Cobra Trailer Solar Vent

[Bob Caldwell (BC)]

Hi Pilots,
My 2016 aluminum top Cobra has now had 3 vents that have all quit working. These "Smart Solar" brand vents seem pretty crappy. Has anyone figured out how to fix one? Does anyone have a suggestion for a better replacement? Does anyone remember the cutout diameter in the trailer roof? I would measure mine but I am not at the trailer. Any help would be appreciated. Thanks.
Bob

[Dan Marotta]

For my Cobra trailer, I cut a round hole in the upper side of the dog
house and covered it with a vent cover backed with window screen.  I did
likewise somewhere in the front of the trailer.  I figured I'd get a
convection current going in the trailer and I don't recall ever seeing
condensation.  The trailer was parked outside in Colorado.

Dan
5J

[Dan Marotta]

I forgot to mention, the one time I bought and installed a solar vent,
it quickly died.  What a waste.

Dan
5J

[Jim N]

For long lasting ones, look to the marine world. Check out the offerings at places like: Hamilton Marine, West Marine and Defender Marine

Jim Norem
3K

[Jeff Baird]

Bob,
I replaced mine with "SunVent STV-024" from Solar Made in Colorado Springs (719)635-5125. https://www.solarmade.com/store/category/solar-sunvents. Looks exactly like Cobra with rechargeable battery. Also available with metal top. Required me to shave about 1/4 inch from one quarter of factory opening due to irregular shape of opening from Cobra.
Jeff
XI

[Herbert Kilian]

Sounds good, Jeff. But how do you get that thing to run if your trailer is kept in a hangar?
Herb

[R]

I'm confuse.....Herb...how did yours run in a hanger.? When it worked.
R

[2G]

The reviews of this vent are not promising:
https://www.amazon.com/Sunvent-SVT-224S-Solar-Ventilation-Greenhouse/dp/B07DFQJ5Z1/ref=sr_1_3?crid=3HXHJ57HYRX4U&keywords=solar+powered+rv+vent+fan+SOLAR+SunVents&qid=1643655552&sprefix=solar+powered+rv+vent+fan+solar+sunvents%2Caps%2C172&sr=8-3#customerReviews

Tom

[Mark Mocho]

I bought one of these 17 years ago. Still running, and the trailer lives outside in New Mexico. Works for me.

https://www.westmarine.com/buy/nicro-ventilation--solar-minivent-1000--183733

[2G]

On Monday, January 31, 2022 at 1:05:25 PM UTC-8, jonatha...@gmail.com wrote:
> I am looking for my Third Fan since 2015! Think I will try the west marine one.

> On Monday, January 31, 2022 at 11:42:07 AM UTC-8, Mark Mocho wrote:
> > I bought one of these 17 years ago. Still running, and the trailer lives outside in New Mexico. Works for me.
> >
> > https://www.westmarine.com/buy/nicro-ventilation--solar-minivent-1000--183733

I'm afraid that these small vent fans will not move enough air to make a difference. Someone with one of these needs to measure how much the interior temperature drops when the thing runs vs not running.

I ordered my Cobra trailer with the interior insulation option. This should reduce the temperature rise when in direct sunlight (the heat will not radiate from the interior side of the aluminum). It also protects from condensation.

Tom

[Stuart Venters]

On 1/31/22 13:42, Mark Mocho wrote:
> I bought one of these 17 years ago. Still running, and the trailer lives outside in New Mexico. Works for me.
>
> https://www.westmarine.com/buy/nicro-ventilation--solar-minivent-1000--183733

Thanks for the link.

It says it is an exhaust vent. I have the solar vent on the top near
the front of the trailer and a simplevent on the top of the tail
doghouse in the rear.

To cooperate with convection, should the solar vent exhaust or intake air.

[Mark Mocho]

> To cooperate with convection, should the solar vent exhaust or intake air.

I have mine set up to exhaust, as I have multiple vents in the nose area, the doghouse and various other leaks. My solar vent came with two fans: one innie and one outie. Of course, New Mexico's dry climate minimizes condensation inside the trailer. I'm more concerned about introducing dust into the trailer. We got PLENTY of dust. Want some? It tells you which areas need to be cleaned. Just check out my living room

[Reigh Walling]

I have replaced the motor in my solar fan twice. It cost only $8, last source was solarmade dot com. There was a minor amount of shimming required to make the new motor fit. The fan blade also cracked, and so my son printed me a new one on his 3-D printer. There isn't really anything else left to fail except the battery.

My trailer's prior owner removed the battery, with the assumption that ventilating at night is bad because of the higher relative humidity. However, dew point is what counts, and the dew point is actually less at night on the average. The original battery was a NiCad, and I couldn't find an available new NiCad "C" battery to replace it. I tried a NiMH battery but it appears to have a lower voltage and the fan stalls. I'm back to running without a battery.

Bottom line: solar fans can often be fixed easier than replaced.

[Martin Gregorie]

On Wed, 02 Feb 2022 07:45:32 -0800, Reigh Walling wrote:

> My trailer's prior owner removed the battery, with the assumption that
> ventilating at night is bad because of the higher relative humidity.
> However, dew point is what counts, and the dew point is actually less at
> night on the average. The original battery was a NiCad, and I couldn't
> find an available new NiCad "C" battery to replace it. I tried a NiMH
> battery but it appears to have a lower voltage and the fan stalls. I'm
> back to running without a battery.
>

General comment: in my experience NiMH batteries aren't worth buying.

For starters, they have a much higher self-discharge rate than NiCD
batteries - so much so that for anything critical, they should be fully
charged no more than the 12-24 hours before they will be used and, when
not being used should be recharged every 1 - 2 months: allowing them to
go flat destroys them.

Then, some years back, when NiCD had become generally unavailable and
NiMH was about the only game in town, I went through a number of brands
trying to find a set of NiMH AA cells that would run my Pentax K100 DSLR,
a nice, though big, heavy camera, that I bought because my old Spotmatic
F's lens collection fitted it and film was starting to get scarce.

Every set of AA size NiMH cells I tried in the K100 lasted one charge
cycle before failing to recharge. Finally, I tried a set of Sanyo
Eneloops when they came on the market: they solved the problem and ever
since have been my go-to rechargeable batteries for anything that needs
AA or AAA cells. They also have a very low self-discharge rate, which is
nice to have.

[Steve Leonard]

On Monday, January 31, 2022 at 3:30:42 PM UTC-6, 2G wrote:

> I'm afraid that these small vent fans will not move enough air to make a difference. Someone with one of these needs to measure how much the interior temperature drops when the thing runs vs not running.
>

> Tom

Just as an FYI, the purpose of the fan is not to cool the trailer, but to keep it from getting above ambient during the heat of the day. The way it does this is by bringing in ambient air. The spec sheet for the one Mark referenced says it can move 700 cubic feet of air per hour. Estimating on the high side, a Cobra trailer probably has less than 350 cubic feet of air inside it (that would be 4 by 28 by about 3.1 feet), so that fan will bring in a full compliment of ambient air every 30 minutes. The battery keeps it going for a while after the sun goes down to help with cooling from the peak temp.

Maybe not as good as insulation, but everyone makes their own decision as to what provides value to them.

Steve Leonard

[Moshe Braner]

Yeah the old NiMH batteries were always dead exactly when I needed them.
But Eneloops changed all that. And now there are many other brands of
"low self discharge" (LSD) NiMH battery cells. Some are better than
others, but all have been useful. The LSD type are also called
"precharged" because they have significant charge in them when you buy
them. Don't go for the highest capacity, go for the brands reported to
actually keep their charge while sitting around for months (or even years).

[Martin Gregorie]

Update: Yesterday I dug out the Pentax K100, which hasn't been touched
for at least six years ever since I got seduced by a cute little
Panasonic TZ70, to check its model number. I discovered a set of Eneloops
were still in it and showing 0.00v on my multimeter.

So, I put them on charge yesterday, which worked. Last night the charger
reported them as fully charged, so I took them off it. This morning I put
the meter on them. All four show 1.367v, exactly the same voltage as
another, newer, Eneloop that I'd recharged a few days ago using the same
charger. I'm impressed: I'd assumed the Eneloops taken from the Pentax
would be extremely dead and only put the meter on them to confirm that.

Just now I put them back in the camera and took a few shots before taking
them out and using the multimeter again. Surprised and happy to see the
Eneloops showed no voltage drop after that short test.

[Moshe Braner]

The big danger with batteries sitting for a long time in unused devices
is not that the batteries may die (easy to replace) but that they may
leak, exuding chemicals that damage the electronics, or at least corrode
the contacts hampering connection to future batteries.

So if you carry some rarely-used extra devices with you when you go to
the airport: flashlights, an old GPS, a spare digital camera, etc., that
use replaceable batteries, now is a good time to open them up and check
the batteries' condition and age.

[Martin Gregorie]

Good advice. That's usually what I do, so I was surprised to find
batteries in the DSLR and no idea why I left them in it, the more so as
none of my other film cameras have batteries in them.

[2G]

And you BELIEVE those spec sheets, right? If they EVER met those specs, they did it with a new unit under ideal conditions, namely noon at the equator with max sunlight. What you are talking about is the heat that builds late in the day (4-5 pm) which is well past max reduced sunlight. The best approach, IMO, is to never let the heat enter the trailer in the first place, hence insulation. It might also be possible to install heat reflecting foil (https://www.ecofoil.com/collections/double-bubble-insulation) to in inside of the trailer.

Tom

[Tony]

I bought a rather expensive Marinco N20804W and it failed within a few months. They gave me a replacement under warranty and it is doing fine about 18 months later. Years ago I bought a cheaper brand, the Nicro N20604S and it failed within months...Nicro sent me replacements under warranty 3x and the final one worked a few years before crapping out. With the heat and humidity in Florida I think it's worth the trouble but maybe not!?

[Tony]

Also, remember to turn the fan off on these things before you take them on the road - not designed to withstand hurricanes for hours on end.