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Building a bed platform for Prius Prime 2021

Discussion in 'Prime Accessories and Modifications' started by Gabriel Gonzalez, Sep 20, 2024.

  1. Gabriel Gonzalez

    Gabriel Gonzalez New Member

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    Hello,

    My living situation is about to change. I was thinking that moving into my car for a few months may be the best option available to me at this time. I am looking for advice as to how to attach some 2 x 4s to the car

    I attached the smaller 2 x 4s with the same bolts that came off from the rear seat assembly. For the longer 2 x 4s, I bought m8-1.25 x 70mm bolts and I drilled a hole in the piece of wood to try and use the same thread from the car, but it ended up all wobbly, so I took it apart

    I uploaded a few pictures, the first two are how the platform looks with the plywood sitting on top of the 2 x 4s (the longer pieces are just held together with double-sided tape for now
    The third picture shows how it looks now, I drew circles around the threads I was planning on using as well as the original 2 x 4 I poorly attached

    I am not sure if I can directly drill into the car instead of using the pre-existing threads. In the fourth picture, I highlighted where I was thinking of maybe drilling so I could attach 2 pieces of wood, one on each side.
    The last picture is just a close-up of the pre-existing holes

    I may be doing a poor job of explaining myself here, but basically, I am wondering if there is an easier way to attach the 2 x 4s using the holes already there.
    And if that does not work out, maybe it would be better to actually drill into the car, the question then is where can I safely do so without damaging any cables or really anything important

    Thank you
     

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  2. vvillovv

    vvillovv Senior Member

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    Have you watched many of the prius camper builds on youtube or tiktok
    heres one to get you into the camper build video section if you haven't seen any of them yet.
    I'm linking in the middle of the video, and this dude did a wood cabinet that is earlier in the video.

    Hope you find some great ideas for your build.
     
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  3. Gabriel Gonzalez

    Gabriel Gonzalez New Member

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    Hey thanks for the reply man!
    I did see that video, in fact, I added it to a playlist on youtube for, as you said, get ideas for the build. I guess I am worried if I drill into the car I will damage something that will cost me a lot to fix

    Another thing is that a lot if not most videos I have seen are for the hybrid gen2 and gen 3 prius, and this one being a prime is proving difficult to find videos/tutorials on how to build the car, or where is it safe to drill, etc
     
  4. vvillovv

    vvillovv Senior Member

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    I'd recommend using brackets from available fasteners and try to keep the drilling new holes to a minimum.

    Attaching stuff inside the Prime is an art and most of the campers I've seen (not all but most) use removable supports and double as storage. Especially in that bugger of a back seat area. I see you've already pulled the seat so you've got a decent idea of what's back there. You might want to pull your plywood out and remove the battery over too so you can see more of what's in that area too. That cover panel has to be push gently toward the front of the car about a 1/2 inch before you can left it up and out. There are probably a few plastic clips to pull as well, but it's been a while since I've been in there. But it you want let me know and I'm take some pics and see if I can provide any help.
     
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  5. BiomedO1

    BiomedO1 Senior Member

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    FWIW; I'd use 4x4 legs, so they won't 'flop around'. You shouldn't have to drill into the car, just use existing fastener holes. Your using wood, just shape it properly so it doesn't rock and you've got a solid foundation. Talk to a cabinet maker, if your confused; there's lots of craftsmen in Pa & NJ area.

    Good Luck
     
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  6. vvillovv

    vvillovv Senior Member

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    When I first looked at your pics of the platform before I saw the back seat area pics, my first thought was if that was me I'd try to think of a way to make theat one piece sleeping platform foldable, so you could fold it back and raise the read seat backrests to their normal positions.

    Another idea I got after reading @BiomedO1 post was to make your 2z4 supports kind of like upside down trusses, connecting the legs together at the bottom with one 2x4 lengthwise. Tnen, if needed, instead of attaching with bolts, a bead of gorilla glue might work and also be semi removable.
     
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  7. Gabriel Gonzalez

    Gabriel Gonzalez New Member

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    Thank you for the reply man!
    When you wrote about using brackets and fasteners you are talking about the zinc-plated corner brackets and stuff like that right? I took the 1st picture showing the brackets I bought thinking they would be useful,

    As for the fasteners, you are talking about existing attaching points already built into the car, right? I circled the ones I thought could be useful in the 2nd picture, and show a fuller view of them in the 3rd picture, but I don't picture in my mind how could I use them with brackets and the wood. That may be a skill issue on my part, I am not experienced in woodworking at all, unfortunately

    Also, for the board of plywood covering the battery and cargo area. I actually made that one, I had to remove the original one because it had rigid flaps that prevented me from putting the bed platform in place
    Lastly, when you wrote about removing the battery, did you mean just take it all apart and take the battery off from the car completely?
    The last pictures show how the cargo area looks without the plywood, the original cargo liner, the one I made

    And sorry if this was too long, I just wanted to add, that I would very much appreciate you taking the time to take some pictures, and I would welcome any help you could provide

    Thank you man
     

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    #7 Gabriel Gonzalez, Sep 24, 2024
    Last edited: Sep 24, 2024
  8. Gabriel Gonzalez

    Gabriel Gonzalez New Member

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    Huh using the 4x4 never crossed my mind. I've seen many videos guides/tutorials of people modifying their Prius, and they always used 2x4s but 4x4s make a lot of sense, especially since I am very preoccupied with the stability of the bed platform given that there are only 4 threaded holes in the car that I think could be used

    Also, man damn that idea of talking about cabinet makers is amazing. It just blew my mind, because I am not experienced with woodworking, I have had to watch a lot of YouTube guides to get to the point I am in the build. I started fooling woodworking craftsmen near me to see if anyone is interested in giving me some pointers

    I think the idea of the foldable platform that allows keeping the back seats could work in the earlier generations Prius. However, I found that the headroom of the car I bought is very small. For instance, with the platform in place and a mattress topper to lay on, I would probably have 20 inches between my face and the ceiling, is not pretty haha

    Man I am trying to picture the upside-down trusses idea in my mind, even tried making a drawing to see if I was picturing it correctly, let me see what I can come up with, and edit this reply
     
    #8 Gabriel Gonzalez, Sep 24, 2024
    Last edited by a moderator: Sep 24, 2024
  9. Gabriel Gonzalez

    Gabriel Gonzalez New Member

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    I am not sure what happened, I was editing a reply but apparently, I ran out of time, only 15 minutes to edit expired. Now all my replies say that they are awaiting moderator approval, not sure if I messed up something, maybe all my replies were already subject to moderator approval to begin with, not sure

    I am only going to reply with the edit I was going to make to my original reply, in case the reply does go through after being approved by a moderator

    Edit: okay so this is what I came up with, first it has the 2x4 lengthwise at the bottom, then the trusses-like constructions. The last two pictures are images I used as reference. Is this close to what you were thinking?
    Thank you man
     

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  10. BiomedO1

    BiomedO1 Senior Member

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    Your making this way more complicated than it needs to be! Talk to someone with lots of construction/structural engineering experience or a cabinet maker.
    All you need is (2) 4x4 legs (near the doors) and (1) 2x4 joist between the two, plus two joist hangers.,
    https://www.homedepot.com/p/Simpson-Strong-Tie-PF-18-Gauge-Galvanized-Post-Frame-Hanger-for-2x4-Nominal-Lumber-PF24/1003749754x4
    A 3/4 plywood sheet going all the way back to the trunk lid, should be able to support you. If your really big, you may need to place another set of support legs near where the back seat cushion back rest used to be - but I really doubt that. Use the cargo hook screw holes to keep the plywood in place. You don't want that plywood sliding forward and severing your spine! That can happen if someone rear ends you or you make a panic stop.
    Also put together some sort of protective cage or box around the battery control ECU and wires - so you don't jam, break, or rip something out accidentally while shoving, pulling stuff from under the platform.

    Hope this helps....
     
  11. vvillovv

    vvillovv Senior Member

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    Hey, don't worry or try explaining what is going on with your posts, it's a forum and unexpected stuff shows up all the time. Post what ya can when ya can and if anyone gives ya grief about something, you can explain what you meant than of ignore, which ever suits you best at the time.

    Dang, you're way ahead of me, as I look at the new pics above. You already have the trunk area battery cover taken out and the battery case showing and that's exactly what I was thinking.
    And no way, don't mess around with the battery pack.
    Once you get into that, if you ever do, it's a lot to take in, even for someone that has experience with older hybrid batteries. The five banks of 19 cells each are covered with wires, connectors and the BMS modules that has wires of each of the packs 95 cells. The small and tiny parts count is high and disassembly is not trivial.

    As I look at your truss mockup I'm thinking the one 2x4 on the bottom should be good enough by itself, but if you want more support you could add a 1x1 or across the top and one diagonally or two in a V shape from the outside corners and meet in the middle on the upper or lower side which ever is the opposite side from the corners side. The one diagonal will make it easier to use the space available on the driver side under your platform. I've slept in the back of the Prime while charging early in the morning and it's way easier to just recline the front seat for me, since I used to doing that while on multi day drives. I wouldn't ever want to have to pre plan using the car and as a near full time camping vehicle.

    There another thing about the Primes to be aware of while camping. They shut themselves off easy and quickly. So having HAVC on all night is not easy to figure out. That is if it's at all possible. I recommend you get an OBD11 bluetooth adapter and DrPrius app so you can monitor both the 12 volt and the 351 volt batteries while camping. And make sure you know what your car is going to do under each weather condition you are going to be camping in. The Prime behaves a lot differently in winter weather that is does during the summer months.
     
  12. vvillovv

    vvillovv Senior Member

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    The first thing to get out of the way when attaching to the available mounting holes is just attach anything to them so you can measure what you're working with. Once you see how an attachment point works for a piece of scrap wood or a simple bracket, you can work out what else you might need to make the attachment secure to car and the items you want to attach to the car.
     
  13. Gabriel Gonzalez

    Gabriel Gonzalez New Member

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    Alrighty, so for the Simpson strong tie, this is how I picture the whole thing going together

    Yes, I remember someone recommended also talking to a cabinet maker. I think I have to find a smaller business because the ones I have been cold calling seem to have a lot of business with their regular services that my situation does not seem worth it, or something

    Also, I did manage to attach a back set of support legs with some corner brackets, so I am not that big, only 5'9 but regardless those support legs can't hurt, hopefully
    Man, that tidbit about the cargo hook screw holes is golden, I definitely do not want a board of plywood severing my spine à la Final Destination movie

    I was planning to build a sort of little "house" for the battery control an electric motor. There are some pieces that are kinda flexible near that place. I have kicked/bent one of them, did not cause any damage, but definitely better to keep it secure and away from other objects
     
  14. Gabriel Gonzalez

    Gabriel Gonzalez New Member

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    Alrighty, after I successfully attach the first 2x4s I will add the bottom 2x4 lengthwise, and asses from there, maybe I just do the same thing at the top and call it good

    From the research I did, apparently, the workaround to have the Prius Primes have the AC all night long, is to keep the car in Ready mode, AND lock the car from inside the car using the door controls, not the lock located in the fob, if that makes sense

    I do have an OBD11 device, I did not know those were capable of monitoring the batteries, I will look into the DrPrius app, that sounds interesting for sure
    Theres hundreds of things I got to do before I can successfully camp in prime but first among them is getting the bed platform finished haha. Hopefully by next week its done
     
  15. Gabriel Gonzalez

    Gabriel Gonzalez New Member

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    For the photos with the plywood on top I just used double sides tape to keep them from moving, while I took pictures and measurements, its been a whole ordeal, but man it will be worth it
     
  16. vvillovv

    vvillovv Senior Member

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