22 Years' Battery Customization
Jan 08, 2022 Pageview：4511
A voltage drop occurs when there is a voltage loss from the utility power supply. Battery voltage can drop for so many reasons. For instance, if you accidentally left your car's lights on, its battery will run down even when the ignition key is off. Also, some vehicles have a voltmeter gauge for Electric Power Management (EPM). The EPM estimates the battery's temperature and charge then adjusts the voltage for extended life and better performance. Other causes of battery drop are:
Your battery has a charging problem.
Your battery is old and does not hold a charge anymore
Your battery might have a key off parasitic electrical drain that makes it go into sleep mode.
Your battery has a self-discharge
Why Does Battery Voltage Drop Under Load?
Connecting a load across a battery will make the voltage across the terminal drop. Knowing the possible causes for the voltage drop can help you fix the problem appropriately. Below are some common reasons why your battery may be experiencing a voltage drop.
1.Battery and Starter Connections
The voltage will always decrease when the battery runs out of power. Battery and starter connection is the leading cause for any voltage drops. In case of any voltage drops, first, check the starter and battery connection to ensure that neither is the problem.
2.Resistance
All batteries have internal resistance, which is a function of the battery's chemical composition, size of electrodes, and the connections between the cells. To calculate internal resistance, readings of the open-circuit voltage are recorded and compared with the voltage when a load is attached. Resistance is usually caused by cables corroded, damaged, and loose cables. The higher the battery's internal resistance, the greater its voltage drop for a given load current. Note that a typical AA battery will always have its internal resistance between 0.1Ω and 0.9Ω.
3.Checking Connections
By performing a voltage drop test, checking battery connections is the most accurate way of measuring voltage drops. You do not have to disassemble everything, so the test will not take much of your time. Use your digital voltmeter to test for any reduction in the voltage after connecting a load across the battery. If your circuit has too much resistance, some voltage will flow into the voltmeter to give you a reading.
What happens when Battery Voltage Decreases?
When battery voltage decreases, it may cause electrical malfunctions, especially if it is faulty. The average service life for any car battery should be about four to five years and can typically be three years if the climate is hot. The chances are that batteries that are more than five years have reached the end of their service life and need replacement. So if you have a battery cell that is not working usually, use a load tester to tell if the battery is good or bad. A battery that fails a load test needs replacement immediately.
Internal resistance as the primary cause of voltage drops is affected by battery size, age, and temperature. When battery voltage decreases, there is a high chance that your cables and terminals are corroded. Therefore, you should regularly clean cables using a wire brush and replace those with bent shapes immediately. Moreover, it is essential to perform regular checks on the cables and terminals to prevent resistance problems.
A decrease in battery voltage causes the acid in the electrolyte to grow weaker, thus resulting in a constant reduction in the rate at which the fresh acid flows into the plates. The increased internal resistance from the voltage decrease will render the battery unusable in most cases. In addition to that, a voltage drop greater than 5% can easily harm the operational efficiency of the circuit. Usually, the voltage drop should be at least 5% for the furthest load for maximum efficiency. There are a few practical guidelines to contain voltage drops to the recommended levels, as discussed below.
How Do You Fix a Voltage Drop?
1.Decreasing Temperature of Conductor
The temperature of a conductor is a significant factor in its resistance and voltage drop. As far as the flow of power is concerned, conductors of high temperatures will resist the power flow leading to a rise in the percentage of the voltage. So for significantly smaller voltage drops, adjust the temperature of the conductor. The following equation explains the effect of temperature:
R2 = R1 [1+ a. (T2 – T1)]
Where;
R1is the resistance to power flow at temperature T1
R2 is the resistance to power flow at temperature at T2
And a is the co-efficient of electrical resistance
2.Decreasing the Length of a Conductor
The length of a conductor is directly related to the amount of resistance produced. This means that a decrease in the length of a conductor leads to decreased resistance, and as a result, the voltage drops will reduce as well. The most recommended method for reducing conductors is the installation of panels and subpanels next to the loads. This procedure is best for highly sensitive electronic equipment.
3.Increasing Quantity/Size of the Conductors
In regards to the overall power, increasing the quantity/size of the conductors will decrease the resistance, and as a result, the voltage drop will decrease. The use of parallel or oversized conductors will increase energy because of their lower resistance, unlike the minimum-sized conductors. This method increases the battery's operational efficiency and lowers the overall power loss. It is also recommended to install grounded or neutral conductors for best results.
4.Reducing the Power Load
Another efficient way of reducing voltage drops is by limiting the power load (the amount of electrical equipment connected to the circuit). Ensure that the number of equipment connected to each branch of the circuit does not exceed the recommended level of 6. For residential applications, each receptacle should be connected to a single circuit with a minimum capacity of 12 AWG. Install sensitive electronic loads or loads with high currents in their individual circuits.
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