Recommed me a Solar

lolanistalolanista Posts: 1Registered Users
I just want my Nanostation M5 which is 24 V DC written on its power adapter which i wanna keep running 24 hours + i wanna light up 4-6 bulbs might each of 3-5 watt for 3-6 hours

What kind of solar system must i have?

And do i need a inverter to make my Nanostation M5 run

Please suggest me i am new to scene:blush:

Comments

  • BB.BB. Posts: 27,897Super Moderators, Administrators admin
    Re: Recommed me a Solar

    Welcome to the forum Lolanista!

    Are you in Nepal? One of the things that is helpful is to understand how much sun you get per day... One way is the "hours of noon time equivalent" sun... For many regions with pretty good sun, you can average 4 hours of sun or more for ~9 months of the year.

    In other regions, you may have more or less, or sometimes less than 2 hours per day of you have heavy clouds/marine layer.

    Anyway, some equations that will get you started.
    lolanista wrote: »
    I just want my Nanostation M5 which is 24 V DC written on its power adapter which i wanna keep running 24 hours + i wanna light up 4-6 bulbs might each of 3-5 watt for 3-6 hours

    24 VDC system... A true off grid battery system will nominally operate between ~23.0 to 29.6 volts or so, and sometimes charge to 30 to 31+ volts for equalization (and if your system will be in sub freezing conditions, the battery voltage will even be higher).

    That is a pretty wide range for a 24 volt device that may not be designed for a true deep cycle battery system. I don't know anything about the product, so I cannot help you there.

    Also, we need to know the power usage... From here (PDF):

    http://dl.ubnt.com/datasheets/nanostationm/nsm_ds_web.pdf

    It says 8 watts maximum (I am guessing on model/usage)... So the power usage could look like:
    • 8 watts * 24 hours per day = 192 WH per day
    • 6 bulbs * 5 watt * 6 hours per day = 180 WH per day
    • ==========================
    • Total = 372 WH per day

    There are a lot of losses and derating in off grid solar power systems... If you use a small/efficient AC inverter (may be best bet as it should be designed for 24 volt deep cycle application)... you will need to look at its "tare" losses (power used just because it is on). For example 6 watts for TSW (True Sine Wave) inverter is pretty efficient, and since you are running it 24 hours per day, you may need to add these losses to your overall power requirements. So:
    • 6 watts * 24 hours = 144 WH per day for 24x7 AC inverter operation
    • Total power = 144+372 = 516 WH per day AC power

    Assuming an off grid battery based system:
    • 516 Watt*Hours per day * 1/0.52 end to end system efficiency * 1/4 hours of sun per day = 248 Watt minimum solar array

    Now, for battery bank sizing... We normally recommend 1-3 days of backup power with a maximum of 50% battery discharge (for long life), a 2 day / 50% discharge system would require:
    • 516 WH per day * 1/0.85 inverter efficiency * 1/24 volt battery bank * 2 days no sun * 1/0.50 max discharge = 101 AH @ 24 volt battery bank

    Now, we recommend a charging rate of 5% to 13% for a typical battery setup. And in your case, because you are drawing 8 watts 24*7, we need to "remove that" from the solar panel output... So, the solar array needed to support a 5% to 13% rate of charge would be:
    • (8 watt load * 1/0.85 inverter eff + 6 watt inverter operating power) * 1/0.77 panel+controller derating = 17 Watt 24*7 load (related to solar panel)
    • 101 AH * 29 volts charging * 1/0.77 panel+controller losses * 0.05 rate of charge = 190 watt array minimum (without steady state load)
    • 190 Watt + 17 watt load = 207 Watt minimum array (with load calculation)
    • 101 AH * 29 volts charging * 1/0.77 panel+controller losses * 0.10 rate of charge = 380 watt array nominal
    • 380 W + 17 W = 397 Watt array nominal (with load)
    • 101 AH * 29 volts charging * 1/0.77 panel+controller losses * 0.13 rate of charge = 495 Watt array max "cost effective"
    • 495 W + 17 W = 512 watt array max cost effective (with load)

    So, you would need around a 248 watt to 512 watt solar array (based on my above assumptions). And if your weather is poor (less than 4 hours of sun per day) and/or you need more power in winter/backup generator--All needs to be accounted for.
    What kind of solar system must i have?

    This is not a huge system... You could do it with a less expensive PWM charge controller... However, you will have to look at what products you have available in your region of the world. There is an issue between selection of the correct Voltage (Vmp--Voltage maximum power) of the solar panels, PWM vs MPPT charge controllers (MPPT are nicer controllers but cost several times more money).

    Also, you have a choice between 12 volt or 24 volt battery bank (choice of DC or AC power, type/size of AC inverter available, etc.).
    And do i need a inverter to make my Nanostation M5 run

    Don't know--Many networking appliances are actually pretty "battery friendly", so it is possible that it will work OK with a 24 volt battery bank. You would have to contact that manufacturer and ask them (the support people may not know either).

    Lets work out the power/sun requirements first (and if you will use a backup generator or not)... Also, battery banks do not like to be cycled below 50% State of Charge very much--That will shorten life. And taking a battery below ~20% SOC can kill a battery bank. A remote (unattended power system) is a trade off between automation/cost and issues about self protection (i.e., what to do if a battery charge goes low because of poor weather or other electrical issues).

    Then we can talk about hardware choices.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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