"HIGH" cells with C9000

[InHisName]

Who has experimented on "fixing" HIGH cells ?

When a cell's internal resistance increases over time to high enough level, the C9000 will give error of "HIGH" and refuse to charge it.

I have been trying many charge / discharge cycles with another lesser charger and discharging each cell individually with a flashlight bulb. I "may" have made some improvement but not enough change to use the C9000 yet. ---> Voltage seen just before HIGH, 2.38v before experimentation and now 2.29v Better but still shows HIGH. I think the cutoff is 2.0something.....

Has anyone else been experimenting with "fixing" HIGH batteries. What did you try ? and was it successful or not ?:candle:

 

[snakebite]

not even worth trying.
unless you can get some water inside to replace what left via the vent its a waste of time.lazy cells can often be charged at a low rate then discharged "break in mode" to recover.
i have seen sanyo 1500 aa's that had sat around new in the box from 10 years back that did not go high.they would just false terminate.again the break in mode fixed that.

 

[45/70]

I played around quite a bit trying to revive cells like yours. The bottom line is, your cells are at, or very near EOL. I've found that, yes, you can improve the cells to some extent when they show "HIGH" on the C9000, but for the most part, it's a waste of time. Just the same, if you do see a marked improvement with the first refresh or forming cycle, it may be worth spending some time trying to bring them back. Most of the time it's just not worth messing with though, and you'd be better off just replacing the cells.

A lot of times, if you get the cells to charge on a charger, even if they appear to have reasonable capacity, their voltage drop under load will be so bad that the cells aren't worth trying to save. Their only practical use is in wall clocks and such when they're that bad.

The one possible exception to all this, is AAA cells. AAA cells have a high internal resistance from the get go, due to their diminutive size. With problem AAA cells (in regards to the C9000's "HIGH" determination), it may be worth investigating further to see just how bad the cells really are. The same applies however, if the cells can't hold a reasonable voltage under load, then they're at EOL.

Dave

 

[StuMorri]

Who has experimented on "fixing" HIGH cells ?

When a cell's internal resistance increases over time to high enough level, the C9000 will give error of "HIGH" and refuse to charge it.

I have been trying many charge / discharge cycles with another lesser charger and discharging each cell individually with a flashlight bulb. I "may" have made some improvement but not enough change to use the C9000 yet. ---> Voltage seen just before HIGH, 2.38v before experimentation and now 2.29v Better but still shows HIGH. I think the cutoff is 2.0something.....

Has anyone else been experimenting with "fixing" HIGH batteries. What did you try ? and was it successful or not ?:candle:

In seven years time, I have been keeping the original Ni-Cads in my seven Walmart solar pathway lights (two AAs each) going with periodic reconditioning via the C9000/M808s. All have rust spots or cracked end-seals or so-on.

Five cells have shown up as HIGH when seen to be visibly dimming out there, or losing life. Two were hopeless, the other three have been revived with varying success by zapping them, very quickly with a portable auto battery jump starter, then reconditioning them on a Maha recharger. One made it another week and died at recharge, the other two are still going albeit with reduced capacity. These decorative pathway LED lights don't demand much.

What to make of this? One could say I'm using my time and a $40 auto device and an $85 recharger to keep seven-year-old rusty chinese 5/600 mAh cells going. Or, I'm using high-tech solutions to enhance an ecological life-style. Mostly, it's just been fun to see how long I could keep 'em goin'.

_

 

[Lightcrazycanuck]

I played around quite a bit trying to revive cells like yours. The bottom line is, your cells are at, or very near EOL. I've found that, yes, you can improve the cells to some extent when they show "HIGH" on the C9000, but for the most part, it's a waste of time. Just the same, if you do see a marked improvement with the first refresh or forming cycle, it may be worth spending some time trying to bring them back. Most of the time it's just not worth messing with though, and you'd be better off just replacing the cells.

A lot of times, if you get the cells to charge on a charger, even if they appear to have reasonable capacity, their voltage drop under load will be so bad that the cells aren't worth trying to save. Their only practical use is in wall clocks and such when they're that bad.

The one possible exception to all this, is AAA cells. AAA cells have a high internal resistance from the get go, due to their diminutive size. With problem AAA cells (in regards to the C9000's "HIGH" determination), it may be worth investigating further to see just how bad the cells really are. The same applies however, if the cells can't hold a reasonable voltage under load, then they're at EOL.

Dave

Keep up the good work and advice Weird Battery Person.Your knowledge and expertize in thise field is invaluable.:thumbsup::thumbsup::thumbsup:

Like the old saying goes,why be normal.

 

[MarioJP]

I would not spend my time trying to revive lazy cells and here's why.

Its not so much of the internal resistance which can be recovered to some extent. The thing you have to worry about is the voltage during load. This is called "voltage depression"

I have 4 crippled duraloops which was tortured by the 15 min charger. The voltage depression on these cells are so bad that even a 500mA discharge drops the voltage down to 0.99V. It stays there until the cell is discharged. Yet was still maintaining the capacity 1600mAH.

These cells are going to be recycled. Reason why I still have these cells was to see how bad they can get. Well I got my answer and time to recycle.

Bottom line is its not just the capacity and high internal resistance to worry about. Voltage depression is what cause you to just call it quits and replace the cell.

 

[noisebeam]

I have eight AAA cells in regular rotation, four Accupower 1000mah from Feb-08 and four Energizer 850mah that are older. All but one read HIGH on my recently purchased C9000 to my disappointment.

IN practice, all work great for at least a week (5-10hrs+ of use) in my "Planet Bike Super Flash" bicycle taillight (0.5W LED, flash and solid mode mixed use) with no notable degradation in light output from week start to end, even side by side with freshly charged ones.

Up until now I've been charging them every week, sometimes longer intervals, using the maha 401FS in slow mode (200mA). It still accepts all of them (and it does reject some really bad AA's I had)

As I noted one of the Energizers can get accepted by the C9000 and one other I can get to work by discharging, the recharging in 401fs, then the c9000 will barely accept it. I ran one burn in cycle (850mah selected) with these results:

E1: 280mah, 103min, 1.43V (this is the one that doesn't ever read HIGH)
E2: 9mah, 3min, 1.47V (this one I can 'trick' into being accepted)

I am not going to throw any of these 8 AAA away yet.

Should I be charging these fast (300mA) or slow (200mA) on the 401fs ?

Will AAA Eneloop 800mah work longer term with the C9000 if I get them new and use them for this application?

(Yes I realize that weekly to bi-month charging is probably overkill for the relatively small drain these batteries get, maybe that is what killed the batteries? I also realize that NiMH may not be ideal for this application, but so be it.)

 

[InHisName]

What to make of this? One could say I'm using my time and a $40 auto device and an $85 recharger to keep seven-year-old rusty chinese 5/600 mAh cells going. Or, I'm using high-tech solutions to enhance an ecological life-style. Mostly, it's just been fun to see how long I could keep 'em goin'.

Same with me, it's just been fun to see how long I could keep 'em goin'.

MarioJP - When a battery gets larger internal resistance, the voltage takes a big hit, just like you noted. Figuring out how to minimize the internal resistance ought to help keep the voltage up where it needs to be to deliver the goods to the device. Hence the reason for my query to see if it is even possible and then upon analysis, practical. Which for HIGH batts is a probable NO.

 

[Mr Happy]

AAA NiMH cells are quite fussy unfortunately. Both "duraloop" and "hybriloop" AAA cells (I don't have any genuine eneloop AAAs) read 800+ mAh after a break-in cycle on the C9000, whereas Rayovac Hybrids read about 550 mAh. Other cells can be much less.

AAA cells suffer from being smaller and more fragile inside, and from having a naturally higher internal resistance. I have also found some AAA cells are much more prone to missed terminations that can get them cooked and damaged from overcharging. I generally time my AAA cells against the clock and stop them if they do not terminate the charge automatically at the expected time.

When a cell has a reading like 280 mAh, 1.43V on the C9000 after discharge, it means the discharge ended prematurely due to excessive voltage drop at the pulsed 1 A discharge load. The cell still has a lot of charge in it that the C9000 did not measure. There's not a lot you can do about this. If the cell still works for you in your application just keep using it.

 

[OpenGuy]

I have eight AAA cells in regular rotation, four Accupower 1000mah from Feb-08 and four Energizer 850mah that are older. All but one read HIGH on my recently purchased C9000 to my disappointment.

IN practice, all work great for at least a week (5-10hrs+ of use) in my "Planet Bike Super Flash" bicycle taillight (0.5W LED, flash and solid mode mixed use) with no notable degradation in light output from week start to end, even side by side with freshly charged ones.

Up until now I've been charging them every week, sometimes longer intervals, using the maha 401FS in slow mode (200mA). It still accepts all of them (and it does reject some really bad AA's I had)

As I noted one of the Energizers can get accepted by the C9000 and one other I can get to work by discharging, the recharging in 401fs, then the c9000 will barely accept it. I ran one burn in cycle (850mah selected) with these results:

E1: 280mah, 103min, 1.43V (this is the one that doesn't ever read HIGH)
E2: 9mah, 3min, 1.47V (this one I can 'trick' into being accepted)

I am not going to throw any of these 8 AAA away yet.

Should I be charging these fast (300mA) or slow (200mA) on the 401fs ?

Will AAA Eneloop 800mah work longer term with the C9000 if I get them new and use them for this application?

(Yes I realize that weekly to bi-month charging is probably overkill for the relatively small drain these batteries get, maybe that is what killed the batteries? I also realize that NiMH may not be ideal for this application, but so be it.)

I use Rayovac hybrid LSD AAA NiMH cells in my two Planet Bike Super Flashes, which I use 30 minutes per day. The batteries last for ages.

I try to remember to recharge them every month (hmm, haven't done so this month so maybe I should), but they usually don't take a lot to recharge (less than half their rated capacity).

Once I had a AAA battery miss termination on a C9000 when recharging at about 500 mA. Their peak voltage seems to be around 1.42 Volts, whereas all of my AA batteries voltage terminate at 1.47 Volts (at 1A).

I think the LSD NiMH work fine for this application.

 

[noisebeam]

To clarify my AAA usage, I use one PBSF mounted to my bike which is always on solid, 30min every morning, 30min every evening, then 2.5hrs once per week for a night ride - and a 2nd PBSF on my helmet which is always on flash mode. I charge the one that is on solid mode about once every 1-2wks and the one on my helmet about 1/mo. But now as the mornings/evenings are getting lighter I use the one mounted to the bike in flash mode now that the ambient light is greater - so I should correspondingly charge less.

With a C9000 and AAA that it can accept I will be able to better monitor charging rates and times to get a better feel for how often I need to charge. But I didn't want to get more AAA if they will soon be rejected by the c9000.

 

[Mr Happy]

With a C9000 and AAA that it can accept I will be able to better monitor charging rates and times to get a better feel for how often I need to charge. But I didn't want to get more AAA if they will soon be rejected by the c9000.

Fresh AAAs of a kind like eneloops will not be rejected by the C9000. Starting from new, you then will be able to monitor exactly how much charge is put into them and taken out of them so you can judge when they need recharging. And if you run a break-in cycle on them every summer, you will likely never see them reading HIGH.

 

[TakeTheActive]

Attempting to Rejunvenate 2-Year-Old non-LSD AAAs...

I have eight AAA cells in regular rotation, four Accupower 1000mah from Feb-08 and four Energizer 850mah that are older. All but one read HIGH on my recently purchased C9000 to my disappointment.

...all work great for at least a week (5-10hrs+ of use)...

...Up until now I've been charging them every week, sometimes longer intervals, using the maha 401FS in slow mode (200mA)...

(Yes I realize that weekly to bi-month charging is probably overkill for the relatively small drain these batteries get, maybe that is what killed the batteries?)

I use Rayovac hybrid LSD AAA NiMH cells in my two Planet Bike Super Flashes, which I use 30 minutes per day. The batteries last for ages.

I try to remember to recharge them every month (hmm, haven't done so this month so maybe I should), but they usually don't take a lot to recharge (less than half their rated capacity)...

To clarify my AAA usage, I use one PBSF mounted to my bike which is always on solid, 30min every morning, 30min every evening, then 2.5hrs once per week for a night ride - and a 2nd PBSF on my helmet which is always on flash mode. I charge the one that is on solid mode about once every 1-2wks and the one on my helmet about 1/mo. But now as the mornings/evenings are getting lighter I use the one mounted to the bike in flash mode now that the ambient light is greater - so I should correspondingly charge less.

With a C9000 and AAA that it can accept I will be able to better monitor charging rates and times to get a better feel for how often I need to charge. But I didn't want to get more AAA if they will soon be rejected by the c9000.

noisebeam,

Are you up for an 'Experiment'?

My WAG is that a good portion of the chemicals in your 2-year-old AAA cells has been 'untouched' by your frequent charging and could stand some 'exercise'. Everything that I'm now going to recommend is in my Green Sig Line LINK.

1. Label your 8 cells uniquely and set up a 'Text' Record Keeping file.
2. Measure and record the 'C9000 Impedance Check Voltage' for each cell.
3. Perform several 'Deep Discharges' on the cells.
   - You'll need something to use AFTER the C9000 finishes it's 100mA DISCHARGE since that's really a pulsed 1000mA DISCHARGE. An incandescent flashlight or a resistor will do - just don't discharge below 0.8VDC under load.
4. Measure and record the 'C9000 Impedance Check Voltage' for each cell.
   - Did it improve?
5. Run a C9000 BREAK-IN on the cells with Capacity = 900mAh
   - Be there at the end of the DISCHARGE to record the measured Capacities for each cell and end the BREAK-IN.
6. Measure and record the 'C9000 Impedance Check Voltage' for each cell.
   - Did it improve?
7. Perform several 'Deep Discharges' on the cells.
8. Measure and record the 'C9000 Impedance Check Voltage' for each cell.
   - Did it improve?
9. Run a C9000 BREAK-IN on the cells with Capacity = the Average Capacity per set of four, by manufacturer, recorded in Step #5.
10. At the end of the 2nd CHARGE, record the measured Capacities for each cell.
    - Did it improve?

...Will AAA Eneloop 800mah work longer term with the C9000 if I get them new and use them for this application?

IMO, not much better if you treat them exactly the same as you treated the older cells.

What would be interesting is to:

1. Purchase a new set of AAA Eneloops
2. Run a DISCHARGE @ 200mA on the C9000 and record the Capacities.
3. Run a C9000 BREAK-IN @ 800mAh and record the measured Capacities for each cell.
4. Run through your existing usage routine.
5. Instead of CHARGING the cells in the 401FS, run a DISCHARGE @ 200mA on the C9000 and record the remaining Capacities.
6. CHARGE the cells in the C9000 @ 400mA (0.5C)
7. If the 'Percent of Capacity Remaining' as measured in Step #5 is greater than 10%
   • Extend your usage routine correspondingly and go back to Step #5.
   • Else, use this usage routine as your new 'norm'.
8. Every 10th cycle, add a Deep Discharge after Step #5.
9. Every 30th cycle, after the Deep Discharge, run a BREAK-IN @ 800mAh

Looking forward to reading your results!

Good Luck!

 

[alfreddajero]

Re: Attempting to Rejunvenate 2-Year-Old non-LSD AAAs...

I usually just throw the cell or cells away.......this happens when i have had the cells for years.

 

[45/70]

I usually just throw the cell or cells away.......this happens when i have had the cells for years.

Awww, come on, alfreddajero! As TTA pointed out, look at all the "fun" you'd be missing out on!

Dave

 

[alfreddajero]

Well usually i do a discharge and a charge at 1amp.....that usually works for a while......but later on down the road its beyond saving, and these only happen to the cells that are 2 years old or more. I got my use out of them and its just time for me to get more......and please call me Al.

 

[45/70]

OK, Al.

Yes, it is worth an initial try, of course. I've found that spending a lot of time with consistantly under performing cells however, is usually just a means of prolonging their inevitable death, and just not worth the hassle.

Dave

 

[alfreddajero]

I say at least do what you can for the cell.....and if it does it a few more times then its time to recycle......i havent had any problems with new cells, so thats good.

 

[OpenGuy]

To clarify my AAA usage, I use one PBSF mounted to my bike which is always on solid, 30min every morning, 30min every evening, then 2.5hrs once per week for a night ride - and a 2nd PBSF on my helmet which is always on flash mode. I charge the one that is on solid mode about once every 1-2wks and the one on my helmet about 1/mo. But now as the mornings/evenings are getting lighter I use the one mounted to the bike in flash mode now that the ambient light is greater - so I should correspondingly charge less.

I only ever use flash mode on mine, so my usage is a lot less than yours (especially the one that's on solid). Perhaps your habit of recharging every 1-2 weeks is about right. It would be interesting to discharge them completely on the C9000 next time you would normally recharge them to see how much charge they have left.

I also recharge mine at a higher rate. Since one battery missed termination last time (at 500 mAh), I'm going to try a higher rate next time (either 700 or 800 mAh).

I recharge the AAs in my front lights (Fenix L2D) every night. I monitor how many mAh are required to recharge them. I always use them about the same amount (same distance, surprisingly little difference in average speed), but there's a pretty big difference in the mAh required to recharge them on different nights, from as little as 700 mAh to as much as 1000 mAh. I suspect the outside temperature has a significant effect, but I haven't been recording that.

 

[45/70]

......I recharge the AAs in my front lights (Fenix L2D) every night. I monitor how many mAh are required to recharge them. I always use them about the same amount ......

Under these conditions, it's important to do a full discharge of the cells once in a while, or you will run into memory effect. This may be part of InHisName's problem, as well.

There is a common myth that NiMH cells aren't susceptible to memory effect, they are, it's just that it's only about half as much as NiCd's. If you let the effect go on long enough, it's not very likely, to impossible, to recover the cells.

Dave