Solar, Wind, Grid (triple) charging setup.

First, I'd like to say that I have never built a system before so go easy on me, but here's what I want to set up.

I would like to set up a system of batteries to run a load which will be charged by solar panels and a wind turbine, and the third charge controller would be plugged into my outlet but I only want it to run when my battery bank gets below 70-80% or so. From what I gather you can connect multiple controllers to the same battery bank, but how do I get the 3rd controller (which will be plugged into the grid) to only turn on at a set voltage?

I found out that there are voltage sensing switches out there, but my electronics experience is pretty limited, so I am still learning. Does anyone have any suggestions for what kind of components I need for a system such as this.

I am prepared to purchase MPPT charge controllers. I've heard of programmable power relays/ controllers, but dont know much about them (not affraid to learn).

So the way I see it now is: the two primary (solar and wind) charge controllers will be connected directly to the battery bank, and the third (secondary charging system) will be isolated by a voltage sensing relay which will turn on at an appropriate voltage (70%-80% capacity of battery bank).

another question I see in my mind is, should i have a system where only one charge controller is active? reason i ask is, lets say I have a sunny and windy day, wouldnt the two controllers provide too much voltage to the system? Again, I'm sure there is a wiring trick I may not know so please enlighten me please.

i am looking for any input, I know this can be done, but with what equipment. I wonder if there are controllers which can be plugged into my PC in order to program them directly. Anyhow, any and all input is much appreciated.

Comments

  • BB.BB. Super Moderators, Administrators Posts: 28,992 admin
    Re: Solar, Wind, Grid (tripple) charging setup.

    Welcome to the forum Fermer!

    I will attempt to answer the questions "generically" first, then we can talk about specifics for your needs (more information from you--many solar RE components options are very dependent on ratings and needs).
    fermer wrote: »
    I would like to set up a system of batteries to run a load which will be charged by solar panels and a wind turbine, and the third charge controller would be plugged into my outlet but I only want it to run when my battery bank gets below 70-80% or so. From what I gather you can connect multiple controllers to the same battery bank, but how do I get the 3rd controller (which will be plugged into the grid) to only turn on at a set voltage?

    There are voltage controlled switches you can use (like this one, but it is not temperature corrected).

    Estimating battery bank capacity by monitoring voltage is not very accurate. Another, more accurate method, would be to use a Battery Monitor (I believe both these Xantrex and Victron units have a programmable contact that can be used to control a charge controller/generator).

    And, I believe, the higher end charge controllers may be programmable for similar function (I am not sure--would have to research the Midnite, Outback, MorningStar production lines).
    So the way I see it now is: the two primary (solar and wind) charge controllers will be connected directly to the battery bank, and the third (secondary charging system) will be isolated by a voltage sensing relay which will turn on at an appropriate voltage (70%-80% capacity of battery bank).

    This is where it gets "complicated". A solar charge controller connects in series between the Solar Array and the Battery bank. A solar panel can be turned on or off to control energy flow to the battery bank/loads.

    However, a standard horizontal axis wind turbine needs to be loaded all the time so that it will not over speed. Typically, the turbine is connected directly to the battery bank, and a "shunt/diversion/dump" controller. The controller connects to the battery bank and to a dump load (an electric heater or electric water heater typically). When the battery voltage exceeds the programmed charging voltage, the diversion controller turns on and sends power to the "dump load".

    It takes a bit of programming/monitoring (and design trade offs) so that you don't get in the situation where the solar (or even your backup power source) is "charging" the battery bank and the diversion controller is dumping power to the heaters.

    For larger wind turbines, there are MPPT charge controllers that have their own diversion controller (separate from the battery bank)--Which can increase your turbine's output by 2-3 times. Midnite Classic+Clipper is one interesting unit (these are not cheap).
    another question I see in my mind is, should i have a system where only one charge controller is active? reason i ask is, lets say I have a sunny and windy day, wouldnt the two controllers provide too much voltage to the system? Again, I'm sure there is a wiring trick I may not know so please enlighten me please.

    Solar Charge Controllers (both MPPT and PWM) simply turn off the solar array when no charging current is needed.

    However, wind turbines, since they always need a load typically use the diversion controller to simply put a "waste" load on the battery bank when it is at full charge voltage. Diversion controllers do not do "as good of job" of properly charging a battery bank as a "series" type charge controller--So normally you would still want the series controller for your solar array. Also, since dump loads fail, and an battery bank receiving too much current can fail with a fire and/or explosion, the NEC requires a second controller+dump load as backup (not everyone will run backup dump controllers).
    i am looking for any input, I know this can be done, but with what equipment. I wonder if there are controllers which can be plugged into my PC in order to program them directly. Anyhow, any and all input is much appreciated.

    Again, sort of gets back to the size of your system... Larger charge controllers (typically $300-$600+) will have computer interfaces (some even have native Web interfaces). Some have a command bus that you can connect to a dongle for RS 232 programing/control (usually limited control/access).

    By the way, I am not a fan of wind power... Do you have a lot of wind at your site and can support a 60-90+ foot tall tower? There are a few wind turbines that folks here have (or even made themselves) that perform well. But many of the units out there are not very reliable/rugged and/or mounted on tall enough towers in windy enough locations to be effective.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • nielniel Solar Expert Posts: 10,311 ✭✭✭✭
    Re: Solar, Wind, Grid (tripple) charging setup.

    "and the third charge controller would be plugged into my outlet"

    if you mean a 120vac outlet then you will be in for some fireworks. controllers aren't battery chargers that can be plugged into a wall socket.

    you are correct that it is possible all charge sources or any combination thereof could possibly overcharge your batteries. you have to know the limits your batteries can take as speced by the manufacturer otherwise i'd try to limit it to about 13% of the ah rating max. if there aren't any automatic means on your controllers (many can be programmed to limit current) then you may wish to manually monitor the situation or eliminate one of the sources.
  • stephendvstephendv Solar Expert Posts: 1,571 ✭✭
    Re: Solar, Wind, Grid (tripple) charging setup.

    Hi fermer,

    The system is not that complex especially if you will be using an inverter to run the loads from the battery. If you haven't bought anything yet, then the simplest way to connect it all is:

    1. PV using "off-grid" panels that match the battery bank voltage (e.g. Panels with a 17Vmp rating for a 12V battery), connected directly to the battery.
    2. Wind turbine that matches battery voltage also connected directly to the battery.
    3. A dump load PWM controller and it's associated dump load resistors which is connected across the battery and is sized to dump the combined output of PV and Wind.
    4. An inverter/charger which connects to the mains, to the battery and to the load you want to run. This is a single device that is a charger and an inverter and includes an automatic transfer switch. The transfer switch can then be programmed to turn on and off based on the battery voltage. Examples of this type of device are the Outback VFX, Xantrex XW and Magnum to name a few.

    A slightly more complex setup is if you want to use PV panels that don't match your battery bank voltage, then you'd have to add an MPPT charge controller between PV and battery. In this case you'd have 3 chargers to synchronize, the MPPT, the PWM and the inverter/charger.

    The other alternative which you started off with is to use an independent mains battery charger instead of an inverter/charger. In this case, as you point out you'd need some way to automatically turn it on and off, and if you choose morningstar charge controller for the wind and/or solar then you can use their "Relay driver" product which lets you turn on arbitrary relays based on events in the charger controllers. Other solar MPPT charger controllers also have a built in relay (Outback FM and Midnite Classic), which I think you could also program to come on based on battery voltage, hopefully someone else will confirm this. Note that the integrated relay can't handle mains voltage and current, so you'd need it to switch another external relay.
  • solar_davesolar_dave Solar Expert Posts: 2,338 ✭✭✭✭
    Re: Solar, Wind, Grid (tripple) charging setup.

    If you have reliable grid why would you want to get into a battery situation which requires all the maintenance and replacements over time. Grid tie will give you the biggest battery you can get, the grid, with a minimal cost if you have a decent net metering plan with the utility. Off gird power is way expensive, Grid tie power is better and with the right rebates and tax incentives can compete with grid power. A good TOU plan helps the equation as well.
  • fermerfermer Registered Users Posts: 4
    Re: Solar, Wind, Grid (tripple) charging setup.

    Thanks for the replies so far. This is giving me a clearer picture of what equipment I need. So far I have not bought anything because from what I am seeing is, there are significant costs. This is going to be a hobby project at first, but I am planning on expanding the system, but I want my components to be of high quality and of course I want them to match so I do not waste money.
    If you have reliable grid why would you want to get into a battery situation which requires all the maintenance and replacements over time. Grid tie will give you the biggest battery you can get, the grid, with a minimal cost if you have a decent net metering plan with the utility. Off gird power is way expensive, Grid tie power is better and with the right rebates and tax incentives can compete with grid power. A good TOU plan helps the equation as well.

    I'm not doing this to save money, charging from 120 VAC is for backup purposes, as a last resort backup feature and a generator can provide that. It is really there so my batteries don't happen to get discharged too far. This is a personal hobby project.
    This is where it gets "complicated". A solar charge controller connects in series between the Solar Array and the Battery bank. A solar panel can be turned on or off to control energy flow to the battery bank/loads.

    However, a standard horizontal axis wind turbine needs to be loaded all the time so that it will not over speed. Typically, the turbine is connected directly to the battery bank, and a "shunt/diversion/dump" controller. The controller connects to the battery bank and to a dump load (an electric heater or electric water heater typically). When the battery voltage exceeds the programmed charging voltage, the diversion controller turns on and sends power to the "dump load".

    It takes a bit of programming/monitoring (and design trade offs) so that you don't get in the situation where the solar (or even your backup power source) is "charging" the battery bank and the diversion controller is dumping power to the heaters.

    For larger wind turbines, there are MPPT charge controllers that have their own diversion controller (separate from the battery bank)--Which can increase your turbine's output by 2-3 times. Midnite Classic+Clipper is one interesting unit (these are not cheap).

    The reason for wind is simple, where i live (SE Nebraska) there is almost always a pretty good breeze. It would be a shame not to use it. I'm not looking for a very big turbine... maybe a row of 3 or so on my roof in the 600W range or so. It just seems to make a lot of sense to incorporate it into the system.

    I really like the idea of dumping extra power into a water heater, a bunch of wiring questions and on the type of heater come to mind, but that's for later.
    Again, sort of gets back to the size of your system... Larger charge controllers (typically $300-$600+) will have computer interfaces (some even have native Web interfaces). Some have a command bus that you can connect to a dongle for RS 232 programing/control (usually limited control/access).

    I am prepared to spend that amount on a charge controller because once you have it (at least to my understanding) you simply (well not simply probably :) ) add more batteries and more panels
    "and the third charge controller would be plugged into my outlet"

    if you mean a 120vac outlet then you will be in for some fireworks. controllers aren't battery chargers that can be plugged into a wall socket.

    you are correct that it is possible all charge sources or any combination thereof could possibly overcharge your batteries. you have to know the limits your batteries can take as speced by the manufacturer otherwise i'd try to limit it to about 13% of the ah rating max. if there aren't any automatic means on your controllers (many can be programmed to limit current) then you may wish to manually monitor the situation or eliminate one of the sources.

    I'm not sure what you mean, because there are dedicated wall chargers out there designed for this task.
    The other alternative which you started off with is to use an independent mains battery charger instead of an inverter/charger. In this case, as you point out you'd need some way to automatically turn it on and off, and if you choose morningstar charge controller for the wind and/or solar then you can use their "Relay driver" product which lets you turn on arbitrary relays based on events in the charger controllers. Other solar MPPT charger controllers also have a built in relay (Outback FM and Midnite Classic), which I think you could also program to come on based on battery voltage, hopefully someone else will confirm this. Note that the integrated relay can't handle mains voltage and current, so you'd need it to switch another external relay.

    This is pretty much of what I was thinking, but now that I realized temperature is a big deal in determining the state of charge, along with voltage, I wonder if there is a battery health module which has the ability to trigger my VAC charger....


    Anyway, I am in the very early design stage for this as I will not be ready to purchase equipment quite yet, and I will have to do it in steps. But when I am ready to purchase, I want to keep equipment swaps to a very bare minimum especially when I am paying 500-600 dollars for parts (controllers and what not). I am not an electrician so I will have to do some more studying, but again I'm not affraid to learn. I am an architecture student, and self reliance is a very interesting subject for me.

    so the initial system as I imagine will be pretty straight forward solar only, along with a backup charger using 120VAC (genarator, wall, etc), with a fairly small bank of batteries of probably 5-6 100 ah AGM batteries, and some panels to match, then I'd like to add the wind turbines, but nothing big. Once I am ready for my system to grow, I will add more batteries and panels, etc. So far the advice has been very helpful, but now I need to start looking at matching all of this equipment. Ultimate goal is for the system to be automated, and of course with appropriate safety features.
  • inetdoginetdog Solar Expert Posts: 3,123 ✭✭✭✭
    Re: Solar, Wind, Grid (tripple) charging setup.
    fermer wrote: »
    The reason for wind is simple, where i live (SE Nebraska) there is almost always a pretty good breeze. It would be a shame not to use it. I'm not looking for a very big turbine... maybe a row of 3 or so on my roof in the 600W range or so. It just seems to make a lot of sense to incorporate it into the system.

    Reality check:
    1. When you say a good breeze, is it strong enough that you have to tie your hat down? If not, it is not a strong breeze in the wind power sense.
    2. Never mount a turbine on your roof or otherwise attached to any structure you spend time in. It will drive you crazy in short order and maybe shake your roof enough to damage it.
    3. Plan to mount the turbine(s) at least 60 feet above the ground and at least 30 feet above the top of your roof, trees, hills, or anything else that will interfere with the wind flow and is within about 300 feet in any direction from the turbine(s).
    4. Don't buy cheaply made turbines from China. They will produce next to no power, fail quickly and maybe spectacularly, or both. Same for cheaply made US turbines if you can find any, just to be fair.

    Unless you are totally off-grid and have bad enough weather in the winter that you will get no panel output for days at at time, the same amount of money spent on solar will give you a better return. Micro-hydro is another alternative, but you probably do not have a place for that.

    Your goal to get a system that can be expanded at minimum cost is admirable, but given the equipment which is available, there is no easy way to start inexpensive and grow bigger without throwing away what you started with. (For example, to start small, you may use a 12 volt system. But if you get bigger you will need 24 or 48 volts instead, and that will usually mean replacing at least your inverter and possibly your charge controller(s). Adding new batteries to an existing system, either to increase the AH or increase the voltage will not work well.)
    SMA SB 3000, old BP panels.
  • BB.BB. Super Moderators, Administrators Posts: 28,992 admin
    Re: Solar, Wind, Grid (tripple) charging setup.

    Note--I am not a fan of wind (in general). In the "right hands" and a good installation/location, it can be a nice addition to your overall power generation.

    Here are some links that you can read. Many are pro-wind, a few are not:
    BB. wrote: »
    Add links about wind power:

    Wind Power Links
    www.otherpower.com (good forum for DIY Wind Power)
    Hugh Piggott - Scoraig Wind Electric site for tons of info (from mike90045)
    www.greenpowertalk.org (added from "russ"--Like here but more wind/less solar)
    Small windpower a scam ? Survey says SO
    Truth About Skystream & SWWP
    Windmax HY-2000 2kW Wind Turbine (apparently, some vendors don't sell spare parts--just new turbines. However, the owner, Edward has been very happy with its performance from 2010-2012--BB. 5/31/2012)

    -Bill

    Note that many wind turbines have a history of shedding blades and even having turbine heads falling from towers (probably any turbine can be at risk)... I would highly suggest that turbines are not anywhere near occupied buildings and where kids play.

    If you have some turbines you are looking at--Do some research/contact customers and find out how well they are performing. Very few wind installation seem to have any sort of Watt*Hour/Amp*Hour meter attached. Just because a turbine is spinning, it does not mean that it is generating power.

    Going back to my room now. :blush:

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • fermerfermer Registered Users Posts: 4
    Re: Solar, Wind, Grid (tripple) charging setup.

    points taken. After seeing the comments on wind turbines, I think I will pass. I think you're right on simply going solar. but I do still want that backup 120vac option to charge my batteries. So it leads me to this question. The Magnum Energy MS2012 2000 Watt Sine Wave Inverter is also a charger. From what I understand, if it senses current coming in to it, it will charge the batteries. How does that charging compete if it is sunny out? Will the solar panels and the inverter be charging the batteries at the same time?

    Personally that is not an ideal solution for me, because I want to control when the batteries get the help to charge from 120 VAC, basically help the batteries when they get to a certain level which I decide.
  • Blackcherry04Blackcherry04 Solar Expert Posts: 2,490 ✭✭✭
    Re: Solar, Wind, Grid (tripple) charging setup.
    fermer wrote: »
    points taken. After seeing the comments on wind turbines, I think I will pass. I think you're right on simply going solar. but I do still want that backup 120vac option to charge my batteries. So it leads me to this question. The Magnum Energy MS2012 2000 Watt Sine Wave Inverter is also a charger. From what I understand, if it senses current coming in to it, it will charge the batteries. How does that charging compete if it is sunny out? Will the solar panels and the inverter be charging the batteries at the same time?

    Personally that is not an ideal solution for me, because I want to control when the batteries get the help to charge from 120 VAC, basically help the batteries when they get to a certain level which I decide.
    The charger only works when you have AC input on it and you can turn it on or off on the remote. It shouldn't be a issue when you have Solar on the batteries, but it's there as a back up when there is no sun and you use it from Grid or Generator.

    This Inverter is not going to allow you to " SELL " excess power to the grid, if that was your intention. It's a off-grid inverter, but could be rigged to give you off - grid power for some kind of standby situation.
  • stephendvstephendv Solar Expert Posts: 1,571 ✭✭
    Re: Solar, Wind, Grid (tripple) charging setup.
    fermer wrote: »
    The Magnum Energy MS2012 2000 Watt Sine Wave Inverter is also a charger. From what I understand, if it senses current coming in to it, it will charge the batteries. How does that charging compete if it is sunny out? Will the solar panels and the inverter be charging the batteries at the same time?

    You'd have to check the manual for the inverter to see whether it's possible to automate this. Some inverter/chargers will let you program the transfer switch based on the battery voltage or the state of charge. Some also allow you to connect to the grid if a current limit is exceeded, e.g. if you try to draw 3000W from the 2000W inverter, then the inverter will switch to grid and you won't notice the changeover. These features depend on the manufacturer and vary from inverter to inverter, so the manual is a good place to check :)
  • fermerfermer Registered Users Posts: 4
    Re: Solar, Wind, Grid (tripple) charging setup.
    stephendv wrote: »
    You'd have to check the manual for the inverter to see whether it's possible to automate this. Some inverter/chargers will let you program the transfer switch based on the battery voltage or the state of charge. Some also allow you to connect to the grid if a current limit is exceeded, e.g. if you try to draw 3000W from the 2000W inverter, then the inverter will switch to grid and you won't notice the changeover. These features depend on the manufacturer and vary from inverter to inverter, so the manual is a good place to check :)

    Any suggestions on an inverter that has such features. Ie: automatically charge from grid, and/or start charging based on voltage or charge level? Oh. I have no plans to sell power back to grid.
  • SulfurSulfur Solar Expert Posts: 62 ✭✭
    Re: Solar, Wind, Grid (tripple) charging setup.
    fermer wrote: »
    Any suggestions on an inverter that has such features. Ie: automatically charge from grid, and/or start charging based on voltage or charge level? Oh. I have no plans to sell power back to grid.

    It sounds like your asking for a Sunny Island 5048 if your going to have a Sunnyboy with the solar panels. It does what your asking very cleanly, if I read that right.


    what is the load your backing up? is it 120VAC?
  • gww1gww1 Solar Expert Posts: 963 ✭✭
    Re: Solar, Wind, Grid (tripple) charging setup.
    Originally Posted by fermer
    Any suggestions on an inverter that has such features. Ie: automatically charge from grid, and/or start charging based on voltage or charge level? Oh. I have no plans to sell power back to grid.

    I have the outback gridtie inverter and It acts in such a fassion acording to the manual. It can be used as an offgrid inverter but is picky about the generator. I have not read the manuals for the of grid outbacks.

    gww
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