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What resistor to simulate a 2CR5 under load (homemade batt..

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Anonymous
January 1, 2005 5:04:59 PM

Archived from groups: rec.photo.digital (More info?)

Hello, and Happy New Year to everybody.

My battery tester uses a (too weak) 10mA load for its 6V test.

I'm guessing that a 2CR5 Photo Lithium battery should be tested at
150mA, under load.

Any electronics geniuses out there? What type/size resistor should I
connect to the battery, while testing with my battery meter, to
simulate a Canon SLR's load, and provide me with an estimation of the
usability of my 2CR5 (and other 6V lithium) batteries?

I also have a DMM.

Thanks for all advise and tips.
Anonymous
January 1, 2005 8:08:51 PM

Archived from groups: rec.photo.digital (More info?)

"Jack Blake" <smogkiller2004@yahoo.com> wrote in message
news:9e26fed2.0501011404.644180e7@posting.google.com...
> Hello, and Happy New Year to everybody.
>
> My battery tester uses a (too weak) 10mA load for its 6V test.
>
> I'm guessing that a 2CR5 Photo Lithium battery should be tested at
> 150mA, under load.
>
> Any electronics geniuses out there? What type/size resistor should I
> connect to the battery, while testing with my battery meter, to
> simulate a Canon SLR's load, and provide me with an estimation of the
> usability of my 2CR5 (and other 6V lithium) batteries?
>
> I also have a DMM.
>
> Thanks for all advise and tips.

40 Ohms (or about) will work. 2-W is a good power rating.
Anonymous
January 1, 2005 8:17:46 PM

Archived from groups: rec.photo.digital (More info?)

Jack Blake wrote:
>> Hello, and Happy New Year to everybody.
>>
>> My battery tester uses a (too weak) 10mA load for its 6V test.
>>
>> I'm guessing that a 2CR5 Photo Lithium battery should be tested at
>> 150mA, under load.
>>
>> Any electronics geniuses out there? What type/size resistor should I
>> connect to the battery, while testing with my battery meter, to
>> simulate a Canon SLR's load, and provide me with an estimation of the
>> usability of my 2CR5 (and other 6V lithium) batteries?
>>
>> I also have a DMM.
>>
>> Thanks for all advise and tips.

Assuming:
1) your camera represents a 1500 mA load
2) the battery has a 6 volt potential

Then R = V / I, so that R = 6 /1.5 =4
Then W = V x A. so W = 6 x 1.5 = 9

You would need a 4 ohm, 9 watt minimum resister load.

If the load is a factor of ten lower (150 mA), then the resistance would be
40 ohms at 1 watt.

Kevin
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Anonymous
January 2, 2005 5:16:28 AM

Archived from groups: rec.photo.digital (More info?)

Jack Blake wrote:
> Hello, and Happy New Year to everybody.
>
> My battery tester uses a (too weak) 10mA load for its 6V test.
>
> I'm guessing that a 2CR5 Photo Lithium battery should be tested at
> 150mA, under load.
>
> Any electronics geniuses out there? What type/size resistor should I
> connect to the battery, while testing with my battery meter, to
> simulate a Canon SLR's load, and provide me with an estimation of the
> usability of my 2CR5 (and other 6V lithium) batteries?
>
> I also have a DMM.
>
> Thanks for all advise and tips.

Digicams are really tough on batteries. I would guess that a camera with
the LCD screen on, would probably draw 1,000mA.
So, I would connect a 6 Ohm, 5-10 Watt resistor across the battery
terminals while measuring the voltage. I'd leave the load on for 5-6
seconds and see how much the voltage drops in that time.
For a fresh Lithium Battery, I'd expect the voltage drop to be no more
than about 0.2-0.3V
Bob Williams
Anonymous
January 2, 2005 11:45:02 AM

Archived from groups: rec.photo.digital (More info?)

In article <41D7C9FC.3080004@cox.net>,
Bob Williams <mytbobnospam@cox.net> wrote:
>
>
>Jack Blake wrote:
>> Hello, and Happy New Year to everybody.
>>
>> My battery tester uses a (too weak) 10mA load for its 6V test.
>>
>> I'm guessing that a 2CR5 Photo Lithium battery should be tested at
>> 150mA, under load.
>>
>> Any electronics geniuses out there? What type/size resistor should I
>> connect to the battery, while testing with my battery meter, to
>> simulate a Canon SLR's load, and provide me with an estimation of the
>> usability of my 2CR5 (and other 6V lithium) batteries?
>>


Google for "2CR5 specifications" and you'll find manufacturer's pages
that have electrical specs for the battereies that include
voltage/current/time graphs.


--

a d y k e s @ p a n i x . c o m

Don't blame me. I voted for Gore.
January 2, 2005 12:43:20 PM

Archived from groups: rec.photo.digital (More info?)

( R = E/I ) = ( 6V /.150A ) = 40 OHMS

( P = I * E ) = ( .150A * 6V ) = .9W


A 40 ohm, 2 watt resistor will provide the correct load.


THO,
It might be better to go to your local RadioShack,
get a;

6v, 100ma bulb
and a
6v 150 ma bulb

for your tester.
That way, you'll have a quick "visual"
re the state of your battery.

( I'm thinking 100ma load should be adequate for tests )




On 2 Jan 2005 08:45:02 -0500, adykes@panix.com (Al Dykes) wrote:

>In article <41D7C9FC.3080004@cox.net>,
>Bob Williams <mytbobnospam@cox.net> wrote:
>>
>>
>>Jack Blake wrote:
>>> Hello, and Happy New Year to everybody.
>>>
>>> My battery tester uses a (too weak) 10mA load for its 6V test.
>>>
>>> I'm guessing that a 2CR5 Photo Lithium battery should be tested at
>>> 150mA, under load.
>>>
>>> Any electronics geniuses out there? What type/size resistor should I
>>> connect to the battery, while testing with my battery meter, to
>>> simulate a Canon SLR's load, and provide me with an estimation of the
>>> usability of my 2CR5 (and other 6V lithium) batteries?
>>>
>
>
>Google for "2CR5 specifications" and you'll find manufacturer's pages
>that have electrical specs for the battereies that include
>voltage/current/time graphs.

<rj>
Anonymous
January 2, 2005 5:52:58 PM

Archived from groups: rec.photo.digital (More info?)

I find a light bulb works pretty good at the right voltage and wattage as
you can see the drain. so a 6V 10 watt should work or an equivalent 12V
should work fine.

Wayne

"Al Dykes" <adykes@panix.com> wrote in message
news:cr8tsu$nmh$1@panix5.panix.com...
> In article <41D7C9FC.3080004@cox.net>,
> Bob Williams <mytbobnospam@cox.net> wrote:
>>
>>
>>Jack Blake wrote:
>>> Hello, and Happy New Year to everybody.
>>>
>>> My battery tester uses a (too weak) 10mA load for its 6V test.
>>>
>>> I'm guessing that a 2CR5 Photo Lithium battery should be tested at
>>> 150mA, under load.
>>>
>>> Any electronics geniuses out there? What type/size resistor should I
>>> connect to the battery, while testing with my battery meter, to
>>> simulate a Canon SLR's load, and provide me with an estimation of the
>>> usability of my 2CR5 (and other 6V lithium) batteries?
>>>
>
>
> Google for "2CR5 specifications" and you'll find manufacturer's pages
> that have electrical specs for the battereies that include
> voltage/current/time graphs.
>
>
> --
>
> a d y k e s @ p a n i x . c o m
>
> Don't blame me. I voted for Gore.
Anonymous
January 2, 2005 11:25:45 PM

Archived from groups: rec.photo.digital (More info?)

On Sun, 02 Jan 2005 14:52:58 GMT, "wayne" <notme@example.com> wrote:

>I find a light bulb works pretty good at the right voltage and wattage as
>you can see the drain. so a 6V 10 watt should work or an equivalent 12V
>should work fine.

A light bulb initially provides close to a dead short across your
battery because the tungsten starts off relatively cold. I wouldn't
do this to my camera battery. I think using a resistor as others have
suggested, is the better plan.
!