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  • Solar Boost 2000E input voltage

    Hi friends,

    I've just joined the club. I received my 2 Kyocera 135W panels and the Solar Boost 2000E today.
    I had planned to connect the two panels in series to reduce the wiring sizes and guessing that having the panels in series would reduce the impact shading will have on the performance. They will be mounted on a sailboat and will very often be partially shaded, and be at a variable, often bad angle to the sun. So, I really expect much less performance than under ideal conditions.
    Reading the 2000E spec sheet I realize that that controller only allows a max input voltage of 30V. The two panels in series will certainly be above this much of the time. But sometimes these max values are a little conservatively calculated, did any of you try (on purpose, or by accident) feed a higher voltage into this controller? I'd think most of the time my panels would be at 17 or 18 volts, so in series it would put me into the 34-36 range...

    Greetings, Stephan

  • #2

    Re: Solar Boost 2000E input voltage

    Re: Solar Boost 2000E input voltage

    Welcome Stephan!

    Maximum input voltage on any charge controller is just that: maximum. You don't want to go over it. But the good news is the panels are less effected by shading when in parallel, not series. If a shadow falls on one panel connected in series it reduces the output of the whole string - like having one low battery out of two in a flashlight. If they are parallel it effects just that panel. I shouldn't imagine you'd have particularly long wire runs on a boat, so line loss could be kept at a minimum fairly easily. See this thread regarding wire sizing:

    http://forum.solar-electric.com/showthread.php?t=29

    What's the rest of your system set-up? I'm guessing 12 V, and with those two panels in 'partial sun' you should be able to keep 135 A/hrs of battery happy, possibly more. Should be good for 400 Watt hours per day, +/-.

    Comment


    • #3

      Re: Solar Boost 2000E input voltage

      Re: Solar Boost 2000E input voltage

      Paper says 30V max. Sorry. Maybe trade with the vendor?
      Morningstar sun saver http://store.solar-electric.com/mosumpsochco.html
      is good for 75V.

      CAUTION!
      If you have panels in series, and one gets shaded (even a tiny bit), the output of
      the other panel will be cut too, or at lest in proportion of any panel bypass diodes.
      http://tinyurl.com/LMR-Solar
      http://tinyurl.com/LMR-BigLug
      http://tinyurl.com/LMR-NiFe

      Grundfos 10 SO5-9 with 3 wire Franklin motor (1/2hp 240V 1ph # 214505 ) on a timer for 3 hr noontime run - Runs off PV
      Powerfab poletop PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe battery | 15, Evergreen 205w "12V" PV | Midnight ePanel || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT

      Comment


      • #4

        Re: Solar Boost 2000E input voltage

        Re: Solar Boost 2000E input voltage

        Cariboocoot,

        this is indeed great news. I hadn't realized that the panels in parallel are better. Oh, so cool! Some fatter wire won't be a problem, really. You are totally correct.
        The rest of my setup is currently three group 24 dual-purpose lead batteries in parallel, eventually to be joined by a fourth.
        Depending on the space available, I might try to make that fourth battery a group 27 or even 31. But I would ask you first if having dissimilar batteries in parallel would have unexpected bad side effects.
        This group is great! I didn't expect an answer, and such a good one, so quickly.
        Thanks again!

        Stephan

        Comment


        • #5

          Re: Solar Boost 2000E input voltage

          Re: Solar Boost 2000E input voltage

          You will probably be disappointed with your battery choice. For one thing, "dual purpose" usually means "not as good as the proper thing in two different applications." If you want true performance out of your system, it's worth buying real deep cycle batteries of the "electro-motive" type: i.e. for golf carts and electric forklifts. The other thing that matters is the Amp/hr rating: too high and the panels don't produce enough current for proper re-charging (the experts recommend 5%-13% of the battery's Amp/hr rating for charge current). Too low and you don't have enough capacity to run anything or you'll be drawing them down too much. This is called "depth of discharge" (DOD) and it is recommended you keep it below 25% for most deep cycles. Really, really good ones can take 50% DOD repeatedly. So when calculating your usable power, you have to use 50% MAXIMUM of the battery's Amp/hr rating to see how much usable power you have: 100 A/hrs * 50% = 50 A/hrs @ 12 V = 600 Watt/hours. That's six 100 Watt bulbs for one hour, or one 100 Watt bulb for six hours. These are nominal calculations, and don't include the fine tuning that comes with calculating an individual system's particular efficiency losses (which can be substantial). But it gets you "in the ball park".

          Your 270 Watts of panels would also have to be 'derated' for efficiency losses and the (in your case) quite unpredictable amount of sun that will fall on them. It's easier for a fixed location, but even then there's seasonal differences. So figure roughly 60% capacity average over five or six hours of usable daylight. All in all, I'm thinking somewhere in the neighborhood of 200 Amp/hrs of battery capacity might be viable for your system. That would give you the 50 A/hrs mentioned above with lots of margin for error. But it's very imprecise.

          The other thing about batteries is don't mix different types; they don't discharge/recharge the same, and the end result will be premature failure of all the batteries.

          Now the "$64 question": what is your intended usage? It's important to know what you hope to get out of a solar power system before you can figure out what to put in to it. Too many people buy a "package" and then find out it's hopelessly inadequate and often seriously over-priced.

          Comment


          • #6

            Re: Solar Boost 2000E input voltage

            Re: Solar Boost 2000E input voltage

            Coot,
            thanks for taking time to look at my setup.
            My intended use is to power the boats electric system to a degree that running the engine to recharge can be reduced to as little as possible.

            My biggest power hog will be my fridge, which will possibly draw between 480-960 Wh per day. The good thing is that the fridge needs most power when it's day, and hottest, and that usually means it's sunny, so the panels feed immediately into the fridge.
            The rest of my consumption is mostly lights (some of them LEDs, all the rest low power (15W or 10W)), laptop computer (maybe 3 hours a day, 70 W), and the stereo (3 hours, 20W).
            So, a very rough estimate would be that I'd use between 1kWh - 1.5 kWh per day.

            My planned 4 batteries would have a nominal storage of
            75Ah * 4 = 300Ah * 12V = 3.6 kWh
            As you suggest, drawing them down to 50% is the absolute max I should do, better for long life would be to stay higher.

            On sunny days I think I might be fine with this setup, but on cloudy days, my engine will have to be used to recharge the batteries...

            Since I have the 3 batteries already, I thought it would be quite uneconomical to exchange them all for deep cycle at this time. I was thinking of doing this when they start losing capacity.

            I'm aware that, unless I seriously upgrade my battery bank, I'll live hand-to-mouth, so to speak. But still a step in the right direction, right?

            Greetings, Stephan

            Comment


            • #7

              Re: Solar Boost 2000E input voltage

              Re: Solar Boost 2000E input voltage

              Your 270 watts of panel will be lucky if they produce ~5-600 wh/day,, even if you keep them optimally aim,, tough to do on a boat.
              My rule of thumb,, is to take the name plate rating of the array,, (270) divide it by 1/2 to take into account ALL system losses,, (Panel ef, charge controller ef, basic battery charging ef, wiring losses, inverter efficiency etc>) that would make 135,, multiply this number by the expected hours of GOOD sun,, normally ~4 = 540 wh. If you go into this using 1-1.5 kwh/day, you will go into deficit right away. That coupled with non-deep cycle batteries,, and I would predict that you will have expensive lead ballast quite quickly.


              Tony

              PS, I that there is some quibble with my 50% number,, some think it too high,, some think it too low. The point is,, for a quick calc,, it is close enough to realize that in cases such as yours,, you are going to be in deficit regardless of if my number should be 55% or only 45%.
              Please note, being a moderator does not add any weight to my opinions 300 watts Siemens/BP panels,plus a Sun 90,, making ~400. ~30 amps into Rogue MPT-3024, 450 ah of Trojan T-105, Morningstar ts300 inverter, a Tri-Metric meter.a collection of antique generators, plus 2 Honda eu-1000i's (also a BS2512 IX controller) and assorted other stuff!

              Comment


              • #8

                Re: Solar Boost 2000E input voltage

                Re: Solar Boost 2000E input voltage

                Remember: you haven't got 300 Amp/hrs to work with, you've got 150 MAX.

                Those panels are going to be marginal at keeping up with usage and recharging even that amount, especially given the unpredictability of your solar exposure. Any chance for adding more panels in future?

                And Tony is, as usual, right: panel ratings are peak ratings, not continuous. For an over-all average of actual usable power, serious de-rating is required. Although I use 60% rather than 50%, so I must be something of an optimist!

                Comment


                • #9

                  Re: Solar Boost 2000E input voltage

                  Re: Solar Boost 2000E input voltage

                  Thanks Tony and Coot,

                  I understand that I'm marginal to keep up with my electricity drain. I'm not expecting to be able to keep my engine off for good, but to reduce the number of hours I need to run it. I hope that by carefully monitoring the battery condition (the controller has a volt meter) I can avoid discharging them too much.
                  I'm reducing my power use by increasing the fridge insulation and eventually getting a laptop with lower power drain. The LEDs are the only lights I run a lot of hours, all the other lights are on only infrequently. I have no appliances of any kind. So my hope would be to reduce my use to significantly less than 1kWh.
                  I chose the MPPT controller hoping to get higher efficiency than a 'dumb' controller. The current that goes into the fridge compressor doesn't have to be stored, so I have no big loss with the battery. I don't have my inverter hooked up much, unless I'm charging my phone or the hand tools.
                  Last not least, I might get another pair of panels eventually, I'll size my mounting frame accordingly. Unfortunately, the space on the boat is somewhat limited, just like my wallet.

                  Greetings, Stephan

                  Comment


                  • #10

                    Re: Solar Boost 2000E input voltage

                    Re: Solar Boost 2000E input voltage

                    Remember, Voltage is not a very good way of measuring battery condition. The only time voltage is anywhere near accurate is when the battery has been "at rest", neither charging nor discharging for several hours. While charging the battery will show artificially high,, while discharging low. A better way is to check specific gravity with a hydrometer, (not possible with sealed batteries) or use a good battery monitor like the Tri-metric that counts AH out/AH in and gives a real time state of charge.

                    The reality is that the increase from the MPPT on such a system is likely to be under 10%, not insignificant,, but in your world not enough to make much difference.

                    If you haven't already read these: http://www.batteryfaq.org/
                    http://www.windsun.com/Batteries/Bat...of%20Batteries

                    Tony
                    Please note, being a moderator does not add any weight to my opinions 300 watts Siemens/BP panels,plus a Sun 90,, making ~400. ~30 amps into Rogue MPT-3024, 450 ah of Trojan T-105, Morningstar ts300 inverter, a Tri-Metric meter.a collection of antique generators, plus 2 Honda eu-1000i's (also a BS2512 IX controller) and assorted other stuff!

                    Comment


                    • #11

                      Re: Solar Boost 2000E input voltage

                      Re: Solar Boost 2000E input voltage

                      MPPT controller is a good choice because you're going to need to squeeze every bit of available power you can get from the sun.

                      Now about inverters ...

                      What sort have you got? I ask this because you mention re-charging tools. Some battery chargers don't like modified sign wave, particularly those for cordless tools. In essence, the output appears to be 'low voltage' so the reference voltage they use for recharging is low also, and the battery never gets fully re-charged. Eventually it wrecks the battery. AC induction motors don't like MSW either. The smaller ones will usually work on it, but not efficiently and it will reduce their lifespan.

                      Comment


                      • #12

                        Re: Solar Boost 2000E input voltage

                        Re: Solar Boost 2000E input voltage

                        Stephan,

                        Does your boat allow for you to aim the panels correctly free of shadows (i.e., docked house boat vs sailboat at anchor)?

                        Can you / do yo want to change out your current fridge for either propane (if practical) or a converted chest freezer (perhaps ~250 Watt*Hours per day):

                        Chest freezer as a chest refrigerator

                        As others have mentioned--an MPPT controller is not going to be a big help here unless a) you are in a very cold climate, or b) you need to run the panel to charge controller wire a long distance and need the higher panel voltage, or c) you have cool batteries and very hot batteries where you may run into an issue where the battery+equalize voltage (cold) is higher than your Vmp (hot) panel voltage+wiring drops.

                        You are probably severely under solar paneled for your expected loads... Leading to you needing to run the genset more... Run the genset in the mornings to "bulk up" the batteries and allow the panels to finish up in the afternoon.

                        Is your genset "fuel efficient" vs your charging / AC draw? Generally, a genset is most efficient when >=50% load and a real fuel waster when operated below that point (the Honda eu2000i is fuel efficient >=25% load).

                        Lastly, a Battery Monitor is going to be your friend... It will be difficult to operate your system (and not damage the battery bank or have "unplanned outages" that take out your fridge when you are not there to start the engine) with out one.

                        -Bill
                        20x BP 4175B panels (replacement) + Xantrex GT 3.3 inverter for 3kW Grid Tied system + Honda eu2000i Inverter/Generator for emergency backup.

                        Comment


                        • #13

                          Re: Solar Boost 2000E input voltage

                          Re: Solar Boost 2000E input voltage

                          If I read it right, his "genset" is his boat motor. Probably not a very fuel-efficient way of charging!

                          Comment


                          • #14

                            Re: Solar Boost 2000E input voltage

                            Re: Solar Boost 2000E input voltage

                            Cariboocoot,

                            You are probably correct... might be sort of OK if diesel--but even then running a diesel at low rated power probably carbons / cokes them up and adds hours to an otherwise expensive engine to feed and maintain.

                            lachbus,

                            Conservation will be your friend... Finding/using appliances that use the fewest watts (or watt*hours) to do the job is a requirement. Use a kill-a-watt meter to check your loads (watt*hours over a day or so of average usage--especially useful for cycling loads like a fridge or computer). Getting a very low power laptop (if you can use a smaller computer), etc....

                            If your sailboat is at anchor (and subject to tracking variable direction winds)--your arrays will probably produce much less power than you expect/hope for... Any direct shade on a solar PV panel will Usually) dramatically reduce its output. Using a high voltage MPPT charge controller (MorningStar 15 amp MPPT) with the two panels wired in series might do a (slightly?) better job than wiring the 12 volt panels in parallel.

                            However, I am not sure you could measure the difference between series/parallel if lines/etc. are casting shadows across one or both panels for significant parts of the day. That is just bad news.

                            -Bill

                            PS: If you can, measure your fuel flow when running your existing generator (main motor at anchor?) and see how many kWhrs per gallon of fuel (volts*current*hours = Watt*Hours) you are getting...

                            A gasoline genset will get around 5-6kWhrs per gallon of fuel (5,000 to 6,000 Watt*Hours) at the high end of the efficiency scale.

                            Anything less than 3-4 kWhrs per gallon of fuel, can be improved with a separate (small) genset (is it safe/practical for you to use a Honda eu2000i or eu1000i genset?).
                            20x BP 4175B panels (replacement) + Xantrex GT 3.3 inverter for 3kW Grid Tied system + Honda eu2000i Inverter/Generator for emergency backup.

                            Comment


                            • #15

                              Re: Solar Boost 2000E input voltage

                              Re: Solar Boost 2000E input voltage

                              Guys, you are great. Lots of good info. I'm at work and cannot write a lot now, but your point about the hand tools is particularly useful. I have the 18V Ryobi set and I noticed that it's not charging well. I'll take the charger to work and will use it there. Lugging the batteries back and forth occasionally is not a big problem.
                              I have a tiny Rosewill 120W inverter (which of course puts out the 'modified sine wave'), mostly for the phone and the AA battery charger. I use it for my laptop as well, at this time, but plan to get the laptop onto the 12V circuit asap.
                              I just bought the fridge conversion set for my current ice box. It's rated at 40W, and with increased insulation it should hopefully run 50% of the time, thus take 480 Wh.
                              I try to stay away from propane (apart from for the grill), don't like to mess up and blow myself up.

                              Stephan

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