Houseboat Solar

fredrhodesfredrhodes Registered Users Posts: 7
I am new to this forum so be easy on me! And thank you in advance for your assistance.

I have a 14 x 56 houseboat that I am going to try and run via solar. I have 3 - BP 175 watt panels that where gifted to me. My load is going to be very minimmal, almost all of the lighting is flourescent, fridge is gas and we do have a small microwave that will be used occasionaly. I need some recomendations on wiring, charge controller, inverter, battery charger and batteries (how many etc) I intend on having a small generator to charge the batteries if needed. I was thinking a Honda 2000 watt.

I actually work in the solar industry as an electrical superintendent, but 99.9% of what we do is grid tie. I did install one system with batteries, it used a Xantrex XW charger controller, and included the wiring box and Xantrex inverter. Seems overkill for what I am doing and I of course am not going to feed to the grid.

Boat will be weekend use mainly so will have plenty of sun to charge batteries after we are back at work!

Thanks!!

Fred

Comments

  • nielniel Solar Expert Posts: 10,311 ✭✭✭✭
    Re: Houseboat Solar

    it might seem like overkill to you, but it may not be. it all depends on the power consumed and for how long. the max power consumed at one time will also be needed to know for the size of the inverter to be chosen. from there the size of the battery bank can be determined. the use of a killawatt meter to measure this need is invaluable.
    in the case of a generator charging batteries and ac power created through an inverter it is still a need to know situation of the watt hours consumed and the most at one time. the only difference is that the generator is supplying the power rather than the pvs. i do specify the same arrangement with the generator because you don't want to run the generator all of the time so the generator and charger will need to be large enough to supply the power needs in whatever shorter time period that you can deal with. even with pvs present a generator with a utility 3 stage charger is good to have for extended times of little sun or extra power being used that was not accounted for.
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Houseboat Solar

    It's broken record time:
    Loads.
    Loads, loads, loads, loads.
    You simply must get an accurate determination of loads. Get a Kill-A-Watt meter and start measuring everything on the boat over time (at least one day) during 'typical' use.

    Too many people start out with getting panels first and designing from there. They end up asking the question: "I've got this much power; what can I do with it?"

    The question you want to ask is: "I need this much power; how do I get it?"

    Perfectly good panels you've got there, and I love the price! :D
  • fredrhodesfredrhodes Registered Users Posts: 7
    Re: Houseboat Solar

    The boat is in our yard and in the process of being refurbed. I do have a killawatt meter, but this is a new system on basically a new boat. I need some kind of starting point. The lights are circleline bulbs and there is about 12 of them total. Of course they will be only used at night. I need someone with more knowledge than I to come up with a base line. I was thinking of using around 10 ea 6 volt Golf Cart Batteries to start with, a Xantrex XW charge controller and wasn't sure what kind of inverter or battery charger to use. Don't know weather to purchase a Inverter/Charger or to purchase each other seperate.

    Thanks!

    Fred
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Houseboat Solar

    I'd advise you to get the knowledge yourself, because you're going to need it. Even after you have the system up and running you'll find it's less than perfect, and you'll want to 'tweek' it. Understanding what's going on will help you do that.

    Don't jump in buying batteries/inverter/et cetera without some idea of what sort of power you need to supply. As Icarus so warmly says (over and over); "Avoid Ready, Fire, Aim!" You don't want to have the power shutting down at midnight because you didn't get enough battery/panel.

    Even without the boat going you can get a fairly accurate power plan by running the same or similar devices through the Kill-A-Watt to get a picture of your daily use.

    The basic planning procedure from then is:
    Largest cumulative load (including any start-up currents) determines the size of the inverter.
    Average daily Watt hours determines the size of the battery bank.
    Amp/hrs of the batteries determines the amount of panels & charge controller to use.

    You will be at something of a disadvantage with a boat; you can't always get the panels pointed at the sun. This means you will probably want even more panel than would be standard for a fixed location.

    Remember; there's a lot of loss to inefficiencies in a solar power system. By the time you get to usable AC Watts you're often at 50% of the total panel rating.

    The Honda 2000 is a great generator. Quiet, efficient, dependable.
  • BB.BB. Super Moderators, Administrators Posts: 29,509 admin
    Re: Houseboat Solar

    Fred,

    This is how I would do the guesses... Lets say you have 10x 13 Circuline lamps and run them 5 hours a night:
    • 10 x 13 watts * 5 hours = 650 watt*hours per night
    Using the PV Watts program for Sacramento California, assume 0.52 derating (end to end efficiency from panel to AC power outlet). And in your case, assume that you will be using the boat during the six months of summer and will be mounting the panels flat to the roof (no way to point at sun consistently). Use 1kW (1,000 watts) of solar panel as nice round number (also smallest wattage allowed by program).
    "Station Identification"
    "City:","Sacramento"
    "State:","California"
    "Lat (deg N):", 38.52
    "Long (deg W):", 121.50
    "Elev (m): ", 8
    "PV System Specifications"
    "DC Rating:"," 1.0 kW"
    "DC to AC Derate Factor:"," 0.520"
    "AC Rating:"," 0.5 kW"
    "Array Type: Fixed Tilt"
    "Array Tilt:"," 0.0"
    "Array Azimuth:","180.0"

    "Energy Specifications"
    "Cost of Electricity:","12.5 cents/kWh"

    "Results"
    "Month", "Solar Radiation (kWh/m^2/day)", "AC Energy (kWh)", "Energy Value ($)"
    1, 1.87, 25, 3.12
    2, 2.98, 39, 4.88
    3, 4.28, 64, 8.00
    4, 5.92, 85, 10.62
    5, 7.20, 104, 13.00
    6, 7.83, 108, 13.50
    7, 7.88, 110, 13.75
    8, 7.08, 99, 12.38
    9, 5.75, 78, 9.75
    10, 3.96, 55, 6.88
    11, 2.33, 30, 3.75
    12, 1.73, 22, 2.75
    "Year", 4.91, 819, 102.38
    For September, the lowest of 6 months worth of production, we get 78 kWhrs per month or 78/30=2.6 kWhrs per day. Assuming 650 WH per day needed:
    • 650 Watt*Hours / 2,600 WH per 1,000 watt of panels = 250 watts of solar panel minimum (in September, you may need generator during bad weather)
    To size the battery, we generally recommend 3 days of no sun and 50% maximum discharge--so, for a 12 volt system:
    • 650 WH * 1/12v battery * 1/0.85 eff inverter * 3 days * 1/0.50 max discharge = 406 Amp*Hours @ 12 volts
    Now, given that this is a house boat, has a generator, you are not there all of the time, and you may be limited in weight/space for a battery bank--dropping the bank down to 200 Amp*Hours would not be out of the question (you will have to watch charging to make sure you do not run the battery below 20% state of charge and get it recharged > 80% before storage)--Knowing your 1/2 sized bank will need to be replaced 2x+ as often as the larger bank.

    Hardware wise--250 Watts of solar panels is not that much... MorningStar makes a wide range of PWM (cheaper) and MPPT type (more expensive) charge controllers. On the "high end", look at Morningstar SunSaver 15 Amp MPPT Solar Charge Controller. For a PWM controller, you probably need to look at a 25-30 amp minimum rated controller (MPPT does current limit so you can run at the limit without a problem).

    Morning Star also has had a Dual Battery PWM charger
    for use with Starting and House battery systems.

    If you want/need more solar panels, you can also look at the brand new Morning Star TriStar MPPT controllers (45 and 60 amp)... Very nice units.

    You may also want to look at the Rogue MPPT controller too.

    Xantrex also makes very nice larger MPPT controller and has very reliable PWM too.

    The inverter is also an important choice for your system... Some really consume power (6-8 watts or more with no loads) and others have a standby mode where they run a pulse of 120 VAC every couple of seconds to see if there is an >8 watt 120 VAC load... For a smaller 12 volt system the TSW (True Sine Wave) MorningStar 300 watt/600 watt surge/12 volt inverter is a nice product.

    If you have larger loads, some folks will put on a second, large and cheap MSW inverter (run a pump, microwave, etc.)--they do work for the most part--but if you can justify a TSW--I would high recommend one.

    To monitor your battery bank--I really like to recommend a Battery Monitor. Victron Energy also makes a couple of battery monitors that a few people here have recommended too.

    There are lots of FAQ's you can read (on PWM/MPPT controllers, Battery Banks, Inverters, etc...). Please let us know what more information you are looking for.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • fredrhodesfredrhodes Registered Users Posts: 7
    Re: Houseboat Solar

    Bill great info thank you so much!! I have plenty of space for batteries so will probably try to go upwards of 450 amp hours, I would guess more reserve is good and due to it sitting all week in the sun it should charge the batteries to capacity by the weekend.

    Ok on the charge controller, the3 BP 175's in series will be at about 110 volts. It doesn't look like the charger controller you reccomended will work, or will it handle that high of D/C voltage input? I had originally looked into a Xantrex XW because it would take the larger panel voltage. But if there is another cheaper option I am open for sure. My useage is going to be very low, and I have no choice on the panel size for a couple of reasons. One I have the panels, and two the space on the boat is limited.

    You didn't mention a 120 / 12 charger, any suggestions? Again thanks for your help!!

    Cariboocoot not sure what your comment about getting the knowledge myself was meant to imply. That is exactly what I am trying to do. I understand the system but need a little help that is why I came here. Thankfully Bill stepped up and gave me some valuable info. I am limited to the size of array on the boat so 3 - 175 watt panels is what I have to work with. Your answers where of little or no help and a tad rude.


    Fred
  • BB.BB. Super Moderators, Administrators Posts: 29,509 admin
    Re: Houseboat Solar

    I just took a guess at your needs---I have no idea if they are what you will really need...

    For larger charge controllers, the Morning Star MPPT (45./60 amp) or Xantrex 60 Amp MPPT would be fine. Check the logging options... If you are into internet, the MS 60 amp includes an Internet Server.

    You can put the panels in Parallel instead of series (depending on your battery bank voltage)--but in any case, if you are adding more panels, a larger controller will be required.

    Charge Controllers--The Xantrex TC-2 series seems really nice (I like the Power Factor Correction if you are going to be using a small generator to bulk up your battery bank--PF correction reduces the AC current used by the battery charger--and allows a smaller generator to run a larger battery charger).

    There is a larger Xantrex TC-2 charger, but it may be hard to get (call NAWS for more information). Iota is a very nice AC charger too (no PF correction or remote temperature sensor).

    If you will be using dock power/genset a lot--you might want to look at a Inverter/Charger combination... Xantrex makes some very nice ones--Basically they act like a large UPS--Have an internal transfer switch/battery charger and when AC power goes away, they switch to an off-grid inverter.

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

    Fred;

    Sorry if I seem to be rude. I don't mean to be; just realistic. Being a hopeless cynic I guess rude just colours in there somewhere.

    What I mean is you are going to have to become your own expert on your own system, because every one is a bit different. It's amazing some of the nuances that show up among one set-up and another!

    Bill's advice is good, but so is mine. So is reading, reading, reading this forum 'til your eyes start to cross. :p

    At one point you mention having 10 6V 'golf cart' batteries - generally 225 Amp/hrs each. Configured for 12V that would be 5 banks @ 225 Amp/hrs each = 1125 Amp/hrs. Three 175 Watt panels will not properly recharge that much battery. The most you could hope to handle would be two banks @ 225, as per:

    3 175W panels = 525W * 80% efficiency = 420 usable Watts / 14.2 Volts charging = 29.5 Amps charge current, which is enough for 590 Amp/hrs of battery at most. The nearest multiple of 225 without going over is 2 = 450. You need to keep the current rte up otherwise the batteries will sulphate and slowly lose capacity. This doesn't show up right away.

    That would give you a maximum of 225 Amp/hrs to work with (@ 50% DOD) or approximately 2.7 kW/hrs per day, which is pretty good really.

    Your biggest worry will still be getting good insolation on a boat. You may have to run that generator more than you'd like, but those Hondas are great generators!
  • PhotowhitPhotowhit Solar Expert Posts: 4,996 ✭✭✭✭
    Re: Houseboat Solar

    Houseboat, summer,...

    A/C?
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Prosine 1800 and Exeltech 1100, 660 ah 24v ForkLift battery. Off grid for @16 of last 17 years. Assorted other systems, and to many panels in the closet to not do more...lol
  • fredrhodesfredrhodes Registered Users Posts: 7
    Re: Houseboat Solar
    Photowhit wrote: »
    Houseboat, summer,...

    A/C?

    We are going to try without A/C. If you are hot jump in the water!! LOL We used to have a pontoon and it worked ok. We shall see. If we have to resort to a genset to run A/C that is what we will do. For sure the solar wouldn't do that. We are in Northern Calif so no humidity to speak of just HOT!!

    Cariboocoot, apology accepted and you gave me some good info also. All I am trying to do at this point is have a workable system with the 3 panels. You guys have helped a bunch and I appreciate it. I hadn't considered the need to keep the charging current up in the batteries. And your advice will save me $$ I only need to purchase 4 - 6 volts instead of the 10.

    Thanks again!

    Fred
  • icarusicarus Solar Expert Posts: 5,241 ✭✭✭✭
    Re: Houseboat Solar

    Not that I have any idea of why I am asking, but if you are completely re-habbing the the boat, why are you using circuline bulbs instead of conventional CFLs or LEDs?

    Tony
  • fredrhodesfredrhodes Registered Users Posts: 7
    Re: Houseboat Solar
    icarus wrote: »
    Not that I have any idea of why I am asking, but if you are completely re-habbing the the boat, why are you using circuline bulbs instead of conventional CFLs or LEDs?

    Tony


    A couple of reasons, cost and the profile. The circlelines are very flat and fit to the ceiling very tight. The new fixtures are pretty expensive from what I have seen and they hang down or have to be recessed, correct? If I am off base on this let me know. Also I think our nightime lighting will be minimal.

    Thanks!!

    Fred
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Houseboat Solar
    fredrhodes wrote: »
    A couple of reasons, cost and the profile. The circlelines are very flat and fit to the ceiling very tight. The new fixtures are pretty expensive from what I have seen and they hang down or have to be recessed, correct? If I am off base on this let me know. Also I think our nightime lighting will be minimal.

    Thanks!!

    Fred

    I've got CFL's in ordinary surface-mount ceiling fixtures that are relatively flat. They've been working for years, so I assume there's no problem. Look around a bit and see if there's any standard fixture that fits your dimension needs. Most of them will take one of the 'spiral' bulbs or if not then one of the pricier 'bulb-like' CFL's. Although availability in a given area may vary, along with price.
  • icarusicarus Solar Expert Posts: 5,241 ✭✭✭✭
    Re: Houseboat Solar

    A common misconception is that CFLs are only available in the icecream cone spiral shape. Nowdays, CFLs are available in nearly every size and shape an color rendition.
    http://www.nolico.com/saveenergy/products.htm

    Ranging from tiny candellabra based bulbs to Par bulbs, from 3 watts up to ~40 watts.
    LEDs are beginning to come in conventional bulb shapes, including candelabra shape, now under $10.

    The only issue I have ever heard of with CFLs is shorter life span with bulbs installed base up. It seems in a base up orientation, the ballast tends to run warm. I tend to think this is a real issue, but the reality is since the bulbs have gotten so cheap, even if they only live 1/2 as long as usual in a base up orientation,, so what?

    Tony
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