Parasitic Drain

markr6

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Joined
Jul 16, 2012
Messages
9,258
Parasitic drain in today's flashlights is one of my biggest annoyances. What makes it even more annoying is the fact some people try to defend flashlights that have it.

1. "It would take weeks or months for the cells to be completely drained" is a common response. How is that any kind of benchmark or goal? Why should that make me feel any better? So in roughly haft that time I'm "starting" with a 50% dead light when I go to use it after sitting? When would I ever want to do that? This is especially concerning with Li-Ion cells.

2. Some manufacturers have no problems making lights with negligible drain, so it pains me to see others suffer from this when everything else about the light is great. And I'm not comparing an electronic switch to a mechanical switch. Many manufacturers make electronic switch lights with low parasitic drain.

3. Just reiterating number 1
 

vt2nv

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Joined
Jun 29, 2018
Messages
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Oboy, where to start...

Parasitic drain, in a thoughtfully designed device, is measured in tens of microamps. There are 1000 microamps to a single milliamp. There are 1000 milliamps to an amp. Parasitic drain is not nearly as power hungry as you think. Do you take batteries out of a remote control when you're not planning on watching TV? Would you remove the battery out of your key fob when you're not planning on driving your car for a while?


If parasitic drain is a big deal for you, charge the battery for one minute once (if that much) a month.

I'm new here. I registered to reply to your comments, which, IMO, are factually inaccurate.

Cheers
 

Lynx_Arc

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Tulsa,OK
Typically any drain of more than 100 microamps can give you problems especially when the device doesn't shut off at safe voltages and drain rechargeable batteries too low damaging them that is my big pet peeve as I've have several damaged LSD nimh batteries and some lithium ions that were ruined by parasitic drain when I didn't use the device for years. I typically look for 50 microamps or less for batteries less than 2000mah and 80 or less for larger batteries. If it drains a battery in less than 5 years then I typically don't leave batteries in it when I'm not going to use it.
 

terjee

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Jul 24, 2016
Messages
729
Location
Bergen, Norway
Parasitic drain, in a thoughtfully designed device, is measured in tens of microamps. There are 1000 microamps to a single milliamp. There are 1000 milliamps to an amp. Parasitic drain is not nearly as power hungry as you think. Do you take batteries out of a remote control when you're not planning on watching TV? Would you remove the battery out of your key fob when you're not planning on driving your car for a while?


If parasitic drain is a big deal for you, charge the battery for one minute once (if that much) a month.

I'm new here. I registered to reply to your comments, which, IMO, are factually inaccurate.

I fully charged a light a few months ago, and put it aside. Yesterday I wanted to top it off, and found the voltage at 3.52V. That's the kind of thigh he's talking about, and that's not negligible. You're right about thoughtfully designed lights, but not all lights are thoughtfully designed, and that seems to be his very point.

Sure, he could perhaps have been even clearer that he was speaking of significant parasitic drain and not insignificant ones, but with the latter being insignificant in the true meaning of the word, his point seems clear enough for most capable readers.

If you're going to call someone out that hard, you at least need to be right.

You can't go "I signed up here specifically to call you out", then be wrong, and then expect sympathy.
 

tatasal

Flashlight Enthusiast
Joined
Jan 25, 2012
Messages
1,192
Oboy, where to start...

Parasitic drain, in a thoughtfully designed device, is measured in tens of microamps. There are 1000 microamps to a single milliamp. There are 1000 milliamps to an amp. Parasitic drain is not nearly as power hungry as you think. Do you take batteries out of a remote control when you're not planning on watching TV? Would you remove the battery out of your key fob when you're not planning on driving your car for a while?


If parasitic drain is a big deal for you, charge the battery for one minute once (if that much) a month.

I'm new here. I registered to reply to your comments, which, IMO, are factually inaccurate.

Cheers

If you ever owned something like the Lumintop SD75 and the Nitecore EA11, both having horrendous parasitic drain 'features' and ruined a number of li-ions due to over-discharge, then perhaps you will think twice about owning such lights that are, for as far as I know, never declared by the manufacturer in their spec sheets.

Yes, while most of my lights belong to the 'thoughtfully-designed' section and never had problems with after several years, just be on alert on such high-parasitic drain lights, or they will truly ruin your day, or night.

They are just there around us, lurking.:sigh:
 

LRJ88

Enlightened
Joined
May 4, 2014
Messages
615
I have a Zebralight SC5 II that started developing some heavy parasitic drain, as in took a battery down to 1V within a week and could well drop a battery from full from the charger to a little bit above 1.2V in a day or two.

Zebralight took care of it though and now it's still on 4 flashes when i check the battery level, a month or two after getting it back and testing it so it doesn't do the same again.
 

terjee

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Joined
Jul 24, 2016
Messages
729
Location
Bergen, Norway
I have a Zebralight SC5 II that started developing some heavy parasitic drain, as in took a battery down to 1V within a week and could well drop a battery from full from the charger to a little bit above 1.2V in a day or two.

We're closing in on double digits of zebras here, and will keep buying them. Several lights already on the list.

I've had a single light though (SC53c) that had a 44mA parasitic drain ever since it was delivered. That's pretty intense. Seems like a very rare occurrence though. The others are all less than three microamps.

Oh, and Zebralight took good care of me, the issue was quickly resolved, and replacement has been working flawlessly.
 

ven

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Oct 17, 2013
Messages
22,533
Location
Manchester UK
Parasitic drain, it's like having a car using petrol when parked up over night.....no one would want that!

Really bugs me, to a point I won't have a light that does suffer it. As with archi, I also lock out on the tail cap when possible. Also preventing any accidental activation.
 

bykfixer

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Joined
Aug 9, 2015
Messages
20,351
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Dust in the Wind
Oboy, where to start...

Parasitic drain, in a thoughtfully designed device, is measured in tens of microamps. There are 1000 microamps to a single milliamp. There are 1000 milliamps to an amp. Parasitic drain is not nearly as power hungry as you think. Do you take batteries out of a remote control when you're not planning on watching TV? Would you remove the battery out of your key fob when you're not planning on driving your car for a while?


If parasitic drain is a big deal for you, charge the battery for one minute once (if that much) a month.

I'm new here. I registered to reply to your comments, which, IMO, are factually inaccurate.

Cheers

Welcome aboard.

Liking your style, but be careful. Folks around here take minor things pretty serious and typically will defend their points to the end.

It is what it is regarding parasitic drain. Some are power robbers that will deplete a fuel source badly. Most do not. If the light don't suit your tastes.... sell it. If it has a lockout feature, lock it out.
 

Lynx_Arc

Flashaholic
Joined
Oct 1, 2004
Messages
11,212
Location
Tulsa,OK
Welcome aboard.

Liking your style, but be careful. Folks around here take minor things pretty serious and typically will defend their points to the end.

It is what it is regarding parasitic drain. Some are power robbers that will deplete a fuel source badly. Most do not. If the light don't suit your tastes.... sell it. If it has a lockout feature, lock it out.

For me the biggest problem with parasitic drain is damaging batteries in that multiple batteries in series you can drain them so low it reverses the voltage of one of the weaker cells and from then on that batteries reduced capacity will have the set running down in power as the weak cell depletes the only option is to root out the damaged cells and replace them with good ones and either make sure and keep track how much you use the device and battery voltages or don't use it at all. I have several sylvania LED lanterns that in use are great lanterns but sadly the parasitic drain in them kills batteries in about 6 months or so making them useless as an emergency lantern you simply can't leave batteries in them at all. The worse parasitic drain I encountered was 4ma in an incan 4AA tap light. The drain was around 100ma a day in less than a month the batteries were drained with only about 1 hour of usage total of about 40mah of power as I converted it to LED to "save" battery power..... a wasted effort till I trashed the electronic switch for a mechanical one.
Parasitic drain can be a safety issue if a device is relied upon in an emergency when it has no battery power left and leaves you powerless and perhaps even in the dark too. Typically I like reverse clicky switch lights as an alternative to electronic switches as for them "off" is no drain at all vs an unknown amount of drain for electronic switches making you have to remember to either trust the stats on the items manual for standby drain or measure the drain yourself to make sure you don't damage expensive batteries and be stuck without power when you need it.
 

markr6

Flashaholic
Joined
Jul 16, 2012
Messages
9,258
I fully charged a light a few months ago, and put it aside. Yesterday I wanted to top it off, and found the voltage at 3.52V. That's the kind of thigh he's talking about, and that's not negligible. You're right about thoughtfully designed lights, but not all lights are thoughtfully designed, and that seems to be his very point.

Sure, he could perhaps have been even clearer that he was speaking of significant parasitic drain and not insignificant ones, but with the latter being insignificant in the true meaning of the word, his point seems clear enough for most capable readers.

If you're going to call someone out that hard, you at least need to be right.

You can't go "I signed up here specifically to call you out", then be wrong, and then expect sympathy.

Well said, thanks for the defense :) With 1 post of total nonsense, I disregarded his post and won't take it personally. Not worth touching that one. He's obviously never had a flashlight that went from 4.19v to 3.5v in a matter of weeks.

Parasitic drain, it's like having a car using petrol when parked up over night.....no one would want that!

Really bugs me, to a point I won't have a light that does suffer it. As with archi, I also lock out on the tail cap when possible. Also preventing any accidental activation.

Ven, I wanted to use that car analogy! I even had something similar typed out, but thought I would get a bunch of "bad analogy" responses so I decided to skip it.
 

vt2nv

Newly Enlightened
Joined
Jun 29, 2018
Messages
11
In this type of application the processor should be spending most of the time asleep, waking up every now and then looking for user input. If the the quiescent draw of the device in question is more than 75 uA or so, something is wrong. Either garbage code, garbage hardware, or both.



Typically any drain of more than 100 microamps can give you problems especially when the device doesn't shut off at safe voltages and drain rechargeable batteries too low damaging them that is my big pet peeve as I've have several damaged LSD nimh batteries and some lithium ions that were ruined by parasitic drain when I didn't use the device for years. I typically look for 50 microamps or less for batteries less than 2000mah and 80 or less for larger batteries. If it drains a battery in less than 5 years then I typically don't leave batteries in it when I'm not going to use it.
 

vt2nv

Newly Enlightened
Joined
Jun 29, 2018
Messages
11
I fully charged a light a few months ago, and put it aside. Yesterday I wanted to top it off, and found the voltage at 3.52V. That's the kind of thigh he's talking about, and that's not negligible. You're right about thoughtfully designed lights, but not all lights are thoughtfully designed, and that seems to be his very point.

Sure, he could perhaps have been even clearer that he was speaking of significant parasitic drain and not insignificant ones, but with the latter being insignificant in the true meaning of the word, his point seems clear enough for most capable readers.

If you're going to call someone out that hard, you at least need to be right.

You can't go "I signed up here specifically to call you out", then be wrong, and then expect sympathy.

I have spent the better part 50 years repairing devices that customers attempted to repair themselves. We had a customer trash a $55,000 bioluminescence microplate reader by lubricating moving parts using 3-in-one oil (or something similar) A microplate reader of this type collects photons emitted by organic material, like 3-in-one oil. The PMT was swamped and destroyed, it's dynodes blown out. Hydrocarbon contamintion could not be removed. The device was scrapped. A similar event took place when a user was doing preventive maintenance per spec, but forgot to remove the ham sandwich he set inside the reader before powering it up. Another microplate reader destroyed.

My point? A little bit of knowledge can be a very dangerous thing. I don't expect sympathy. I call them like I see them.
 

vt2nv

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Jun 29, 2018
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How many flashlights have you modded and/or repaired ?

I have a decent collection of flashlights. My true love are the emitters. I am hopelessly in love with LED's, a love that spans decades. To me, the flashlight is a life support system for the LED. I modded a few XM-L lights a few years ago. the emitters were under driven, an adjustment to the buck regulator was required to properly drive the emitters.

How many adjustments to the optical path have I made? I de-domed the emitter in my Jacob A60. That's it. How many flashlights have I reworked the electronics? Two.

Personally, I don't see the point of pushing a well-driven emitter harder. What's the point? The emitter is driven close to absolute maximum. Battery life is decreased. Heat is increased. All for the gain of a handful of photons. It all seems pointless. Modding the circuit via firmware revision? That I do like. I'm an engineer in the daytime. At night I'm an enthusiast. I write code for fun, and I appreciate the efforts of others.

Specifically, what have I stated that is factually inaccurate?

Cheers
 

vt2nv

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Joined
Jun 29, 2018
Messages
11
Thank you for the nice welcome, and for the warning, but not to worry. Knowledge is power.

Cheers



Welcome aboard.

Liking your style, but be careful. Folks around here take minor things pretty serious and typically will defend their points to the end.

It is what it is regarding parasitic drain. Some are power robbers that will deplete a fuel source badly. Most do not. If the light don't suit your tastes.... sell it. If it has a lockout feature, lock it out.
 

vt2nv

Newly Enlightened
Joined
Jun 29, 2018
Messages
11
The processor should be sleeping most of the time, where quiescent drain should be a small handful of microamps, if that much. Every now and then the processor wakes up, either by a hardware interrupt, or a simple timed interval. Once awake, the processor scans the user interface (probably a single button). If a state-change of is not detected, the processor goes back to sleep. That's the way it's supposed to go. Very, very low parasitic drain should be the norm. Anything short of that is a problem with firmware, a problem with hardware, or a problem with both.

I've been blinking an LED for almost two years, powered by a single AA Duracell. I'm ready to retire. When that LED stops working, so do I.

Cheers




If you ever owned something like the Lumintop SD75 and the Nitecore EA11, both having horrendous parasitic drain 'features' and ruined a number of li-ions due to over-discharge, then perhaps you will think twice about owning such lights that are, for as far as I know, never declared by the manufacturer in their spec sheets.

Yes, while most of my lights belong to the 'thoughtfully-designed' section and never had problems with after several years, just be on alert on such high-parasitic drain lights, or they will truly ruin your day, or night.

They are just there around us, lurking.:sigh:
 
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