Recommended Inductor

[Frank Miles]

On Fri, 29 Feb 2008, yiminrong@yahoo.ca wrote:

Need to build a rapid discharge system for some lithium batteries.
Would like to draw 1.5A at 7.5V, so used a matching incandescent lamp.
When I plug the lamp in however, it doesn't light up. My guess is the
initial current drain as the lamp heats up exceeds the battery safe
limit of 2.0A and the battery automatically shuts itself off. I'm
thinking of putting an inductor in series to reduce the initial
current draw. Would that work? Approximately how many mH would you
recommend? Sorry for stupid questions, anything outside of realm of
bits and bytes is foreign to me...

Look for thermistors spec'd as inrush limiters. When cold (at start),
they have high resistance. As they warm up, their resistance declines.
Put in series with your bulb. Otherwise, of course, you could use
just a plain resistor though this doesn't give the immediate visual
feedback of the bulb.

-f

 

Need to build a rapid discharge system for some lithium batteries.
Would like to draw 1.5A at 7.5V, so used a matching incandescent lamp.
When I plug the lamp in however, it doesn't light up. My guess is the
initial current drain as the lamp heats up exceeds the battery safe
limit of 2.0A and the battery automatically shuts itself off. I'm
thinking of putting an inductor in series to reduce the initial
current draw. Would that work? Approximately how many mH would you
recommend? Sorry for stupid questions, anything outside of realm of
bits and bytes is foreign to me...

Kind regards, YR

 

[MooseFET]

<yiminrong@yahoo.ca> wrote in message
news:f0cf79e6-6ba9-4c83-a160-75089701a741@i29g2000prf.googlegroups.com...

Need to build a rapid discharge system for some lithium batteries.
Would like to draw 1.5A at 7.5V, so used a matching incandescent lamp.
When I plug the lamp in however, it doesn't light up. My guess is the
initial current drain as the lamp heats up exceeds the battery safe
limit of 2.0A and the battery automatically shuts itself off. I'm
thinking of putting an inductor in series to reduce the initial
current draw. Would that work? Approximately how many mH would you
recommend? Sorry for stupid questions, anything outside of realm of
bits and bytes is foreign to me...

Kind regards, YR

You need a logic control circuit. Do you have a logic to start with? PS.
Wal-mart has a brain on sale.

 

On Mar 3, 11:00 am, Frank Miles <f...@u.washington.edu> wrote:
....

Look for thermistors spec'd as inrush limiters. When cold (at start),
they have high resistance. As they warm up, their resistance declines.
Put in series with your bulb. Otherwise, of course, you could use
just a plain resistor though this doesn't give the immediate visual
feedback of the bulb.

-f
Thank you. Built 18 of them, they work like a charm. I especially like

how slowly it increases in brightness, very gentle on the battery... /
YR