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Filling tires using 12v

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talkingevs

GO AVS! 2022 CHAMPS!
Jan 28, 2018
473
237
Las Vegas, NV
We own a Viair 300p-rvs for our rv we used to have. It is a high powered tire pump for high psi but can also do regular tires. It has two clamps that connect to the car battery. Do you think it is safe to use this on the model 3? All four of our tires need about 5 psi each, so it would only take about 10 seconds each tire with this compressor. I'm just worried about hooking up the compressor to the 12v accessory battery up front.
 
Call me crazy but I top off my tires with a bike tire pump. Takes maybe 10-15 pumps to fill a few PSI.
Okay, you're crazy. And probably a lot more in shape than I am.

@dano9258 Using an air compressor that's clamped onto the 12V battery, as opposed to using one that plugs into the 12V accessory port in the center console (aka, cigarette lighter), is much more reliable considering the 12V port in the 3 is protected by a "circuit breaker" which trips if excessive current is detected (around 15A I believe). However, it's much more involved to open the frunk, remove the plastic cover over the 12V battery and then clamp on. You can find portable 12V air compressor that can plug into the 12V port, yet still draw only 10A or so. Yes, it might take a few more seconds/minutes to pump up each tire but the convenience factor outweighs that. But then again it will cost you maybe $30.

I use a Slime 40051 compressor I found at a local auto parts store. Hasn't failed me yet, nor tripped the car's automatically resetting circuit breaker.
 
Call me crazy but I top off my tires with a bike tire pump. Takes maybe 10-15 pumps to fill a few PSI.

Yep, this is what I do too. It's so much simpler and faster than an air pump (unless you happen to have a continuously available proper air compressor with tank in your garage - I have one, but the act of getting it filled and ready to go takes far longer than just topping off with the bicycle pump).

Good exercise, too.

I also have a compact collapsible bicycle pump for roadside use stored in the trunk cavity. Much more reliable than a portable air compressor.

We own a Viair 300p-rvs for our rv we used to have. It is a high powered tire pump for high psi but can also do regular tires. It has two clamps that connect to the car battery. Do you think it is safe to use this on the model 3? All four of our tires need about 5 psi each, so it would only take about 10 seconds each tire with this compressor. I'm just worried about hooking up the compressor to the 12v accessory battery up front.

It's just fine, as long as you connect directly to the battery. I suppose it's possible it might make the car think the battery is failing due to an unexpected drop in voltage, if you use it a lot at once, but no idea exactly what it takes to trigger that (I don't know how the 12V battery integrity checking works on Teslas but I think I've heard dashcams directly connected to the battery can cause problems?). I doubt it would be a problem at all for an air pump since it's not a continuous load.
 
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I carry a Harbor Freight compressor I have had for several years (they still have it today-now $37 before any of their usual discounts) that plugs into the 12 v socket. It is the quietest compressor I have owned and is OK in speed for the usual few pounds. It takes up much less space than my bicycle floor pumps would and I think it costs less (bought them a long time ago). It fits in the well on the left side of the trunk and it has not blown a breaker (yet).
 
We own a Viair 300p-rvs for our rv we used to have. It is a high powered tire pump for high psi but can also do regular tires. It has two clamps that connect to the car battery. Do you think it is safe to use this on the model 3? All four of our tires need about 5 psi each, so it would only take about 10 seconds each tire with this compressor. I'm just worried about hooking up the compressor to the 12v accessory battery up front.
Lol, I did exactly this with a viair compressor last night, and didn’t think twice about it. My car still got me to work this morning, so knock on wood I didn’t damage my brand new 12v! Maybe next time I’ll try the bike pump instead.​
 
I have a small Viair from my ICE days which clamps to the battery as well, I want to use it on our Teslas. My Model S with the nose cone works fine using the bumper mounted contact points under the nose. I would like to try it on our Y, I realize there is some work under the front to access the battery contacts under the frunk.
I wonder if the car should be left on so the main battery is connected so the 12v does not over discharge? Mind you, this would only be needed to fill a tire that has an emergency patch job on a road trip.