What can a volt gauge be used for?

[onosqv]

Hello, I was thinking about getting a volt gauge for my car. The purpose was to hopefully be able to monitor if the battery is fully charged or getting drained, etc.

The reason why I want to do this is I will be installing an underdrive pulley. Another guy I know had an underdrive pulley on his s14 and kept having problems with it being underdriven.

I just basically want to figure out if my battery is being drained or operating ok before bad things happen. The largest amp I will be running to my subs will be 500 RMS. I have an 89 240sx if that matters.

Thanks

[vancouverbc]

Hydrometers are used to check specific gravity of unsealed batteries. Sealed batteries supposedly have a built_in hydrometer. The terminals and cables should be cleaned yearly. Cables must be tight. I coat the terminals with grease to prevent corrosion.

With a multimeter(voltmeter), the battery should read between 11.5 and 12.5 volts with ignition off. Voltage reading should be greater than 9.6 volts when you crank engine with coil wire from distributor grounded.

I don't think voltmeters are very good for testing batteries.

[JDMaholic]

First of all I hope you mean 500W not 500A to your sub. Also I would get a cheap handheld multimeter, measure across the battery without the car running, it should be somewhere around 12V give or take, next start the car and once again measure the voltage across the battery the alternator should bring the voltage up to about 14V, if not either your alternator is not charging properly or some other part of your charging system is broken. If you want to check and see if you have a short the easiest way to tell is to measure the current coming from the battery with the car off, and the key in the on position but car not started.( this requires you to remove one of the battery leads and place the meter between the cable and the battery, be carefull) make sure you stereo is off it will draw alot of current. There should be some current draw through the system I'm not sure but probably less than an amp or 2, if there is more than that there is a short somewhere.

[Silvia007]

I acutally modified a digital gauge from a capacitor to view the voltage where my clock is, problem is, it's a bit too bright. Anyway, it's a cool mod. I'm running about 3000 watts of audio equipment and when I play it loud hahaha charging system can't do squat.

[onosqv]

Cool, thanks for the replies. Yes, I already have a multimeter, so that's a good start. I'm finally putting my money into this multimeter to good use .

I was wondering if I could use one of those fancy 2" racing gauges, the one for battery volts, and just leave that in my car so I can monitor whenever I feel like it . Will that be good enough or just as effective as the multimeter test? Just another toy for me.

[Ubernoober]

Yes, the gauge can be used to monitor your charging voltage. Should be running 13.5-14.5 normally. If it drops below 12.5 you are generally discharging the battery. If you add an ammeter to the mix, you can know exactly what your charging system is doing at all times. Ammeter is a tad harder to install correctly which is why people go with the voltmeter. Its just stupid-simple to tag on to a car.

[onosqv]

Yes, the gauge can be used to monitor your charging voltage. Should be running 13.5-14.5 normally. If it drops below 12.5 you are generally discharging the battery. If you add an ammeter to the mix, you can know exactly what your charging system is doing at all times. Ammeter is a tad harder to install correctly which is why people go with the voltmeter. Its just stupid-simple to tag on to a car.

suhhhwweeettt!!! More gauges for me then, haha.

p.s. Is it just me, or did they just add the Quote option today? double sweet.

[mynismo]

greddy turbo timer's have a voltmeter bult in