Resistor in series with voltmeter (for reading correction)

[miked]

the voltmeter on my pickup reads in between 14V and 16 V (approx 15V). but my digital tester reads 14.3V at the voltmeter terminals (not on the battery). so charging system is fine and voltmeter is, let's just say, "defective".

Circuit voltmeter VMG-12 V black face with a resistance reading of 306 ohms (not installed). my plan is to add a resistor in series before the gage. ohms law computations tells me to add an aditional 15 ohms.

is it advisable to do so?anybody tried this one. tia

[miked]

so far no "hotness" on all connections.

[confused shoes]

Are you sure your digital meter is reading correctly? Check the back of the voltmeter if you can find an alignment screw and adjust it.

Using a resistor in series, the meter will give you same reading. Get a rectifier diode (1N4001) instead and connect it in series with your meter. This will dropped the reading by exactly 0.7V. Anode to battery (+).

[yebo]

why the fuss with 0.7V?

[dr. d]

why the fuss with 0.7V?

well, that's enough fuss that will decide whether your battery gets charged via the alternator or not.

[yebo]

well, that's enough fuss that will decide whether your battery gets charged via the alternator or not.

yeah but it's reading 15V with the analog and 14.3V with the digital as he said. he only needs 13.6V to charge his bat. so why the fuss? life is too short to be worrying about those small things.

[miked]

yeah but it's reading 15V with the analog and 14.3V with the digital as he said. he only needs 13.6V to charge his bat. so why the fuss? life is too short to be worrying about those small things.

hehe...onga naman. actually its nothing but sometimes i do get rattled when i see it on the overcharging side while driving then thinking that it was calibrated already.

[dr. d]

yeah but it's reading 15V with the analog and 14.3V with the digital as he said. he only needs 13.6V to charge his bat. so why the fuss? life is too short to be worrying about those small things.

what if the digital is correct, and one day, the car's gauge reads 14.2 V ?
my tire gauge has pentel marks on its face..
my 84 centavos' worth.

[oj88]

why the fuss with 0.7V?

Accuracy means a lot to many people, myself included. I think what the TS is asking for is still quite relevant and practical.

If you have to go through the trouble of adding a voltmeter, it's only right to have it report the correct voltage.

[miked]

already bought a 4001 diode. no time to do it today. sa work na lang kapag nagkafreetime. too bad, wala kasing nabibiling plug in digital voltmeter dito sa amin.

[sirkosero]

anong brand ng digital meter gamit mo TS? minsan kasi kahiy digital, hindi ganun ka-accurate unless guaranteed ng manufacturer upto xxx decimal places.

personally, i take the results of a fluke voltmeter as the real voltage. ito din basis ko sa pag calibrate ng ibang meters

[miked]

i always keep in the glove box a pocket size newstar brand digital tester. pero kinalibrate ko na yun sa original na sanwa sa office. my tester reads higher by 0.15 volts than the sanwa unit.

[sirkosero]

sanwa? analog yan diba? medyo hirap ako sa analog but it gets the job done. ingat lang sa paralux error.

para lang din sigurado, get another meter to compare sanwa to. dagat pareho. if it is, may baseline ka na.

meron kami dati plug-in type sa cig. lighter. mas mataas ang reading by about 0.8v. we checked it against the reading of fluke. ngayon, what we do is subtract 0.8v sa reading ng plugin type. generally, for me, yung plugin type is just a general conditon check kung nagchcharge ang electric system or not. for accuracy talaga, fluke na.

minsan nga naiinis ang electrical shop pag fluke dala ko kasi nakikita pati slight drop ng voltage na si nila kaya makita sa ordinary tester

[Retz]

Accuracy means a lot to many people, myself included. I think what the TS is asking for is still quite relevant and practical.

If you have to go through the trouble of adding a voltmeter, it's only right to have it report the correct voltage.

ung mga measuring instrument like voltmeter may tolerance din. +/-5% usually and that already equates to 0.7V difference at 14V.

[Retz]

Pag DC voltage lang naman, I suggest using an analog meter mas malaki kasi usually tolerance kapag digital multi meter ang gamit.

[miked]

sanwa? analog yan diba? medyo hirap ako sa analog but it gets the job done. ingat lang sa paralux error.

para lang din sigurado, get another meter to compare sanwa to. dagat pareho. if it is, may baseline ka na.

meron kami dati plug-in type sa cig. lighter. mas mataas ang reading by about 0.8v. we checked it against the reading of fluke. ngayon, what we do is subtract 0.8v sa reading ng plugin type. generally, for me, yung plugin type is just a general conditon check kung nagchcharge ang electric system or not. for accuracy talaga, fluke na.

minsan nga naiinis ang electrical shop pag fluke dala ko kasi nakikita pati slight drop ng voltage na si nila kaya makita sa ordinary tester

sanwa digital yung nasa office. fluke nga maganda kaso mahal din tsaka mahirap maghanap dito samin. i requested a fluke sa kamaganak abroad yung model na wireless yung monitor para kahit malayo kita mo reading. kaso nakalimutan na ata

[light2light]

syempre, important na accurate ang mga meters. for your peace of mind, install a pot (any value below ikohms). your problem is meter calibration. a fully charged battery will indicate 13.8v. iadjust the potentiometer at this value.

marami sa atin ang naghahangad ng accuracy of our measuring devices. nakakaasiwa kung hindi accurate ang mga ito.

marami rin palang electronic enthusiasts dito sa tsikot. i love...