I bought 2 of these pumps along with the cases recommended.
My car tires were 27psi and I pumped them up to 32psi. (was a very cold day) I don't think I had the compressors charged enough. So, I only got 1 tire pumped up and had to recharge. These would be great if you had 1 low tire and needed to inflate to get somewhere. I'm impressed at the quality.
Update: I found my 2nd Air Compressor, and it was fully charged. I pumped up 1 more tire 27psi to 32psi, but as soon as I began filling the tire, the battery light came on yellow, meaning, the battery was being used up really quick. It lasted 2 tires before I had to charge again. The nice thing about these, is you set the PSI or your measurements, screw on the compressor, then turn on, and it shows you the current pressure of the tire, and then you click on start and let it fill to your desired pressure. It shuts off automatically. It was snowy today so I could use these in the garage and stay warm.
These get a little bit warm while filling but they are ok.
Overall, I am very happy with these products. If it was me, I would keep 2 in the car all charged up just in case I needed extra filling to get somewhere.
You can also charge these in the car- however, it takes longer to charge and would work best if you were on a long road trip. Basically, these worked well.