Fantastic vent: Help making it work.

[Luisafernandes]

So I installed my fantastic vent today, but don't have solar yet, and maybe not for the foreseeable future. What I do have is one of those batteries you can charge by plugging into an electric outlet and them use by plugging in AC or AC devices, USB, etc.
My question is this: can I make the vent work part time connected to that battery? I don't necessary need to have the fan running, but would be nice to have the rain sensor kick in when the unit is open with me somewhere else, or sleeping, when a nice downpour comes by.

 

[Bdog1]

The fan uses 3 Amps on high I think I remember, but way less on low. The battery for a jump box, which is what I think your using, is usually 13Ah-18Ah. So guessing low speed at 1Amp, you could run it for 7 hrs (half battery capacity apx)

You could measure amps on low to test things out.

 

[anm]

...
What I do have is one of those batteries you can charge by plugging into an electric outlet and them use by plugging in AC or AC devices, USB, etc.
...

Only AC?, no 12 volt DC? If no DC you'll need a twelve volt power supply that can plug into the AC, and it'll have to be beefy enough to operate the ventilator...

 

[Luisafernandes]

Only AC?, no 12 volt DC? If no DC you'll need a twelve volt power supply that can plug into the AC, and it'll have to be beefy enough to operate the ventilator...

I meant DC also, 12 volt DC.

 

[RogueRV2]

An inexpensive very low draw fan that can be left on for many hours to assist ventilation is a 'muffin fan'. This is the kind that is seen computer towers and inverters. These draw between .25 to .35 amps 12vdc. I found 5 of these over time at the local thrift store at an average cost of about $2 each. They are found in many kinds of devices, but ones I get are mostly from transformers for gaming. Because of their flat and small size and low draw, they can be easily placed in vents and on window frames. Currently I have two installed and will eventually get around to the rest. Another low cost, but a powerful 12vdc fan can be found at the junkyard or automotive dismantling yard. These are from 12 to 20 inches in diameter, and are no more than 3 inches thick, as these are used for cooling a radiator or automotive A/C condenser. I have one of these that I'll use only on the hottest days, and only during the daytime when the solar is kicking out the power, as these draw a serious amount of power, many amps, but they do blow like the wind! Noisy too, yet good and cheap.

 

[highdesertranger]

I would say yes, luis. if you are only going to use the rain sensor and the fan sparingly or on low. but I am just guessing here. see if you can find the specs on the vent and battery box and compare, or just give it a shot and see what happens. myself I would give it a shot. highdesertranger

 

[Luisafernandes]

This is what I have coming out of the vent;

Just a couple wires. How do I go about connecting them to the battery? That's my question. I guess I will have to connect them to other wires, and that's my problem, I have no clue which.

 

[Donedirtcheap]

This is from Fantastic install instructions

If you have one black and one white wire, black will be positive (+) and white will be negative (-). Is that a 12 volt light next to it?

Since it's an RV part they always have to do things the half arse way. It would be too simple to just stick with automotive red/pos, blk/neg.

 

[RogueRV2]

Be sure to use heavy/thick wire. Look up a voltage drop calculator on-line if you are going to make a long run to the fuse block or directly to the battery. 3amps x 12vdc = 36 watts. The old incandescent bulbs used in my 1986 MH, #1141, use about 35 watts each. If you have such a light near by, that circuit should easily handle the fan if you remove the light bulb. If there are two bulbs in the fixture, just remove one. Pull the fixture down, take up the slack in the wires and confirm which wire is positive. Yes, black is positive and white is negative when there are only black and white wires present. Don't worry, if it gets hooked up backwards the worst that can happen is a.) the fan does not run, or b.) the fan runs in reverse.

My voltage drop calculator says you'll do okay if you use no more than 20 feet of 14 awg. 20 feet should get you there, and 14awg is fairly easy to find at a hardware or automotive parts store. The fan will run stronger and last longer if large enough wire is used. If you can only find 16 awg, try to keep that run under 10 feet. Of course you could use a bit longer wire of either choice. The size wire coming out of the fan is probably the size wire you'll need, but that is not always the case especially if the run is longer than 10 feet. Use a 5 amp automotive spade type fuse.

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If too thin of a wire is used, it will feel warm or even hot to the touch. This means there is danger of a fire and the excessive amperage is being used to run the appliance. BTW, that fan looks awesome.

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Be sure to use heavy/thick wire. Look up a voltage drop calculator on-line if you are going to make a long run to the fuse block or directly to the battery. 3amps x 12vdc = 36 watts. The old incandescent bulbs used in my 1986 MH, #1141, use about 35 watts each. If you have such a light near by, that circuit should easily handle the fan if you remove the light bulb. If there are two bulbs in the fixture, just remove one. Pull the fixture down, take up the slack in the wires and confirm which wire is positive. Yes, black is positive and white is negative when there are only black and white wires present. Don't worry, if it gets hooked up backwards the worst that can happen is a.) the fan does not run, or b.) the fan runs in reverse.

My voltage drop calculator says you'll do okay if you use no more than 20 feet of 14 awg. 20 feet should get you there, and 14awg is fairly easy to find at a hardware or automotive parts store. The fan will run stronger and last longer if large enough wire is used. If you can only find 16 awg, try to keep that run under 10 feet. Of course you could use a bit longer wire of either choice. The size wire coming out of the fan is probably the size wire you'll need, but that is not always the case especially if the run is longer than 10 feet. Use a 5 amp automotive spade type fuse.

 

[Bdog1]

I don't know where your battery is located, but perhaps you could use a coat hanger to fish the wiring above your roof panel and into the cabinet. Also perhaps pick up the light wiring there too. ( LED is very low draw). Make a nice connection there and route to the house battery. You should add a small fuse box close to the battery ($10) to feed each circuit you add.

If you don't yet have a house battery, there's usually a spare accessory power, usually on the wall behind the driver, use this for your fuse block power for now and if you later add a house battery, only the one power supply will have to be changed out.

 

[Luisafernandes]

Two things; 1- I have a12v extension cord that I bought in case I wanted to plug in up front while sitting in the back of the van using the phone. Would I be able to connect the fan wires to that extension, and then plug that into the battery? 2- would I be able to wire the fan to the ceiling light, and would the fan work if the key is off the ignition?

 

[highdesertranger]

yes and yes. but would it work without the key on? I don't know. will the light come on without the key on? is your outlet hot without the key on? highdesertranger

 

[VanLifeCrisis]

i wired mine backwards at first, fan operates fine but the in and out switch is reversed if you dont have actual terminals on your battery but a lighter plug socket, youll have to wire a lighter plug onto those wires i think. i used 14 guage automotive wire for mine, and its good to go...i wired mine straight to batt with ring connectors..then later to fuse box.

 

[Luisafernandes]

yes and yes. but would it work without the key on? I don't know. will the light come on without the key on? is your outlet hot without the key on? highdesertranger

Without the key I can turn the ceiling lights on, is that good?
Also would I need to disconnect the battery? I was hoping I wouldn't have too.
Thanks!

 

[SternWake]

Keep in mind if you are tapping a lighting circuit for power, which is (?) still connected to engine battery, and not house battery, the fantastic fan will be drawing down the engine battery instead.

Best to rewire all ciggy plugs, stock lighting, and stereo to house battery and save engine battery, for engine only. All loads should goto the house batteries, not just most of them, but anything can be made to work, just know if you are depleting the engine battery when you thought the loads were on the house battery instead.

On my van, only the courtesy lights are still connected to the original system, and these are now LED's, so with doors open and courtesty / dome lights on the draw on engine battery is very little, and my 3 manual switches could still allow for complete isolation of one battery or the other, as I try to keep one or the other at or very close to 100%, and have ALL loads on the other, but within reason too. I know the LEDs could go 5 days before taking wither battery to the 80% range.

There is also a small current draw( 0.38a) for a time delay relay when the doors are open and headlight switch not rotated fully clockwise to shut off map lights. So I like to make sure this is off too, as I keep my doors open often and might have the courtesy lights switched off.

I would never have known about this .38a mp draw of the time delay relay without my battery monitor, and it does explain my batteries depleting prematurely back in the early days of my van dwelling when I was mostly ignorant of most things electrical.

 

[Luisafernandes]

Keep in mind if you are tapping a lighting circuit for power, which is (?) still connected to engine battery, and not house battery, the fantastic fan will be drawing down the engine battery instead.

Best to rewire all ciggy plugs, stock lighting, and stereo to house battery and save engine battery, for engine only. All loads should goto the house batteries, not just most of them, but anything can be made to work, just know if you are depleting the engine battery when you thought the loads were on the house battery instead.

On my van, only the courtesy lights are still connected to the original system, and these are now LED's, so with doors open and courtesty / dome lights on the draw on engine battery is very little, and my 3 manual switches could still allow for complete isolation of one battery or the other, as I try to keep one or the other at or very close to 100%, and have ALL loads on the other, but within reason too. I know the LEDs could go 5 days before taking wither battery to the 80% range.

There is also a small current draw( 0.38a) for a time delay relay when the doors are open and headlight switch not rotated fully clockwise to shut off map lights. So I like to make sure this is off too, as I keep my doors open often and might have the courtesy lights switched off.

I would never have known about this .38a mp draw of the time delay relay without my battery monitor, and it does explain my batteries depleting prematurely back in the early days of my van dwelling when I was mostly ignorant of most things electrical.

Thank you for the explanation. If I connect the fan to the ceiling light it would only be temporary until I get solar, and only to allow the fan to automatically close in case of rain. The fan wound not be running.
Connecting to the ceiling light temporarily, or connecting to the house battery; which would be the better option? The house battery would be charged about once a week when I have access to electric power.

 

[SternWake]

I guess the automatic lid closer is not going to drain the house battery.

You should consider hooking the house battery so it can be fed by the alternator.

If properly wired, the alternator can achieve in an hour what it takes the solar 6 hours to do, and i've found high recharge rates are appreciated by a regularly cycled battery.

The solar excels in getting that last 20% into a battery, and that is where the alternator is least effective. The two in combo are best for this lifestyle, but either or , are better than requiring one plug into the grid and recharge.

When you do get the solar, and wire the FF to the house battery, I'd recommend oversizing the wire, so that if you want to add another device up there, the wire is more than capable of passing the extra current and with minimal voltage drop.

The Fan might be able to spin 5% faster with 10 gauge, compared to 14 gauge as it will receive higher voltage. Those blistering hot days, this can be appreciated.