Digital Voltmeter

**rsnald** · June 26th, 2006 07:52 PM

Originally Posted by alwayz_yummy

me also wants to put a voltmeter on my van....this is much better in monitoring your car's charging system, unlike the somewhat useless ammeter..

parang disagree ako dito pre... mas accurate na indication ng battery charging yung ammeter... pag positive yung reading while you're revving, that means your alternator is providing current,while you're on idle, sometimes makikita mo naglalaro between positive to slightly negative value, meaning your electrical components in your car is drawing current from your battery and/or alternator.

a battery's voltage does not really indicate it's reserve power. subukan mo kunan ng voltage ang diskargadong baterya na size A or AA, babasa pa rin yun na around 1.5V kahit mahina na sya. what would really indicate its reserve power is the ampere reading or the amount of electrical current it can deliver.
kaya ang makikita mong reserve power ratings sa mga car batteries, measured in ampere-hours, not voltage-hours, and battery chargers are also rated on how fast they charge based on amperage w/ matching voltage. imho. i could be wrong but that's how i understand it...hth

**ghosthunter** · June 26th, 2006 09:44 PM

Originally Posted by jan_m

nakabili n ako ng volt meter. readng nya 12-13v kpg full load. ok lng b un? d b mababa?

depends on the load. My car's voltmeter reads around 13.5v with engine running and without else anything turn on.

**ghosthunter** · June 26th, 2006 09:47 PM

Originally Posted by rsnald

parang disagree ako dito pre... mas accurate na indication ng battery charging yung ammeter... pag positive yung reading while you're revving, that means your alternator is providing current,while you're on idle, sometimes makikita mo naglalaro between positive to slightly negative value, meaning your electrical components in your car is drawing current from your battery and/or alternator.

a battery's voltage does not really indicate it's reserve power. subukan mo kunan ng voltage ang diskargadong baterya na size A or AA, babasa pa rin yun na around 1.5V kahit mahina na sya. what would really indicate its reserve power is the ampere reading or the amount of electrical current it can deliver.
kaya ang makikita mong reserve power ratings sa mga car batteries, measured in ampere-hours, not voltage-hours, and battery chargers are also rated on how fast they charge based on amperage w/ matching voltage. imho. i could be wrong but that's how i understand it...hth

it really depends. I use my voltmeter to monitor the battery voltage because I have upgraded my headlights to 90/100 watt bulbs and I also have 100 watt foglights. Add the load from the A/C and the engine running at idle... I can see my voltage dropping from 13.5v to almost 12v if left long enough.

**jan_m** · June 27th, 2006 12:02 AM

Originally Posted by ghosthunter

depends on the load. My car's voltmeter reads around 13.5v with engine running and without else anything turn on.

13.5v dn readng ng voltmeter ko engine running. pero pg on k a/c at headlyt. baba sya ng 12-12.6v tpos minsan baba sya ng 11.8v pero mga 1 seconds lng un tpos balik n uli sa 12-12.6v. ok lng kaya un? la defect batt or alternator? ano brand ng voltmeter m? ano reading m kpg on a/c, headlyt at headunit m?

**puroy** · June 27th, 2006 01:46 AM

ako rin, parang gusto ko nyang digital VOM. saan po pwede bumili ang magkano po price range? tia

**anthon05** · October 30th, 2009 12:46 PM

hi sino may alam sa banawe? kung saan makakabili ng digital voltmeter gauge pati installation na rin.

thanks

**franzhelmer** · November 19th, 2009 07:39 AM

Originally Posted by rsnald

parang disagree ako dito pre... mas accurate na indication ng battery charging yung ammeter... pag positive yung reading while you're revving, that means your alternator is providing current,while you're on idle, sometimes makikita mo naglalaro between positive to slightly negative value, meaning your electrical components in your car is drawing current from your battery and/or alternator.

a battery's voltage does not really indicate it's reserve power. subukan mo kunan ng voltage ang diskargadong baterya na size A or AA, babasa pa rin yun na around 1.5V kahit mahina na sya. what would really indicate its reserve power is the ampere reading or the amount of electrical current it can deliver.
kaya ang makikita mong reserve power ratings sa mga car batteries, measured in ampere-hours, not voltage-hours, and battery chargers are also rated on how fast they charge based on amperage w/ matching voltage. imho. i could be wrong but that's how i understand it...hth

You are absolutely 100% totally correct... Ampere is the best way to measure how much you are charging. Voltage will only tell IF it is charging but not by how much you are charging

. In short more ampere means more "juice" in your battery. More volts just means that there is a juice going into your battery but doesn't indicate how much. This is also related why batteries are rated in "Ampere-Hours" since this will indicate how long they can last.

Using digital voltmeter can be annoying. Unless this is a digital voltmeter with averaging function. It kinda looks weird seeing the numbers go up and down very fast hehe. I think this is why we have a charging light indicator sa gauge eh.. This is to indicate if the battery is being charged or not... Try removing your alternator terminals for fun lang.. Hindi mawawala ung red battery ilaw sa gauge kc it's not charging... FYI lang... Very very old cars have an analog meter for the battery voltage reading para makita kung charging or not.. later models 88 and up to today may indicator nalang nilagay with a battery symbol... It usually lights up when u start ignition but not the starter yet..

**incus** · November 19th, 2009 08:42 PM

Originally Posted by franzhelmer

You are absolutely 100% totally correct... Ampere is the best way to measure how much you are charging. Voltage will only tell IF it is charging but not by how much you are charging

. In short more ampere means more "juice" in your battery. More volts just means that there is a juice going into your battery but doesn't indicate how much. This is also related why batteries are rated in "Ampere-Hours" since this will indicate how long they can last.

Using digital voltmeter can be annoying. Unless this is a digital voltmeter with averaging function. It kinda looks weird seeing the numbers go up and down very fast hehe. I think this is why we have a charging light indicator sa gauge eh.. This is to indicate if the battery is being charged or not... Try removing your alternator terminals for fun lang.. Hindi mawawala ung red battery ilaw sa gauge kc it's not charging... FYI lang... Very very old cars have an analog meter for the battery voltage reading para makita kung charging or not.. later models 88 and up to today may indicator nalang nilagay with a battery symbol... It usually lights up when u start ignition but not the starter yet..

noob here, yun sa Getz ng wife ko battery reading sa digital volmeter is 12.6 pa pero ayaw ma-start un car. kailangan itulak muna bago mag-start then my wife decided to buy a new battery, hayun one click lang but the voltmeter reading for the new battery is 12.7, so it means na kahit 12.6 pa ang reading nung lumang battery eh mababa na ang ampere nito?

**Phoenix67** · November 19th, 2009 08:49 PM

duda ko, loose contact lang ang battery mo dati. 12.6v is still high

**franzhelmer** · November 20th, 2009 02:20 AM

Originally Posted by incus

noob here, yun sa Getz ng wife ko battery reading sa digital volmeter is 12.6 pa pero ayaw ma-start un car. kailangan itulak muna bago mag-start then my wife decided to buy a new battery, hayun one click lang but the voltmeter reading for the new battery is 12.7, so it means na kahit 12.6 pa ang reading nung lumang battery eh mababa na ang ampere nito?

Yun yung point ko. 12.6 or 12.7 is the same reading dude. It just indicates that it is charging. Pero kung may laman nga yung batterya hindi mo makikita kase volts un. You need to measure it via an ampere meter para malaman mo status ng battery or alternator. Ampere meters are connected also in series FYI. 12.6 ro 12.7 volts is a bit LOW also but it can differ on alternators. This is no standard as a 12V battery gives roughly 11.8V without charging meaning no load etc etc just the battery though this is really an inacurrate way to measure like how I pointed out a while ago. My car Battery reads 11.8V today. Tomorrow maybe 12.2V. Last week maybe 11.6V (It's not a perfect battery anymore pero it'll do its job). But if you read 6V or 8V or 10V, well siguradong sira ung battery cell mo.

Imagine it like this.. very very basic... I have a tank of water which is your battery. I have a balde of tubig this the volume is your "Volts". Pero kung ilang tubig talaga pumapasok sa tanke mo is your ampere. Natural walang transfer of tubig gaganap kung patay ung battery or kung puno sya (alternator to battery). Knowing na may balde ka means that your alternator is capable of charging but by how much you need to know the amperes.

The second post is also correct. Loose battery contacts or pangit na grounding will also prevent the starter from turning. The entire power is transfered through that loose contact hence it can even spark or smoke (It gets really hot na pwede ka nga mag sindi ng yosi eh). Parang tubig ulit... na may tagas ung hose.. Bali dun lalabas ung excess. D dadaloy lahat ng tubig. In the end might not be even enough water to drive your starter to turn or crank the engine.

And we don't say wala na syang "amperes", we use the term AH (Ampere Hours). Everytime you recharge your battery it recharges the AH.
When you purchase a battery be sure to know how much AH it has. This is what's important to know and not the brand

Bigger batteries have usually also higher Ampere hours.

That's why a digital/analog voltmeter is only a crude way of knowing kung charging ung battery or hindi. That is what your battery icon in the gauge is for. Just to indicate if alternator is running or not. Exactly the same role as a voltmeter except without the numbers. If you want numbers then install a VOM panel inside the gauge. This is cheap. Get it in Alexan Raon. Dami dun. I build those in my college days as project sa mapua hehe. May DIY kit pa nga ata un.

http://en.wikipedia.org/wiki/Car_battery

In my opinion what should be indicated digitally is the amount of gas in your car. I am currently making one for fun. To convert that analog pointer to numbers. Para pag nagpakarga ako ng gas. Malalaman ko talaga kung ilan liters pinakarga ko talaga. Same principle po din ito ng Voltmeter. You get a voltage reading from the fuel floater. This voltage reading lifts the pointer up and down same ng analog voltmeter. If you readjust your digital voltmeter in such a way you can display the fuel in liters parang sa airplane. Which is way cooler kc malalaman mo talaga ung real gas consumption ng car mo.

Hope this helps