Interesting... but not recommended...

[65535]

Re: I Don't Understand Your Logic?!?

Just came across this thread. A few years back when I raced RC electrics, a few guys (generally those sponsored so as long as you got the highest voltage per run you didn't care about battery life as they were replaced at your whim free ~$100 a pack).

Anyways, some of these guys swore by dead shorting their packs when done with them for the day, these were mostly 3300mAh sub-C NiMH packs at the time 6 cell.

At some point a few companies even came out with dead short trays which did just that, shorted the cells individually for storage.

And some people swore by it. That it gave a higher voltage after charge and improved the discharge curve giving more on tap power for a race.

You guys would be surprised some people were balancing NiMH racing packs long before lithium made it out of portable electronics and into the consumers hands on a large scale.

 

[Lynx_Arc]

Re: I Don't Understand Your Logic?!?

Lynx_Arc, I'd also put them on a timed charge for a while. They are basically useless to you so anything at all would be an improvement. Have you measured the voltage of one of them under a known load? And compare that to a healthy cell?

I haven't done that, but put them in a 1AA task force luxeon light and it works fine for hours.

 

[45/70]

Re: I Don't Understand Your Logic?!?

......Anyways, some of these guys swore by dead shorting their packs when done with them for the day, these were mostly 3300mAh sub-C NiMH packs at the time 6 cell......

I wasn't aware of that. Admittedly, my R/C days were a long time ago. I sorta keep an eye on the hobby from time to time though. I Know they used to do that to NiCd's, but have never heard of doing it to NiMH packs.

I was never (at the time) really into R/C cars, they were pretty new at the time (all electric). I did have a couple "Monster Trucks" though. Mine were low end and used individual AA NiCd cells in the truck and a 7.2 volt NiCd in the transmitter. This was before NiMH cells were readily available.

Dave

 

[Lynx_Arc]

Still toasting and strangling my damaged hybrid AA cells. I have completed two refresh cycles one of them working on the third while the other is working on the second. The 250ma one on it third session is showing 749ma while the 500ma on its second cycle is showing 620ma. I have two other "good" cells refreshing at the low rate that are still working on one refresh session as it takes days when they are over 1500ma I am guessing they have gone through several cycles with one at 1973 ma taking almost a day to charge and half a day to discharge.

 

[TakeTheActive]

Still toasting and strangling my damaged hybrid AA cells...

If you're interested, look back (in this thread, IIRC) for the discussion of SECOND and THIRD STAGE DISCHARGE DAMAGE (or something to that effect). As I recall, SECOND STAGE was rather large. But, it's past the time for heading out on my evening walk (sun below the tall trees, mosquitos 'still sleeping') so I'll try to look for it later (or tomorrow or...) :thinking:

 

[Lynx_Arc]

If you're interested, look back (in this thread, IIRC) for the discussion of SECOND and THIRD STAGE DISCHARGE DAMAGE (or something to that effect). As I recall, SECOND STAGE was rather large. But, it's past the time for heading out on my evening walk (sun below the tall trees, mosquitos 'still sleeping') so I'll try to look for it later (or tomorrow or...) :thinking:

I am almost sure these got reversed, it is interesting that the bc900 went through two refresh cycles and didn't gain any capacity but this hard exercising has the two cells that were about 250/500 ma to 650/750 now. I think I will continue draining them to about half a volt and charging them with the 15 minute charger till there is no more improvement to them. It is possible the excessive heat from the hard charging is helping to regain some capacity but I suspect that it also is damaging them at the same time. I was at first trying to drain them to zero but don't have the patience to wait days for it to happen so I just put them in an LED light that drains them to about 0.4v, then short it with a paper clip for an hour and then fry it for 15 minutes on the energizer 😀

 

[TakeTheActive]

Re: I Don't Understand Your Logic?!?

1. I'd rather just be able to read them (easily). 🙁

   Well, sadly, the FIRST thing that comes to *MY* mind is that you're a rather DULL / "Set-in-Your-Ways" / STODGY person. 😱 (Sorry! If you research my post history, I'm FAIRLY CERTAIN that this is the *FIRST* time that I've replied to one of *YOUR* REPEATED criticisms NEGATIVELY.)
   
   Life is short.
   
   IME, we get OLD *WAY* too suddenly (one day you're feeling *GREAT*, next day you get a 'Bad Report' from a test your doctor just had you take, shortly afterwards, you get the ''Required Surgery', and then the follow-up 'Required Surgery', and then the follow-up to the follow-up 'Required Surgery'' and , life as you knew it is no longer the same... 🙁 You're UNEMPLOYED / You're TOO OLD / Yada, Yada, Yada... ). So, if you can find opportunities to LAUGH and HAVE SOME FUN 'here-and-there' (without HURTING anyone!), DO IT! 😀
   
   A Sig Line that I created ALMOST A DECADE AGO for some new forums that I had just joined still, IMHO, applies today:
   
   
   "Low Post Count <> Low Knowledge" ergo "High Post Count <> High Knowledge"​
   
   My "Modus Operandi" when arriving at a NEW FORUM is to "LURK & READ", possibly for MONTHS before I actually register and begin posting. From *MY* perspective, at that 'point-in-time', I have an idea of "Who's Who"
   
   / "Who Knows What" :thumbsup: / and "Who's FOS" :thumbsdow 😛.
   
   MONTHS AGO, someone with THOUSANDS of posts, challenged my knowledge with a "I'M NOT AN IDIOT! - LOOK HOW MANY POSTS I HAVE!!" Only a few days ago, due to his 'notable' Sig Line, did I eventually equate
   
   - DING, DING, DING! (aka "put 2 and 2 together") WHO he was, WHEN I previously communicated with him, and thus, out of sheer curiosity, I CLICKed on "Find all posts by ???" from his CPF Profile - :huh2:
   Let's face it folks - you can accumulate THOUSANDS of posts (in a relatively SHORT amount of time) on *ANY* forum. (Honestly, I don't even know what this "I'd hit it" smilie means), but, IMHO, THOUSANDS of THE CAFÉ or short, incomplete "SNIPE" posts don't amount to a "Hill of Beans" towards someone's credibility (NO intentional slander to ANY SPECIFIC INDIVIDUAL intended!).
   
   It takes just a minute or two to post a "SNIPE" - it could take an HOUR OR TWO to post an intelligent, complete reply.
   
   One thing we *ALL* know though - I'm Different! 🙂
   
   You choose to REPEATEDLY criticize my (random / light-hearted / humorous) EXCESSIVE FORMATING - if "Forced into a Corner", I choose to challenge *YOUR* CPF Contributions.
   .

2. ...Oh wow TTA you had me laughing even before reading your aside there. And you were doing so well for a while? Kinda had me wondering if you were suffering from colour depression lately...

   See!
   THAT'S the kind of response I like to read!!! :thanks: 😀

(Although I *REALLY* didn't intend to continue, another thread from a 'poor Newbie from Brazil' induced me to INDULGE once again... 😱)

 

[TorchBoy]

Re: I Don't Understand Your Logic?!?

Way-hay! Is there a flash or strobe tag you could add in there?

 

[65535]

Re: I Don't Understand Your Logic?!?

I wasn't aware of that. Admittedly, my R/C days were a long time ago. I sorta keep an eye on the hobby from time to time though. I Know they used to do that to NiCd's, but have never heard of doing it to NiMH packs.

I was never (at the time) really into R/C cars, they were pretty new at the time (all electric). I did have a couple "Monster Trucks" though. Mine were low end and used individual AA NiCd cells in the truck and a 7.2 volt NiCd in the transmitter. This was before NiMH cells were readily available.

Dave

Hey Dave, lets just say circa 2005 some people were making a living off of being good at racing high end ($1-5k) RC cars. Not to mention the money put into other non car parts of racing.

 

[65535]

I am almost sure these got reversed, it is interesting that the bc900 went through two refresh cycles and didn't gain any capacity but this hard exercising has the two cells that were about 250/500 ma to 650/750 now. I think I will continue draining them to about half a volt and charging them with the 15 minute charger till there is no more improvement to them. It is possible the excessive heat from the hard charging is helping to regain some capacity but I suspect that it also is damaging them at the same time. I was at first trying to drain them to zero but don't have the patience to wait days for it to happen so I just put them in an LED light that drains them to about 0.4v, then short it with a paper clip for an hour and then fry it for 15 minutes on the energizer 😀

Fast charging does nothing to help a cell, it will not boost the power, it will lower capacity and damage the cell even more.

Do a 16 hour charge on a wall wart putting out about .1C then discharge at .5C and repeat a few times, might work to bring back some life. Some people have had mixed results with zapping cells. (High current low impedance capacitive discharge through the cell at maybe 80 volts and some rather large amount of current) but it wasn't designed to increase life, just increase voltage and the discharge curve. It was never conclusively proven to work 100% afaik.

 

[TorchBoy]

Fast charging does nothing to help a cell, it will not boost the power, it will lower capacity and damage the cell even more.

So you're not a car racer who believes that cells should be charged at a similar rate to what they're discharged at?

 

[Lynx_Arc]

Fast charging does nothing to help a cell, it will not boost the power, it will lower capacity and damage the cell even more.

Do a 16 hour charge on a wall wart putting out about .1C then discharge at .5C and repeat a few times, might work to bring back some life. Some people have had mixed results with zapping cells. (High current low impedance capacitive discharge through the cell at maybe 80 volts and some rather large amount of current) but it wasn't designed to increase life, just increase voltage and the discharge curve. It was never conclusively proven to work 100% afaik.

what is .1C? is it based upon original mah stats of 2000mah or on current 650-750mah measured? I would have to tinker and monitor a power supply for 16 hours at 65ma etc... while my charger charges at 100mah for 6-7 hours with no changes.. trickle charging heats up a battery so does the 15min charger I don't know which is worse to heat it up at 2C for 15 mins or trickle for 16 hours. I would say neither is worse than the other I chose to scorch em for fun instead of falling asleep waiting for them to slowly fry trickling 😀

 

[TakeTheActive]

Re: I Don't Understand Your Logic?!?

Way-hay! Is there a flash or strobe tag you could add in there?

4569 Posts + 1 vs 728...
IMHO, If *EVERYONE* posted such *USELESS* replies as you, they *TOO* could amass THOUSANDS of posts. :toilet:
(Why don't you INVEST some of your "otherwise WASTED" time looking up VALID replies to Newbie posts? 😕)
Fortunately, that's *NOT* my goal. :wave: :goodjob: (aka Take the Bait, Hook, Line and Sinker ...) :sick2: )
(Thus, by your response with yet another *WONDERFULLY IN-DEPTH* reply, you simply ADDED to my 'theory' of QUANTITY vs QUALITY. BAIT + FISH = GOTCHA!)

Why won't you just allow "Off-the-Wall / Willing / Able / *INTELLIGENT*" folks, like me, to (at least to ATTEMPT to) COMPLETELY answer questions (*SOMETIMES* in an UNORTHODOX / OVERLY FORMATED - but *STILL* POLITE *AND* LOGICAL!!! - manner- not *THAT* often), while DULL / "Set-in-Your-Ways" / STODGY folks, like yourself, stick to places like THE CAFÉ? :huh:

IMHO, if "PUSH-Comes-to-SHOVE", I feel that, for the Contributions / aka Time-and-Effort I've devoted to this forum (CPF 'Batteries Included'), you need to either STAND DOWN *OR* "Make a Valid Case" ("$H!T or Get Off the Pot" is another "Old-Fashioned Phrase" that come to mind).

What do *YOU* have to offer?
(I try my *DARNEDEST* to avoid confrontations and "Take the High Road", but eventually you get PUSHED *TOO* FAR and need to take a stand for your beliefs!)​

If you find an ERROR in my posts, by all means, reply and correct it. Otherwise, I think you should follow the "Golden Rule" of "If You Have Nothing Good to Say... yada, yada, yada" aka "Move Along - These Aren't The Droids You're Looking For..." 😗)

I'm a mostly "Stuck-in-the-House", semi-disabled, UNEMPLOYED, "Old Fart" trying to still USE MY MIND, LEARN new things, and help others, while you !@#$%'s *STILL* find pleasure in ridiculing me!

You must be SO PROUD of yourself!​

So what if I go overboard with FORMATING every 'now-and-then'! From *MY* point of view, I'm *STILL* doing more good than *YOU*! :nana:

P.S. You !@#$%'s are *SO* easy to BAIT! 😀

(I apologize for this OUTBURST, but, there is just so much ***CRAP*** you can take from others... 🙁 )

 

[TakeTheActive]

Fast charging does nothing to help a cell, it will not boost the power, it will lower capacity and damage the cell even more.

Do a 16 hour charge on a wall wart putting out about .1C then discharge at .5C and repeat a few times, might work to bring back some life...

what is .1C? is it based upon original mah stats of 2000mah or on current 650-750mah measured?...

Geez!

*TWO* folks (Myself and SOMEONE *SMARTER*!) are now suggesting that you CHARGE @ 0.1C (or less!) for SEVERAL HOURS and *HOPE* that the chemicals "realign".

What don't you understand? 😕

(And folks, with THOUSANDS of posts, continue to ridicule and MAKE FUN OF me?!?)

 

[SilverFox]

Hello Lynx Arc,

As cells age, I base the 0.1C charge rate on the previous tested capacity.

If you have cells labeled as 2500 mAh, and they test to 2200 mAh, I would set the 0.1C charge rate to 220 mA.

Your cells are CRAP and should be recycled, however, since they are testing at around 700 mAh, do a 16 hour charge at 70 mA and see if there is any improvement. If they, for example, jump up to 1000 mAh, then increase the 0.1C charge rate to 100 mA.

While there is no set rule for this, I have used this a lot and found it to be effective in that I get lots of cycles from my cells and have good mid point voltage retention.

Tom

 

[Lynx_Arc]

Geez!

*TWO* folks (Myself and SOMEONE *SMARTER*!) are now suggesting that you CHARGE @ 0.1C (or less!) for SEVERAL HOURS and *HOPE* that the chemicals "realign".

What don't you understand? 😕

(And folks, with THOUSANDS of posts, continue to ridicule and MAKE FUN OF me?!?)

I understand completely, this is an experiment so far of my own I started. It is working to an extent so far. I may take one of the two cells and try the 16 hour ordeal and keep going on with the current regime on the other to see which improves the most.

 

[Lynx_Arc]

Hello Lynx Arc,

As cells age, I base the 0.1C charge rate on the previous tested capacity.

If you have cells labeled as 2500 mAh, and they test to 2200 mAh, I would set the 0.1C charge rate to 220 mA.

Your cells are CRAP and should be recycled, however, since they are testing at around 700 mAh, do a 16 hour charge at 70 mA and see if there is any improvement. If they, for example, jump up to 1000 mAh, then increase the 0.1C charge rate to 100 mA.

While there is no set rule for this, I have used this a lot and found it to be effective in that I get lots of cycles from my cells and have good mid point voltage retention.

Tom

I may try that with one of the two cells but as I don't have a constant current power source it would require me to use a power supply and monitor the current and adjust it many times to compensate for increase in the cell voltage while charging which would drive down the charging current. I haven't kept good track of this experiment it was just a whim of the moment I never considered it would have any interesting results and was a little shocked to see the batteries did improve in capacity while two sets of refreshing on my bc900 did almost nothing at all (less than 10mah improvement on one cell). so far it appears this method has about doubled the capacity of the cells but as I haven't really paid attention well I cannot remember if I did 2 or 3 cycles of toasting/refreshing on both cells or not
I bought these hybrids and never got around to running them through my lacrosse like I have all my other cells I didn't start checking them except the ones that got overdischarged. Luckily these are the batteries got with the $5 off coupons I ordered from ebay so I have about $1 in each of them and I have plenty of them plus some duraloops so toasting these doesn't make me flinch unlike those insisting I "save" them 😀. If they had been the $2+ duraloops I probably would have tried to resurrect them.

 

[45/70]

In my experience, if you're dealing with cells that are poor performers due to having a damaged separator (leaking), that you can't really charge them at a slow rate such as 0.1C. At such a slow rate, most of the current applied is turned into heat and very little is left to charge the cell. So, really all you can do is "boosh" a high rate of current in, and hope for the best. It goes without saying, that cells in this condition are recycle bin/disposal items. 🙂

Gotta quit posting now. It's Friday, and I have much real work to do!

Dave

 

[Lynx_Arc]

In my experience, if you're dealing with cells that are poor performers due to having a damaged separator (leaking), that you can't really charge them at a slow rate such as 0.1C. At such a slow rate, most of the current applied is turned into heat and very little is left to charge the cell. So, really all you can do is "boosh" a high rate of current in, and hope for the best. It goes without saying, that cells in this condition are recycle bin/disposal items. 🙂

Gotta quit posting now. It's Friday, and I have much real work to do!

Dave

this makes some sense to me, I think I will continue one cell on the toast/drain to 0.5v/refresh via bc900 and the other I will attempt a 16 hour trickle at about 75 ma and see what happens. My guess is the 16 hour cell will improve perhaps 5% (or maybe nothing) and the toasted one will improve 10-20% more. I expect to be surprised for sure as I wasn't expecting anything from that 15 minute energizer charger in all of this 😀

 

[Lynx_Arc]

Ok, I just got through taking one AA hybrid that started at 250ma and was up to 750ma and put it on a power supply for 21 hours at ~80ma, then put it on my BC900 and it came up measuring 682ma which doesn't impress me at all. The other one that was 500ma is now up to 1023ma using the energizer charger and draining them to about half a volt then running it through the refresh mode at 100/200ma.