How to test a Battery With a Multimeter – Checking Car charging systems

In today’s world, we have a lot of products in our homes and offices which are primarily powered through batteries. Especially in the case of cars, motorboats, marine and other vehicles where all electronic circuits and accessories run only through batteries. In that case maintaining battery’s health is mandatory for smooth functioning of our equipment and that can be easily done through a best multimeter.

Multimeters are handy tools for troubleshooting and solving general electric faults. Their main functions are to test voltage, current, and resistance. In the case of batteries we only need these three parameters, keeping it simple we can assess battery health by checking its voltage level only. By using a multimeter you can avoid your maintenance bills for minor faults.

If you don’t know much about how to use multimeters please read our guide for simple multimeters usage operations. These are some of the main checks and tricks that anyone can easily do by learning the basics of multimeters.

How to test a Battery Voltage with Multimeters

It’s a simplest test which anyone can do at home or anywhere to check battery health. First of all, bring a quality multimeter with fully charged batteries. After turning on meter set it to lowest range of dc voltage which is 20vdc in general multimeters. Now insert black lead probe to neutral socket and red one into a socket having dc voltage test illustration. Please keep in mind that the multimeter should be accurate as there is no room for inaccuracy in voltage testing.

Before checking the battery’s voltage please do confirm that the battery is fully charged and at no load. No load means at the time of test there should be no load running on battery, a running load will give lower voltage readings. We suppose a 12v battery in this case, now connect black lead to negative terminal of battery and red to the positive one. You can identify negative and positive terminals of a battery by – and + signs on its terminals.

Results on the multimeter should be somewhat between 11.8 to 13 volts. If it,s 12.5 or more that means the battery is in good health, 12 or more is satisfactory and voltage under 11.8 is suspicious and requires more tests like gravity and cell checking.

How to Check Battery Amps with a Multimeter

Procedure is almost the same as in voltage testing of batteries. In this case, we suppose a battery of 100 ah, in modern multimeters with battery testing features we got this test of checking battery amperes. Now we have to reset the range from voltage to Ah, most of multimeters have a basic range of100 ah and more. After setting it to 100 AH now connect probes to terminals in a proper manner, result should be somewhere between 85 to 98. If it lies in this range that will mean the battery is in excellent condition.

A lower ah reading may be half or more can be a sign of poor battery health and it indicates that the battery should be replaced as soon as possible. We’ll recommend you to use digital multimeters for these tests although you may also use voltmeters and analogue multimeters.

How to use a Multimeter to test Car Battery

In the case of cars and other vehicles where all systems and engine starting depends on battery strength, a more powerful battery is a mandatory thing. Testing a car battery is not much different from ordinary battery testing but requires some necessary steps to follow. As you know batteries energize headlights, audio systems, and engine electric parts. Its most important function is to cranking engines in vehicles. If you are running with weak batteries you may face slow engine starting, dim lights, and frequent jump starts. If you’re facing any of these issues the first step should be checking your car battery.

Preparations before Testing Car Battery

The vehicle on which you are going to conduct a battery test should be at rest condition at least for 4 to 6 hours. Otherwise, you may turn on headlight for two minutes to neutralize any surface charge. Now set the multimeter range to 20 vdc, if you have battery of 12v. After setting probe position connect positive test lead to positive and negative to the negative terminal of batteries. In case you didn’t find battery terminals you can get help from car manuls. Most modern cars have a plastic covering over batteries and you can easily find naked terminals.

Now check results on the multimeter, a strong should give 12.5 to 14 volts normally. Results up to 12 and more are satisfactory but if you get a reading below 12v that means battery needs to be replaced as earlier as possible.

How to Check a Car Battery while Cranking engine

It’s basically a two people job, one of them will start the car engine while the other will observe fluctuations of battery voltage. First of all, do park your car in a safe place, don’t forget to pull hand brakes and make sure that the car is in neutral state. After setting range and preparing multimeter to test batteries send your companion to start the engine. At very time when he ignites engine check battery volts reading. If it fluctuates to 10v then battery is in an ideal state and needs no maintenance. If results are between 5v to 10v that indicates that your battery is slowly weakening and soon it may need a replacement.

Finally, the voltage reading under 5v during engine starting clearly indicates that the battery is already near to dead state and you should replace it on an urgent basis. You’ll notice that once the engine was started, the declined voltage improved back after the alternator started giving charge to battery. Battery volts will recover back to 13 or 14 volts.

Most mechanics use automotive multimeters for detailed engine checkups, rpm testing, ecu and other maintenance. But don,t worry if you are doing it yourself you can easily assess about battery and alternator. For this after checking the battery at idle and starting state now let the car engine on and observe the difference in voltage. Ideally, a battery should give 13 to 14 volts or more in this state, when the battery is receiving continuous charge by alternator.

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