M12 inflator burns through batteries


Hi all, I have a question: For those using the m12 inflator, does it suck up batteries like nothing else. Barely lasted for one car. Ran through 2 legit branded xc 4.0 batteries, one per car. Outside temp 60 degrees. Cars were 15 psi in deficit x all 4 tires on each car. One car a Camry, one a minivan. I know they are different size tires so more air/volume to achieve pressure in the van. I have knock off Vanon 6.0’s. I didn’t bother. I only trust those for led lights, nothing which powers a motor. I am horribly disappointed in this product. It is only marginally better than my old C3 inflator with xc 19.2v batteries. I wonder if everyone’s inflator performs like this or if mine is defective. My batteries are fine, they power other tools for extended times.




I just had use of mine last week
Tires looked OK in Florida (high 80’s) .
TPMS alarmed on low pressure in the early morning (high 20’s) - driving north after stopover.
Filled 4 tires from about 25psi back up to recommended 33psi using 2Ah battery - no issue - battery did not seem drained. Recharge seemed quick using Milwaukee 12V plug-in charger in the car.
This was my first use of the M12 inflator - as I have a ViAir 88P in my other car that hooks onto the battery terminals with clamps


My experience is similar to Fred’s, added about 5 PSI to all 4 tires tires on two cars, and about 10 to the motorcycle (been sitting a while), and the 2Ah still has one light left. Also it had been sitting for a month probably in the back of the car not being used with the same battery.

Sounds like yours may have an issue, I’d suggest reaching out to Milwaukee about it and see if they can help troubleshoot or otherwise assist. Did you break it in at all? I don’t think the book said anything about it, but I ran it like most compressors for 20 minutes or so unloaded when I first got it to break everything in and it’s been great since.


I never broke it in. I didn’t know that I was supposed to. However, I may have a faulty unit. I guess I’ll call support next week. I added more air, but used 4 ah batteries so I still think I have a problem. Thanks for the replies.



Air compressors use a LOT of electricity. Like, seriously a lot. Battery-powered compressors are convenient but borderline silly because of how much power they guzzle.

I don’t think your experience is unusual or indicates a malfunction. If you have a plug-in wattmeter like the P3 Kill-A-Watt, plug your regular AC-powered compressor into it and see how many watt-hours it takes to do the same amount of work. (It’ll be tricky to start and stop the measurement at the same point in the cycle, but I think just after the compressor shuts off is an easy mark to hit.)

Some very back-of-the-envelope math for comparison: My little pancake draws about 400 watts running, and needs about 2 minutes of run to bring a tire up 15-20 psi. That’s roughly 13 watt-hours per tire.

Now, how much energy is in those batteries? 4AH at 12v is 48 watt-hours. In practice, only about 80% of that is usable even under ideal conditions (don’t draw lithium too flat, or it’ll be damaged – the batteries have a protection circuit that prevents this), and Peukert’s factor says that the faster you draw it, the less efficient it is. Lithium has a very low Peukert exponent but it’s still non-zero. Let’s say about 35-40 watt-hours usable per battery.

Assuming the compressors are similarly efficient at turning juice into air (which, for a single stage reciprocating machine, operating below 80 psi, is probably a reasonable assumption), you’d probably get about 3 tires per battery, assuming they’re the same size as my car’s tires.

I think you’re doing pretty well!