Roll up solar panels - fridge power

[Christophe Noel]

I have an ARB fridge in my future and wanted to explore options for providing it auxilury power via a solar panel. For the most part, this will only be used while the vehicle is parked for a few hours while we hike, bike, and enjoy the woods. We will usually be away from the vehicle during these periods.

I appreciate that a solid solar panel provides better expense per watt and has the advantage of being more secure while we're away from our rig, but I have access to Brunton rolled solar panels at cost. Even then, I don't know if they're a good value. At any rate, here's what I have available to me:

Brunton Solaris 26 watt Tri Fold - MSRP $635, for me $320
Brunton Solaroll 14 watt - MSRP $655, for me $299
Brunton Solaris 9 watt - MSRP $420, for me $188

Are any of these options even in the ballpark of helpful?

 

[Corey]

I would go with a 60 watt minimum.
That is what Martyn recommended to me last year.
http://www.expeditionportal.com/forum/showthread.php?t=28712

Mine is a folding one though, they look more durable than the roll up ones IMO.

Mine would put out enough on its own to power the fridge I think, but I am using it to keep the batteries topped off while being parked at up to a week at a time.

 

[goodtimes]

Any of the panels you mention will *help*.

If you are only gone a few hours, and assuming your starting battery is in good shape and fully charged when you leave, you will be fine. I used to leave my fridge run all night off the starting battery -- but I never let it sit for more than 10 - 12 hours before restarting the Jeep, and of course the ambient temperature was lower at night than during the day, and the fridge had a low voltage cut off on it. On some trips, we even ran the fridge off of one of the cheap battery jump-start packs plugged into the cigarette lighter when using a car w/o a outlet that stays hot with the key turned off.

It helps to load the fridge with as much water as you can, and make sure it is cooled off to your set temperature before you park the truck and head out for the day.

 

[Christophe Noel]

I would go with a 60 watt minimum.
That is what Martyn recommended to me last year.
http://www.expeditionportal.com/forum/showthread.php?t=28712

Mine is a folding one though, they look more durable than the roll up ones IMO.

Mine would put out enough on its own to power the fridge I think, but I am using it to keep the batteries topped off while being parked at up to a week at a time.

Gad zooks!!!! With the price of the fridge, I'd be looking at $2000 to keep my $8 six pack cool. That looks awesome, but maybe overkill for my needs. Thanks so much for linking that post. That's great info.

Thanks, Brian. I really don't see myself leaving the fridge running with the vehicle off for more than 12 hours. Maybe, but doubtful. Maybe I'm barking up the wrong tree. Maybe I need to look into dual battery systems as well. This is soooo not in my scope of expertise.

 

[vanderpooch]

I too am way out of my scope on this stuff.

I use this for my van. 50 watts
http://www.gowesty.com/ec_view_details.php?id=4287&category_id=338&category_parent_id=
I also have a second battery. I use the fridge constant, nightly dvd for kids movie and some occasional tunes. Also phone and ipod charging. It has worked flawlessly but I rarely ever long term camp. I usually hit and run and never stay longer than one whole day and a night. I am a diagnosed chronic bobtailer and always on the go.

But you are right...It is pricey!!
I agree on keeping the fridge full helps tremendously with efficiency. I thought about keeping it full and using a transit bag being good enough until I saw the cost of the transit bags:Wow1:

I did do three weeks in Baja with the fridge hooked up to the main battery (no solar/ no second battery)and had no issues. bobtailed everyday like your needs never more than 12 hours with out engine running.

So I guess I offer nothing more than my experience. Wish I understood the math behind it all

 

[Rando]

While the 26W panel would help, I am not sure it is worth the price or effort. You can do a simple dual battery system (with a solenoid) for less than the price of the 26W panel and have the reassurance that you will never run down your starting battery. A 26W panel will approximately offset the power used by the fridge while the sun is shining, about 2 Amps (average) out for the fridge and 2A in from the panel. But you only get about 8 hours equivalent of sun per day, so it is still only reduce the total consumption of your fridge by about 1/3.

In my estimate you would need 60 - 100W of solar to allow you to run a fridge and a few lights indefinitely.

Even with these discounted prices, you would still be better off with either a rigid panel, for about 1/3 the cost per Watt or a semi-flexible panel for about half the price.

However if price is not a factor, or you really can't transport a semi-flexible panel, that is an excellent price on a Brunton panel.

Brunton Solaris 26 watt Tri Fold - MSRP $635, for me $320
Brunton Solaroll 14 watt - MSRP $655, for me $299
Brunton Solaris 9 watt - MSRP $420, for me $188

Are any of these options even in the ballpark of helpful?

 

[wrcsixeight]

You will use less battery power if you can keep the interior cooler while you are away.
Make some custom fit reflectix window shades for the windows which face south.

Home depot sells Nashua Flex fix tape which is flexible, and reflective, and works nicely to bend around the edges to keep the reflectix insulation from ripping. 10 dollars a roll, for 120 yards of tape. My HD does not sell the reflectix insulation, but I hear Lowe's does.

Also keep the fridge low, and make sure the vents are not obscured.

Any Solar helps, but as said, you probably need 60 watts to offset the fridge useage, with good sunlight.

 

[Corey]

Gad zooks!!!! With the price of the fridge, I'd be looking at $2000 to keep my $8 six pack cool. That looks awesome, but maybe overkill for my needs. Thanks so much for linking that post. That's great info.

Thanks, Brian. I really don't see myself leaving the fridge running with the vehicle off for more than 12 hours. Maybe, but doubtful. Maybe I'm barking up the wrong tree. Maybe I need to look into dual battery systems as well. This is soooo not in my scope of expertise.

I run duals too, for a just in case

It is expensive at this time still.
I decided last year to pull the trigger after looking at Dave and Yoshi's setup.
It is a huge peace of mind though to have it.
When I camp, I like to stay in one spot for a week if on vacation, and to not have to start the rig.

One day I will pick Martyn's brain again for one of the in cab monitor charge controllers, but the one I have now is very sufficient.

 

[dzzz]

You will use less battery power if you can keep the interior cooler while you are away.
.

It can work at cross-purpose to end up parking in the sun to run the solar panels. It is a bit tricky to figure out the best solution. I would be cautious of using a regular starting battery to run a fridge. See one of the several Odyssey/Sears Platinum discussions.
The design life of a regular starting battery is based on not going below 90% charge. It's less expensive over time to spend 2X on an AGM starting battery. It's also less frustrating.

 

[vanderpooch]

I did do three weeks in Baja with the fridge hooked up to the main battery (no solar/ no second battery)and had no issues.

Just to be clear I was definetly not suggesting this as a solution. My intention was to show how little battery is really needed to run these incredibly efficient fridges for short periods of time.

 

[JIMBO]

:sombrero: My 60watt-sunforce-HARD Solar Panel, has kept my trailer cooler (ENGEL), lights and occasional inverter use at ease

I don't have the trailer connected to the vehicle battery, unless I'm moving, the trailer battery is now close to 4 years old, still ticking (lead acid)

60 watts may not be the minimun, but I'd be careful of any less and then most of the day in DIRECT SUNLIGHT!

:costumed-smiley-007:wings: JIMBO

 

[LandCruiserPhil]

I have a flat mounted Siemens 55Watt panel. With daytime temps of 100+ and inside temps of 140° my Waeco CF-50 can run 24/7 and provide 30° beverages. I live in AZ where we are provide long days and lots of Solar Insolation. Your solar mileage will vary.

 

[Christophe Noel]

It can work at cross-purpose to end up parking in the sun to run the solar panels. It is a bit tricky to figure out the best solution. I would be cautious of using a regular starting battery to run a fridge. See one of the several Odyssey/Sears Platinum discussions.
The design life of a regular starting battery is based on not going below 90% charge. It's less expensive over time to spend 2X on an AGM starting battery. It's also less frustrating.

So, for my Discovery I would be better served wandering over to the Rover section to pose questions about dual batteries?

Being a minimalist by nature, it's already a stretch for me to bring along a fridge, so the idea of a hulking solar panel isn't really on the top of my list.

How complicated is it to add a second battery?

 

[Martyn]

So, for my Discovery I would be better served wandering over to the Rover section to pose questions about dual batteries?

Being a minimalist by nature, it's already a stretch for me to bring along a fridge, so the idea of a hulking solar panel isn't really on the top of my list.

How complicated is it to add a second battery?

How minimal is a second battery? A group 31 has 60 lbs of lead in it. A second battery is the least expensive way to gain power reserves. You'll be lugging it around everywhere you drive your vehicle. Not an easy balancing act.

 

[Cabrito]

I really don't see myself leaving the fridge running with the vehicle off for more than 12 hours. Maybe, but doubtful.

For those types of time periods I wouldn't be overly concerned. I run an old ARB MT35 with a Two Zone and carry a jumper pack for just in case. I also have it in one of those fancy insulated bags, but it does not cover the two zone.

I have been using it for a year with some week long trips and frequent weekenders. As long as I start the truck once a day I'm good. No real power loss. No jumpstarting needed.

Once it's at the temperature it just cycles on and off so it's not constantly draining the battery. Normal use would mean that it's getting down to the required temperature while you are driving to your destination.

Another trick is to turn it off during the night if it's cold enough outside it doesn't really loose much. Sometimes when I sleep in the back of the truck I turn it off so I can sleep better.

I recommend a jumper pack and a lot of testing so you can figure out what your own vehicle's tolerance is.