Car & Motorcycle Battery Tester

With rechargeable lead-acid batteries it’s invariably useful — if not essential — to determine whether the power source you’re hauling along on your travels is losing capacity and needs to be topped up. The same circuit would also come in handy when going on a car or motorbike trip as it can check the status of a 12 V (car) or a 6 V (motorcycle) battery. Although the circuit draws so little power that it will not noticeably load the battery under test, it should not be left connected permanently.