Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems.

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Default Those Red/Yellow/Green 3-LED Battery Level Indicator Voltage State Of Charge

Would anyone know where to purchase the small 3-LED battery indicators seen
on flashlights or other battery powered items which indicate the condition
of the battery?

There is a very compact side-by-side rectangular red, yellow, green 3-LED
indicator on some products to show when the battery charge is good/low/bad..
but I haven't been able to locate a supplier.

--
Cheers,
WB
..............

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Default Those Red/Yellow/Green 3-LED Battery Level Indicator Voltage State Of Charge


"Wild_Bill"

Would anyone know where to purchase the small 3-LED battery indicators
seen on flashlights or other battery powered items which indicate the
condition of the battery?

There is a very compact side-by-side rectangular red, yellow, green 3-LED
indicator on some products to show when the battery charge is
good/low/bad..



** No way it will work with rechargeable cells like NiCd or NiMH.

Only good for non-rechargeable like alkaline.



.... Phil




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Default Those Red/Yellow/Green 3-LED Battery Level Indicator VoltageState Of Charge

Phil Allison wrote:
"Wild_Bill"

Would anyone know where to purchase the small 3-LED battery indicators
seen on flashlights or other battery powered items which indicate the
condition of the battery?

There is a very compact side-by-side rectangular red, yellow, green 3-LED
indicator on some products to show when the battery charge is
good/low/bad..



** No way it will work with rechargeable cells like NiCd or NiMH.

Only good for non-rechargeable like alkaline.



... Phil




This is contrary to my expectation. Please enlighten...
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Default Those Red/Yellow/Green 3-LED Battery Level Indicator Voltage State Of Charge


"mike"
Phil Allison
"Wild_Bill"

Would anyone know where to purchase the small 3-LED battery indicators
seen on flashlights or other battery powered items which indicate the
condition of the battery?

There is a very compact side-by-side rectangular red, yellow, green
3-LED indicator on some products to show when the battery charge is
good/low/bad..



** No way it will work with rechargeable cells like NiCd or NiMH.

Only good for non-rechargeable like alkaline.



This is contrary to my expectation. Please enlighten...



** Simple fact is that no voltmeter reading will show the state of charge of
a NiCd or NiMH battery.

The discharge curve of the cells is almost flat - ie the terminal voltage
does not vary until the cell is nearly exhausted.

This is quite unlike non rechargeable cells like carbon zinc and alkaline.




.... Phil





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Default Those Red/Yellow/Green 3-LED Battery Level Indicator Voltage State Of Charge

Charge state indicators are used on professional rechargeable packs, and
give a quick indication of when they're not suitable for service/need
recharged.

LED charge indicators would be useful for sealed lead-acid types and other
rechargeable types.

The charge state voltage is what causes intelligent chargers to start and
stop charging, or switch to trickle charging.

I don't know about the newer chemistry types, but I spotted a comment a
couple of days ago that claimed one type can't be recharged if discharged
below a specific level (don't recall if it was lithium or poly-something).

NICD and NIMH types shouldn't be used when discharged to a point below
approximately 80% of full charge, some manufacturers claim the limit should
be about 0.8V per cell.

SLA types should also be limited to specific discharge levels, or
approximately 10.8V for a 12V battery.

So.. if a user can quickly, easily and reliably detect when a battery or
pack needs to be recharged, and cautioned wrt further discharge.. they can
avoid taking low batteries out in the field and finding themselves without
portable power.
Additionally, keeping charge levels above minimum levels will result in
longer battery life. (ideally, one would take a vehicle out in the field and
a charger that would operate from the vehicle's 12V source).

The other option would be to keep all SLAs and rechargeable packs on trickle
chargers or automatic maintenance chargers.

Rechargeable batteries wouldn't be very economical if owners needed to own
enough chargers for every battery or pack that they might own.

--
Cheers,
WB
..............


"mike" wrote in message
...

** No way it will work with rechargeable cells like NiCd or NiMH.

Only good for non-rechargeable like alkaline.




This is contrary to my expectation. Please enlighten...




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Default Those Red/Yellow/Green 3-LED Battery Level Indicator Voltage State Of Charge


"Wild_Bull**** "

Charge state indicators are used on professional rechargeable packs,


** But do not indicate the actual *state* of charge - only if they are
flat or not.


The charge state voltage is what causes intelligent chargers to start and
stop charging, or switch to trickle charging.


** Separate scenario.

Placing a NiCd or NiMH cell or battery on charge and observing what happens
is a way to tell its state.



NICD and NIMH types shouldn't be used when discharged to a point below
approximately 80% of full charge,


** Horse poo.


some manufacturers claim the limit should be about 0.8V per cell.


** That equates to 100% discharged.

****wit.


.... Phil




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Default Those Red/Yellow/Green 3-LED Battery Level Indicator Voltage State Of Charge

In article ,
Wild_Bill wrote:

I don't know about the newer chemistry types, but I spotted a comment a
couple of days ago that claimed one type can't be recharged if discharged
below a specific level (don't recall if it was lithium or poly-something).

NICD and NIMH types shouldn't be used when discharged to a point below
approximately 80% of full charge, some manufacturers claim the limit should
be about 0.8V per cell.


My own preference is to stop when the battery hits 1.0 volts per
cell... this is usually soon enough to keep the weakest cell in the
battery from being over-discharged into a state of voltage reversal,
and since there's usually only 5-10% of the battery charge left at
that point it isn't really wasteful.

Part of the problem here - and I suspect what Phil was alluding to -
is that some types of batteries have a voltage-discharge curve which
makes it difficult to measure their charge state accurately over much
of their charge range.

Alkaline battery output voltage tends to "droop" quite a bit over the
battery's useful discharge lifetime, and the "voltage droop vs.
percentage of charge used" curve is fairly flat over much of this
range. The voltage per cell (under load) can drop by half a volt or
more, between the "10% used" and "90% used" points.

A standard "battery level indicator" intended for use with alkaline
batteries will probably use this phenomenon - put a load on the
battery, measure the voltage, and show a rough indication of lifetime
remaining based on the voltage.

This isn't as easy to do with NiCd and NiMH cells. These chemistries
have a much flatter voltage-discharge curve... a bit of droop at the
beginning, a nearly constant output voltage over most of the remaining
time, and then the voltage "drops off a cliff" when there's only a few
percent of the charge remaining.

So, with these batteries, you can probably distinguish "fully
charged", "almost entirely dead", and "somewhere in the middle"
without too much trouble, but it's difficult to get a more accurate
estimate of just *where* in the middle the battery might be. "10%
left" and "90% left" don't look very much different, voltage-wise.

A battery measurement tool calibrated for alkaline batteries is likely
to give misleading readings when used with NiCd/NiMH batteries.

Take a look at http://www.powerstream.com/AA-tests.htm to see one
example of some of the data.

--
Dave Platt AE6EO
Friends of Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!
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Default Those Red/Yellow/Green 3-LED Battery Level Indicator Voltage State Of Charge


"Dave Platt"

This isn't as easy to do with NiCd and NiMH cells. These chemistries
have a much flatter voltage-discharge curve... a bit of droop at the
beginning, a nearly constant output voltage over most of the remaining
time, and then the voltage "drops off a cliff" when there's only a few
percent of the charge remaining.



** Most users do not run cells flat in a *single* discharge session - they
turn the load on and off many times.

NiCd and NiMH cells recover voltage after a time and if you plotted a curve
of typical usage - it would look like a saw tooth wave. At each peak of the
wave, the voltage is very similar right up until the cells are quite flat.

Users will switch the device on and *then look* at the 3 LED charge
display - and never see any change no matter what the state of charge.


.... Phil





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Default Those Red/Yellow/Green 3-LED Battery Level Indicator Voltage State Of Charge

Apparently I asked the wrong question again (posted previously in Jan).
Maybe because I described what the indicators are typically used for.

What I would like to know is where to buy the indicators.. red/yel/green,
miniature bar graph in a compact package.

Usenet.. a greasy spot on the ground where a dead horse once lay.

Thanks

--
Cheers,
WB
..............






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Default Those Red/Yellow/Green 3-LED Battery Level Indicator Voltage State Of Charge


"Wild Bull****artist "

Apparently I asked the wrong question again (posted previously in Jan).
Maybe because I described what the indicators are typically used for.

What I would like to know is where to buy the indicators.. red/yel/green,
miniature bar graph in a compact package.



** China.

Take a slow boat and enjoy the trip.



.... Phil







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Default Those Red/Yellow/Green 3-LED Battery Level Indicator Voltage State Of Charge

I agree with your comments, Dave.

If I knew where to buy the indicators that would take care of my inquiry. I
don't know if they're made for just one specific purpose or not.. it appears
that I'd be better off gluing 3 LEDs together.

Discharge rates, gotcha.. (and seriously) good of you to explain it for
those who don't know there's any difference from one battery chemistry to
another.

I believe the .8V/cell level was stated as the absolute maximum safe
discharge level I had read, but neglected to state it exactly (wasn't
implying an average safe level).

I've seen the circuit board inside the older "deluxe" Sony camcorder
batteries (NP-77HD etc).. about 1.5" x 3" and fully populated on a single
side with SM devices to illuminate 1 to 5 LEDs to indicate remaining
capacity (press a button and 1-5 of 'em are on, or none).
The semis apparently track the amount of charge going into the pack, and
monitor the amount of discharge to give a useful indication of remaining
capacity.
There is a 0.02 ohm ceramic resistor in series with the pack's charging
terminal, and 3 micro-sized pots (suggesting there might've been a service
manual available at one time), 2 ICs and a couple dozen smaller devices.
When this circuit is connected to a set of fully charged cells, no LEDs will
lite, because the circuit hasn't tracked and stored the charge level.

This circuit's functions could probably easily be done with one of the many
tiny uPs commonly available today.. but it would all be fairly pointless
without an indicator.

--
Cheers,
WB
..............


"Dave Platt" wrote in message
...

My own preference is to stop when the battery hits 1.0 volts per
cell... this is usually soon enough to keep the weakest cell in the
battery from being over-discharged into a state of voltage reversal,
and since there's usually only 5-10% of the battery charge left at
that point it isn't really wasteful.

Part of the problem here - and I suspect what Phil was alluding to -
is that some types of batteries have a voltage-discharge curve which
makes it difficult to measure their charge state accurately over much
of their charge range.

Alkaline battery output voltage tends to "droop" quite a bit over the
battery's useful discharge lifetime, and the "voltage droop vs.
percentage of charge used" curve is fairly flat over much of this
range. The voltage per cell (under load) can drop by half a volt or
more, between the "10% used" and "90% used" points.

A standard "battery level indicator" intended for use with alkaline
batteries will probably use this phenomenon - put a load on the
battery, measure the voltage, and show a rough indication of lifetime
remaining based on the voltage.

This isn't as easy to do with NiCd and NiMH cells. These chemistries
have a much flatter voltage-discharge curve... a bit of droop at the
beginning, a nearly constant output voltage over most of the remaining
time, and then the voltage "drops off a cliff" when there's only a few
percent of the charge remaining.

So, with these batteries, you can probably distinguish "fully
charged", "almost entirely dead", and "somewhere in the middle"
without too much trouble, but it's difficult to get a more accurate
estimate of just *where* in the middle the battery might be. "10%
left" and "90% left" don't look very much different, voltage-wise.

A battery measurement tool calibrated for alkaline batteries is likely
to give misleading readings when used with NiCd/NiMH batteries.

Take a look at http://www.powerstream.com/AA-tests.htm to see one
example of some of the data.

--
Dave Platt AE6EO
Friends of Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!


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Default Those Red/Yellow/Green 3-LED Battery Level Indicator VoltageState Of Charge

On 05/11/2011 10:04, Wild_Bill wrote:
Apparently I asked the wrong question again (posted previously in Jan).
Maybe because I described what the indicators are typically used for.

What I would like to know is where to buy the indicators..
red/yel/green, miniature bar graph in a compact package.


Something like

http://spiratronics.com/pcb-mounting...light-led.html

??

Usenet.. a greasy spot on the ground where a dead horse once lay.


That's not very nice to Phil... is he dead and really that greasy?

--
Adrian C
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Default Those Red/Yellow/Green 3-LED Battery Level Indicator Voltage State Of Charge

That's the closest to what I was referring to, Adrian, and maybe the little
pips/nipples could be trimmed off so it would look like 3 rectangular LEDs
arranged like a mini bar graph.

Thanks

--
Cheers,
WB
..............


"Adrian C" wrote in message
...
On 05/11/2011 10:04, Wild_Bill wrote:
Apparently I asked the wrong question again (posted previously in Jan).
Maybe because I described what the indicators are typically used for.

What I would like to know is where to buy the indicators..
red/yel/green, miniature bar graph in a compact package.


Something like

http://spiratronics.com/pcb-mounting...light-led.html

??

Usenet.. a greasy spot on the ground where a dead horse once lay.


That's not very nice to Phil... is he dead and really that greasy?

--
Adrian C


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Default Those Red/Yellow/Green 3-LED Battery Level Indicator Voltage State Of Charge

On Sat, 5 Nov 2011 06:04:43 -0400, the renowned "Wild_Bill"
wrote:

Apparently I asked the wrong question again (posted previously in Jan).
Maybe because I described what the indicators are typically used for.

What I would like to know is where to buy the indicators.. red/yel/green,
miniature bar graph in a compact package.

Usenet.. a greasy spot on the ground where a dead horse once lay.

Thanks


If you just want the LEDs, Digikey lists four types with R-G-Y LEDs.

350-1755-ND
350-1809-ND
350-1751-ND
350-2208-1-ND

If you're talking about the ones that are a frame with rectangular
LEDs pressed into them, I don't think they are widely sold outside of
Asia, as Phil implies.



Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com
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Default Those Red/Yellow/Green 3-LED Battery Level Indicator VoltageState Of Charge

On 11/5/2011 9:41 AM, Wild_Bill wrote:
That's the closest to what I was referring to, Adrian, and maybe the
little pips/nipples could be trimmed off so it would look like 3
rectangular LEDs arranged like a mini bar graph.


They do have 10 segment ones available from Mouser.
http://www.mouser.com/Optoelectronics/LED-Displays/_/N-6j73g?P=1z0yqad&Keyword=bar+graph&FS=True

Jeff


--
"Everything from Crackers to Coffins"


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Default Those Red/Yellow/Green 3-LED Battery Level Indicator Voltage State Of Charge

Thank you Spehro.. I guess I'll need to investigate all those eBay sellers
from Hong Kong and nearby regions.

I didn't imagine that the framed rectangular LED indicators would only find
one purpose in consumer equipment, or be difficult to find.

Been a spectacular week for that guy, since a couple of people actually
agreed with him. I've gotten used to ignoring the rarely-civil, like so many
in RCM.

--
Cheers,
WB
..............


"Spehro Pefhany" wrote in message
...

If you just want the LEDs, Digikey lists four types with R-G-Y LEDs.

350-1755-ND
350-1809-ND
350-1751-ND
350-2208-1-ND

If you're talking about the ones that are a frame with rectangular
LEDs pressed into them, I don't think they are widely sold outside of
Asia, as Phil implies.



Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
Info for manufacturers:
http://www.trexon.com
Embedded software/hardware/analog Info for designers:
http://www.speff.com


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