How to judge the quality of car battery

Multi-meter energy only measures battery voltage. It is usually not easy to detect the advantages or disadvantages of the battery (if the voltage is very low or even zero, of course, the battery must be is broken).It is better to take a larger power and larger load current, then the multi-meter in series to check the current size. If the current is large for a long time, the battery is good; Or the battery is aging, or even broken.

Choose the dc voltage blocking multi-meter, symbol is V (a rung above, a curve is communication) usually 9 V battery you can't use in measuring less than 8.9.It is related to the load resistance.

Judging from the appearance

Observe appearance without deformation, bulging, leakage, burst blasted, burning, screw joint presence of oxide leakage, etc.

Load measurement

If no abnormal appearance, UPS work in battery mode, with a certain amount of load, if the time of discharge is obviously shorter than the normal discharge time, charging after eight hours, but can't restore normal standby time, determine the battery aging.

Measured with a multi-meter

Battery discharge mode measurement: measure the voltage of the battery in the battery pack, if one or more of the voltage of the battery show higher or lower than the nominal voltage (nominal voltage of 12 v/day), determine the battery aging.

Mains mode measurement: the charge voltage at the various battery of battery pack, if one or more of the battery charging voltage reveal higher or lower than the other, determine the battery aging.

Measure the voltage of battery pack, battery voltage always significantly lower than the nominal value (in nominal value is 36 v C1K battery, for instance), charge is not back to normal after eight hours, even if to return to normal, can not meet the normal discharge time, discharge time determine cell aging.

Battery boot measurement: UPS don't boot, also don't answer the mains, use multi-meter measure the battery voltage, first may be between 36 v - 40 v voltage, belongs to the normal, pens and don't leave, has been pegged to the multi-meter's instructions, and then connect the power button, if the battery voltage always immediately dropped to below 30 v and 10 volts, UPS automatically shut down, shut down voltage immediately after the return to the original value. Determine the battery aging.

Usually judge the battery voltage by the multi-meter to directly and don't see anything, because the new battery with the old battery voltage difference is not very big, because the trigger voltage of the charger when two battery will stop charging, and the trigger voltage is the same, so don't see any single quantity voltage, unless the amount is a completely broken battery, battery no voltage at both ends.

But with a multi-meter can be indirectly measured the battery internal resistance, remember is indirectly measured, directly with the multi-meter is above can't detect the battery internal resistance (to directly measure requires a dedicated instrument), remember that don't use multi-meter resistance directly on both ends of the battery, is likely to destroy the multi-meter to do so.

Need to measure the first parameter is the no-load voltage of battery, the so-called no-load voltage is on both ends of the battery even when nothing at the ends of the battery voltage, measuring method is simple with multi-meter voltage profile can be measured directly, the assumption is that U1, and then find a load, the load in theory the better the greater the power, can look for a light bulb or fan, etc., but the load of the rated voltage and battery voltage at the ends of the same.

Loads from the actuators to a power supply, the next step the multi-meter to measure the current file current size, I write down this parameter, the multi-meter to down load to attached to the battery, the multi-meter at the ends of the voltage profile to measure the battery voltage, assuming that the measured voltage is U2, then know that the three parameters can calculate the battery internal resistance R, calculation formula is R = (R1, R2)/I, pay attention to the unit conversion, where units are international unit, typically 12 ah battery internal resistance in 14.4 m Ω, 20 ah battery at about 10.6 m Ω, usually the smaller the greater the capacity of battery internal resistance will be.

Battery internal resistance increase is the most intuitive performance at the time of the battery discharge calorific value will increase, this is according to the ohm's law can be judged, and came to raise the temperature of the battery, battery calorific value increases, in turn, will speed up the battery electrolyte in evaporation, generally refers to the evaporation of moisture, cause the solution concentration increased, further speed up the battery aging, the previous battery adding distilled water, is a matter of science, it can make the solution concentration diluted back again.

Usually judge the battery voltage by the multi-meter to directly and don't see anything, because the new battery with the old battery voltage difference is not very big, because the trigger voltage of the charger when two battery will stop charging, and the trigger voltage is the same, so don't see any single quantity voltage, unless the amount is a completely broken battery, battery no voltage at both ends.

But with a multi-meter can be indirectly measured the battery internal resistance, remember is indirectly measured, directly with the multi-meter is above can't detect the battery internal resistance (to directly measure requires a dedicated instrument), remember that don't use multi-meter resistance directly on both ends of the battery, is likely to destroy the multi-meter to do so.

Need to measure the first parameter is the no-load voltage of battery, the so-called no-load voltage is on both ends of the battery even when nothing at the ends of the battery voltage, measuring method is simple with multi-meter voltage profile can be measured directly, the assumption is that U1, and then find a load, the load in theory the better the greater the power, can look for a light bulb or fan, etc., but the load of the rated voltage and battery voltage at the ends of the same.

Loads from the actuators to a power supply, the next step the multi-meter to measure the current file current size, I write down this parameter, the multi-meter to down load to attached to the battery, the multi-meter at the ends of the voltage profile to measure the battery voltage, assuming that the measured voltage is U2, then know that the three parameters can calculate the battery internal resistance R, calculation formula is R = (R1, R2)/I, pay attention to the unit conversion, where units are international unit, typically 12 ah battery internal resistance in 14.4 m Ω, 20 ah battery at about 10.6 m Ω, usually the smaller the greater the capacity of battery internal resistance will be.

Battery internal resistance increase is the most intuitive performance at the time of the battery discharge calorific value will increase, this is according to the ohm's law can be judged, and came to raise the temperature of the battery, battery calorific value increases, in turn, will speed up the battery electrolyte in evaporation, generally refers to the evaporation of moisture, cause the solution concentration increased, further speed up the battery aging, the previous battery adding distilled water, is a matter of science, it can make the solution concentration diluted back again.

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