Creating a battery charger indicator

In summary, the conversation discusses the speaker's desire to add an LED indicator to a battery charger they have built for a cordless drill. They express frustration with constantly having to check the voltage to see if the battery is fully charged and are open to various methods for the indicator to work. Suggestions are given for using comparators and Zeners, as well as monitoring temperature or voltage rise to detect when charging is complete. The possibility of using a microcontroller to measure voltage drop is also mentioned.
  • #1
lrprath
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0
I have built a battery charger for a cordless drill. It works fine, however, I would like to add an LED indicator to let me know when the battery is fully charged. I'm getting tired of checking the voltage across the battery all the time to see if the thing is charged. I'm not picky on how exactly this indicator works. The simpler, the better.
 
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  • #2
Welcome to PhysicsForums!

The difficulty with the charge indicator (and you neglect to mention the chemistry and number of cells here) is that the difference between a fully charged and a 75% run-down battery is usually fairly low (under a half volt) per cell. Nevertheless, it is possible to design a circuit using comparators and Zeners (or even better, with an ADC and a microcontroller) to indicate this difference in a battery of cells. You can even Google for schematics and circuit diagrams.

However, it may be better to detect the completion of charging using temperature or voltage rise (especially if you're wanting to monitor the charge for the purpose of stopping the charging).
 
  • #3
You might try interrupting the charging, measuring the no-load voltage across the battery, then momentarily putting a resistor equal to full load across it and measuring how much the voltage drops from no-load. A uC should be able to do that.
 

FAQ: Creating a battery charger indicator

What is a battery charger indicator?

A battery charger indicator is a device that shows the status of a battery while it is being charged. It typically displays information such as the battery's current charge level, the charging rate, and the estimated time until the battery is fully charged.

Why is it important to have a battery charger indicator?

A battery charger indicator is important because it allows the user to monitor the charging process and ensure that the battery is being charged properly. It also helps prevent overcharging, which can damage the battery.

How does a battery charger indicator work?

A battery charger indicator works by measuring the voltage and current of the battery being charged. It then uses this information to calculate the battery's charge level and estimate the time until it is fully charged. Some indicators also use LED lights to display the charging status.

What are the key components of a battery charger indicator?

The key components of a battery charger indicator include a voltage and current sensor, a microcontroller, and a display. The voltage and current sensor measures the battery's parameters, the microcontroller processes the data and calculates the charge level, and the display shows the information to the user.

Are there different types of battery charger indicators?

Yes, there are different types of battery charger indicators. Some use LED lights to display the charging status, while others have digital displays. Some are designed for specific types of batteries, such as lead-acid or lithium-ion batteries. There are also indicators that are built into the battery charger itself, and others that are separate devices that can be connected to any charger.

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