[SOLVED] Power switch problem with lithium baterry

[jaschek]

Power switch problem

dear all

I am designing a 7.4 V/2Ah lithium polymer battery operated device. The power switch (single pole single throw) is in series with between the battery. On turning on the device abruptly the device rarely turns on, If the switch is slowly turned on, it powers on almost everytime. The device works perfectly all right with DC sources like an adaptor.

I suspect this is because of the internal over current protection feature of the lithuim battery.

how can this problem be solved ?

 

[IanP]

Re: Power switch problem

You may try to install a decent low-ESR electrolytic capacitor in parallel with the battery, so if you suspect that the battery for some reasons limits the inrush current, on power-on the cap should help to deliver what’s required ..
The reason capacitors can be used is often because of their quick discharge ability ..

Rgds,
IanP

 

[jaschek]

Re: Power switch problem

thanks IANP for the suggestion.
but the capacitor is not helping!!

 

[karesz]

Re: Power switch problem

....
but the capacitor is not helping!!

Hi,
I think you need low ESR type, min. 2000uF pro A, and good, wide/thick wireing...
K.

 

[jaschek]

Re: Power switch problem

capacitors however large are not working!!

edited : capacitors are helping.. the moron in me was trying to include capacitors after the switch which was not working..

the switch is working.. thanks guys...

 

[karesz]

Power switch problem

yur welcome!