what equipment do you people use to test battery
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Alan B
Flashlight Enthusiast
I use the West Mountain Radio Computer Battery Analyzer.
http://www.westmountainradio.com/CBA_ham.htm
This USB device is programmable for drain current level and shutoff voltage.
-- Alan B
http://www.westmountainradio.com/CBA_ham.htm
This USB device is programmable for drain current level and shutoff voltage.
-- Alan B
Alan B
Flashlight Enthusiast
The other way I did it was to build a small microprocessor based solution. I used a PIC micro, these days I prefer the AVR.
Another way is to use a digital voltmeter that has an RS 232 output. They are available on eBay, and Radio Shack used to have some as well. This will only measure one value, and does not provide a load resistor or constant current load device which will be required.
One problem with the less sophisticated solutions is they don't generally have an automatic stopping point, so the cell will overdischarge. This will damage some rechargeable cell types and can be dangerous with lithiums.
The CBA sounds expensive until you consider all the features and safety it provides. I'm not aware of a lower cost solution with the features.
-- Alan B
Another way is to use a digital voltmeter that has an RS 232 output. They are available on eBay, and Radio Shack used to have some as well. This will only measure one value, and does not provide a load resistor or constant current load device which will be required.
One problem with the less sophisticated solutions is they don't generally have an automatic stopping point, so the cell will overdischarge. This will damage some rechargeable cell types and can be dangerous with lithiums.
The CBA sounds expensive until you consider all the features and safety it provides. I'm not aware of a lower cost solution with the features.
-- Alan B
MrAl
Flashlight Enthusiast
Hi there,
I use a chip and software i designed made just for monitoring cell charging
and discharging, but can be used for monitoring any voltage. It can
do 4 cells at the same time. I sell the chip + software (Windows) for
$4.50 plus shipping. For the basic version it requires about 6 resistors
and maybe a cheap low current 5 volt regulator. For the isolated version
it also requires a cheap 50 cent opto isolator ic. This is mostly for people
who build their own circuits and is about the lowest cost thing you will
find for monitoring cells with the computer. You can also monitor the
cell temperature with cheap thermistors as the software is set up to
accept many different model thermistors. Recently i calibrated a thermistor
that was 17 cents and it's about 1 percent accurate, but it was a little
harder to solder than the usual thermistor because it was a SM 'chip' type
thermistor. Worked great once i got it soldered though
I've used the chip a number of times already and it has enabled me to check
various things about the cells. Just recently i did a self discharge test
on some Kodac low self discharge cells by fully charging them and then
using the chip+software to check remaining capacity. There's a thread
somewhere in this Forum with the results.
I use two 10 ohm 1/2 watt resistors in parallel for each cell for the discharge
test. These are quite cheap also. BTW first class shipping is about a
dollar in the USA, a little more for out of the country.
If you want a graph i have software i can also provide that will take the
log from the chip+software test and convert it into a run time graph.
It's kind of a waste of time however as the curve looks amost the same
for every cell except for the actual length of time. The software provides
a capacity readout for all 4 cells as the cells are discharging (or charging)
so you can simply read off the value when the test is complete (alarm sounds).
Before i made this chip+software i used an ordinary RS meter with a computer
interface. It worked just great, but i needed to do more than one cell
at a time so i needed at least two meters, then i wanted to do 4 at a time
and i didnt feel like buying 3 more meters ha ha so i made the chip.
I've tested NiMH mostly but i also tested Li-ion and it will also do
Lead acid with the addition of two 1/4 watt (cheap) resistors.
Im also eventually going to do a fully automated cell tester that will cycle
four cells for some 500 to 1000 cycles and log each and every data point
for later analysis. This is to find out what cells work good and what cells
dont work good. Tom has already said he would do some testing with it
too and provide some cells to test. Cant wait for this to happen.
Too bad the self discharge tests take so long though, i'd like to do more
of those too.
I use a chip and software i designed made just for monitoring cell charging
and discharging, but can be used for monitoring any voltage. It can
do 4 cells at the same time. I sell the chip + software (Windows) for
$4.50 plus shipping. For the basic version it requires about 6 resistors
and maybe a cheap low current 5 volt regulator. For the isolated version
it also requires a cheap 50 cent opto isolator ic. This is mostly for people
who build their own circuits and is about the lowest cost thing you will
find for monitoring cells with the computer. You can also monitor the
cell temperature with cheap thermistors as the software is set up to
accept many different model thermistors. Recently i calibrated a thermistor
that was 17 cents and it's about 1 percent accurate, but it was a little
harder to solder than the usual thermistor because it was a SM 'chip' type
thermistor. Worked great once i got it soldered though
I've used the chip a number of times already and it has enabled me to check
various things about the cells. Just recently i did a self discharge test
on some Kodac low self discharge cells by fully charging them and then
using the chip+software to check remaining capacity. There's a thread
somewhere in this Forum with the results.
I use two 10 ohm 1/2 watt resistors in parallel for each cell for the discharge
test. These are quite cheap also. BTW first class shipping is about a
dollar in the USA, a little more for out of the country.
If you want a graph i have software i can also provide that will take the
log from the chip+software test and convert it into a run time graph.
It's kind of a waste of time however as the curve looks amost the same
for every cell except for the actual length of time. The software provides
a capacity readout for all 4 cells as the cells are discharging (or charging)
so you can simply read off the value when the test is complete (alarm sounds).
Before i made this chip+software i used an ordinary RS meter with a computer
interface. It worked just great, but i needed to do more than one cell
at a time so i needed at least two meters, then i wanted to do 4 at a time
and i didnt feel like buying 3 more meters ha ha so i made the chip.
I've tested NiMH mostly but i also tested Li-ion and it will also do
Lead acid with the addition of two 1/4 watt (cheap) resistors.
Im also eventually going to do a fully automated cell tester that will cycle
four cells for some 500 to 1000 cycles and log each and every data point
for later analysis. This is to find out what cells work good and what cells
dont work good. Tom has already said he would do some testing with it
too and provide some cells to test. Cant wait for this to happen.
Too bad the self discharge tests take so long though, i'd like to do more
of those too.
Last edited:
Fallingwater
Flashlight Enthusiast
Hmm.
I wonder if one could do the same thing for cheap with two standard multimeters, resistive load, webcam and carefully calibrated OCR software... it'd need an application written exclusively for it, but it'd cut the prices a lot.
I wonder if one could do the same thing for cheap with two standard multimeters, resistive load, webcam and carefully calibrated OCR software... it'd need an application written exclusively for it, but it'd cut the prices a lot.
Curious_character
Flashlight Enthusiast
- Joined
- Nov 10, 2006
- Messages
- 1,211
I use a USB-connected A/D converter connected to my laptop. For a load I have a homemade constant current source I can set for any current from near zero to one amp. Both are used for other purposes too.
c_c
c_c
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