Home » Battery Chargers » Battery Health Checker Circuit for Testing Battery Condition and Backup
Battery Health Checker Circuit for Testing Battery Condition and Backup

Battery Health Checker Circuit for Testing Battery Condition and Backup

The article discusses a simple battery health checker circuit which uses ordinary components for enabling the user to get an instant reading of the battery efficiency or regarding its effective discharge rate. The idea was requested by Mr. Shrishail.

Circuit Objectives and Requirements

  1. I need a circuit of a battery checker. It needs to show, the battery under evaluation, the power of the battery, standby time period, AH etc. the circuit must be such which could be made by just about anyone & with inexpensive, quick existing components.
  2. Nowadays i confirm the battery depicted below.
  3. First the battery under evaluation recharge fully with normal charger, which goes through its specific time to charge completely.
  4. After that I hook up certain load that is able to discharge the battery upto reasonable limit. as just stated it consume its specific time to discharge entirely.
  5. Subsequently I assess the time utilized by each of the above measures
  6. Using this method is extremely time intensive & tier-some.
  7. For this reason I require the circuit as above noted battery checker

The Design

In one of the previous posts we learned regarding the significance of internal resistance of battery and realized how this parameter affects the efficiency of a battery in terms of its charging rate, and discharging rate.

The internal resistance of a battery ultimately decides how much current the battery may be allowed to accumulate, retain efficiently and discharge at the same efficient rate to the load.

Higher internal resistance would make the battery lower with its efficiency and vice versa.

Therefore the health of a battery can be evaluated by correctly and quickly judging the average internal resistance of the battery, but since this method may not be easy to detect using ordinary methods, an alternative way of determining the health of a battery is to capture the instantaneous amount of current it's able to retain, and deliver through a quick discharging method.

This procedure is devised by me, although I am not sure whether or not this would be helpful enough in determining or checking the health of a battery quickly.

Circuit Diagram

Battery backup time Checker Circuit

The diagram shows the proposed battery health checker circuit using very ordinary components and the set up hopefully can be used for determining the battery's overall condition by pressing ON the switch.

First the battery is charged to an optimal extent, this procedure cannot be avoided because unless the battery is properly charged the level of current it has retained cannot determined.

Hence after the battery is optimally charged using any ordinary high current battery charger, the above shown circuit set up can be attached with the battery for getting a rough idea regarding its AH efficiency specs.

How the Circuit Functions

The circuit is supposed to function in the following manner:

As soon as the indicated switch is pressed, the battery is subjected to an instantaneous short circuit condition via the 2200uF capacitor and the 0.1 ohm resistor.

This action forces the battery to throw its stored maximum current across the 0.1 ohm resistor, which in turn develops a equivalent amount of voltage across the 0.1 ohm resistor.

This equivalent amount of voltage which is supposed to be the direct measure of the battery's AH efficiency level gets stored in the 10uF/25v capacitor and can be measured or read over any suitable digital voltmeter across the selected range.

By performing a few repeated tests through the above method, and by assessing the corresponding voltage levels across the 10uF capacitor, an overall health of the connected battery can be estimated and checked.

The values of the 0.1 ohm resistor may vary according to the AH of the battery, and must be selected appropriately such that a measurable reading is achieved over the selected range of the V meter.


About the Author

I am an electronic engineer (dipIETE ), hobbyist, inventor, schematic/PCB designer, manufacturer. I am also the founder of the website: https://www.homemade-circuits.com/, where I love sharing my innovative circuit ideas and tutorials. If you have any circuit related query, you may interact through comments, I'll be most happy to help!

14 thoughts on “Battery Health Checker Circuit for Testing Battery Condition and Backup”

  1. Thanks sir.Pls,if I want a 24v 400arms battery to N/C or N/O to contact on a relay so that a generator will start through that battery.What’s going should be the relay rating.thanks.

    • Hi Nsonic, is the generator supposed to only start with the battery or fully operate using battery power?, in other words is the generator a diesel powered or battery powered system??

  2. Hi Mr swagatam,when I put the multimeter,what is going to display as no if the battery is healthy or not. (2)What’s another method of testing an healthy battery.

    • Hi Nsonic, it will display some value which can be compared with the value of a good battery. The good battery value can be saved as the benchmark level, and the doubtful battery values can be compared with this good battery reading for the estimation

    • Hi, sir i have 2nd question. Can resistor 0.1ohm 10watts can be replaced with a metal rod? Just like in battery tester use by battery dealer. Cold cranking tester. Wherein for several testing the inside metal rod becomming to hot turning red hot. Specially if you test several battery. I think 10watt resistor will broke for heat. Thanks.

    • Hi Edmund, if the metal resistance is within the range and capacble of generating the required potential drop then it can eb used.

      the short circuit will probably last only for some milliseconds, so a 10 watt resistor will not heat up or get burnt, even with repeated tests, in my opinion.

  3. Thank u Very Much for this very simple, low cost & basic circuit. And , last but not least, for ur kind attention to my small problem.

Leave a Comment