Detection of ReChargeable / NonRechargeable Batteries.

A

Anju

Guest
I want to construct a charger that can charge NiCd, NiMH, alkaline
batteries (AA size, 1.2V). When a nonchargeable battery is plugged
then it should be able to detect it and stop the charging process. Can
anyone suggest a method for this detection of whether the battery is
chargeable or Nonrechargeable.

regds
anju
 
abhartiya@grundfos.com (Anju) wrote:
I want to construct a charger that can charge NiCd, NiMH, alkaline
batteries (AA size, 1.2V). When a nonchargeable battery is plugged
then it should be able to detect it and stop the charging process.
Click to expand...
I'd imagine you're going to need to measure not only the open-circuit
voltage, but the ESR of the battery. Dunno if you need more than one
datapoint, or if charge and discharge will show different ESR, but
you're probably going to need to get a number of batteries of each
type and characterize them before you can really answer that question.

[What's wrong with the warning label that says "Don't attempt to
charge non-rechargable batteries!"?]

--
William Smith
ComputerSmiths Consulting, Inc. www.compusmiths.com
 
In article <3j2j80lranb7rhp92vkc3ljar6hjuai4tb@4ax.com>,
William P.N. Smith <> wrote:

[What's wrong with the warning label that says "Don't attempt to
charge non-rechargable batteries!"?]
Click to expand...
What's wrong with it? Nothing at all. Except that you can bet the farm
that sooner or later (and my bet is on sooner, given the mind-bogglingly
low aggegate IQ of "John Q. Public") *SOME* idiot is going to ignore it,
then promptly turn around and sue your socks off.

--
Don Bruder - dakidd@sonic.net - New Email policy in effect as of Feb. 21, 2004.
I respond to Email as quick as humanly possible. If you Email me and get no
response, see <http://www.sonic.net/~dakidd/main/contact.html> Short
form: I'm trashing EVERYTHING that doesn't contain a password in the subject.
 
Don Bruder <dakidd@sonic.net> wrote:
sooner or later (and my bet is on sooner, given the mind-bogglingly
low aggegate IQ of "John Q. Public") *SOME* idiot is going to ignore it,
then promptly turn around and sue your socks off.
Click to expand...
Well, sure, as long as it's "attempt to sue your socks off", and
that's what business insurance is for. 8*) Besides, when your
product gets a reputation for being overpriced (all the hardware and
software involved in this extra safety circuitry), and being unwilling
to charge certain brands of batteries at certain charge levels, your
company's going to fail anyway. 8*) [Hmm, USB interface, firmware
updates, naw, it's the stupid people you have to worry about, which
brings us full circle.]

--
William Smith
ComputerSmiths Consulting, Inc. www.compusmiths.com
 
On 22 Apr 2004 21:51:03 -0700, abhartiya@grundfos.com (Anju) wrote:

I want to construct a charger that can charge NiCd, NiMH, alkaline
batteries (AA size, 1.2V). When a nonchargeable battery is plugged
then it should be able to detect it and stop the charging process. Can
anyone suggest a method for this detection of whether the battery is
chargeable or Nonrechargeable.

regds
anju
Click to expand...
I can't see how it can be done successfully. For a start, if a battery
(or cell) of any type, whether chargable or non-chargable, has been
left till it is dead flat, ie, little or no voltage can be read, then
there is no way any sensing circuit can know what type it is. It would
take some pretty fancy (and expensive) technology to attempt to find
out by doing a range of tests, any, or all of which may not reveal the
correct (or any) answer. I'm afraid that the warning label is still
the most effective and efficient way of handling the situation.
Anybody who knowingly tries to charge a non-rechargable battery when
there is a warning given is unlikely to be able to sue the socks off
anybody.
 
Ross Herbert <rherber1@bigpond.net.au> wrote:
I can't see how it can be done successfully.
Click to expand...
Well, it's not un-doable, it's just very difficult to get right over
all the possible battery technologies, manufacturers, lot variances,
and even future batteries that might come on the market after your
release your device.

Someone hands you a battery with no label and asks you to characterize
it. You measure the OCV, then you do a 4-quadrant impedance test at a
range of currents, voltages, frequencies, etc. Then you compare
against a table of known batteries and see how close your match is.
Now do it automatically in software. Decide it's <this> kind of
battery, and watch to make sure the charge voltages and currents do
what they should while it's charging, and you can charge it.

No, it's not easy, definately non-trivial, and the development work to
get it right would make the thing cost _way_ more than some random
Radio Shack charger, so it's probably economically infeasable, but
it's not impossible.

--
William Smith
ComputerSmiths Consulting, Inc. www.compusmiths.com
 
Don Bruder wrote:
In article <3j2j80lranb7rhp92vkc3ljar6hjuai4tb@4ax.com>,
William P.N. Smith <> wrote:


[What's wrong with the warning label that says "Don't attempt to
charge non-rechargable batteries!"?]


What's wrong with it? Nothing at all. Except that you can bet the farm
that sooner or later (and my bet is on sooner, given the mind-bogglingly
low aggegate IQ of "John Q. Public") *SOME* idiot is going to ignore it,
then promptly turn around and sue your socks off.
Click to expand...
That's why most solutions are mechanical. Put a hole in the positive
contact so the nubbin on a alkaline cell can't make contact. Will only
recharge cells with a fatter nubbin.
mike

--
Return address is VALID.
Bunch of stuff For Sale and Wanted at the link below.
Toshiba & Compaq LiIon Batteries, Test Equipment
Honda CB-125S $800 in PDX
Yaesu FTV901R Transverter, 30pS pulser
Tektronix Concept Books, spot welding head...
http://www.geocities.com/SiliconValley/Monitor/4710/
 
On Sat, 24 Apr 2004 08:49:48 -0400, William P.N. Smith <> wrote:

Ross Herbert <rherber1@bigpond.net.au> wrote:
I can't see how it can be done successfully.

Well, it's not un-doable, it's just very difficult to get right over
all the possible battery technologies, manufacturers, lot variances,
and even future batteries that might come on the market after your
release your device.

Someone hands you a battery with no label and asks you to characterize
it. You measure the OCV, then you do a 4-quadrant impedance test at a
range of currents, voltages, frequencies, etc. Then you compare
against a table of known batteries and see how close your match is.
Now do it automatically in software. Decide it's <this> kind of
battery, and watch to make sure the charge voltages and currents do
what they should while it's charging, and you can charge it.

No, it's not easy, definately non-trivial, and the development work to
get it right would make the thing cost _way_ more than some random
Radio Shack charger, so it's probably economically infeasable, but
it's not impossible.
Click to expand...

I think you have spelled out just how difficult it is to do
"successfully", and on a repeatable basis.

I have yet to see any test method which can correctly identify whether
the battery inside a piece of equipment is rechargeable or not "when
it is DEAD flat", as they will be when left for a number of months. I
know that in the majority of cases most batteries will still be
readable and able to be characterised, but, this charging device must
be capable of being able to recognise either battery type even in the
worst case situation, in order to be considered "successful" imo. If
it can't do that on a repeatable basis and you have to physically
inspect the battery in extreme cases then all the expense in
development of the device is wasted .
 
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