EVBase R1S Air Mattress: Fit, Feel, and Storage Options

My kids slept on this mattress before I made a video about it. We took it to Vegas, they used it in the hotel room, and they liked it. That’s the most honest product test I can give you. EVBase sent it over for a full review, and I wanted to put it through real use first. This is the EVBase custom-fit air mattress for the Rivian R1S.

Sherwin standing in his garage next to a white Rivian R1S with the frunk open, holding the EVBase air mattress bag

Where to Store It

Before you even inflate it, you need somewhere to put the bag on the way there. It’s about the size of a school backpack, maybe two gallons of milk in weight. Not heavy, but not small either.

The frunk fits it, and that’s where we kept it on the Vegas road trip. But it takes up about 65 to 70 percent of the frunk. You can still close it, and you’ve got a roughly 1x1 foot strip left on one side. That works for light items, but it’s not nothing.

In the trunk, it fits flat with the main floor in, and it still stands upright with room beside it. If you pull the sub-trunk floor out, you can drop it in there and close it over, though it bulges slightly. Something heavy on top holds it. With the third-row seats folded, it just goes in the back and you’re done.

Setup

Fold your second and third rows flat. The cargo area of the R1S is wide at the second row and narrows toward the rear, and the mattress is shaped to match that exactly.

It comes out of the bag rolled up with two clip straps. No velcro, just clips. The pump is built into the mattress and rechargeable via USB-C on the mattress side. Here’s the gripe: the included cable is USB-A on the other end. The R1S only has USB-C ports. You’ll need a separate USB-C to USB-C cable to charge it from the car. That should have been in the box.

Interior of a white Rivian R1S with second and third-row seats folded completely flat for car camping

The direction you slide the pump determines inflate or deflate, and it’s labeled clearly on the unit. Inflation runs about two and a half to three minutes. Deflation is similar, maybe a touch longer depending on how firm you went. You can also use the standard valve with your Rivian’s built-in air compressor if you prefer.

The Fit

Once inflated, the wider end sits toward the second row, the narrower end toward the rear. You can slide it forward and back to position it. Along the sides, you still have access to the 120V outlets and the air compressor. It doesn’t block everything.

Close-up of the light blue EVBase inflatable mattress perfectly fitted in the Rivian R1S cargo area, with outlet access visible on the sides

I tried a twin bed sheet over it. It doesn’t work. Too small for one reason, wrong shape for another. You’d want something closer to a queen fitted sheet, or just a flat sheet you can tuck. Worth sourcing before a trip rather than figuring it out at the campsite.

Blue and white patterned bed sheet draped over the EVBase inflatable mattress inside the Rivian R1S

I’m 5’5”. I can lie down without my head hitting the rear glass divider, but you have to position yourself so your head is in the glass section, not against the hard trim. Taller than me and you’ll want to think about this. The glass roof makes it nicer than it sounds once you’re actually in there.

One Thing to Plan Around

When the mattress is inflated and you’re sleeping on it, everything that was in the cargo area has to go somewhere else. That means outside, in bins, on a roof rack, wherever. This isn’t a knock on the product, it’s just how any in-vehicle sleeping setup works. But if you’ve packed your gear for a camping trip, you need a plan before dark.

Deflating and Packing

Slide the pump to deflate, wait a few minutes. While it’s running, I fold and press along the mattress to help push air toward the valve. It packs back into the bag the same way it came out, and the bag has both a drawstring closure and a shoulder strap.

Sherwin pointing to the deflation valve on the EVBase air mattress inside the Rivian R1S cargo area

The whole thing, inflate to deflate and packed up, takes under ten minutes. For something you’re going to use at a campsite or a hotel room or a beach, that’s a reasonable ask.

Worth It

The mattress is shaped to the R1S, comfortable, and self-contained. The built-in pump is the right call. The USB-A cable is an easy fix with a cable you probably already own. My kids validated it without being asked to, and that’s a better endorsement than anything I’d write here. If you have an R1S and want a car camping option that actually fits, EVBase built it for this vehicle specifically.

If you’re still figuring out whether the R1S fits your family’s road trip style, the Vegas road trip post covers how it handles six people, extreme heat, and 518 miles.