MJLorton Solar Power and Electronic Measurement Equipment Forum

General Category => General Discussion => Topic started by: squirrel on October 01, 2015, 09:48:26 PM

Title: converting from button cell to AAA
Post by: squirrel on October 01, 2015, 09:48:26 PM
i have a laser pointer that is powered by 3x1.5 button cells. testing the batteries results to 4.5+ volts and .14A.
i want to convert it to use 3xAAA that has 1.2v and 800mA

what i've done so far

used 3xAAA with 1.2v = 3.6+ volts and 800mA
it lights up for a few seconds only
removed the power source for a minute
it lights up again for a few seconds

used 4xAA with 1.2v = 3.6+ volts and 2000mA
it blinked and did not light up again

what do i need to make it work? thanks
Title: Re: converting from button cell to AAA
Post by: TechJunkie on October 19, 2015, 06:57:00 PM
The current rating on the batteries will not matter unless it drops below what the laser & driver chip need to function. The voltage is MUCH more important here. How did you have the batteries wired up? I hate to say this, but the last round with 4 batteries sounds like you may have caused some damage. Did you return the laser pointer back to it's original configuration to make sure it still works? Also, how did you determine the button cell voltage and configuration?
Title: Re: converting from button cell to AAA
Post by: squirrel on October 21, 2015, 06:32:01 PM
ok so the voltage is what i should determine.

i dont have data sheet for the laser pointer so i used a multimeter to determine the voltage and the amperage

button cell batteries 4.32v

when its lighted up

voltage on the red laser tips 3.07v
amperage .03A

if i will use 4 AA batteries with 5.22v

which of the two forward voltage do i use 4.44v or 3.07v

(5.22-4.32)/.03= 30ohms
(5.22-3.07)/.03= 72ohms

thanks.