Looking to put a fridge in my Prius

Discussion in 'Gen 3 Prius Accessories and Modifications' started by Jasminealeiah, Jul 20, 2021.

  1. Jasminealeiah

    Jasminealeiah New Member

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    So, I'm looking to put a fridge in my Prius and I'm having trouble figuring out which option is better or what the Prius can actually handle. I haven't pulled the plug and bought a fridge yet, but I don't know much about the electic side of things and am struggling to figure out what would be better for both me and the Prius, overall. The first thing that needs to be understood is that this is for a car camping setup, and I eat a lot of frozen food, so much that I would need more freezer space than fridge space. I mean, I would use the fridge too, but only just often enough to need both, and the dual zone models I'm looking at are either really small or really big. I'm talking, 20L vs 75L at the next size up. So, I was thinking of using the 75L version in my prius (I have a place in mind for it, so it actually fitting isn't an issue), as it runs on a 12V system with the normal car charger plugs you see everywhere, but it also pulls about 800 watts of power, and I'm not sure whether or not the Prius could handle that kind of constant draw. My alternative idea was just getting two smaller ones that would draw about a maximum of 60 watts each and using one as a fridge and one as a freezer. The thing is, I'm not sure which version (if any) is better for the car, itself. What's worse, drawing 800 watts on one unit or drawing 60 watts each on two separate units? And can the prius actually handle that kind of draw, anyway?
     
  2. Jasminealeiah

    Jasminealeiah New Member

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    So, I did more research, and the product info on the bigger 75L model says that it draws 800 watts per hour, not 800 watts as a constant draw. Just watched a youtube video about the product, and the powerstation (about the size of a 500 watt Jackery, but a different brand) it was plugged into was saying that it was drawing less than 50 watts. Said that it would probably draw more power getting down to temp initially than it would draw to keep it cold once it was already down to temp. Don't know anything else for sure but that, but it's already looking better to me, as an option. Would still like to hear some opinions on all this though, as I am by no means an expert when it comes to electronics and power and all that.
     
  3. PriusCamper

    PriusCamper Senior Member

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    When it comes to transition from fossil fuels to electric the biggest challenge is cooling systems, which use a lot of energy. Least expensive is getting a super insulated ice chest and filled with dry ice and frozen foods is going to work great for a few days... But if you plan to be off grid longer than that I'd recommend buying a 2nd 12v battery like this one: https://ebay.us/vN4JsP and wire it up so 12v is charged with solar when car is off and charged by the car when the car is on. That way you won't risk being out in the middle of nowhere and having the fridge drain down the car's 12v and making it so you can't start the car.

    Aside from those strategies and in general, as long as the car is on and in ready mode you can tap directly into your 12v with the 800w fridge as long as you're using heavy gauge wire and a fuse... But make sure to not drain too high above 1000w or you'll being pushing the limits too far. Drawing this much power from the cigarette lighter is a bad idea because the wires are tiny and will run really hot and might fry.
     
  4. black_jmyntrn

    black_jmyntrn Member

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    Fridge in the Prius is one of my favorite subjects. The main question to ask yourself is, where will you put it? Will you have to move it often based on your usage and its placement?

    Currently, I have an Alpicool and my refrigerator is hardwired into my Prius now to a 12port fuse box that's powered from a second 12v battery that's installed.

    Initially, I used a fuse tap to power my fridge that way when the car is off the fridge is still powered. The best part about a lot if not most of these refrigerators, is they have a low voltage setting so it will turn off if your battery reaches a certain voltage.

    There really is no better for the car, it's do you have a battery that's young enough to support the load. I actually replaced the OEM 12V with an 85AH battery, if you had one you wouldn't have to worry much at all. I really don't because I have two 85AH batteries but I not only have a fridge, but a cell booster, raspberry pi, mini pc, and some other interesting add ons, all of which run off the second 12V battery.
     
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  5. Jasminealeiah

    Jasminealeiah New Member

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    Yeah, solar is an option I've been looking into, but rather than an inverter, I'm leaning more towards a good quality portable powerstation I can tap into and charge up as needed to avoid the risk of messing something up with wiring because I don't know what I'm doing. Unfortuantely, I can't feasibly run a fridge and everything else I'll need all on the same powerstation on a constant basis without needing to unplug to charge it all back up again. Still an option but it's something I'll have to look into more before I decide for certain which is better. It helps that the fridge comes with the correct wires for plugging into both a car and a traditional outlet, so I'm not worried about that side of things, at least. I've just been worried if the bigger fridge would be too much for the car even while it's in ready mode because of the 12V system. (Thinking back on it, something made for 12V systems shouldn't overwhelm a 12V system, so maybe I'm worried for nothing, but we'll see.)

    But this is really a long-term setup as once I have everything I need, I'll be basically living out of the prius while I travel and work and such, so that's why I'm considering the bigger model so seriously, at all, rather than using something tiny/ a regular cooler for smaller trips. Based on my research, the product description on the fridge must have had things written out in a confusing manner (at least for folks like me who don't fully understand the electrics), because while the fridge apparently draws about 800 watts per hour, power tests shown on youtube videos I've seen show it drawing less than 50 watts at any one time. Which confuses me. Is there a difference between 800 watts and 800 watts per hour?
     
  6. Jasminealeiah

    Jasminealeiah New Member

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    Well, it's just me and I'm basically going to be living in it, so I'm removing the back seats (and maybe the passenger seat as well, if necessary), so I'll be finding one place to put it so it doesn't have to be moved around any with my setup. I like your ideas with the second battery but I also don't trust myself to do that kind of thing without issue, right now, so my power alternative is a good quality portable powerstation (like Jackery or the ones Light Harvest Solar sells) with high enough wattage to handle anything I throw at it and a good solar charge method to go along with that. Also, yes, I love the low voltage setting; these fridges are all made in really cool ways for car camping. I'm super excited for getting one. I just need to be sure I get the right one for my Prius setup.
     
  7. Jasminealeiah

    Jasminealeiah New Member

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    For anyone else looking at this thread, I am clearly a total newb with this kind of stuff. Turns out, I was probably reading the product page wrong on the power consumption rating, and it looks like it only pulls 800 watts on the max mode over the course of 24 hours (0.805kw/24h), maybe. I checked online how to find the wattage rating (Volts X Amps, apparently), and based on all that, it only actually pulls at max a range somewhere between 80-100 watts, depending on the other factors involved. That's way better than I was first thinking. And since it has an edo mode, it will probably pull about half that at the lower power setting. I think I was actually worried for nothing, all things considered (even if I'll still have to be careful to unplug it when the prius isn't in ready mode, just to be safe). Now, I just need to save up to buy the fridge and then figure out how I'm going to set it up and lock it in so it doesn't go sliding around everywhere while I'm driving. Any advice or tips on that side of things would be amazing, even if it isn't what my original question really was.
     
  8. ChapmanF

    ChapmanF Senior Member

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    Something about that isn't adding up for me. For starters, there is an amount of power a fridge uses when it runs. That's what you'll see when you first plug it in and it has to run constantly to bring the temperature down. Once it is controlling at temperature, it will not run all the time, and effectively it is drawing a lower power that's the average of the running power for the part of the time that it runs and no power for the other part.

    My 28L fridge will use about 80 watts while it is pulling the temperature down, and then it will settle in to something like an 18 watt average routine.

    If I imagined scaling that fridge up from 28L to 75L, then maybe I wouldn't be too surprised to see maybe 215 watts while it cools down, then maybe even as much as 50 watts on average ... probably even less than that.

    800 watts, now, that would surprise me a lot. Have you double-checked the source of that figure? If it is accurate, maybe part of the solution is to keep shopping for a fridge that sucks less. Even the one in my house would be ashamed to draw 800 watts.
     
  9. Jasminealeiah

    Jasminealeiah New Member

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    Yeah, as I did more research, I realized that I'd read the product info wrong because I know nothing about the electric side of things. It actually draws about 80-100 watts on max and probably also as it cools down and runs about half that on eco mode. Of course, it didn't help that the page only listed how many kilowatts it uses over a 24 hour period on max at the lowest temp setting, and in trying to figure out what it actually draws, I did the math wrong. Because of course I did.
     
  10. ChapmanF

    ChapmanF Senior Member

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    The page probably listed how many kilowatthours per 24 hour period it uses, which sounds weirdly redundant but is correct in the units. When you do that indicated division by 24 hours, the hours top and bottom cancel, leaving you with kilowatts, a proper rate of power consumption.
     
  11. Jasminealeiah

    Jasminealeiah New Member

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    Yeah, as accurate as I'm sure the reading is, it does sound like a really weird way to list it out to potential buyers when you don't also list out the wattage and such, especially for those buyers who don't understand the readings well enough to know what it's all referring to.

    But at least it's all worked out now, and I know it won't hurt the car, if I'm careful, so it's just down to saving up to buy everything, figuring out where it will all go, and deciding what kind of solar I can actually put into a prius.
     
  12. ChapmanF

    ChapmanF Senior Member

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    For most of the fridges I've looked at, there seems to be a convention where they give two numbers.

    One will just be watts, and represent the power it consumes while running. That figure is probably required by the usual electrical labeling standards.

    Another figure will be given in the verbose-looking "watthours per (however many) hours" form, and after you do the indicated division and the hours cancel, you're left with another, lower, "watts" number, representing its average consumption while it is cycling to maintain temperature.
     
  13. Jasminealeiah

    Jasminealeiah New Member

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    For some reason, this particular listing didn't actually show what it consumes while running, just how many kilowatts per 24 hours, which didn't really help me any when I was looking everything up.
     
    #13 Jasminealeiah, Jul 22, 2021
    Last edited: Jul 22, 2021
  14. PriusCamper

    PriusCamper Senior Member

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    Keep in mind all these power stations really are is a battery and an inverter inside expensive packaging and you can save a huge amount of money by buying a cheap inverter, cheap 12v and voltage meter and connecting the wires yourself and building customs mounts or container for it.
     
  15. rjparker

    rjparker Senior Member

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    Just because it is made for 12v systems does not mean it won't eventually overwhelm that system if used much when it is not being charged faster than it is being used. The only reasonable solution for a large portable refrigerator is to ensure you have more charged battery capacity than it uses before recharging can take place again. Recharging could be solar, Ready mode or through a 120 vac connection (least costly). Or a combination.

    Since the refrigeration you selected also runs on 120 vac, power usage is often spec'd in killowatt hours (kwh) since that is how it is metered and billed by a utility. So kwh per day is useful. A good refrigeration device that is well insulated and air sealed may only run ten minutes an hour or 240 minutes per day. So 0.805 kwh as spec'd (thousands of watt hours) on 120 vac would cost about 12 cents per day at 15 cents per kwh.

    With dc power using battery backup, watt hours is more useful, primarily to size batteries and charging systems. In these applications, worse case current draws are important since 100 watts at 12 vdc draws over 8 amps. This is similar to leaving your headlights on. Ok for a while, not so great overnight. So having an extra battery is really not optional in many cases. Having it electrically isolated when not charging is important. RV shops do this all the time and are therefore a good local source of expertise. There are formulas and iterative design practices but why reinvent the wheel when doing it right is just down the road.

    Costs to run, which is really cost to recharge, will be high using Ready or Solar compared to utility power. Either in gas consumed or more significantly in upfront costs for solar panels and controls. Plus battery costs which will wear out sooner. Most charging will be primarily gas unless you have a very large solar array and are in a very sunny climate. Solar on homes often takes 20 years to pay back, but for those without the grid, its an option. Solar scales down but costs to do it right can be a consideration.

    Prius battery cca.jpeg
     
    #15 rjparker, Jul 22, 2021
    Last edited: Jul 22, 2021
  16. ChapmanF

    ChapmanF Senior Member

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    I pretty much always find that my ventures into custom cabinetry make a mockery of my time and budget estimates.
     
  17. Jasminealeiah

    Jasminealeiah New Member

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    While that may be true, I've got my eye on a specific company to buy from because they cater specifically to people who build out solar systems into their vehicles and they run good quality parts, as well. On top of that, while I'm starting off in a Prius, I do plan to eventually upgrade to a van, and purchasing the same kind of products I'll be using when that happens just makes more sense to me, in the longterm. Another bonus to using a portable powerstation rather than using an inverter setup is that I can take my power with me when I'm not in my car; I won't be tied down to the prius for all my electrical needs if I don't want to be. Also, the roof on a prius doesn't exactly lend very well to mounting solar panels, so it leaves me with few options on that front, something I'm still trying to work out, honestly.
     
  18. Jasminealeiah

    Jasminealeiah New Member

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    It took me a minute to get through all that, but you're totally not wrong. That's pretty similar to what I was worried about, if the fridge would be too much for the prius to handle, either immediately or over time. I'd prefer some kind of solar charging method, but as a Prius really isn't that capable of handling a solar mount the same way bigger cars with flatter roofs are, it's been a challenge to figure out what method I'll be using. It's really unfortunate that the panels I'll be using when I upgrade to a Sprinter later on won't also fit on the prius because that would be helpful overall, but it honestly seems like I'm stuck between flexible panels and some kind of folding panel setup. Whichever turns out to be better for my setup, in the end.

    An alternative I've considered is just buying a second portable powerstation so I have 2 of them and then cycle back and forth to use one while I'm charging the other (assuming the fridge is plugged up into it constantly and I can't get enough sunlight to charge faster than the fridge draws), but that would cost a lot more up front than I'm sure I'm really going to have access to. At the very least, if the prius can handle the fridge in ready mode, it should be okay, as I'm planning to unplug the fridge when the car is off and won't be plugging anything else into it at the same time. All my other electric will be taken from the powerstation once I've got it. A major downside to using the prius like this to power the fridge is, as you said, how fast it will end up draining the gas, but if I can't find a good solar setup to go with it, I might be stuck to using what I can get from the other methods.

    I think it might help that the fridge has an eco mode that's rated to 3.7A (rather than the 7.5A rating on max), which is right in the middle of what the max/ eco modes display on the smaller fridges that I'm fairly sure the car actually can handle in ready mode, at least. I mean, I'm by no means an expert, but it looks like the fridge will draw a lot less power staying at temp than it will just getting down to temp initially, except in really hot environments where the fridge might struggle to keep up, and there's nothing that says I can't plug into my powerstation when that happens to prevent overwhelming the Prius, right?
     
  19. ChapmanF

    ChapmanF Senior Member

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    In READY mode you've got pretty much no worries. The car itself uses an unavoidable base figure of three or four hundred watts in READY for its own entertainment, the fridge will add only a small fraction of that, and the DC/DC converter maxes out at over a kilowatt. The fridge, assuming it's an efficient compressor model, will be a very light load.

    If you make sure that getting the fridge down to temperature is done on utility power or in READY, then holding temperature might be possible for longer than you might think, even on the stock battery.If you have an inexpensive DC watthour meter, you can watch what it actually does in some different conditions, and judge from there.
     
  20. fotomoto

    fotomoto Senior Member

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    That is what I did. I already had a portable solar panels + LiOn battery power bank setup for storms, camping, etc. So, all I needed next was the fridge......

    I plug the power bank into the cars’ 12v power port and plug the fridge into the bank. My small 15L fridge/freezer draws about 40-50watts when chilling and zero watts when it’s not (it’s an igloo basically). The car charges the power station (and in effect the fridge too) while ON and the power station runs the fridge whenever the car is OFF. It works seamlessly. My 575Wh (.5kwh) power station can run the fridge from 8-14 hrs depending on ambient temperatures. I have two 120w solar panels that will charge station from empty to 100% in as little as 3-4 hrs of peak sunshine here in sunny south Texas.

    Having a seemingly never ending supply of 35f water bottles on a road trip through the American southwest during the summer? Priceless.

    Cons: power bank fan runs anytime it’s plugged in and charging its battery. It’s loud enough to hear even at moderate road speeds so I kept it in the trunk (Honda Clarity) with the fridge in the back seat while traveling but slide it back into the trunk via the pass-thru when security is needed.

    FWIW
     
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