Alkaline battery tester - Page 1
Forum section: electronics / projects

author: wolf9545
author_rank: Newbie
timestamp: August 06, 2017, 07:35:37 pm
content: I have been building electronic projects for a while but have never really designed anything so please bare with me.I want to make something like this:https://www.amazon.com/ANSMANN-ENERGY-BATTERY-TESTER-ALKALINE/dp/B000KHVKV6but I don't want to spend the almost $100 just to test some batteries. I would like to be able to test AA, AAA, C, D, coin cell and 9V batteries. I wanted to test the battery under a load because I know you will get a better idea of the current capacity.I figured I would make something like the harbor freight multi-meters that have a battery tester function. They just pass the battery through a 360ohm resistor and display the mA on the meter. More info for anyone that doesn't know:http://www.instructables.com/id/Add-Battery-Test-to-a-Multimeter/I ended up buying this meter:https://www.amazon.com/gp/product/B00D2M623C/ref=oh_aui_detailpage_o04_s01?ie=UTF8&psc=1and I put a 360ohm resistor inline with the tester side. That way I can get a reading of 25mA for a 9V, 4mA for a 1.5.What I am wondering is if there is a better way to check the batteries? I found this circuit:https://www.eeweb.com/blog/extreme_circuits/battery-tester-circuit-schematic. Would I get a better idea if a battery is good or not? If I read the article and schematic right I would connect a volt meter to the circuit and watch the numbers. If I am testing a 1.5V battery I would see if 1.5 stays steady on the meter or drops.Sorry about the massive amount of links.

author: rdl
author_rank: Super Contributor
timestamp: August 07, 2017, 01:38:45 pm
content: Checking a battery under load is probably the best way, but it seems like the load should be scaled to fit the capacity of the battery.

author: sasa
author_rank: Regular Contributor
timestamp: August 07, 2017, 03:02:38 pm
content: Calculating internal battery resistance will give a bit more reliable info of the status and future life of the battery.For a bit more concrete info:https://learn.sparkfun.com/tutorials/measuring-internal-resistance-of-batteries

author: Kleinstein
author_rank: Super Contributor
timestamp: August 07, 2017, 05:42:02 pm
content: With alkaline cells just measuring the voltage is usually good enough. However this does not work with the old style dry cells: they show some 1.52 V all the way till the end. So to test the dry cells one would need a load.An alkaline cell starts at some 1.6 V with a low internal resistance (e.g. < 0.1 Ohms for AA). When about empty they have some 1-1.2 V and still a low resistance maybe in the 0.1-0.5 Ohms range. In contrast the dry cell may start at 1.53 V with a reasonably low impedance (maybe 0.5-1 Ohms) - when empty its at something like 1.5 V but the internal resistance goes really up and can reach 100 kOhm (depending on how empty). So testing would be ideally without an with a certain load (e.g. 10 mA). So one would get both the open circuit voltage and the output resistance.

author: wolf9545
author_rank: Newbie
timestamp: August 24, 2017, 09:56:51 pm
content: Thank you for all your help. Sorry I am replying so late, I never got any notification that people replied.I did find this circuit:https://www.eeweb.com/blog/extreme_circuits/battery-tester-circuit-schematicand I am waiting for the components to arrive. I like the idea of a constant current to act as a load. Like the description says I will then look to see if the meter stays on a steady voltage for the battery or it decreases. I wish I could use a digital volt meter so all you would have to do is read the digits. I could not find any that worked on 1.5V. I ended up getting a analog meter that goes up to 20V.

author: rdl
author_rank: Super Contributor
timestamp: August 26, 2017, 11:36:44 pm
content: LCD panel meters can run a long time from a 9 volt battery as long as there's no backlight on all the time.

author: 6PTsocket
author_rank: Regular Contributor
timestamp: August 25, 2018, 11:01:41 pm
content: The apprropriate test load really depends on the application. A battery can have high internal resustance and still run a device that draws very little current. Any tester that has load resistors estimates what they consider a typical load.Sent from my SM-G900V using Tapatalk

author: floobydust
author_rank: Super Contributor
timestamp: August 26, 2018, 01:07:16 am
content: I use an old analog Radio Shack Micronta 22-032 battery tester. The pass/fail voltages are in this table.It uses 10R load for 1.5V 150ma, 30R load for 1.5V 50ma.

author: yo0
author_rank: Regular Contributor
timestamp: February 17, 2020, 08:15:35 pm
content: Quote from: sasa on August 07, 2017, 03:02:38 pmyou can test batteries with a esr meter, "blue esr meter" is a good one for that.Quotebest regardsPio

author: OldEE
author_rank: Contributor
timestamp: February 18, 2020, 12:49:50 am
content: The best battery tester I've found is from ZTS and uses a pulse load. The mini version that I have is $45 and it also does NiMh and lithium.Check out the patent for more information.https://patents.google.com/patent/US6823274B2/enLarry