BatteryBeak: Utility of making internal resistance and state of charge measurements

[Ether]

Quick pic of poor man's battery discharge tester.

Battery voltage is on the left. Battery amps on the right^*. Meters can be had for less than $5 each at Harbor Freight.

Sealed beam headlight is from my 68 Camaro, I think. Found it in a pile of old auto parts. Not quite 36 watts.

Battery is from my lawn tractor.

For actual use, the wiring should be cleaned up, and the headlight secured safely on a fireproof surface.

sealed beam for safety (do not use a replaceable bulb). no cracks or chips or signs of damage. competent adult supervision required. always use safety glasses.



^*The ammeter is just to confirm the lamp's wattage. You don't need the ammeter for the test if you know the wattage.