Dashboard solar for fridge?

[stingray1300]

Does anyone make a solar 12vdc charger that one can just put on the dash of the truck - that actually fits? I'm talking about 18" - 24" x 6" - 9" max. Something that won't be too obtrusive while riding on the dash. (for when we're stopped camping for a day or two)
.
Anything like that available?
.
Thank you!

 

[Ducky's Dad]

My experience with three of the dashboard solar panels on three different vehicles is that they won't even keep the battery topped off. Mine were Noco and were a waste of money. There should be something out there that will help, but I did not find it.

 

[1Louder]

You would need at least 60 watts to keep up with a fridge. That is depending on outside temperatures, inside the vehicle temperature and fridge setting of course. In 105 degree outside temp with it 115 degrees or more in my vehicle to 60 watt rollout panel I have can't keep up. Temps below the 80's it works great and keeps my battery topped off. So I would say they are not there yet with enough power available in such a small size.

 

[PIC4GOD]

The other problem is the windshield. It will block a significant amount of the light spectrum and intensity needed to produce power. At least with today's technology the only way to get the power you need will be external and you will need more than a 60 watt panel unless you track the sun for maximum output.

 

[wirenut]

What you want doesn't exist. Anything that would fit on the dash is going to have a worthlessly low power output. Something like 20 watts or so at the most.
It would be most helpful to know what kind of fridge we're talking about and how much power it uses.
Either way, a panel of 100 watts or more mounted on the roof will probably be the realistic minimum.

 

[stingray1300]

Hey, thanks for the come-backs guys! Sorry, always need more input... I have an ARB 37qt fridge (just got it), so it supposedly draws up to 2.3 amps, roughly 28 watts (Amps x Volts = Watts), right? So I'm wondering if a 20watt panel, along with my Optima yellow top will be good for a few days in the backwoods or desert.
.
I hear ya about the panel being behind the windshield. I was just hoping to have something there pretty much all the time to keep the Optima topped-up, as I don't drive long distances much, more short runs around town. I have an RTT on my truck cap, so that leaves that option off the table, and I really don't want (actually "won't") attach anything to my truck's cab.
.
So I guess what I'm reading here is to just get a rigid panel and pull it out and set it up when we camp, right? Then I worry about security if while on a hike. Oh the troubles of modern day living... (I want my horse back!) :sombrero:
.
I appreciate any advice or input on this subject, even brands, etc.
.
Thank you!

 

[rayra]

yeah the dashboard panels are typically meant as battery tenders. Better than nothing.
On top of the windshield, in the full sun, etc etc.
But you'd get just about as much power from starting you vehicle up for a fast idle for 10mins a day.

 

[mellorrob]

I've been eyeing one of these to keep my yeti 400 topped off when running my ARB fridge. It would be convenient to just hang off the roof rack but it's $$$

http://www.goalzero.com/mobile/p/337/nomad-100-solar-panel

 

[wirenut]

Your fridge would run how many hours a day? I'll guess 8. So you would need 8 hours x 28 watts = 224 Wh. A 20 watt panel would only put out 20 watts under ideal condition: full direct sun and only about 70 degrees. So let's say it puts out 15 watts. You would need 224 Wh / 15 watts = 15 hours of full sun a day. That's not going to happen. Especially not if it's cloudy.

 

[stingray1300]

So I see where this is going... I need a full, 12 panel array to run my 37qt fridge, right? :sombrero:
.
Naw, I get it: more is better. A friend of mine (he's on this forum) has 2 rigid panels that he acquired for nothing. He's going to check on their wattage, but they're like 36" x 24", so maybe 100 watts + (?) he offered to give me one if we worked to get them set up for our rigs. I guess I'll just have to engineer a swivel mount that will allow deployment when we're camping. That really shouldn't be too difficult actually... mount it to my RTT rack.
.
So I guess my question now turns to: "what do I need, equipment-wise, to make this all work on the truck?"

Any input is MUCH appreciated! :bowdown:

 

[4x4junkie]

Basically, all you need is a suitable charge controller for it. Connect the charge controller to your battery, then connect the solar panel to the controller, and it should immediately begin charging (provided sunlight is actually hitting the panel, of course).

You may want to have your friend also check what the "Vmp" (volts @ max power) rating is on those panels, as that can affect what type of controller you need for it. Vmp ratings between 17-19V will let you use just about any controller you want for it (provided it has a sufficient current rating), however panels with Vmp ratings higher than that will not be very effective unless you use it with a "MPPT" type controller.

For mine I have a pair of 85W rigid panels that fold together (portable setup), and a Morningstar SunSaver MPPT-15 controller. This not only keeps my fridge going, but also a bunch of LED campsite lights, stereo, and occasional charging of large R/C vehicle & craft batteries, among other things.

 

[spikemd]

While I have my panels set-up at camp and am not there, I have a cable and small locks that secure the foldable panels to the truck through the grommets built into the panels. Of course if someone really wants it, they can cut them, but at least it deters the snatch and grab folks. For a Powerfilm 60 watt panel and other smaller GoalZero panels, it helped to give some peace of mind while gone for a few hours. You really need the panels outside the truck and in good light to be efficient. Unfortunately, foldable efficient panels are pricey. My solar goes to a Goal Zero power pack, Extreme350, but just purchased a Yeti400 for increased capacity.

 

[stingray1300]

OK, so I just got the panel, got a Morningstar SunSaver 10 controller. I bought some 10ga marine grade stranded Romex and some solar panel connectors. The panel is a Solarex53 (53 watts, VPmax 17.2) This panel is nice. I was registering 18.8vdc on a mostly cloudy day!
.
I mounted the controller to the firewall as far away from the engine and battery as possible. So now, I'm ready to go! :victory:
.
I also got my ARB fridge monitor hardwired, and it's functioning perfectly. And, I got to use my new RTT "crane" to lift my tent on top of the truck. 1-person: piece of cake! :sombrero:

 

[dstock]

OK, so I just got the panel, got a Morningstar SunSaver 10 controller. I bought some 10ga marine grade stranded Romex and some solar panel connectors. The panel is a Solarex53 (53 watts, VPmax 17.2) This panel is nice. I was registering 18.8vdc on a mostly cloudy day!
.
I mounted the controller to the firewall as far away from the engine and battery as possible. So now, I'm ready to go! :victory:
.
I also got my ARB fridge monitor hardwired, and it's functioning perfectly. And, I got to use my new RTT "crane" to lift my tent on top of the truck. 1-person: piece of cake! :sombrero:

Not to be a downer but that's not going to be enough for multiple days in one place in high ambient temperatures. You will likely only get 2/3 of the rated wattage of the panel even in the best conditions and it's amps you need, not voltage, the morningstar is going to limit the voltage so you don't nuke your battery. I have a thread from last year going that is worth a read when you have the time, you can learn from my mistakes! A 100 watt panel will serve you better.

http://www.expeditionportal.com/forum/threads/126732-100-ambient-Temp-ARB-50qt-100-watt-solar-panel-Not-enough

 

[stingray1300]

Hey dstock, thanks for the input! No downer at all, the panel was *FREE*, so I'm only out $75 for the controller and wiring (which is can be repurposed). Not bad, eh?. I can always get a different panel if I see the need. It would be a 5 minute job (to install the connectors). Plus, we're not in the habit to camp in one place for many multiple days, so the solar panel will not be expected to carry the entire load. This is just a last minute throw-it-together experiment - that worked. How well remains to be seen. I just want it to help keep the battery topped off.