# How Much Should battery voltage drop?

Table of Contents

## How Much Should battery voltage drop?

A fully charged battery should read over 12.6 volts. If the battery reads 12.45 volts or less, it is low (less than 75 percent charged) and needs to be recharged.

### What should the voltage drop be between load and ground?

about zero
Electrical pressure (voltage) is used up operating the load. Therefore, voltage falls to about zero on the ground side, but current keeps flowing toward the battery. Because the voltage in a healthy ground circuit should be about zero, some technicians call it ground zero.

What causes a battery voltage to drop?

A voltage drop is usually caused by the electrical current being used in excess of the battery’s capacity. When an electrical load is placed on a battery, it causes resistance and a voltage drop across the terminals. The greater the demand for current, the greater the voltage drop will be.

How do I reduce the amperage of a resistor?

Lowering amperage is done by applying Ohm’s law, given by the formula I = V/R, where I is the circuit’s total current in amperes, V is the voltage and R is the resistance. Add resistors to the circuit to increase the total resistance. A higher resistance results in a lower amperage.

## How many amps does it take to drain a car battery?

Generally, a car battery pulls approximately 400 amps for small vehicles to start and more than 1000 amps for the large ones.

### How much battery draw is acceptable?

A normal amount of parasitic draw for newer cars is between 50-milliamp to 85-milliamp current draw. A normal amount of parasitic draw for older cars is a reading less than 50-milliamp. Anything past these amounts indicates an electrical issue and should be addressed by a mechanic.

What is a good voltage drop reading?

If a connection is good, you should find little or no voltage drop and see less than 0.4 volts for most connections, and ideally less than 0.1 volts. But if you find more than a few tenths of a voltage drop across a connection, it indicates excessive resistance and a need for cleaning or repair.

How do you fix voltage drop?

There are many ways to minimize these voltage drops which include decreasing the temperature of the conductor, decreasing length of conductor, increasing quantity/size of the conductors, or reducing power load.

## What does it mean if your battery gauge is low?

Readings of 14 to 14.5 volts on the gauge when as a good sign. This is typical of a properly operating charging system. If the voltage reading drops below 12.5 volts, the charging system is not operating properly, and the battery is having to provide current, meaning it will eventually go dead.