Mini Volt Meter Inquiry

[akarimov]

I came across the mini volt meter on this site:

I am considering buying this unit, but I first I got a question. I want to use it in the car to measure the voltage in the system. Does the unit has the battery in it or it draws the power from the circuit?

My plan is to run the wires to the cigarette lighter fuse. Is that safe, I mean its not going to drain the battery when car is off?

ps: i am not very knowledgeable in electricity, so I am sorry if I am asking silly questions. thanks


See Rule #3 Do not Hot Link images, sales link also removed - Norm

 

[Norm]

The OP was referring to a Lipo Voltmeter similar to

Search around the type of meter you link to is available at a number of hobby suppliers for less than the meter linked, they are generally used by hobbyist to check the state of their Lipo batteries.

Most I've seen use power from the circuit being measured rather than having there own battery. I purchased one some time back and the example I have has an error of about .3 of a Volt, the error varies with the Voltage being measured.

Norm

Moved to Flashlight Electronics - Batteries Included - Norm

 

[Mr Happy]

I came across the mini volt meter on this site:

I am considering buying this unit, but I first I got a question. I want to use it in the car to measure the voltage in the system. Does the unit has the battery in it or it draws the power from the circuit?

My plan is to run the wires to the cigarette lighter fuse. Is that safe, I mean its not going to drain the battery when car is off?

ps: i am not very knowledgeable in electricity, so I am sorry if I am asking silly questions. thanks

Why don't you simply look for a "car digital voltmeter"? Purely for illustration and for educational purposes, something like this for instance:

Vector VEC008 Digital LCD Voltmeter, 12 Volt

There are many such devices like this that plug directly into your car cigarette lighter socket and show you the system voltage. Once you know what you are looking for you can pick and choose your favorite.

 

[akarimov]

There reason why I am looking at this meter, is because it is tiny and can be easily integrated into my dash. I am trying to maintain the clean look.

 

[Mr Happy]

There reason why I am looking at this meter, is because it is tiny and can be easily integrated into my dash. I am trying to maintain the clean look.

Unfortunately you said you are not very knowledgeable about electricity. Which means you probably should not try to make any changes to the electrical system in your car. Maybe you should consult an auto-electrician and ask them to install a voltmeter for you?

 

[Norm]

Check this Google image search, you'll notice that you can buy panel mount meters that would better suit your application.
Taking in to account Mr Happy's advice.
Norm

 

[Mr Happy]

I was all set to write a reply about digital panel meters, but I reasoned that you still need some electronics knowledge. For instance you need to get a "common ground" meter to avoid needing an independent power supply. Then the meters often need a 5 V or 9 V supply, so you would need to provide a voltage regulator to step down the 12 V from the car system to the 5 V power supply needed by the meter. Lastly digital panel meters are often configured for a 0 - 200 mV input range, so you need to divide down the voltage from the car system and calibrate the meter reading. Overall it seemed like a basic knowledge of electronics would be needed so I withdrew that advice.

But maybe the easiest thing is to go to a car accessory shop or an auto-spares shop and look for a voltmeter accessory? Such a meter will be all set up just to wire into the car electrical system, no electronics knowledge needed.

 

[Illum]

http://www.wowhobbies.com/batterymeter-turboacebmeter-16measure1-6celllipo-2.aspx
Try this, 2.8V-25.2VDC, accuracy +/-0.005V. It was originally meant as a monitor for lithium ion packs, monitoring each cell voltage in series, but I found using one per battery in a bank of UPS batteries actually works very well.
$7 is worth a try, I've bought from these guys before, nice quick shipping.

 

[akarimov]

I am not changing anything in the system. Voltmeter will be wired to the cigarette lighter fuse. This way when I turn off the car - voltmeter turns off as well. The fusebox is already grounded, so I don't need to worry about it.

2 Illum
Thanks for the link, I am gonna search for something like that locally

 

[Illum]

akarimov, I'm trying to understand why the voltmeter is to go through the cigarette lighter socket and disconnected with the ignition switch. When the car is operating, the battery is being fed by the alternator... so your meter should read something like 13.8-14.4V at all times, what do you intend to find out with this value? voltage sag under load?
As long as the alternator is running, measuring the voltage of the circuit would not tell you whether the battery is good or bad.

Secondly, when the car starts up, there will be a voltage spike that will go through the car rather quickly (up to ~18V), take not whatever you decide to use as a meter [analog or digital] that can take this voltage spike without damage

 

[Illum]

:oops: