How To Make Battery Charging Fault Indicator Circuit

The blog post clearly shows a battery status indicator circuit which is competent at suggesting no matter whether the battery condition is good, bad or damaged.

The thought listed here handles all the limitations needed for charging a battery optimally and easily.

Making reference to the presented battery charging fault indicator circuit, the design could be realized by making use of the following tips:



The IC LM3915 which can be a dot/bar LED exhibit driver IC forms the main charging indicator module of the circuit.

It’s pin5 is the sensing input, the rising battery voltage is imagined as of this pin as well as the IC reacts to it by giving rise to a equally sequencing LED illumination across its 10 outputs, as presented with the 10 hooked up LEDs.

A LM317 IC could also be noticed joined at the input of the circuit, it’s wired as a persisting current generator in order that the circuit has the ability to deliver error free indications and functions irrespective of the input current level. Rx is picked well so that you can permit this appropriately.

When power is activated, the 100uF/25V capacitor across the pin5 preset of the IC shortly grounds pin5 in order that all the outputs of the IC start by left switch off. This will be relevant to be sure that the TIP122 has the ability to begin the charging practice as well as the BC557 is inhibited from an accidental activate on account of the initial surge transients.

Whenever the 100uF is charged up, pin5 is able to identify the actual voltage that is been applied by the battery while it’s been charged, which need to be usually anywhere around 3 to 3.3V for a fully discharged 3.7V Li-ion battery.

Below each LED could be set to reveal an increment of 0.42V, which means that that the illumination of the 10th LED shows 4.2V which might be realized to be the battery full charge level indication.

Additionally this shows that during power ON, 7 LEDs ought to be activated to signify an appropriate battery discharge level and charging procedure.

Less that 7 LEDs activated would likely reveal a badly discharged battery or a damaged battery utilizing excess current than the specified range.

With all the LEDs lighting during power activated would likely indicate whether the battery is fully charged or the battery is not accepting charge and is damaged.

Under standard circumstances, around 7/8 LEDs needs to be activated at power switch ON and as the battery voltage enhances on account of charging, the LEDs will probably sequence by illuminating the 8th, 9th and the 10th LED in sequence.

Once the 10th LED is illuminated, a low logic is made available to the base of the TIP122 that may be now inhibited from a base bias and the charging voltage to the battery is as a result block, switching off the charging voltage to the battery.

The low logic from the 10th pin is usually made available to the base of the presented BC557 which carries out and hooks up pin5 of the IC instantly to the 5V supply to make sure that the 10th LED evolves into latched as well as the scenario is locked until power is switched OFF and ON for further behavior.

Find out how to the create the discussed battery negligence with indicator circuit

It’s the simplest part in the design.

Initially do no attach any battery across the shown points.

Apply an exact 4.2V at the input.

Now begin adjusting the pin5 preset such that the LEDs light up in sequence as well as the 10th LED merely brighten brightly.

Seal the peset once this is guaranteed.

Your circuit is geared up now for the suggested battery fault conditions including charge level indications.

Battery Fault indicator making use of a Flashing LED.

The following replace displays a convenient design which may be employed for suggesting a battery charging malfunction by way of a flashing LED




Originally both the opamp outputs could be deemed to be low, if the battery is discharged below 11V, which is mentioned with a swift blinking of the LED. C1 ought to be set for acquiring this fast blinking.

The lower opamps is focused choosing pin5 preset such that once the hooked up 12V battery touches around 12.5V, its output pin goes high, once this occurs the BC547 activates and contributes a high value capacitor C2 in parallel with C1 slowing down the flashing rate drastically and suggesting that the battery has accessed the next upper charging level including that the battery is good which explains processing the charge nicely.

As the battery proceeds to get charged and gains a voltage level of around 14V, the upper opamp that may be set making use of pin3 preset to result in at this stage generates and offers a high across the hooked up LED stopping its flashing and illuminating it to solid.

The moment this occurs the user may consider the battery to have reached the optimal charging level and may remove it from the charger.

How the fault of the battery charging is Suggested in the above circuit

1) If the LED blink swiftly would certainly originally signify that the linked battery is over discharged, still this situation need to develop as well as the LED need to transit into a slow flashing after an hour or so relying upon the sate of the battery. If this will never take place, the battery could be deemed not taking the charge on account of internal destruction or short circuit.

2) If the LED brightens solid when power is activated would clearly suggest a defective battery which might be entirely inactive internally and struggling to accept any current.

The above design tend to be enhanced for an automatic over charge cut off by way of a few modification as presented in the following diagram:



Though creating the two presets ensure that the 100K link continues shut off in the upper opamp.

After creating the thresholds, the 100k link could be reconnected into position.

The circuit would not cause until a battery is hooked up, so confirm the battery to be charged is first hooked up then simply power is activated.

For a 3.7V battery, the 4.7V zener will have to be replaced with two.