How To Use A Voltmeter On A Car Posts

How To Use A Voltmeter On A Car

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4 How To Use A Voltmeter On A Car Loading

5 How To Use A Voltmeter On A Car Loading

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Top Questions and Answers

Can I connect my small voltmeter to a car battery to check the voltage? Or will it bust it? My car battery keeps going flat and I want to know the actual voltage.

mile high replied: "Yes, If it is rated above the output of the battery. For instance, if it's a multi meter or 12V. Most common ones today should give you the choice of what type of readout you want. My car does'nt have an ammeter on the dash, so I found a 12v plug that will fit in the cig. lighter, cut the wires and attatch the leads of my volt meter to that and plug it in. This way I can see the charge on my battery when the car is off, and watch the voltage jump up when the car is on. (the alternator is turning and recharging the battery)"

R P replied: "Yes, you can. You can also check each cell ( if she isn't sealed ) for 2.1 volts. =^ )"

tony m replied: "Have a look on your voltmeter, if you can change settings to 12 volt go for it. If it is only a 240 volt meter (i'm in Australia) it will measure 12 volt okay (not very reliable in small numbers) If the meter is only for testing 3 volt batteries or less, don't put it on those terminals. Try smaller appliances/ batteries first. If you have access to a 9 volt battery or less try that first. Remember electrical power is very dangerous, it can kill you and you can't even see it."

Kenneth P replied: "Take it to an auto supply store...they will check it for you at no charge...In the US anyway."

Hydro replied: "no"

chevyss396427 replied: "If you go to the parts store they will test batteries and alternators for free, not just the voltage, but the condition and function of your entire charging and electrical system. plus, you wont have to worry about blowing up your voltmeter. most will be able to read it fine, its hard to say with the limited information provided"

I tested my car battery with a voltmeter and it read 12 DCV, is that bad? Is something draining my battery? I disconnected the positive cable off the battery and put the positive probe to the positive of the battery then negative probe to the positive cable and I got a 12DCV reading. What should it be at? Everything on my car was off, even the hoodlight.

exputkimies replied: "that is what it is supposed to be"

nickoname replied: "Test it while running if over 13 volt your ok, while off 12 volts is fine"

Fordman replied: "Right on the money. Your good. Now put the battery cables back on and start the engine. Put your voltmeter back on the posts and read the voltage again. This time you should see the alternator charging the battery and the voltage should be somewhere in 13 to 13.7 volts. If this happens, then you should be OK. good luck"

mdk68gto replied: "12.6 is the exact voltage that a battery should be with the engein turned off and every thing else off also."

Dizel replied: "12 v is not good, you need to recharge your battery. The best is 12.6V believe it or not 12 V is almost 50% discharged I know it sounds strange but that is the truth. With engine running it should be between 13.7-14.5 V"

Rayvin replied: "you have a battery drain somwhere. When u touch ur cable to battery post do you get a spart?? Doors all closed? Radio off? Start taking out fuses, when volts drop u've found the curcuit."

How do I use a voltmeter to track down my problem? New battery. New alternator. Both test good individually, but when my car is running and I test, it shows that the alternator is not providing power and the battery light is on. Since both work properly, I'm assuming the problem is somewhere between the battery and alternator. From what I can see, the connections look good. I wanted to know if I could use a voltmeter to track down specifically where the connection is lost. Thanks

drewsiferxxx replied: "test light would be easier. find a ground and gently poke the pointed tip of the volt meters probe in to portions or the cable sthat connect the two. check for a blown fuse.... I had the same problem in an Eclipse it was a 100 amp fuse made into a box in the engine bay fuse box."

Eddie W replied: "The voltmeter won't help you much in this situation. Try the simplest first. 1) Check for short circuit. 2) Inspect the cables make sure they are not corroded. When a cable is corroded, the internal impedance is increased and that resists the current to flow. If the cables are in good condition, 3) Turn on your head light and drive around the block. It's even better if you can do it after dark. If when you stop the car, the head light is noticeably dimmer, and noticeably a lot brighter when you press the gas. Your battery is bad, 4) With you engine running, disconnect your battery entirely. If your engine stalls, that'd mean your alternator is bad. Is yours a brand new alternator or a re-manufactured one? One more thought. Other than the alternator power output connections, there is also a connector that is plugged at the back of the alternator for the battery charging indication. If that connection is open, that'd give an indication that the battery is not being charged. Check that connector also."

jeff m replied: "the connector with 2 smaller wires on the back of the alternator- one of them controls. the warning light, the other one turns the alternator on when the key is on. both should have 12volts on them, when the key is on. if not , might be a broken wire check the fuses inside the car, too. 12v on each side of each fuse damaged wires are often found where new gadgets have been wired in, under the dash"

catmandew replied: "AAARRRGGGHHH!!!! Sorry, I just had to vent a little after reading the first 2 replies. Yes, a 12 volt test light would be "easier", but a Voltmeter is infinitely more useful in testing high amperage circuits, or situations where you want to know what the actual voltage is, as opposed to just whether or not there is any at all. And also, DO NOT disconnect your battery while the car is running! Unless of course, you enjoy replacing blown solid-state circuitry because of the voltage spike. I've got a good mind to report people who recommend that. Note the big red warning in each of these articles. As I mentioned in reply to your other post, a Voltage drop test is the ideal diagnostic tool for many of these kind of problems. You can learn more about how to do it here, including specific instructions on how to check a problem like you are having with your Alternator. Like to see drewsiferxxx do that with a 12 volt test light!"

How do you connect a voltmeter gauge to a battery/car correctly??? I just would like to know the correct way about it. Thanks for any help.

mistyeyedkitten replied: "You connect each voltmeter lead to each of the battery terminals!"

Jac replied: "Red probe to positive post,black probe to negative post.Turn volt meter to dc volts on a 20 volt scale."

Arthur A replied: "Connect positive (+) red clamp to red terminal, connect negative (-) black to terminal of battery or any none moveing metal part for a good ground."

chevy c replied: "connect the positive to the + sign and - the negative to the - sign if your meter has voltage options: select minimum voltage of 20 volts dc or less. safety; never smoke or arc around the battery"

Paul Rein replied: "Turn on the voltmeter and set it to DC volts to the 20 dial and then connect red probe to red battery connector and black probe to ground any metal part on the car that is not painted or the black connector on the battery."

mebncas replied: "follow the instructions that came with the gadget.disconnect the battery be4 doing any cable connections as mistakes can be expensive,in fact save any hassle, go to a garage."

cjk44t replied: "Like was said, red on the + terminal and black on the - terminal. But why? I'm going to guess you want to check to see if your battery is charging right? Easy way is to check battery volts with the car off, then compare it to the battery volts with the engine running. If its higher when running, your charging systems is functioning."

Determining car battery charge with voltmeter? Using a handheld volt meter can I determine the charge left in a 12V car battery? How do I go about it and how do I know if the charge is at max, or min capacity? Much obliged for your help, thanks in advance.

jumbobret replied: "A voltmeter will tell you what voltage of it is, but will not tell you if it can start a car. You need a machine that can pull a load on it. That's really the only way to determine if it is strong enough."

Michael B replied: "A fully charged battery will deliver 12.6 volts with no load connected. If the voltage reads 11.6 volts it has about half its charge. A battery with a voltage of 10.5 volts or less is totally flat and will probably never recover its charge. The voltage needed to charge a car battery is between 13.8 and 14.3 volts. This is somewhat over-simplified as it does not take account of any load being connected across the battery. You need to measure the voltage when a high current (eg headlamps) is being drawn. If the battery loses its charge rapidly or if the voltage drops significantly under load, the battery needs replacing."

If the car alternator recharges the battery... will a voltmeter across the battery terminals indicate this? If the car alternator recharges the battery... will a voltmeter across the battery terminals indicate this is actually occurring? engine running of course.

strech replied: "Yes. In fact, the reading should increase as engine rpms increase."

Shane A replied: "Yes, with the engine running at higher than idle, you should be reading between 13.5 to 15 volts. Then when you shut the car off you will see the voltage drop to 12.5 to 12 volts."

catmandew replied: "Basically, a DC voltmeter across the battery terminals with the engine running will tell you if the alternator to some extent, and even more so the voltage regulator, is working properly. With all electrical items turned off, you should see at least 13.5v. With headlights, heater fan and everything going, it may be lower at idle, but should pick up with engine speed. Alternators are not capable of full output until engine speed is about 2,000 RPM. Whether the battery is accepting the charge requires some other testing though, called a load test. With the battery reading a good solid 12.6v minimum (engine off), a draw is induced for 15 seconds to simulate a starter cranking, and the voltage should not go below 9.6v or so, depending on battery CCA. You can buy an affordable version of these testers at most auto parts stores for about $30-$40. If you want to thoroughly test an alternator, it should be full fielded while using a carbon pile or other similar device to draw power out of the battery, while engine RPM is 2,000. This is the only way to definitively test your alternators total amperage output capacity. Also, connect an AC voltmeter with the + lead to the alternator output terminal and the - probe to the + battery terminal, to check for AC voltage, to make sure the diodes aren't leaking."

Question about car alternator and voltmeter? Hello on my car the battery seemed to die. I had it replaced and it works. When the place but this piece of equipment on the battery they showed me that this line was going back and forth. he said that the the alternator wasn't holding a charge. ---

randy_ishere replied: "the alternator is what charges the battery, without it the battery will go dead pretty quickly maybe they meant the alternator was not charging the battery, but if that's the case then your new battery would go dead too"