Why Do Some Lights Have Parasitic Drain?

[shuter]

Parasitic Drain - Why do some lights have parasitic drain?

Why design a light that may be dead when needed? For example: Put a light in your car for emergency use and three months later when the light is needed, it's dead or nearly dead.

 

[csshih]

some lights, like the nitecore D20, have a parasitic drain out of design.

the light is electronically activated, making it less likely to fail via mechanical means, and is "sparkless" making it inherently safe.

I will hasten a guess that other lights that have parasitic drain are electronically activated? or, use the power to keep memory?... unlikely, but strange things tend to happen

 

[Turbo Guy]

I will add (point out) that an easy way to stop said drain is to remove the cells or at least lossen the tailcap. Most quality light discussed here have insulated threads and a bare spot which only makes contact when fully tightened. In the real world lights stored for months or years without normal maintaince should have the cells removed anyway.,IMO

 

[Canuke]

Electronic switched lights could be a culprit here. They have a very high resistance when "open", but it's still not infinite.

Of course, this ought not to be an issue under normal circumstances. The River Rock 4AA lanterns that were around a couple of years back have a 7uA "leakage" current through their electronic switch according to my measurements. 7uAh loss per hour =~ 285,000 hours to draw down 2000mAh cells, or about 3 years. So I'd say that would only be a problem for long-term emergency light storage with lithium cells; for that sort of application, insist on physical switches.

If the light or device has other electronics in it, those could also draw "standby" current (e.g. to store settings); if you have a device that kills batteries within a year, that's probably what is going on.

 

[Mark620]

parasitic drain will occur in ANY device that uses an electronic switch. A mechanical switch is needed to stop this. Note : mechanical switch needs to be clean or it could happen with it too.

 

[altis]

Not to forget the self-discharge rate of your battery too...

 

[Milan]

What do you mean by "clean mechanical switches"? I'm curious.

 

[Chrontius]

If the switch is dirty, the grime might be (slightly) conductive.

 

[VidPro]

If the switch is dirty, the grime might be (slightly) conductive.

like he said, some switches they have greace in them to keep them going around and around, and after much time and many many clicks depending on the switch type, there can be tiny metal grindings in the greace,bits of carbon and all from switching, and stuff, an old switch of some styles can become parasitic.
we have also had old electronic switches become More parasitic over time, as the Electronic switch was designed poorly, and was failing internally, became worse and worse, till i realised it was the electronic switch itself. sure it was supposed to be some pico usage, but it grew into mili usage.

Also have had water , from rain, water from working around water , including dunks, and even water from SWEAT effect full disconnect switches into becomming parasitic.
i never would have thought that i was loosing power in tiny key lights just because of human sweat, and setting sprinklers , and stuff. but one even started glowing the led it has so much conductance.
is funny because where i live it only rains some 17inches a year, but my light was effected by water heck there aint no water.

 

[Bullzeyebill]

Why has this thread been started? This thread http://www.candlepowerforums.com/vb/showthread.php?p=2922230

has a last post date of 4/17/2009 and so, in effect, is current. Please contact a moderator and have this thread closed or merged with the other thread.

Bill

 

[shuter]

Bill - Yep, you're right. Same subject. Mine should be closed or merged into the other. Whatever the moderator thinks. I didn't search first. Sorry.

 

[Bullzeyebill]

Bill - Yep, you're right. Same subject. Mine should be closed or merged into the other. Whatever the moderator thinks. I didn't search first. Sorry.

Shuter, don't feel so bad. Yes, searching is good. I found the other thread by using google CPF only, at the top of every CPF page. I put in parasitic drain, and those two words brought up info.

Bill

 

[VidPro]

OMG, call in the internet police, a thread with similarities is created, and dont forget to merge all the Fenix 3PD threads together too :sick2: geesh dont you know how to search by now :thumbsup: i cant imagine the bandwith wasted by this, its atrocious. check this out http://www.gpspassion.com/forumsen/topic.asp?TOPIC_ID=72478 now there is how you keep people on topic 136 Pages, write a Book then try to read it all.

 

[Bullzeyebill]

OMG, call in the internet police, a thread with similarities is created, and dont forget to merge all the Fenix 3PD threads together too :sick2: geesh dont you know how to search by now :thumbsup: i cant imagine the bandwith wasted by this, its atrocious. check this out http://www.gpspassion.com/forumsen/topic.asp?TOPIC_ID=72478 now there is how you keep people on topic 136 Pages, write a Book then try to read it all.

?

Bill

 

[SilverFox]

Hello Shuter,

I'll close this thread and you can continue your discussion over in the other one.

Tom