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

In today world we have a lot of products in our homes and offices which are primarily powered through batteries. Specially in case of cars, motorbots, marine and other vehicles where all electronic circuits and accessories run only through batteries. In that case mantaining battery,s health is mandatory for smooth functioning of our equipments 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 case of batteries we only need these three parameters, keeping it simple we can asses battery health by checking its voltage level only. By using multimeter you can avoid your mantainence 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 main checks and tricks that anyone can easily do by learning 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 socket having dc voltage test illustration. Please keep in mind that multimeter should be accurate as there is no room for inaccuracy in voltage testing.

Before checking battery,s voltage please do confrim that 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 volatge readings. We suppose a 12v battery in this case, now connect black lead to negative terminal of battery and red to positive one. You can identify negative and positive terminals of a battery by – and + signs on its terminals.

Result on multimeter should be somewhat between 11.8 to 13 volts. If it,s 12.5 or more that means 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 same like in volatge 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 range from voltage to Ah, most of multimeters have basic range of100 ah and more. After setting it to 100 AH now connect probes to terminals in proper manner, result sould be somewhere between 85 to 98. If it lies in this range that will mean battery is in excellent condition.

A lower ah reading, may be half or more can be sign of poor battery health and its indicate that battery should be replaces 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 case of cars and other vehicles where all systems and engine starting depends on battery strength, a more powerfull battery is a mandatory thing. Testing a car battery is not much different from an ordinary battery testing but requires some neccesary 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 coduct battery test should be at rest condition atleast for 4 to 6 hours. Otherwise you may turn on headlight for two minutes to neutralize any surface charge. Now set multimeter range to 20 vdc, if you have battery of 12v. After setting probe position connect positve test lead to positive and negative to negative terminal of batteries. In case you did,nt find battery terminals you can get help from car manuls. Most of modern cars have plastic covering over batteries and you can easily find naked terminals.

Now check results on multimeter, a strong should give 12.5 to 14 volts normally. Results upto 12 and more are satisfactory but if you get reading below 12v that means battery needs to 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 car engine while other will observe fluctuations of battery voltage. First of all do park your car at safe place, don,t forget to pull hand brakes and make sure that car is in neutral state. After setting range and preparing multimeter to test batteries send your companion to start engine. At very time when he ignites engine check battery volts reading. If it,s fluctuate to 10v then battery is in ideal state and needs no maintenance. If results are between 5v to 10v that idicates 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 battery is already near to dead state and you should replace it on urgent basis. You,ll notice that once the engine was started , the declined voltage improved back after alternator start giving charge to battery. Battery volts will recover back to 13 or 14 volts.

How to Test Car Alternator with Multimeters

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

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