How and by what to know that the car battery is discharged?

Measure the voltage

The voltage is a fairly reliable indicator of how charged the car battery is. Just take it voltmeter or multimeter with a voltmeterput the spikes on the poles and you know what you’re in for right away. 12,6-12,8 V the car battery is charged. At 12.5 V, you’d better recharge it. 12.4 V is the voltage at which sulphation begins, this value a any value below 12.4 V means you should charge the battery immediately. In reality, however, most cars start even with a much lower voltage of the car battery, even below 12 V. Operating such a discharged battery is equal to its gradual execution.

Clicking instead of starting

If instead of starting you only hear fast clicking of the starter relay, it’s a 90% dead car battery. That is, so exhausted that there is no other solution than start via cablesor recharge the battery.

Light test

There is a fairly simple test to determine if the car battery has sufficient voltage, or not. This applies to batteries that can still start the engine. Immediately after starting, just turn on the lights, ideally somewhere against the wall and add gas. You don’t need much, just enough up to three thousand revolutions. If the lights will shine noticeably brighter with the engine running and after the throttle is eased to idle they will go out easily again, the car battery is not sufficiently charged. Attention, this test applies to older cars incandescent lights.

Magic eye

Most car batteries have a simple signaling system change in electrolyte density when discharged. If the battery is sufficiently charged, it should be green magic eye. A dead car battery means he has a magic eye color red or black. It is a very simple system, but it does not solve, for example, a battery failure. It only measures the density of the electrolyte in one single place in the battery.

Electrolyte density

There are electrolyte hydrometers that use the same principle as the aforementioned magic eye. Just open the cap, take some electrolyte to the hydrometer and on the scale to read the value. For simplicity, the scale is colored (green means a charged battery, red means discharged), however, the electrolyte density value for a fully charged battery is 1.28 g/cm3. 1.2 g/cm3 is the value for half charge, dead car battery she will have 1.14 g/cm3.

How to open a car with a dead battery?

If your battery is totally dead, don’t despair. Every car has a classic key hidden in the remote control and it also has a lock somewhere on the driver’s door handle. Most often under the cover. Just remove the cap and unlock with the key.