Not sure how accurate but good enough to monitor the charging system on a car. The meter overall dims are 1 inch x 2 inches so the display will be kind of small but good enough. At some point I want to add one to my battery charger.

If you got another shunt and a selector switch, you could monitor glow plug current and get an instant indication that one is burned out. ( If the GP are in parallel )

$ 18.00 now, on sale for an unknown period of time $ 13 . They have lots of other meters and much more in the way of electronic goodies.

https://www.mpja.com/Mini-Panel-Meter-Dual-Red-LED-Display-30-Volts-100-Amps-DC/productinfo/32063+ME