Wind and solar charge controller issue

kouts5
kouts5 Registered Users Posts: 5 ✭✭
Hey guys, Im a newbie. So we have 3 PV panels that produce 250 Watts each so 250x3= 750 W in total.
We use a non-mppt charge controller, batteries, and a 1500W inverter.

My father wants to buy a new charge controller, a mppt. But we are also thinking of buying next year a wind turbine
with a 600W max output. What kind of charge controller should we get? A hybrid one?
Or can we buy a solar mppt controller this year and a wind controller next year ( along with the wind turbine) and
make them run all together? Whats the "healthiest" option for my system and the most economic.

Im kinda confused

Thanks a lot for your time. If you need any more info about the batteries and our current charge
controller οr anything other, I can give it to you tomorrow that I will be in our beach house where all this stuff is.

Comments

  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: Wind and solar charge controller issue

    Welcome to the forum.

    I think you would get the most benefit from an MPPT controller on your existing panels. The reason being that at 250 Watts they probably are 'GT style' meaning their Vmp is around 30 which is not suitable for any battery system without some significant losses. You don't say what your system Voltage is nor the actual specs on the panels, but believe me it all makes a difference.

    As for wind, several places in Greece have good wind. Be sure you are at one of them before investing any money in a turbine: you can't harvest what isn't there. The type of controller used for this will depend on the particular turbine you choose. Most common for medium-size installations (750 Watts solar & a turbine would count as such) is one controller regulating the charge from the panels and another (usually diversion type) working for the wind.

    As always the devil is in the details.
  • kouts5
    kouts5 Registered Users Posts: 5 ✭✭
    Re: Wind and solar charge controller issue
    Welcome to the forum.

    I think you would get the most benefit from an MPPT controller on your existing panels. The reason being that at 250 Watts they probably are 'GT style' meaning their Vmp is around 30 which is not suitable for any battery system without some significant losses. You don't say what your system Voltage is nor the actual specs on the panels, but believe me it all makes a difference.

    As for wind, several places in Greece have good wind. Be sure you are at one of them before investing any money in a turbine: you can't harvest what isn't there. The type of controller used for this will depend on the particular turbine you choose. Most common for medium-size installations (750 Watts solar & a turbine would count as such) is one controller regulating the charge from the panels and another (usually diversion type) working for the wind.

    As always the devil is in the details.

    Thanks for your reply. Our place is by the sea, and usually it is windy 20/24 hours of the day,
    during the summer. Doing a quick search earlier I easily found hybrid controllers but they were about 600W for solar
    and 400-2000W or more for wind. I couldnt easily find a hybrid with more W for solar than wind, and as I've seen
    they are kinda more expensive than buying 2 different controllers.

    So i guess I should try to find a solar controller and a wind (diversion type) controller and ask around to take care of the devil :)
  • westbranch
    westbranch Solar Expert Posts: 5,183 ✭✭✭✭
    Re: Wind and solar charge controller issue

    Look at the MidNite Charge controllers, they each can do wind OR solar, but not both together.

    http://www.midnitesolar.com/products.php?menuItem=products&productCat_ID=21&productCatName=Charge%20Controllers%20-%20Classics

    Look on NAWS online store for better prices. See the yellow banner above these posts.
     
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Re: Wind and solar charge controller issue

    Make sure you understand "EVERYTHING" about your present and proposed off grid power system.

    First--The solar panel power side. As Marc "Cariboocoot" says, there is a good chance that your solar panels are Vmp~30 volt panels.

    What this means, is on a very cool day, the optimum output voltage of the solar panels is ~30 volts. However, for "real life" situations (full sun), typical to hot days, the actual output Vmp voltage can get down towards 24 volts or so.

    And if your battery bank is a 24 volt bank, the charging voltage should be around 29 volts plus a couple of volts for voltage drop/battery equalization/etc.

    Roughly, with a PWM solar charge controller, the Array Voltage (Vmp-array) using the panel specifications should be:

    12 volt bank = 17.5 to 20 volts
    24 volt bank = 35 to 40 volts
    48 volt bank = 70 to 80 volts

    If you have a Vmp~30 volt panel => PWM Controller => 12 volt battery bank, you will be getting much less output power from your panels because of the "miss-matching" array voltage vs battery bank voltage with a PWM controller. You could be losing almost 1/2 your array Wattage with a Vmp-30 volt array and a 12 volt battery bank.

    And if you have a Vmp-30 volt array and a 24 volt battery bank, you will probably undercharging your battery bank (as battery bank voltage rises during charging, current from the array will fall because array voltage is too low).

    With MPPT charge controllers--They are very efficient "voltage down converters" (technically speaking a Buck Mode switching power supply). They can take "high voltage/low current" from the solar array and efficiently (~95% efficiency) to low voltage/high current for charging the battery bank.

    A good quality/higher end MPPT charge controller can take upwards 150 VDC maximum input from the solar array... And roughly a maximum of Vmp~100 VDC (Vmp/Voc is temperature sensitive, in very cold weather/locations, Vmp and Voc rise). So the above table for a "Midnite Classic" MPPT charge controller would look like:

    12 volt bank = 17.5 to 100 volts (~30 volt Vmp "typical optimal")
    24 volt bank = 35 to 100 volts (~58 volts Vmp "optimal")
    48 volt bank = 70 to 100 volts

    Next--For wind turbines, there are several methods to connect them up. The "typical" wind system would have a Horizontal Axis wind turbine (HAWT) connected directly to the battery bank (with rectifier diodes), and a second "shunt/bypass/dump" controller. Typically a PWM controller that is connected from the battery bank to a resistor (heater) bank. The PWM controller monitors the battery bank voltage--When the wind turbine is charging (really any charging source) and the battery voltage hits the set point--The dump controller "turns on" and sends current to the heater(s)/resistors until the battery voltage falls a bit, then it turns off (cycling again).

    The reason is that HAWT usually need a permanently connected load--If the load "goes away", the HAWT can over-speed and self destruct. That is why a second "dump controller+load" is typically used with a HAWT.

    There is a second way of using a charge controller... You could use an MPPT charge controller between the turbine and the battery bank--And just like an MPPT controller "matches" the Output of the PV Array to the Input of a Battery Bank, it can better match the Turbine's alternator output to the battery bank. In some cases, Midnite found up to 3x increase in turbine output energy collection.

    In general, I would recommend that you design the battery bank based on your loads/power needs--Design the solar array based on the bank's AH (and voltage) and your daily loads_amount of sun. Solar is (usually) much more predictable and repeatable vs wind. And a fuel driving generator can usually make up for winter/poor weather conditions.

    Once you have the system designed (and built)--Then you can always look into adding a wind turbine for additional charging current.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • kouts5
    kouts5 Registered Users Posts: 5 ✭✭
    Re: Wind and solar charge controller issue
    BB. wrote: »
    Make sure you understand "EVERYTHING" about your present and proposed off grid power system.

    First--The solar panel power side. As Marc "Cariboocoot" says, there is a good chance that your solar panels are Vmp~30 volt panels.

    What this means, is on a very cool day, the optimum output voltage of the solar panels is ~30 volts. However, for "real life" situations (full sun), typical to hot days, the actual output Vmp voltage can get down towards 24 volts or so.

    And if your battery bank is a 24 volt bank, the charging voltage should be around 29 volts plus a couple of volts for voltage drop/battery equalization/etc.

    Roughly, with a PWM solar charge controller, the Array Voltage (Vmp-array) using the panel specifications should be:

    12 volt bank = 17.5 to 20 volts
    24 volt bank = 35 to 40 volts
    48 volt bank = 70 to 80 volts

    If you have a Vmp~30 volt panel => PWM Controller => 12 volt battery bank, you will be getting much less output power from your panels because of the "miss-matching" array voltage vs battery bank voltage with a PWM controller. You could be losing almost 1/2 your array Wattage with a Vmp-30 volt array and a 12 volt battery bank.

    And if you have a Vmp-30 volt array and a 24 volt battery bank, you will probably undercharging your battery bank (as battery bank voltage rises during charging, current from the array will fall because array voltage is too low).

    With MPPT charge controllers--They are very efficient "voltage down converters" (technically speaking a Buck Mode switching power supply). They can take "high voltage/low current" from the solar array and efficiently (~95% efficiency) to low voltage/high current for charging the battery bank.

    A good quality/higher end MPPT charge controller can take upwards 150 VDC maximum input from the solar array... And roughly a maximum of Vmp~100 VDC (Vmp/Voc is temperature sensitive, in very cold weather/locations, Vmp and Voc rise). So the above table for a "Midnite Classic" MPPT charge controller would look like:

    12 volt bank = 17.5 to 100 volts (~30 volt Vmp "typical optimal")
    24 volt bank = 35 to 100 volts (~58 volts Vmp "optimal")
    48 volt bank = 70 to 100 volts

    Next--For wind turbines, there are several methods to connect them up. The "typical" wind system would have a Horizontal Axis wind turbine (HAWT) connected directly to the battery bank (with rectifier diodes), and a second "shunt/bypass/dump" controller. Typically a PWM controller that is connected from the battery bank to a resistor (heater) bank. The PWM controller monitors the battery bank voltage--When the wind turbine is charging (really any charging source) and the battery voltage hits the set point--The dump controller "turns on" and sends current to the heater(s)/resistors until the battery voltage falls a bit, then it turns off (cycling again).

    The reason is that HAWT usually need a permanently connected load--If the load "goes away", the HAWT can over-speed and self destruct. That is why a second "dump controller+load" is typically used with a HAWT.

    There is a second way of using a charge controller... You could use an MPPT charge controller between the turbine and the battery bank--And just like an MPPT controller "matches" the Output of the PV Array to the Input of a Battery Bank, it can better match the Turbine's alternator output to the battery bank. In some cases, Midnite found up to 3x increase in turbine output energy collection.

    In general, I would recommend that you design the battery bank based on your loads/power needs--Design the solar array based on the bank's AH (and voltage) and your daily loads_amount of sun. Solar is (usually) much more predictable and repeatable vs wind. And a fuel driving generator can usually make up for winter/poor weather conditions.

    Once you have the system designed (and built)--Then you can always look into adding a wind turbine for additional charging current.

    -Bill

    Thanks a lot Bill. Our PV panels are 30 Vmp and we use a 24V battery bank. Im gonna buy a MPPT charge controller now, and later if we're to add a wind turbine in our system we'll get another charge controller just for the wind turbine.

    Again thanks a lot for your help!!!