Powering Electric Cooler- Questions

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We are headed down to TX in June for 10 days camping at Big Bend and Guadalupe. I currently have 100W portable solar panel and a Rockpals 300w battery. Before I go off and buy an electric cooler, I had some concerns about the heat and how we are going to maintain power on the trip. For those who use similar set ups, I assume I can have my solar panel powering my battery while it runs the cooler? But what about the times when the cooler needs to be stored in the car during the day (bears in the area)? Will the high temps in the car cause units (cooler and battery) to shut down or malfunction due to the high heat?

We haven't bought a cooler yet, but the Dometic line is too expensive for us. Any recommendations on what unit to buy and how to power it would be welcome.

Thanks!
 

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Personally I think the Dometics are over priced. I have an Engle 35qt in my Cruiser and a Whynter 50qt in my teardrop. My 120 watt panel in full sun will keep my 55qt happy in the summer as well as charge my group 24 battery (90 AH). I have camped with that for as long as two weeks. My Cruiser has a 50 watt and wont keep up with the 35qt fridge probably due to other things on the circuit. I will be upping that one to a 100 sooner or later.
If you dont have a panel yet a 120 will probably cover whatever you get in the way of a fridge and the 100 for the smaller ones

Here's a Whynter, the next size smaller than mine. Truck Fridge normally has the best price on Engle
I can say, both of my fridges, especially the whynter have gone through some rough treatment. The Whynter being about 6 years old now. There are a few knock offs out there, the difference being how much power the compressor draws and the insulation.
 

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Honestly, the budget fridges have gotten quite good in the last few years.

I'm running a 40 qt Massimo fridge I picked up from Costco last year for 270 shipped. We use it as a drink fridge when it's not in the truck, and its been running non-stop since we got it. It pulls about 40W when it's running.

That 100w panel should be able to keep the 300w power station charged without much issue.

I will warn you though, the rockpals don't have regulated output on the 12v socket, so the fridge will shut off due to low voltage once the battery hits about 50%.

You can get around that by wiring an inline voltage stabilizer in between the battery and the fridge. This will give the fridge a constant 11.9v, allowing it to use the full charge on the battery.

To charge while driving, I'd actually recommend plugging the battery's ac charger into an inverter. This will charge it much faster than 12v.

As far as heat goes, I would leave the windows cracked, so the interior gets some ventilation, and you should be fine.

With a 300w battery pack, and a voltage stabilizer, you can expect somewhere between 22-24 hours of continuous run time. I get about 24-36 hours with my 540wh rockpals unit.
 
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smritte

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To charge while driving, I'd actually recommend plugging the battery's ac charger into an inverter.
it doesn't have a 12 volt charging port? If it does your way better off using that. The amount of loss going from 12v-110v-12v is pretty high.
 

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We are headed down to TX in June for 10 days camping at Big Bend and Guadalupe. I currently have 100W portable solar panel and a Rockpals 300w battery. Before I go off and buy an electric cooler, I had some concerns about the heat and how we are going to maintain power on the trip. For those who use similar set ups, I assume I can have my solar panel powering my battery while it runs the cooler? But what about the times when the cooler needs to be stored in the car during the day (bears in the area)? Will the high temps in the car cause units (cooler and battery) to shut down or malfunction due to the high heat?

We haven't bought a cooler yet, but the Dometic line is too expensive for us. Any recommendations on what unit to buy and how to power it would be welcome.

Thanks!
Dometic is in my opinion overpriced and has a solid “Overland“ tax on it because provides owners forum cred.
I picked up an ICECO VL45Pro S last summer and run it as follows:
12v aux port -> Jackery 300 12v -> Iceco 12v
This way while I drive or have car on it’s charging the Jackery and once I turn car off runs off Jackery. The 300 will easily run fridge for about a full day I augment that with SolarSaga panels during day or just turn car on for a while. I’m in Miami so summer tempera are comparable to,TX if not worse and even more humid and I can run 34 degrees all day long.
 

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it doesn't have a 12 volt charging port? If it does your way better off using that. The amount of loss going from 12v-110v-12v is pretty high.
It has a charing port. It can accept 12v-18v input. While I agree, charging direct via dc would be ideal, in practice, it's much slower. It's also prone to rattling loose (I've tried charging them everyway you can think of, and ac via inverter gives the best results).

If you're charging while driving, why does the loss in conversion matter? A 300w inverter will be more than enough to charge one of these things from dead flat to full in about 4 hours.
 

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This will solve all your 12v cigarette plug woes. The plug head unscrews redialing a two prong threaded connector that threads onto the socket.


 

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This will solve all your 12v cigarette plug woes. The plug head unscrews redialing a two prong threaded connector that threads onto the socket.


This works great for DIY installs, where you're dealing with a traditional second battery, and aux system, but the plugs can still pop out of power stations.

Ask me how I know. ;)

Maybe I need to go and create a long post in the Electrical section regarding power stations, fridges, and such.
 

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If you're charging while driving, why does the loss in conversion matter?
Good point.
For me its just another place to fail. I dont see the point of buying another piece of gear that turns out redundant. If the lighter plug rattles out for your fridge, its gonna rattle out on your inverter anyway. That's why I have special sockets and most is converted to anderson connectors.
Not sure why it would charge faster on 110. In the unit the voltage has to be dropped, converted to dc then regulated. AC or DC input will still go through the same regulator inside.
 

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Good point.
For me its just another place to fail. I dont see the point of buying another piece of gear that turns out redundant. If the lighter plug rattles out for your fridge, its gonna rattle out on your inverter anyway. That's why I have special sockets and most is converted to anderson connectors.
Not sure why it would charge faster on 110. In the unit the voltage has to be dropped, converted to dc then regulated. AC or DC input will still go through the same regulator inside.
That's a fair point. My inverter is hard wired into my auxiliary electrical, so it's not likely to rattle loose, but that's not the way everyone does it.

As far as charging, it may come down to voltage. Most of these units have an unregulated 12v Charging cord (12v plug on one end, barrel plug on the other). Ac on my 540Wh rockpals is 18v output, 7.5a (or 24v output, I can't remember). I'm guessing the system is limited to how many amps it can charge with, while the voltage can be higher or lower depending on the input.

Im merely guessing though, based on wheat I've seen through experience.
 
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smritte

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My inverter is hard wired into my auxiliary electrical, so it's not likely to rattle loose,
My life lesson was 2 days into a week trip to find out the fridge wiggled loose. Killed the food. Back into town we go.
 

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We haven't bought a cooler yet, but the Dometic line is too expensive for us. Any recommendations on what unit to buy and how to power it would be welcome.

Thanks!
Many of the generic brands also use dometic compressors. A 45L alpicool with either a dometic or LG compressor will run about $300.

Mine has the LG compressor and will easily run 2-3 days without starting my rig. It’s hardwired in. I do have twin batteries. I imagine even in summer heat a single battery will do fine if you’re doing any driving at all each day.
 

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Dedicated circuit to the battery with 10 AWG wire, with a fuse at the battery. Many car eletrical systems use 18 AWG wire and were never designed to handle this kind of load. Cut off the cigarette lighter plug with enough space to connect an "Anderson 50A" plug to is as well, just in case you have to plug it into a cigarette lighter socket. I use Anderson 50a plugs for everything, black gray for 12v stuff and red for solar panels. Black and gray will connect to each other but no other color will, so it is great for dummy proofing the wiring from your solar panels. They don't wear out like the MC4 connectors that come on many solar systems that were never designed to be re-connected over and over. Get a proper crimp tool to crimp them, soldering them can lead to them getting hot on battery connections. 400 watts of solar going to my lithium battery nearly created a fire. You need a DC to DC converter in the 20 amp range if you plan to connect a lithium battery to your system. Lithium batteries will take every amp your alternator will deliver, this will probably lead to it's early demise.
 

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Couple of questions to ask yourself.
1) Does your Rockpals support 12 Volt pass-through charging? If it can- good. If it cannot, you cannot charge and run the fridge at the same time.

2) What kind of solar charge controller does your Rockpal have (PWM or MPPT) ? MPPT is more efficient and will allow you to use a smaller panel than a PWM controller. If it does not have a MPPT controller, it may be worth investing in one.

I am using a 120W Folding panel with a Victron MPPT controller to charge either my group 31 AGM in my vehicle or Type 27 AGM in a Trolling Motor Box while running a Dometic CFX 50. All runs are using pure copper 10AWG wiring with Anderson plugs. I can sucessfully keep everything fully charged and going while I am stopped down in Baja for a week in or running around the SW. I use my fridge to chill room temp beers as I drink the cold ones- so there is a bit of additional load I am placing on the system.