New Off Grid Project (My First Project)

o2bnMaineo2bnMaine Registered Users Posts: 14 ✭✭
I am very new to solar. I fashion myself a light DIYer -- I know my limits and will hire an electrician to help with the project.

I have a contractor building a boat dock that will have a hoist to lift the boat out of the water. I am having difficulty thinking through how to approach this project. The project is in FL where the shortest day is around 10+ hours of daylight. I have found that that means we have just over 6 hours of usable time to power the solar panels.

There will be two types of power needs. [A] Always on (networking/security/lights) and [B] Intermittent usage (hoist/ceiling fan).

[A] I calculate this to require 2.4Kw per day (including a 30% buffer)
[B] The hoist is 11.6 amps @ 110 volts. Typically, the hoist will run for a few minutes at a time (down/no load will use less energy, I think). Lifting the boat will take a couple/few minutes each time. My calculations say this is less than 100 watts per "lift" action. The ceiling fan is supposed to peak at 75 watts while running.

One may lift a boat quite a few times in the day if you have ADHD. My family's pattern is to lower the boat into the water in the morning. Then, lift it so the hull is just barely out of the water when not in use during the day. When the day is over, the boat is lifted up higher in case a storm comes in. It only takes 15 seconds to lift the hull just above the water's surface (estimated).

Until I get this all figured out, I plan on buying a car battery and using it on the DC motor I plan on getting installed for the hoist. Typically, they sell hoists with AC, so I'm getting one special ordered. I will be talking to the motor company today or tomorrow to see what they think about all this.

EVENTUALLY, I want the boat dock to be 100% off grid. It will run me $3,000-4,000 to run electricity to the dock (300ft distance, burrow under a public road). 

The dock builder will be done in a week regardless if I get power to the dock or not. 

I am curious what suggestions you all will have. Am I missing anything in my logic?

[A] I will need 400 watts of solar panels to supply enough juice to charge the batteries (in 6 hours) to run the always on electronics.
[B] The hoist's energy requirement seems inconsequential when looking at always on. The ceiling fan won't be used very much at all and can be turned off when the hoist is running (so can the lights, for the matter). 

For this sort of application, does it make sense to go with 12, 24, 48-volt battery configurations? I anticipate the batteries will be stored under the roof of the boat dock on a shelf. Would any one option be better than another with that in mind?

Thanks in advance. Hopefully, I got all my thoughts down in one shot!

Bill

Comments

  • EstragonEstragon Registered Users Posts: 3,034 ✭✭✭✭✭
    Just to clarify, are you getting grid now for $3-4000 and wanting to eventually go off-grid?
    Off-grid.  
    Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
    Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
  • jonrjonr Solar Expert Posts: 1,125 ✭✭✭✭
    edited April 2017 #3
    Not clear to me that once you include maintenance, corrosion, heat reducing battery life, equalization, etc that $3-4K might not be the longer term better deal.

    48V will keep the amps to the motor reasonable.    Try to keep the batteries cool - I'd put an insulated roof over them.  

  • o2bnMaineo2bnMaine Registered Users Posts: 14 ✭✭
    Estragon said:
    Just to clarify, are you getting grid now for $3-4000 and wanting to eventually go off-grid?
    I'm hoping to only go off grid with this.
  • o2bnMaineo2bnMaine Registered Users Posts: 14 ✭✭
    jonr said:
    Not clear to me that once you include maintenance, corrosion, heat reducing battery life, equalization, etc that $3-4K might not be the longer term better deal.

    48V will keep the amps to the motor reasonable.    Try to keep the batteries cool - I'd put an insulated roof over them.  

    The boat dock will not have any walls. Having insulation will make that much of a difference? Not just putting a fan over the bank to push the hot air around sufficing?
  • o2bnMaineo2bnMaine Registered Users Posts: 14 ✭✭
    I'm looking at this partially as a "I want to see if I can do this off grid" so whether it costs more isn't a huge factor (unless it is considerably more). I may choose to scale back to "always on" part of the project since that's what is driving the need for a large battery bank.
  • jonrjonr Solar Expert Posts: 1,125 ✭✭✭✭
    edited April 2017 #7
    In hot areas, roofs block the direct sun, but the IR radiation gets transmitted to everything below it.   And battery life is very sensitive to heat.  Insulation (say 2" of foam) above the batteries (not necessarily the entire roof) helps with little expense.  A fan would help whenever the air temp is cooler than the batteries (evening and night, perhaps afternoon).
  • EstragonEstragon Registered Users Posts: 3,034 ✭✭✭✭✭
    Ok. So can we make a few assumptions?

    - the lift will rarely if ever be used at night?
    - lighting will be used mainly at night. Will it all be on constantly, or can some be sensor lights? Is it LED?
    - security will be 24/7

    So of the 2.4kw estimate, maybe some can be reduced by conservation, and some may be daytime use?

    The lift is really a different application than the other loads, so I'd be tempted to treat it by itself. Are the other loads AC or DC?

    The lift need a lot of current for a short time. You mentioned getting a DC lift motor - do you know the voltage? A car starting battery (or 2 in series) would likely work for that. They're made to discharge quickly at high current, but not for long.
    Off-grid.  
    Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
    Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
  • dennis461dennis461 Registered Users Posts: 108 ✭✭✭
    quote
    [B] The hoist is 11.6 amps @ 110 volts. Typically, the hoist will run for a few minutes at a time (down/no load will use less energy, I think). Lifting the boat will take a couple/few minutes each time. My calculations say this is less than 100 watts per "lift" action. .
    quote

    I get higher numbers for this.
    11.6 amps at 110 VAC is 1276 watts (approximate).
    The "lift' action is 1276 watts for as long as it's lifting (lowering will likely be similar, no great savings)
    Now, run it for a total of 15 minutes per day, would be 319 watt hours per day.

     A 12 VDC battery would need to supply 11.6 A 110/12 = 106 ADC, easily done with a single car battery or marine, or other type.
    Night or day does not matter much, as your panels will most likely not provide 106 ADC, which is why you have the batteries.
    Also, a good quality 200+ watt panel in FL can get the battery charged up.
    The "lift' action is 1276 watts for as long as it's lifting (lowering will likely be similar, no great savings)

    Is the fan going on the boat? I think a river, lake bay will have plenty of natural ventilation.  
    If this was my dock, I'd make sure there was some way to use your car to power up the lift in case a hurricane takes your solar panels for a long trip.
    Camden County, NJ, USA
    19 SW285 panels
    SE5000 inverter
    grid tied
  • o2bnMaineo2bnMaine Registered Users Posts: 14 ✭✭
    Luckily IR heat through the roof will impact me during the day (when there's more likely to be some wind to move the hot air). I'll plan on a bit of foam above the batteries for sure. 

    Thanks Dennis for correcting my numbers. I think I was using 120 instead of 110 on my spreadsheet and I clearly have something else wrong in my assumption! 

    I like the idea of separating the hoist from the 24/7 system requirement. That's easy to do. I expect the hoist to be used to lift the boat the most (longest run time) at the end of the day, which may be in the dark. There's always a chance we'll want to use it late at night, which would be a 2nd and 3rd burst of energy needed in the dark. Worst case is we leave the boat in the water if there's not enough power. That won't be the end of the world. I'll probably keep a spare battery in the garage that's on a trickle charger in case I need extra power to get the boat back up again. By isolating this from the rest of the system, I'll have more flexibility (also because it is going to be DC). 

    Everything except the hoist motor will be AC. I'll want the video cameras during the day to see how the wind is shaping up (I like to windsurf). I'll want the cameras at night for security purposes. So, they will have to be 24/7. There's a wireless bridge to beam the WiFi across the road. Each camera will need a PoE injector to get them power them. I'll look into the most energy efficient PoE options (one device for both or one device for each). I see that the wireless bridge I would like to get is ~24 watts. There's an alternative one that's slower (but maybe fast enough) that is 7 watts. That's a big difference. 

    We are going back to Maine in a month or so. So! I'll plan on using a car battery or two that I carry to the dock to start off with. Then after I return in the fall I'll get back on this. I'll try to set up a thermostat (hopefully its range will be long enough to reach the house!). I'll get it to log the temps under the roof every hour the whole summer.

    Thanks everyone for helping me think this through!!
  • o2bnMaineo2bnMaine Registered Users Posts: 14 ✭✭
    The PoE solution for most of my power needs looks to be shaping up well.

    The current plan is to trench a power line as close as I can (burying a conduit). I'll get an electrician to run electric (and a gigabit ethernet connection) in the conduit. From there, I'll have a 48v, 60w PoE device injecting power into 5 separate ethernet cables. The PoE injector will be in a watertight housing for easy access.

    I believe the longest run will be just under the 100meter maximum (phew). If this works, I won't have to spend the $90 on PoE amplifiers to for 4 of the ethernet runs extend the PoE range beyond the theoretical max of 100 meters.

    By running power closer to the shore, I will end up with an outlet port I can use for an extension cord. If I really need more (temporary) power over by the water, I can connect a long extension cord. 

    Under the bridge (that separates the lot with my house and the waterfront lot) I'll have a conduit zip-tied to the irrigation pipe I already run under the bridge. This will house the low voltage over ethernet. 

    Line 1 = webcam/flood light
    Line 2 = webcam/flood light
    Line 3 = trickle charger for boat battery
    Line 4 = 12v lighting around dock
    Line 5 = webcam (not going under bridge)

    The boat hoist will still be solar. I'm trying to decide whether I want a 4-battery, 48-volt system or just a 2-battery, 24-volt configuration. I'll probably over-size the solar panels so that there is no issue getting a charge in the winter or on cloudy days. I have been thinking I'll choose one of these kits (if they have a kit for a 48v battery configuration). Or I'll choose a 24v option. https://smile.amazon.com/Solar-Battery-Charger-batteries-components/dp/B004TIPKUE/


  • mike95490mike95490 Solar Expert Posts: 8,027 ✭✭✭✭
    You need to run 2 conduits, one for electrical, one for ethernet.  HV & lo voltage can't/should not share same conduit
    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 ,

  • EstragonEstragon Registered Users Posts: 3,034 ✭✭✭✭✭
    I think you can run high and low voltage together, but with the low voltage being used for signal, the AC is likely to interfere with signal. They should be run perpendicular if they get close to each other.

    At that range, I'd consider wireless for signal unless there are line of sight obstructions.
    Off-grid.  
    Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
    Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
  • BB.BB. Super Moderators, Administrators Posts: 28,173 admin
    If I recall correctly, the NEC basically says that all wiring in a conduit has to be for the same application (i.e., all AC branch circuits, all signal circuits, etc. and cannot mix circuit types in a single conduit) and that the lowest rated insulation has to meet the code for all wiring in the conduit (i.e., mixed 100 VAC and 600 VAC max is not allowed, all wiring has to be 600 VAC max rated for typical AC wiring).

    There is riser and plenum grade CAT communications grade insulation too... Plenum grade is low smoke/toxicity (fire) and is allowed to run in heating and A/C ducts.

    http://www.lanshack.com/pdf/PlenumVsRiser.pdf

    -Bill

    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • o2bnMaineo2bnMaine Registered Users Posts: 14 ✭✭
    Good point about the AC in line with the CAT6! I wasn't thinking that far ahead. This gets me thinking about a variation on my above configuration!

    I started out with trying to get all devices on solar. That would require a relatively large battery bank to be totally off-grid. Now I'm shifting to using the low voltage set up on PoE to get around having to get a permit to send power from one side of the road to the other. 

    I don't have a clean line of sight for a wireless bridge, unfortunately. I had originally planned on going this route. The distance isn't too long, so the degradation from the tree that's in the way should be tolerable. I think. If I have to, I plan on giving this a go regardless of signal degradation. With 802.11ac, one can get a bridge that supports 800Mbps close up. So, through trees, I would be happy to get 200-300Mbps.

    The new, simplified option:

    Ethernet and power run (in separate conduits) to the southern fence bordering the road. A 48v60w PoE injector to send power for two cameras, two flood lights (daisy chained with cameras, sharing PoE), 12v lighting over the 1 CAT6 cable. I'll install a network switch on the dock that supports PoE PassThrough, which will split the 1 CAT6 cable into 2 supplying each with enough power. It will split off to a 3rd cable for the 12v lighting. All but the 12v lighting, which isn't a requirement, will use ~28 watts on a 48v power supply. I can send 60 watts over the PoE I'm planning on getting, so there should be enough room for a minor light source. 

    This is a much cleaner solution for burial. (I'll end up sending two CAT6 just in case I need to expand things.) I'll have to check operating temperatures for network switches and figure out how hot it will get up under the roof of the dock. Foam insulation above the devices will be helpful.

    Thank you all for weighing in. Having a group to "discuss" this project with has been very helpful!
  • EstragonEstragon Registered Users Posts: 3,034 ✭✭✭✭✭
    If you have a clear line of sight between two points on each side between the trees, maybe directional wifi antenna?
    Off-grid.  
    Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
    Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
  • o2bnMaineo2bnMaine Registered Users Posts: 14 ✭✭
    Estragon said:
    If you have a clear line of sight between two points on each side between the trees, maybe directional wifi antenna?
    Unfortunately, I would have to take down trees that were planted during the Roosevelt era Works Project. They are 100-year-old live oaks. 
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