Turn on/off exhaust fan

[bds70]

Hi, I have an off grid system in my bus. The locker containing all my equipment is subject to high environmental temperatures. I would like to fit an exhaust fan to it, to start/stop automatically via a set temperature range.

Does anyone know if any of the following Victron items could do this. Solarsmart MPPT, bmv702, lynxx distributor, or Multiplus inverter.

If not anyone got any suggestions?
Cheers

 

[Samsonite801]

I have a BMV-712 and use the little relay in it to switch a larger relay, which turns on and off my basement heater in my RV to keep my LFP warm enough through the Winter. I set on temp to 42° F, and off temp to 48° F, can invert relay as well.

 

[bds70]

Thanks, what sort of external relay are you using?

 

[Steve_S]

I use products from AC Infinity.
They make Ball Bearing Cast Aluninium Fans and are SILENT ! These are NOT cheap PC box fans with sleeve bearings.
These are an EXCELLENT SOLUTION and Low Power.
Operating Voltage 3 to 7V DC, Power 2.2 W, Current 0.44 A

AIRPLATE T3, Home Theater and AV Quiet Cabinet Cooling Fan System, 6 Inch

Your source to create smart growing systems with components including advance grow tents, inline fans, clip-on fans, LED grow lights, and UIS™ controllers.

acinfinity.com

Another alternate which provides even more flexibility
TIP: The "dual fans sets" are 2 fans in the same circuit (paired). The singles are for each circuit when using the controller module.
These are Marvelous and Extremely well priced.

Quiet USB fans

USB fans for receivers, DVRs, Xboxs, amplifiers,

acinfinity.com

 

[mptx]

The Victron BMV-712 has both a temperature probe connection and a 1A relay that can power a suitable fan. Be sure to fuse the relay at 1A or less to make sure you protect the 712. There are several YouTube videos about the 712 and programming the relay.

 

[Vigo]

Im still too much in my ‘quick and dirty’ phase to pay for Victron, but as a low dollar contingency ill add that i have PC case fans on my autotransformer controlled by a small temp controller that i got a 4 pack of for like 20 bucks on Amazon.

Actually $17 for the 4 pack now:
temp controllers

Downsides? Celsius only ??‍

 

[Samsonite801]

Thanks, what sort of external relay are you using?

I used an automotive type 30a relay which has a diode on the primary winding to protection from flyback current (field collapse on shutdown).



More info:

Using Flyback Diodes in Relays Prevents Electrical Noise in Your Circuits

What is a flyback diode, and how does a flyback diode protect a circuit? When used properly, flyback diodes can reduce electrical noise and prevent flyback voltages from building up.

resources.altium.com

You can also just add your own diodes. I like to put two 1a diodes for extra protection, one across the + and - of the primary and one in series pointing one way on the + wire (I do this especially when it is a transistor supply for the primary trigger, helps protect the spike if you're using a transistor for the trigger voltage source, allows it to neutralize / freewheel down the - side only).



My heater is only a 200w 12v heater, but I want to put as little load on the Victron relay as possible, so as not to wear it out too soon, so the brunt of current is going through my add-in relay, since it is easier to replace.

 

[42OhmsPA]

I use products from AC Infinity.
They make Ball Bearing Cast Aluninium Fans and are SILENT ! These are NOT cheap PC box fans with sleeve bearings.
These are an EXCELLENT SOLUTION and Low Power.
Operating Voltage 3 to 7V DC, Power 2.2 W, Current 0.44 A

AIRPLATE T3, Home Theater and AV Quiet Cabinet Cooling Fan System, 6 Inch

Your source to create smart growing systems with components including advance grow tents, inline fans, clip-on fans, LED grow lights, and UIS™ controllers.

acinfinity.com

Another alternate which provides even more flexibility
TIP: The "dual fans sets" are 2 fans in the same circuit (paired). The singles are for each circuit when using the controller module.
These are Marvelous and Extremely well priced.

Quiet USB fans

USB fans for receivers, DVRs, Xboxs, amplifiers,

acinfinity.com

Another vote for AC Infinity. Solid units.

I've been using this to control a blower on my coal stove since 2017, might work for you too.
WILLHI WH1436A 10A Temperature Controller 110V Digital Thermostat Switch Sous Vide Controller NTC 10K Sensor Improved Version https://a.co/d/79Fb1HW

 

[Ampster]

I have 120 volt AC fans in my attic and THIS device works fine for those fans It also works well when fermenting wine to keep the fermenting vessel at the right temperature by turning on the heating pad under my crock.

https://www.amazon.com/Inkbird-Max-1200W-Temperature-Controller-Greenhouse/dp/B01HXM5UAC/ref=sr_1_2_sspa?crid=3ITJPXG062JVO&keywords=temperature%2Bcontrolled%2Boutlet&qid=1703974125&sprefix=temperature%2Bcon%2Caps%2C152&sr=8-2-spons&sp_csd=d2lkZ2V0TmFtZT1zcF9hdGY&th=1

 

[bds70]

Awesome information. Thank you all for taking the time to help. Have a great and safe new yrs night.

 

[Rednecktek]

Noctua makes a near silent IP67 industrial 120mm fan. I've run a 4p bank of those on those white controllers a few times. They work great and I use them for not only the fans, but also the fans and heaters on my big battery build.