FM80 vent fan setup question

bbqjoebbqjoe Posts: 2Registered Users
I'm all turned around, maybe someone can get me dialed in.
I have everything required, I just can't determine how I should set my exhaust fan up.

I'm running a 24V system, using the FM80. It looks to hold the float at 28V.

Obviously we want the fans to run during the bulk and absorb stages, the float not so much, and certainly not at night.

(It appears only one setpoint can be made, where on and off points might be better.)

How do you set up the fan mode to do this, and not run when it doesn't need to especially at night?

Or should a different aux mode be used instead of fan mode?

Thanks,

Joe

Comments

  • mcgivormcgivor Posts: 1,903Solar Expert ✭✭✭✭
    The auxiliary output could be programmed by voltage and an external digital time clock used to enable between certain hours.
      1500W, 6× Schutten 250W Poly panels , Schneider 150 60 CC, Schneider SW 2524 inverter, 8×T105 GC 24V nominal 

  • mike95490mike95490 Posts: 7,713Solar Expert ✭✭✭✭
    I'd set it for Absorb only.  Or for sensing and triggering on your absorb voltage

    If your battery box is properly vented, there should be natural convection to disperse gas buildup.  To rely on a fan for such a critical function, should only be needed if proper engineering cannot be accomplished due to other constraints.
    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 ||
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  • mcgivormcgivor Posts: 1,903Solar Expert ✭✭✭✭
    Voltage would allow function during EQ as well as absorption.
      1500W, 6× Schutten 250W Poly panels , Schneider 150 60 CC, Schneider SW 2524 inverter, 8×T105 GC 24V nominal 

  • petertearaipetertearai Posts: 311Solar Expert ✭✭✭
    28 volts float seems a bit high 

    2225 wattts pv . Outback 2kw  fxr pure sine inverter . fm80 charge controller . victron battery monitor . 24 volts 450 ah surette batterys . off grid  holiday home 
  • bbqjoebbqjoe Posts: 2Registered Users
    Thanks for the replies so far.
    Is the fan needed, maybe not, but it gets pretty hot here in the summer, so having something to exchange the air when the batteries are boiling can't be bad, and it would make me feel good.
    28v seems a bit high to me too. My solar goto guy says that's the factory setting, and to just leave it alone.

    How can one set this auto fan function to only operate during absorb?
    Or... How can a person set it so it comes on at say 25V and shuts off at 28V?
  • mcgivormcgivor Posts: 1,903Solar Expert ✭✭✭✭
    @petertearai  My solar goto guy says that's the factory setting, and to just leave it alone.

    The float setting should be according to the battery manufacturers recommendations, ~27V is normal for lead acid. 

    As far as the settings go for the auxillary output, each controller differs, but having the output trigger at a voltage where gassing is most likely, say 28.8V resetting when it drops below may be all that is required, as the sun sets the voltage would never be this high so the fan would not run.
      1500W, 6× Schutten 250W Poly panels , Schneider 150 60 CC, Schneider SW 2524 inverter, 8×T105 GC 24V nominal 

  • VicVic Posts: 2,900Solar Expert ✭✭✭✭

    There is a description of the Vent Fan Aux function on page 30 (your pdf reader call it page 32,  or so) in the Manual at the link below:
    http://www.outbackpower.com/downloads/documents/Make_the_Power/flexmax_6080/owner_manual.pdf

    If you have limited net bandwidth,  we could copy and paste it here,   or describe if for you,  if needed.

    The voltage setting is battery voltage,   even though it does not seem to say that.
    Would set this voltage a bit below Gassing voltage.

    What type,  make and model number are your batteries?

    Vic

    Off Grid - Two systems -- 4 SW+ 5548 Inverters, Surrette 4KS25 1280 AH [email protected], 11.1 KW STC PV, 4X MidNite Classic 150 w/ WBjrs, Beta KID on S-530s, MX-60s, MN Bkrs/Boxes.  25 KVA Polyphase Kubota diesel,  Honda Eu6500isa,  Eu3000is-es, Eu2000,  Eu1000 gensets.  Thanks Wind-Sun for this great Forum.
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