What do you do when you need to check the condition of a car battery, whether it’s charged or not, and if can still hold charge yet you have no multimeter?
Is it possible and how accurate is it? What tests can and can’t you do without a multimeter?
Read on to find out if you can still test a car battery without a multimeter and if so how plus what you’ll not be able to do without a meter.
Can you Test a Car Battery without a multimeter?
To a certain extent yes – you can get a rough indication of whether a battery is charged or not and if it needs to be charged or replaced.
However, there’s a higher risk of error in judgment without the accurate battery voltage reading that you get with a voltmeter.
For example, a car battery with a resting voltage of 12.4V can still successfully start a car but without the voltage reading, you’re unable to determine that the voltage is low and needs to be topped up.
Checks and Tests you Can Do without a Meter
1. Visual inspection of the battery condition. You can still do a visual inspection of the battery’s physical condition.
For example, you can check whether the case is intact or leaking, if it is bulging or not, overheating, or if there’s a buildup of corrosion around the battery posts that affects battery charging and starting of the car engine.
For example, a cracked or leaking battery should be disposed of immediately.
2. Crank test. Start the car engine and check if the engine starts slowly with hesitation or turns over instantly.
If it cranks as normal without any hesitation then this indicates that the battery has enough charge and can still supply the cranking amps the starter needs to turn the engine over.
To determine if the cold cranking amp rating is low and the battery needs to be replaced, take the battery to an auto parts store for testing.
3. Battery Reserve Test. This can give a rough indication of the battery’s ability to hold charge. Make sure the battery is charged fully and then monitor how long the car headlights last with the engine off.
Assuming the car battery is fully charged, if the headlights last for a considerably shorter time than the indicated battery reserve then the car battery is probably on its way out and needs to be replaced.
For example, if the lights dim in say 15-20 minutes on a battery with a reserve capacity of 90 minutes then there is an issue.
Either the battery is not charging properly or it’s losing its capacity to hold charge.
When you Need a Multimeter
You definitely need a multimeter for the following:
1. Accurate Car Battery Voltage Measurement
A multimeter set to read DC volts can help you determine whether a battery is fully charged or not. For example, a car battery with a resting voltage of 12.6-12.7V DC is fully charged.
2. Measure the Parasitic current draw accurately
You can also use the meter set to read mA to accurately measure the current draw in mA from the battery to determine if it is an issue and is therefore draining the car battery flat.
3. Voltage Drop Tests
With a meter, you can conduct a voltage drop-test to check for damaged wire or improper wire connections that need to be replaced, cleaned, or tightened.
A voltage drop test can help you pinpoint the reason why a car battery may not be charging or why the car engine may be cranking slowly.
Without a multimeter, you can only get a rough indication of whether a car battery is charged or can still hold charge. Only consider the tests described above in an emergency when no meter is available.