (~120W, 12V), I wired up a small DC fuse box for central distribution. I bought the one below:

    http://bluesea.com/category/5/21/productline/126

    It's a nice box - 12 different exit points and all are fused as needed. I put in a 25A "master fuse" on the 10ga Cu feeder from the batt. The 25A fuse may not be needed, but adds an additional level of protection.

    Best
    Wayne
  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    Re: Help filling out my schematic

    The smaller pump may have a lighter, starting surge.

    I'd hook it to a timer, with a "sump full" override, so it generally runs daytimes, off the PV array when voltages are higher, and not so much off the batteries at night. What's the size of your holding tank, can it set 24 hrs, without pumping ? (like pump afternoons when batteries are in absorb, and you have "extra" power0

    Another important question is, Is one pump more likely to clog, than the other ? Fixing a clog looks pretty gross.
    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 ,

  • icarus
    icarus Solar Expert Posts: 5,436 ✭✭✭✭
    Re: Help filling out my schematic
    thentro wrote: »
    This is the pump, it is for a pumping septic effluent up a hill to a drain field (we are very limited where we can build things). I might be able to use the 4/10 HP one that uses less power, but would need to run longer.

    http://www.lgpc.com/Product/ItemDetail.aspx?ProductID=476#

    But it is AC pushed through an inverter, running at 115v at 11.4 A = 1,311 Watts. It doesn't give me the watt rating, just amp. (11.4).


    EDIT: According to my calculations, the smaller pump running at 8.9A pumping 20 GPM would take 2.66 Amps/week, while the larger 11.4A pump moves 50 GPM and thus only need to use 2.6A a week!

    Also, I can not find any DC submersible effluent pumps, and that is what is required. Thus the AC.


    1311 watts @ 120vac = ~11 amps
    1311 watts @ 12vdc = 109.25 amps!

    Remember, watts is the measure of power, what a device draws. It is a combination of VxA=Wts.

    Ten times the voltage= 1/10 the amps, with the same wattage draw,,, and vice versa.

    Tony
  • System2
    System2 Posts: 6,290 admin
    Re: Help filling out my schematic

    Just when you think you have it figured out...

    Ok, I got it confirmed that I can use the lower power one, which is better because it does have a lower start up surge (they both have capacitor assisted start, which is good, but there is still a spike) so that load will be 1023 Watts AC (8.9A @ 115VAC). I emailed the company to see if they could tell me what the spike would be but no reply.

    And if I understand it right now, while the sump is drawing 8.9 amps off the inverter it is really drawing 85 Amps off the battery and through the breaker and into the inverter. That starts getting really expensive in circuit breakers/boxes alone!

    Is there anyway I can get around the problem of this one pumps' massive draw? While its draw isn't much (80w pr day) I don't know how to handle a possible 100 Amp draw, even if it would be for 2 minutes at a time. Should I convert to a 24v system?
  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    Re: Help filling out my schematic

    Your motor startup surge can be several times the run power. Which means your battery will need to supply 300-400A for 5 seconds. A single 12V may not do it. You may want to look into a bank of 4 golf cart 6V batteries, and run a 24V inverter. They are a fair amount more $ though.

    What size is your effluent holding tank ? Once started, how long will the pump be running ?
    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: 33,404 admin
    Re: Help filling out my schematic

    Higher voltage battery banks and smaller pumps are about the only way to lower the currents...

    It is possible with the large loads (even for a short time), you may be better off with a 48 VDC bank when all is said and done...

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • icarus
    icarus Solar Expert Posts: 5,436 ✭✭✭✭
    Re: Help filling out my schematic

    I'm thinking,,,,

    Are you just pumping into a conventional drain field, or is it a pressurized "mound system"? Does it run on a float switch.

    Can you pump down to almost nothing less often? In other words instead of pumping as needed, can you empty the tank, and then let it fill until you can run the pump for a longer period of time. The advantage is you could use a smaller pump for a longer time. Permit issues aside, could you use a small wind powered pump with a electric back up?

    If you use the national standard (way high) of 250 gallons per person per day you would only have to move say 1000 gallons a day. (I bet it is less than half of that, given the numbers you suggest. If you have 6 hours of sun, you would only have to move ~2.7gpm to get the 1000 gallons.

    Why does it have to be a submersible? How about something like this: http://www.plumbersurplus.com/Prod/Little-Giant-SPBS-12-12-Volt-DC-Sump-Pump-Back-Up-System-(506400)/13145/Cat/697

    Just ideas,

    Tony
  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    Re: Help filling out my schematic
    icarus wrote: »
    Why does it have to be a submersible? How about something like this: http://www.plumbersurplus.com/Prod/L.../13145/Cat/697

    It's a sewage pump, not a sump pump. Likely has a "grinder" in it to chop stuff up so things don't clog. the grinder may need a big motor, like a garbage disposal.
    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 ,

  • System2
    System2 Posts: 6,290 admin
    Re: Help filling out my schematic

    Thanks for all the replies. A few responses
    - it is a pressurized mound system and I am waiting to get an exact measure of the rise, but I am estimating 13-15ft. This was the only possible spot to build it.
    - The little giant pumps do not have a grinder, as this is a 2 stage septic.
    - I need to talk to our builder more about specs! That takes days.

    I got a response about the 1/2 HP version of that pump. I asked, "...and I need to know what the start-up surge amps (or watts) is for that pump."
    Reply.
    "The start up/locked rotor amps on that pump is 24 amps and its pulling 1180 watts."

    Running it takes 11.4 Amps. That math doesn't make sense to me on 115VAC.

    But, I am hoping that I can get around all this because I found a DC effluent pump designed for yachts that might do the trick.
    http://www.johnson-pump.com/JPMarine/products/lavatorysystem/vikingpower32.html
    Of course the max lift+head of the big one is 16 ft, and that's getting close to our height. But, 3.2 Amp on 12v! And it even has a handle if there is zero power :D But like I said, there are many reasons it might not work too so I will have to wait and see.
  • BB.
    BB. Super Moderators, Administrators Posts: 33,404 admin
    Re: Help filling out my schematic

    Regarding the 24 amps locked rotor rating...

    That means the VA (Volts*Amps) = 120 VAC * 24 Amps = 2,880 VA

    Basically, a stopped/stalled/starting motor is very "inductive"--so the Voltage and Current are not in phase...

    When you size your wiring and inverter, you need to account for a short operation (a few seconds) of a current surge of 24 amps.

    But, for the power coming out of the inverter (energy required from the battery), it is 1,180 watts--which is the actual work being performed.

    Here is a relatively short PDF paper on Power Factor and motors if you want to get a bit more understanding....

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • icarus
    icarus Solar Expert Posts: 5,436 ✭✭✭✭
    Re: Help filling out my schematic
    mike90045 wrote: »
    It's a sewage pump, not a sump pump. Likely has a "grinder" in it to chop stuff up so things don't clog. the grinder may need a big motor, like a garbage disposal.

    Over the years I have installed several sewage transfer pumps that are not submersibles, mostly for basement toilet installations. The last was a kennel area for a Vet clinic in a strip mall. Used to pump dog waste and water up over the ceiling and then into the sewer via the vent. Building dept. bought it in a heart beat with documentation. (Can't recall the brand at this point.

    Icarus
  • System2
    System2 Posts: 6,290 admin
    Re: Help filling out my schematic

    I have to see if this will be ok with everyone involved, but I found the Jabsco 18590 marine macerator waste pump that runs 12VDC @ 16 amps and pumps 20ft. up. Perfect! 70% energy savings right there. The grinder will be good backup for the drain field too. I will let you know what they say.

    http://www.jabsco.com/products/marine/toilet_waste_systems/waste_pumps/sealed_macerator_18590_series/iid_20/index.htm

    Back to my schematic, I would like to attach our Honda 2000i generator to charge the batteries, but am unsure the best way how. Is there a common switching mechanism to move from solar charging to generator charging? It doesn't need to be automatic.

    The 2000i produces unregulated 12VDC at 8A and 120VAC at 16.7Amps. So I assume that I should get a battery charger to use the much stronger AC side of things. These are AGM batteries so they can take a faster charge and I increased my battery bank to 156Ahr. The system might be a little over-powered now, but thanks ok. I can live 4.5 days in blackness and silence until I hit 50%.
  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    Re: Help filling out my schematic

    Now that you mention chargers, I looked back and see you only have a 104AH battery. Is that Actual Capacity, or your 50% discharge, with 50% reserve ?
    There is a funny thing called Peukert’s law http://en.wikipedia.org/wiki/Peukert%27s_Law that the faster you discharge, the lower your capacity. When you start having high current draw, you may want to consider a parallel battery, to help share the load .

    As for fast recharging, you can't beat an AGM for sucking up a fast charge that would melt other, more mortal batteries. You HAVE to be sure your charge controller is properly configured for the particulars for your AGM brand (some don't allow an EQ charge & ANY overcharge vents moisture you cannot replace)
    But back to recharging, assuming a 100AH battery, I don't know if I would want much more than 30 or 40 amps fast recharge. It cuts down on the fuel bill, but having only heard that high charge is OK for AGM, I don't want to say do it daily.
    But if you want fast recharge, this is my personal suggestion. It may not be a true "off gridder's" method, but I haven't heard anyone say that it's not good, (so if I'm wrong, shout out). I'm partial to the VEC1093 automotive battery charger. It has a switching power supply, deep cycle battery selector, some extra cycles that aren't used with AGM's, but it has a true 40 amps output, and drops to a true float charge afterwards.
    Yes, its jumper cable connections, yes, you have to program it each cycle, but it's under $150, which is a good bargain, compared to some +$300 units that you can't boost your vehicle battery with. Made by Vector, marketed by Black & Decker, and many autoparts stores carry it too.
    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 ,

  • System2
    System2 Posts: 6,290 admin
    Re: Help filling out my schematic

    I upgraded the plan, so now it is 2x 69Ahr batteries in parallel. I figure I might be drawing 25A for a steady time, so that brings it down to about 110Ahr. I need 13.5 a day, so that gives me 4 dark days until I hit 50% and have to turn on the generator. I probably wont use more than a 30 amp spike, and realistically it will usually be way below 25A - more like 10A.

    Why not get a IOTA 30 Amp charger? It costs the same as the VEC1093, but seems more specific to the purpose.
    http://store.solar-electric.com/dls-30.html
  • BB.
    BB. Super Moderators, Administrators Posts: 33,404 admin
    Re: Help filling out my schematic

    The Honda 12v @ 8 amps is an unregulated output... It is only 48 watts--so it is really not going to give you much power in the grand scheme of things (if you are charging at 500 watts or more). You could attach it directly to your 12 volt battery bank--but probably should disconnect it when the generator is off (or at least fuse the connection if left permenantly connected).

    And using "13.5 a day" is, I presume, really 13.5 Amp*Hours per day... otherwise it looks like your are saying 13.5 amps*24Hours per day = 324 AH per day.

    And, lastly, if you could justify a Battery Monitor--it would make running off-grid battery management much easier.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • Brock
    Brock Solar Expert Posts: 639 ✭✭✭✭
    Re: Help filling out my schematic

    I would recommend the iota for a great robust charger. I have used black & decker/vector, iota, deltran and many more. The new switching B&D / Vectors are very versatile, but they lack the tight control on the voltage side. I have 5 matched units for a 60v electric moped. The final voltages vary from 14.8 to 15.4 on just those four. The larger Vector was about 15.1, so that worried me a bit. The Deltran and Iota were dead on between units for final voltages.

    The Iota's can also take any voltage between 80 and 220 and I have been told they even accept DC. They run fine on a mod sine wave inverter happily putting out their max current at a set voltage with input voltages and frequencies all over the place.
    3kw solar PV, 4 LiFePO4 100a, xw 6048, Honda eu2000i, iota DLS-54-13, Tesla 3, Leaf, Volt, 4 ton horizontal geothermal, grid tied - Green Bay, WI
  • System2
    System2 Posts: 6,290 admin
    Re: Help filling out my schematic

    Alright, I think this is ready to go. Thanks so much for every ones help! I think I have a much better understanding about everything and saved a lot of headache in the future.

    Here is my plan right now. The box is a MidNite Baby Box with breakers, and the DC loads will be run of a ATM "blade" fuse box like was mentioned before. For me the DC loads are much more demanding, and automatic, so much of the system is geared towards DC work. The max load wont be on for more than 5 min. Any more fuses needed? I need this to be as safe as possible, as we are in the middle of some very fire prone remote area.

    solar_diagram2.jpg
  • BB.
    BB. Super Moderators, Administrators Posts: 33,404 admin
    Re: Help filling out my schematic

    I am not quite sure I understand your drawing... The CB/Bus Bar interface is confusing me...

    Normally, everything connected to the bus bar shall be fused/CB to the rating of the wiring, or less. The battery may or may not be fused/CB to the bus bar... If the wiring between bus bar and battery is kept short and protected (and heavy enough to carry the rest of the planned loads)--it is probably not needed.

    With 12 volts DC--you will have real problems with voltage drop.

    63 amps for a 10 foot run on 4 awg wire (20' round trip) will give you 0.35 volts of drop... Add fuses (which have to have a voltage drop to work) and circuit breakers, and long runs off to other places--and run your battery down to 12 volts--you are pretty quickly below 11 volts at the load...

    Again, from your drawing, the solar panels go through a CB directly to the charge controller--and are not connected to a bus bar.

    You have a volt meter indicated--but it is draw in as a current meter.

    I would really suggest a battery monitor--AGM's, the only other way to measure state of charge is with a volt meter--after the batteries have rested for a few hours (no charge/discharge). With a battery monitor--you get the direct state of charge (and current voltage/charge/discharge information) with a good meter. Very good to help keep your expensive AGM batteries healthy for years to come.

    If you don't install a battery monitor, you should probably have an amp meter so you can at least monitor the amount of discharge and the charging currents you have... So you can tell if something is broken before you kill your batteries.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • System2
    System2 Posts: 6,290 admin
    Re: Help filling out my schematic
    thentro wrote: »
    The box is a MidNite Baby Box with breakers, and the DC loads will be run of a ATM "blade" fuse box like was mentioned before.

    solar_diagram2.jpg

    Ok, I'm stuck on my plans. I'm confused about the drawing above. If the buss bar (BB) connects all the "items" (i.e. CC (twice), Batteries, Inverter, etc.) together, then how do you keep them separated? How do I ask this...It appears that the buss bar would direct power around the CC and have the power from the PV's go directly to the batteries. I know this is not true (since no one has mentioned it), but I'm missing something. I would like to use 1 panel box for a PV discon. and for power out, etc. Please explain this to me. Sorry for my ignorance.

    (Thanks for the drawing Thentro
  • n3qik
    n3qik Solar Expert Posts: 741 ✭✭
    Re: Help filling out my schematic

    What box are you using?? Is it a Square D, Midnight Solar, or other ??

    If you are using a Square D, this is how it could be done.

    First need to jump the 2 main lugs with #4 wire, this will be the positive buss. The ground buss bar will be the negative buss bar.

    The panels- wire to separate inline fuse, then to the charge controller. Then it is wire to a 12 amp circuit breaker. Positive to the breaker, negative to the ground bar.

    Batteries are wire to the 60 amp breaker. Positive to the breaker, negative to the ground bar.

    30 amp charger is wired to the 40 amp breaker. Positive to the breaker, negative to the ground bar.

    DC load fuse box is wires to the 40 amp breaker. Positive to the breaker, negative to the ground bar.

    Inverter is wire to the 30 amp breaker. Positive to the breaker, negative to the ground bar.

    I will try to post a pic of my CB panel later or do a drawing.
  • icarus
    icarus Solar Expert Posts: 5,436 ✭✭✭✭
    Re: Help filling out my schematic

    Iota makes a simple automatic transfer switch (30 amp and 50 amp available)
    It automatically recognizes if it is being fed from the inverter or the generator. It is wired so that there is no draw while running on the inverter. The relay is energized only when running from the generator. I think the site host carries them

    Tony

    Ps The Xantrex TrueCharge series generators work very well with Honda Eu gensets. I run a TC20 on a eu 1000 and it runs it at idle
  • System2
    System2 Posts: 6,290 admin
    Re: Help filling out my schematic
    n3qik wrote: »
    What box are you using?? Is it a Square D, Midnight Solar, or other ??

    If you are using a Square D, this is how it could be done.

    First need to jump the 2 main lugs with #4 wire, this will be the positive buss. The ground buss bar will be the negative buss bar.

    The panels- wire to separate inline fuse, then to the charge controller. Then it is wire to a 12 amp circuit breaker. Positive to the breaker, negative to the ground bar.

    Batteries are wire to the 60 amp breaker. Positive to the breaker, negative to the ground bar.

    30 amp charger is wired to the 40 amp breaker. Positive to the breaker, negative to the ground bar.

    DC load fuse box is wires to the 40 amp breaker. Positive to the breaker, negative to the ground bar.

    Inverter is wire to the 30 amp breaker. Positive to the breaker, negative to the ground bar.

    I will try to post a pic of my CB panel later or do a drawing.

    Ken,

    Thanks for the help. did you get a chance to post a pic or drawing? It's nice to put a face to the posts/words.:roll:
  • n3qik
    n3qik Solar Expert Posts: 741 ✭✭
    Re: Help filling out my schematic

    Nope, after I posted, reread the thread and saw an Midnight Solar Baby Box was being used. I have not used one so my post/pic/drawing would be of no help or even misleading.

    May do it anyway but in a new thread as not to take this one off topic.