Does anyone make a digital 12 volt amp gauge that can read at least 30 amp. I have a friend that wants one in his car.
I don't think amp gauges care about voltage, as they measure current flow, but may be that is different for digital gauges.
Suggest you search Summit Racing or similar supplier. 3 digital amp 0 to 250 amps gauges shown. Price range $100 to $242
If you search on Ebay something like "digital 30 amp meter" there are loads of them at very low prices. Here is one I used in my generator test stand. Be warned the meters are quite accurate but the shunts supplied with them leave a bit to be desired, I had to fine adjust mine considerably to get an accurate reading. The supply voltage for these to rang 5~30v. Regards John