Hi,

I have a portable design which use 2x16 LCD. The whole boards required 50mA. Initially I use 2 CR2032 in palleral to supply 3 V to the board. However, the LCD starts flickering.

I use bench supply to develop the system and I didn't notice the problem. Only after I switch the design to battery supply, the board doesnt work.

The battery datasheet can be found here:
http://www.batteryprice.com/productspec/cr2032.pdf

Please advise me what kind of battery I should use. Thanks!

 

What is the min and max operating voltage range of your project?

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Uncle $crooge

 

the project is a portable device. the LCD i suppose requires 5.0 V. PIC can run above 2.8 V, i guess.

I have a DC/DC converter, which boost from 3 to 5 V.

 

A 3V alkaline battery will quickly drop to 2.4V, then slowly drop to 2V over its life.
A 4.5V alkaline battery will quickly drop to 3.6V, then slowly drop to 3V over its life.
A 4.5V lithium battery will slowly drop to 3.9V over its life.

I suggest using 4 Energizer AAA lithium cells in series. With 4 cells, you won't need the DC/DC converter and could use a low-dropout regulator for the 5V for the LCD.

Attached Images

aaa_lithium.png (35.0 KB, 326 views)

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Uncle $crooge

 

oh, thanks.

But litium battery sounds expensive.

I am designing a SIM card reader. I hope 6.4V wont kill the SIM card

 

It is the most expensive disposable battery I have ever seen. I was lucky to get free samples. It lasts and lasts and lasts and ...
Its voltage drops much more gradually over its long life than an alkaline battery.
Think about its value. It costs about 2 or 3 times as much as the best alkaline battery but it lasts about 7 times as long. Plus you don't have to replace it as often. Its shelf life is at least 15 years!

I think anything over about 5.4V would fry it. That's why I recommended using a low-dropout 5V regulator that would still regulate when the battery voltage drops to about 5.4V.

Attached Images

aaa_comparison.png (45.4 KB, 297 views)

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Uncle $crooge

 

audio, you must have a knack for coming up with these battery datasheets. Every time I need info, I can't find squat. :lol:

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I go to www.energizer.com , click on "Technical Info" at the top, selact a battery type on the left, then click on the pic of the battery I need info about.

They used to have "premium" alkaline batteries with what they said is titanium in them. Their specs were exactly the same as their lower priced ordinary alkaline batteries.

See if you see any difference in the performance of their "premium" e-squared alkaline batteries. They cost a lot more but I don't see a difference.

They gave me samples of their latest and best lithium cells because I filled out a survey about them. Guess what the survey was about: How much they can overprice them! :lol:

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Uncle $crooge

 

Why are two batteries used in parallel?

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-=: The best low-priced components to troubleshoot with are the speaker and the LED :=-

 

Look at the tiny battery's max current rating in its link in the start of this thread. 13 of them in parallel might supply enough current. 250 of them in parallel are recommended by the manufacturer for this project's high current.

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Uncle $crooge