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I knew it. Sigma was a robot this whole time

Posted: Tue Sep 05, 2017 6:51 pm
by Isaac
Image

Re: I knew it. Sigma was a robot this whole time

Posted: Wed Sep 06, 2017 1:30 pm
by Tunnelcat
I don't think he was an actual robot machine. I think he was a human soldier or officer in the military sitting in front of a computer who's sole act was to spread FUD and influence our election, all under the auspices of his government. You'll notice that ever since Putin's little edict came out after Trump won, where he told all Russians everywhere to quit talking about Trump, sigma's been silent here. Too bad. He was, or IT was, at least entertaining. :wink:

Re: I knew it. Sigma was a robot this whole time

Posted: Wed Sep 06, 2017 5:46 pm
by Isaac
No goodbye? What rude robot.

Re: I knew it. Sigma was a robot this whole time

Posted: Wed Sep 06, 2017 10:10 pm
by vision
I believe he's had a few normal posts on the Overload site since the election.

Re: I knew it. Sigma was a robot this whole time

Posted: Wed Sep 06, 2017 11:15 pm
by Nightshade
Isaac wrote:Image
Dude...you really should charge your phone.

Re: I knew it. Sigma was a robot this whole time

Posted: Fri Sep 08, 2017 7:15 am
by Jeff250
Nightshade wrote:
Isaac wrote:Image
Dude...you really should charge your phone.
Suddenly a new contender has emerged.

Re: I knew it. Sigma was a robot this whole time

Posted: Mon Sep 11, 2017 8:46 am
by Isaac
"5% then charge" is the most thrilling and battery longevity friendly rule.

Re: I knew it. Sigma was a robot this whole time

Posted: Sat Sep 16, 2017 4:49 pm
by LightWolf
I've heard "No lower than 20%"

Re: I knew it. Sigma was a robot this whole time

Posted: Sat Sep 16, 2017 5:44 pm
by Krom
It is a lithium ion battery, they don't get the "memory" effect that was a problem for nickel-cadmium batteries. Lithium ion batteries can be safely charged back to 100% at any point in the discharge without significantly impacting its lifespan. They do degrade over time, but there is absolutely nothing that can be done to stop it, they start degrading from the moment they are manufactured.

The majority of cell phones automatically shut off if the battery drops below the cutoff voltage which is typically 3.3v per cell. Below 3.2v per cell lithium ion batteries can become chemically unstable and will degrade significantly faster, and for most cells below 3v a protection circuit permanently disconnects them because most attempts to charge a cell that has been depleted that far will cause it to burn up or explode.

Actually in general it is better to do partial discharges instead of deep discharges on lithium ion batteries, so charge it more often not less. Generally speaking, if you take two identical lithium ion batteries, use one in some device charging it regularly and the other you sit on a shelf with both kept at roughly the same temperature, if you test both batteries again a year later the one that was used and charged regularly will retain a greater capacity.

Re: I knew it. Sigma was a robot this whole time

Posted: Sun Sep 17, 2017 2:04 am
by Isaac
Krom, I normally side with your opinions, but this seems like the complete opposite of what we're supposed to do.

I thought I've researched this already. More charging = lower longevity. That's not true?

Re: I knew it. Sigma was a robot this whole time

Posted: Sun Sep 17, 2017 5:45 am
by Krom
It is important to know the chemistry of your batteries. Small charge and discharge cycles are better because what actually accelerates the degradation of lithium ion batteries the most is heat. Combine the extra heating from a deep cycle with the chemical instability at lower voltages and they wear out just a little bit faster. Smaller partial cycles don't heat them up as much, this is also why you shouldn't leave your cell phone or other devices with li-poly batteries in a hot car or direct sunlight.

Re: I knew it. Sigma was a robot this whole time

Posted: Sun Sep 17, 2017 1:56 pm
by Tunnelcat

Re: I knew it. Sigma was a robot this whole time

Posted: Tue Sep 19, 2017 8:29 pm
by Ferno
Krom wrote:It is a lithium ion battery, they don't get the "memory" effect that was a problem for nickel-cadmium batteries. Lithium ion batteries can be safely charged back to 100% at any point in the discharge without significantly impacting its lifespan. They do degrade over time, but there is absolutely nothing that can be done to stop it, they start degrading from the moment they are manufactured.

The majority of cell phones automatically shut off if the battery drops below the cutoff voltage which is typically 3.3v per cell. Below 3.2v per cell lithium ion batteries can become chemically unstable and will degrade significantly faster, and for most cells below 3v a protection circuit permanently disconnects them because most attempts to charge a cell that has been depleted that far will cause it to burn up or explode.

Actually in general it is better to do partial discharges instead of deep discharges on lithium ion batteries, so charge it more often not less. Generally speaking, if you take two identical lithium ion batteries, use one in some device charging it regularly and the other you sit on a shelf with both kept at roughly the same temperature, if you test both batteries again a year later the one that was used and charged regularly will retain a greater capacity.

Recent findings show that a full DOD severely impacts cycle count and lifespan, anywhere between dozens to hundreds of cycles. This is why it's imperative to not discharge lower than 3.87v/cell, or lower than 60% SOC.

Re: I knew it. Sigma was a robot this whole time

Posted: Wed Sep 20, 2017 1:32 pm
by Isaac
This is all good info :E

Re: I knew it. Sigma was a robot this whole time

Posted: Thu Sep 21, 2017 8:24 am
by Sirius
Hmm. What are the best practices for NiMH batteries?

Re: I knew it. Sigma was a robot this whole time

Posted: Thu Sep 21, 2017 5:23 pm
by Isaac
Aren't those all super old?

Re: I knew it. Sigma was a robot this whole time

Posted: Thu Sep 21, 2017 7:01 pm
by Top Gun
"Don't use them" would probably be the best practice.

Re: I knew it. Sigma was a robot this whole time

Posted: Thu Sep 21, 2017 10:39 pm
by Ferno
Sirius wrote:Hmm. What are the best practices for NiMH batteries?

Just charge them up every so often.

Re: I knew it. Sigma was a robot this whole time

Posted: Thu Sep 21, 2017 11:00 pm
by Isaac
There's probably a point where it's a fire hazard.

Re: I knew it. Sigma was a robot this whole time

Posted: Fri Sep 22, 2017 1:19 pm
by Tunnelcat
Sirius wrote:Hmm. What are the best practices for NiMH batteries?
https://www.batterystuff.com/kb/article ... ttery.html

Re: I knew it. Sigma was a robot this whole time

Posted: Sat Sep 23, 2017 12:37 am
by Ferno
Isaac wrote:There's probably a point where it's a fire hazard.

Only if you hit them with an absurd amount of amps. A buddy of mine who was heavy into RC racing came near a pack that was being charged and not supervised was being charged at such a high rate that the pack literally exploded -- like a shotgun shell going off -- and the bits smashed into my buddy's face.

Not a pleasant experience.

Re: I knew it. Sigma was a robot this whole time

Posted: Sat Sep 23, 2017 5:57 am
by Krom
NiMH batteries and high amps should never mix, it is where the NiMH chemistry is weakest. They have high capacity, but also have a high internal resistance so they aren't suitable for high load applications.

If you need high amps/high load, then lead acid, most NiCD and some LiPoly batteries are designed for it, but it is usually a tradeoff of capacity vs peak power. A NiMH simply can't deliver that kind of amperage and the LiPoly in your cell phone that is designed for maximum capacity would meltdown or outright explode under that kind of load. For peak power, lead acid is basically second to none on the raw amps one can safely deliver, but they are pretty low on the capacity side.

Re: I knew it. Sigma was a robot this whole time

Posted: Sat Sep 23, 2017 9:26 am
by Sirius
Thanks TC :)

NiMH is, to my knowledge, newer than NiCd... not as high-performance as Lithium-ion I presume but I don't tend to see those sold in AA format. Only catch is I've been using them pretty heavily for wireless controllers, which I don't always use consistently, and I'm not sure they hold their charge well when not in use.

Re: I knew it. Sigma was a robot this whole time

Posted: Sat Sep 23, 2017 9:51 am
by Krom
Sirius wrote:Thanks TC :)

NiMH is, to my knowledge, newer than NiCd... not as high-performance as Lithium-ion I presume but I don't tend to see those sold in AA format. Only catch is I've been using them pretty heavily for wireless controllers, which I don't always use consistently, and I'm not sure they hold their charge well when not in use.
They don't hold a charge well over time so they have to be periodically topped off when not in use, although the same is true for pretty much all rechargeable battery types. NiCd will self discharge in as little as a week, NiMH takes a month or so, some lithium-ion types can last up to a couple months. IIRC lead acid lasts the longest out of common chemistries, but I'm not 100% sure of that.

I had to eventually ditch all our cordless tools because the batteries gave out a couple years after we finally finished the bulk of our home improvement projects. Replaced with fewer corded tools that get the occasional repair or touch up done and store without issue for 12-18 months at a time otherwise. :P