Timer for battery bank vent fan?

midijeep

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.....  ?

Estragon

How about using the aux to just signal (not power) a relay, and have the relay control fan power?

midijeep

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.

Estragon

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.

porch13

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.

BB.

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

Dave Angelini

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!

Photowhit

a 10 watt panel and a small computer fan...

midijeep

Dave Angelini said:

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.

mike95490

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.