I tinkered a battery tester bought at the sign zoziautique, by removing the tongs to replace it with a cigarette lighter plug (hello soldering iron shot) and I note that both products are not really interchangeable : The tester has six LEDs, red for 11.5Volts, 12.0Volts yellow, green for 12.6Volts, 13.2Volts yellow, green to red and finally to 14.5Volts 15.5Volts; when the engine has just been started, the colemeter voltmeter indicates values between 14.4 and 14.6, while the tester turns on only the first four diodes. 14.5V The green comes only after twenty minutes. The tester actually displays the average battery voltage, while the colemeter indicates the peak voltage. It is therefore both gadgets to interpret the situation !!!
PS: the power consumption seems a tad too high for this kind of gadget, do not let the whole night on the cigarette lighter of a vehicle in a more permanent, if we want to start on the battery !!!