Battery Testers

Brooke Clarke 2007

Background
State Of Charge
    Radio Shack 22-080 Household Battery Tester
    ZTS Mini-MBT
    ZTS MBT-1
    TS-183 Mil Dry Battery Tester
    PSM-13 belt carry Mil Radio Battery Tester
    TS-4403 LiSO4 Mil Radio Battery Tester
    TS-23  BA-1574/U Mercury battery Tester
    Drop Test
Capacity Testing
    Amrel 1132
    Watt's Up
Internal Resistance
    EVB ESR/Low Ohms Meter
    HP 4328A Milliohm Meter
    ESR-Cap meter
    Battery Impedance Meter
Shelf Life 
   

Background

There are a number of reasons why you might want to test the capacity of a battery.  For household type batteries it's good to know if it's the battery that has died or the device holding the battery.  When working with rechargeable batteries it's good to know the state of charge, i.e. what's the capacity.

I've found a number of cases lately where the Radio Shack battery tester shows in the middle of the green, yet the battery is not powering the device.

State of Charge

These testers estimate the remaining life of a battery.  For Carbon Zinc and to a lesser extent Alkaline this can be done by measuring the battery voltage while a light load is applied.  If the proper load is chosen for a given battery capacity the loaded battery voltage works well as an indicator of remaining life.  The idea is to determine the state of charge using as little of the batteries capacity as possible.

HP 66311A Mobil Communications DC Source

This test instrument was specifically designed to measure the power consumed by battery operated devices, like cell phones, and to measure the associated battery and battery charger.

Radio Shack 22-080 Hand Held Battery Tester

Radio Shack 22-080 Battery TesterAug 2007 - Added test jack table to TS-183 web page so that the Radio Shack load resistors could be compared to the TS-183 load resistors.  The Radio Shack tester showed a 9 volt battery as good yet the battery would not work in the Stamps.com postal scale.  The TS-183B showed the resistor as bad after abut 5 to 10 seconds.  There's a 100% difference in the load resistors for this voltage.  Need to check the others.

In addition to the test leads this battery tester also has metal contacts for a 9 volt battery on the front panel, the negative contact and be used on the bottom of AA, C, D battery and the red lead to make testing easier.  On the right side is a slot for button cells and part of the front panel can be depressed to make contact to them.  For most common batteries I have used this tester, but now am no longer as confident in it's abilities.
 
Range RS
Load R
Yellow
V
FS
V
TS-183
Load R
1.5v 1 ma button cell
1k7
1.13
2

3v 1m Lithium cell
3k4
2.27
4

AAA & N 50 ma
30
1
1.6

AA  &  C  &  D  150 ma
10
1
1.6
6
Photo 6v
600
4
6

9 volt
900
6
9
544
12v 1k2
8.3
12

15v 1k5
10
15

22.5v 2k3
15.5
22.5


ZTS Mini-MBT

ZTS MBT Mutiple Battery TesterSince the above Radio Shack tester does not work very well I've been on the lookout for an improved tester.  ZTS makes a number of handheld battery testers and the Mini-MBT (Multiple Battery Tester) is what got.  They have a utility and a design patent.

6823274 Apparatus and method for testing remaining capacity of a battery, Nov 23, 2004, ZTS, 702/63 ; 320/125; 320/136; 702/64; 702/65; 702/79
uses voltage at end of resistor load pulse.  D515444 Battery Tester - packaging for the 6823274.

When a battery is connected it's immediately under load and after a few seconds the loaded voltage is read.  The capacity is based on the loaded voltage at the end of the test time.   The patent has data on the load resistance for 8 different battery types as well as capacity information in 20% steps for 3 & 6 Volt versions of the CR123 photo battery and for the 1.5 volt alkaline terminal.

The four battery types that the MBT will test are:
Cell Type
Details
Ni-MH
1.2 volt
Alkaline
AA, AAA, C, D, N
Lithium
CR123, CR2, CRV3
Alkaline
9V
I checked the same battery that the Radio Shack tester showed in the green and this tester either shows it as bad or on the second try it failed to start the test, meaning it's dead.
Also checked some CR123 cells that have been here for years.  They test at different levels.  I haven't made any controlled discharge tests to see how accurate this tester is, but at a first look I like it.
ZTS Mini-MBT InsideThe Mini tester uses a socketed 18 pin micro controller without a seperate MUX IC and without an external crystal.  The circuit board is soldered to the positive and negative battery terminals and so can not easily be removed.  There's a 4 post 0.1" header for testing the unit, but it's between the PCB and back cover so is not accessible after the front cover is removed. 

Instead of using a switch like on the Radio Shack tester, this one uses 4 different positive battery terminals and a common negative test lead.  There's a groove around the tester to hold the lead and a pocket for the short probe body on the left side not shown in the photo.  The On button is on the right side.

There are two lower priced ($30) models this one (Mini-MBT) and the MINI-MBT9R.  The difference is that on this one the lower left terminal is for the CR123 Li-MnO2 primary battery and on the other one it's for a Rechargeable 9 volt battery.  I specifically wanted to try the CR123 battery test since I use these in some of my products (5BA, 90BA Battery Adapters).

The TS-183 works the same way.  You pick the test jack to match the battery instead of using switches.  The load is permanently associated with the jacks.  For example on the TS-183 jacks 1, 2, 3, & 4 are for single cell batteries and 1.40 V is the 80% indicator.   Jack 3 is for a "D" Zinc Carbon battery and uses a 6 Ohm load.  The ZTS tester is using a 9.1 Ohm for alkaline cells with a 80% voltage of 1.41 V.  ZTS could eliminate the whole relay circuit and thus lower the cost of the tester since one of the connections to the cell under test is by the probe.  That's to say whoever is testing the battery has to hold the probe on the cell   If there was a socket holding the cell then the relay has some merit, but in this case it's not likely someone will "forget" and keep holding the probe on the cell for an extra hour or more.

There are some  aspects that could be improved. 
These are nit picks.  This is be far the best battery tester I have.
They make more expensive testers that can test a longer list of batteries.

ZTS MBT-1

ZTS MBT-1 Battery Tester

Runs on 4 AA batteries.
3.6 V Lithium-Ion
RCR123A
18500
17650
18650
1.5V Button Cell
S76
A76
A625
A640

1.2 V NiMH
AA
AAA
C
D
1.5 V AA Lithium
LS91
3V Lithium Button
CR2016
CR2025
CR2032
CR2320
CR2450
CR1/3N
6 V 28 Series
28A
S28
28L
3V Lithium
CR123
CR2
CRV3
1.5 V Alkaline
AA
AAA
C
D
N
12 V Alkaline
A23
9 Volt Alkaline

TS-183

Army dry battery tester.  Works by measuring loaded voltage.

PSM-13

The set can be carried on a belt and tests radio batteries, Vietnam era.  Uses high current load to activate Magnesium batteries.

TS-4403

Tester for LiSO4 primary batteries BA-5590/U, BA-5598/U and BA-5588
4725784  Method and apparatus for determining the state-of-charge of batteries particularly Lithium batteries, Feb 16, 1988, 324/427 ; 320/149; 320/150; 320/162; 340/636.15
Uses pulse loading and voltages measured at various times in relation to the load pulse as well as temperature correction.  Capacity depends on manufacturer as well as model.

TS-23

Tests the BA-1574/U Mercury battery used in the SDU-5/E Emergency Survival Strobe Light and the flash rate of the strobe.
BT-2 - Tests BA-1568/U as used in the PRC-90 Survival Beacon Radio and others, BA-1113/U used on the URC-64 Survival Radio, the K308A battery  used on the RT-10 Survival Radio, and the  BA-1574/U used on the SDU-5/E Emergency Survival Strobe Light.

Drop Test

The idea is to drop a AA battery with the + end up on a reasonable hard surface.
This may work for other Alkaline cells?
A good battery will make a thud sound, no bounces and may stand up.
A bad battery will sound metalic, bounce and fall over.
How To Test a AA battery, Easiest Way For Any Battery Fast, Easy!
The comment about testing with a volt meter is wrong.  A no load test does not mean anything.
For a meter test to mean something the battery needs to be loaded.  See the TS-183.  Even load testing does not work well on modern batteries.

Capacity Testing

The idea here is to drain the battery using a known load until it's voltage is down to the end voltage and record the delivered Amp hours, or better delivered Watt hours.  Note that when the battery starts the test it's voltage is highere than at the end where the voltage is the pre assigned ending voltage.  So the early amp hours are at a higher voltage than the ending amp hours.  The early Watt hours are higher than the ending Watt hours.  So reporting the run time using a load resistor or constant current source is not as accurate as reporting the delivered Watt hours.

The results for a given battery will be different as a function of the load. 

Resistor

A fixed resistor is the load.  The load current decreases as the battery voltage goes down. 

Filament Flashlight Bulb

The resistance of the bulb changes in a non linear way with the battery voltage.  The bulb gets dimmer as the battery voltage gets lower.  How dim does the bulb need to get to say the battery is dead?  Kind of a fuzzy feely thing maybe not the best capacity test method.

Constant Current

When a constant current load is used the delivered Watt hours are directly proportional to run time.  This is the most constant load type. 

Constant Power

Switching Mode Power Supplies, like used in most modern battery powered devices consume what's pretty close to a constant power in Watts.  This means at higher battery voltages they draw smaller currents than when fed lower battery voltages.  This is the oppsite of the resistor load.

Amrel EL1132 Electronic Load

This is an electronic load that can be set to look like a constant resistance or constant voltage load.  By using a computer to control the load and read back the battery voltage and current almost any test sequence can be accomplished.  There is a low voltage limitation of  2.5 Volts.

Watt's Up

This is a handy gadget that not only measures voltage and current but also has an internal clock so that it can count coulombs.  This allows displaying Amp Hours and Watt  Hours.  It's a natural to have power pole connectors on the input and output.  A battery might be the input and a motor might be the output, or a battery charger might be the input and a battery on the output.  For measuring voltages below maybe 4 volts an external power supply is needed.  There's a 3 male pin connector next to the SOURCE wires where an external battery can be connected to power the Watt's Up when testing below 4 Volts.

wu100v2_user_manual.pdf  (at RC Electronics)

Watts Up
                      Coulomb counter
Watt's
                        Up with Aux Battery

Watts Up Coulomb counter
Aux battery connected to allow working with voltages below 4.
With test leads shorted there's a reading ov 0.05 volts.
Org : gnd, Red:+9 drawing 5 ma Brn: Reset when grounded.
Aux cable at PowerWerx

Maha 777Plus

Ni-Cad, Ni-MH or Li chemistry charger discharger with LCD readout of parameters.  Does packs.

Maha MH-C9000

Intended for Ni-MH AA or AAA cells.  Only tests single cells, not packs.  Four independent channels and can do different things to each channel.

Triton2

Multipurpose Charger Discharger Cycler for a number of chemistries with plenty of adjustments.  One battery at a time.  Can do packs.

Internal Resistance


SM8124 (20R) Battery Impedance Meter

SM8124 Internal
            Battery Resistance Tester
I let the smoke out of my ESR-Cap meter when trying to measure the internal resistance of some 7.2 Volt RC batteries, so found this unit from eBay seller hkwisefield (eBay search for Internal Battery Resistance Tester).

The top switch is Off-Ohms-Volts and the bottom switch is 100V/200mOhms-20V/2 Ohms- 2V/20 Ohms.
There are two wires to each test probe (i.e. Kelvin connections) to cancel test lead resistance.
The test signal is about 1 kHz at more than 1 VAC.
By using an AC test signal the meter can use AC coupling for the resistance measurement keeping DC out of the test circuitry.
The AC test signal also has the advantage of not being influenced by voltages caused by thermal differences at metal junctions.

To replace the 9V battery peal the rubber case from the top side just enough to get to the battery compartment.

PS this meter is also called "20R" and there is a very similar meter called SM8124 that's for measuring UVA and UVB light.

For a practical application see testing RC Car 7.2 Volt battery sticks for Maximum Current by measuring battery resistance.

EVB ESR/Low Ohms Meter

EVM ESR meter modified with
        no protection diodes, added resistor & switchYou can use one of the hand held capacitance ESR meters to measure the resistance of individual cells and of battery packs.  But first a couple of modifications need to be done.
(1) The two large protection diodes need to be removed from the PCB.  They are located near where the banana jacks are wired.
(2) A SPST normally open push button switch is added near the tip of one of the test leads and in series with the lead.  Across the switch place a 470 ohm resistor.  When the probes are first connected to a live battery the 470 Ohm series resistor pre charges the internal non polarized blocking caps without hitting them with a really fast rise time pulse, thus tending to protect the internal circuitry.

To make a measurement first do the calibration by:
Then to make a measurement:
The meter I'm using from EVB in Portugal, is the same circuit designed by Bob Parker and sold by Dick Smith Electronics  in Australia as a kit.  I saw mention of battery testing at Hints for techs using Bob Parker's ESR meter(kit)...  and an email from Bob suggested the switch and resistor to reduce the likelihood of damage to the meter.

I'll be using it to test the battery packs for my 5590BA Battery Adapter.

HP 4328A Milliohm Meter

I haven't tested the 4328A on a battery but it's my recollection that it's rated for up to 150 Volt batteries.

ESR-Cap meter

The ESR-Cap meter can easily measure internal resistance.  See the example table of data.

Shelf Life


New for me Oct. 2007 are the "Ready to Use" rechargeable batteries.  Sanyo eneloop brand in AA Ni-MH format.  Capacity of 1.9 to 2.0 AH.  Testing capacity can be typically done in less than 24 hours, but shelf life may take months or years.  See the eneloop Ready To Use battery web page for the test plan.

self-discharge (Wiki) causes most rechargable batteries to loose charge just sitting.
Chemistry
% / month
Ni-MH
30
Ni-Cad
15 to 20
Li-xx
2 to 3
Ready to Use Ni-MH
1.5

Fast Amps

This is the current a battery can source when a load of 10 milli Ohms is applied for 200 milli seconds.  So far the only mechanical relay I've found that can handle 40 Amps (needed for "D", "F" and No. 6 dry cells) with a contact resistance will below 10 milli Ohms  is the one used in car starter motor circuits typically rated for 400 Amps.  Solid state devices have way too much resistance.  A method of getting the required load is to connect just under two feet of 14 AWG copper wire across the terminals.  The problem is only connecting it for 200 milliseconds and then disconnecting.  If left connected longer serious problems with the battery or load may occur.

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