Timer for battery bank vent fan?

midijeepmidijeep Posts: 85Registered Users ✭✭
I recently installed an Automatic transfer switch (ATS) to my SMA SunnyBoy, Sunny Island setup.  I had to use the DigIn-BatVtgOut along with Relay2 on the Sunny Island to install the ATS.  SMA doesn't recommend double-lugging on the BatVtgOut terminal to power the vent fan. This may conflict with the DigIn signal.
I now have to directly wire the vent fan to the 48 volt battery bank.  Anyone have ideas on how to not have the fan run 24/7?  Timer, fuses, breakers, etc.....  ?



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  • EstragonEstragon Posts: 2,219Registered Users ✭✭✭✭
    How about using the aux to just signal (not power) a relay, and have the relay control fan power?
    Off-grid.  
    Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
    Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
  • midijeepmidijeep Posts: 85Registered Users ✭✭
    edited May 1 #3
    Thanks for the reply.  If I understand the SMA relays, they don't provide any power like the DigIn-BatVtgOut.  If I understand you correctly you are saying to power the vent fan directly off the battery bank but use the other relay 1 in the SI to control the fan?

    FYI:  Relay 2 and DigIn-BatVtgOut is being used for the ATS now.

  • EstragonEstragon Posts: 2,219Registered Users ✭✭✭✭
    I'm not familiar enough with the SMA aux port operations to say for sure. One mode of operation is for an aux port to simply close the circuit, which sounds like what you're describing. The circuit isn't normally designed to carry much current, but you could check the max amp spec for the port, and the fan amp draw.

    Assuming the fan draws close to or over the max for the aux port, you just need a source of voltage and current appropriate for the signal circuit in the fan relay (could be the 48v bank if appropriate for the relay, but could just be some AA size in series or maybe a 9v to trigger a 5v triggered relay). The aux port relay closes to send the low current (eg) 9v signal circuit to the fan relay, which then closes the higher current 48v fan power circuit.

    The aux port may be able to open/close the fan power circuit directly (in which case a fan relay wouldn't be needed), but it depends on the fan and the port specs.
    Off-grid.  
    Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
    Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
  • porch13porch13 Posts: 58Registered Users ✭✭✭
    I went with an external voltage controlled switch on my setup so I could use the 48V Zephyr battery box fan.  It's adjusted to run when the batteries are in absorb.  Works great.  I had purchased the switch from NAWS, but it doesn't appear to be offered any longer.  You can still find it by searching the web for VCS-1AH, though.
    Northern Arizona...4050 Watt off-grid system - Outback FP1 - Rolls 605 in a 48V bank
  • BB.BB. Posts: 27,351Super Moderators admin
    edited May 4 #6
    I asked about the voltage controlled switch: A bit of detail about the Voltage Controlled Switch and other products from Solar Converters (Canada). Via Rick from NAWS (our host here):
    Unfortunately, the company that
    made the voltage controlled switches has gone out of business. The
    company was called Solar Converters and they were located in Canada.
    They made some great products including some minimalist MPPT
    controllers and battery desulfators. We still haven't found anything
    to take their place on our website yet. They made some very unique
    products and their engineering team was excellent. I'm not sure what
    caused them to close their doors. We never received any warning. One
    day we submitted an order and we just never heard back from them.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • Dave AngeliniDave Angelini Posts: 3,631Solar Expert ✭✭✭✭
    The OP should describe his set-up better. He may not need the fan or other means can be used to get the desired outcome.
    Air in a small shed or air in a 4,000 square foot structure for battery venting can be approached many ways.
    Less is more sometimes!
    "we go where power lines don't" Sierra Mountains near Mariposa/Yosemite CA
     http://members.sti.net/offgridsolar/
    E-mail [email protected]

  • PhotowhitPhotowhit Posts: 4,481Solar Expert ✭✭✭✭
    a 10 watt panel and a small computer fan...

    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Prosine 1800 and Exeltech 1100, ForkLift battery. Off grid for @13 of last 14 years. 1000 watts being added to current CC, @2700 watts to be added with an additional CC.
  • midijeepmidijeep Posts: 85Registered Users ✭✭
    The OP should describe his set-up better. He may not need the fan or other means can be used to get the desired outcome.
    Air in a small shed or air in a 4,000 square foot structure for battery venting can be approached many ways.
    Less is more sometimes!

    Using a 48V Zephyr vent fan in a 10' x 4' battery box with NiFe batteries in it.  They out gas like a mother.  So, I would  like to set up the fan to work as originally connected to the Sunny Island with use of its relay.  Originally both the relay and and BatVlgOut on the board were tied together.
    SMA advised not to  double-lugging on the BatVtgOut terminal for the power but the powering the fan can come from any where.  I still need to figure out how to wire the fan into the relay, since now I have wired the fan directly off the battery bank for its power source.  Originally the relay and BatVlgOut had been tied in together.
    By using the relay the SI can control the on/off of the fan.
  • mike95490mike95490 Posts: 7,611Solar Expert ✭✭✭✭
    midijeep said:

    Using a 48V Zephyr vent fan in a 10' x 4' battery box with NiFe batteries in it.  They out gas like a mother.
    at mid-morning, my battery shed sounds like a den of vipers, all the hissing and gassing.
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

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