Strange VOM Issue

Lamps can be very useful. I many times advocate putting a large wattage bulb in series with battery ground when finding shorts, to protect the system/ wiring. "My favorite" test lamp is an old "Cal-Van" (I think) lamp which uses a cartridge style bulb. Some of the "modern" LED lamps can get you into trouble, as they sometimes don't draw enough current to "help you" if looking for intermittent fuses, etc.

Two lamps I will not be without is an old headlamp, and a stop/ tail socket. You can parallel or series various combinations of the two filaments to provide various loads

Years ago, I had no small trickle/ maintenance charger that was safe for small motorcycle batteries. I used to charge them with my 10A charger, using a tail or stop filament in series to limit current