Eneloop Batteries and LaCrosse BC-900 Mode Usage

[Mitch470]

I ran my new Eneloop batteries through a LaCrosse Test Mode Cycle (Charge/Recharge/Charge) and came to the following deductions on how to use the LaCrosse BC-900 Modes:

I noticed that with my 16 AA Eneloops all exceeded the Minimum mAh recommendation of 1900 mAh Capacity except one which its first Test Mode Cycle produced 1930 mAh. The second Test Mode Cycle produced a Capacity of 2080 mAh.

When I ran my 8 AAA Eneloops through a Test Mode Cycle, all came in less than 800 mAh rated Capacity with 2 below the minimum Capacity of 750 mAh and one just slightly above. The 2nd Cycle had 5 come near or above its rated Capacity while 3 were above the Minimum but still below the rated Capacity. I ran those 3 in a 3rd Cycle but only 1 improved but 2 got worse. All of those 3 were still above the minimum Capacity and below the rated Capacity.

 

[SilverFox]

Hello Mitch,

If I may throw out a couple of comments...

When I was using my BC-900 with Eneloop cells I charged AA cells at 1000 mA, and AAA cells at 500 mA. If the BC-900 misses the end of charge signal and you are charging at the rates you listed, you will most likely damage your cells.

I would also suggest that you will get more cycle life if you don't completely drain your cells each time you use them. Run your radio and flashlight for a while, then re-charge. You don't have to go all the way to where the radio won't turn on, or the flashlight dims. Your once a year "conditioning" cycle should take care of any "issues" involved with shallower discharge cycles.

You may also want to reconsider your discard policy. The Eneloop cells list the minimum at 95% of rated capacity. I generally use cells down to 80% of initial capacity. If you recycle your cells at 95%, you will be throwing away cells that are still good.

Just some thoughts...

Tom

 

[Mitch470]

Hello Mitch,

If I may throw out a couple of comments...

When I was using my BC-900 with Eneloop cells I charged AA cells at 1000 mA, and AAA cells at 500 mA. If the BC-900 misses the end of charge signal and you are charging at the rates you listed, you will most likely damage your cells.

I would also suggest that you will get more cycle life if you don't completely drain your cells each time you use them. Run your radio and flashlight for a while, then re-charge. You don't have to go all the way to where the radio won't turn on, or the flashlight dims. Your once a year "conditioning" cycle should take care of any "issues" involved with shallower discharge cycles.

You may also want to reconsider your discard policy. The Eneloop cells list the minimum at 95% of rated capacity. I generally use cells down to 80% of initial capacity. If you recycle your cells at 95%, you will be throwing away cells that are still good.

Just some thoughts...

Tom

Tom,

Thanks for the advice. I'm learning most of this from you. So far as missing the end of charge signal, I do 4 at one time. If one of the 4 is at 1.51 or 1.52V and the other 3 have ended, I just take out the one without the signal anyway. I learned that from my Ansmann Energy 8 which did miss end of charge signals on a regular basis. Sanyo's instructions state that charge rates should be as low as possible to extend the Cycle Life of the cells.

My Sangean ATS 800 radio, gives a low battery signal before power runs out entirely. Thus, I don't ever run it until its dead. That kind of process could damage the radio. By the way, that radio still has the best speaker of any portable on the market with the largest LCD screen of any others. Its 10 years old on the market but still being sold today on certain web sites as new.

I have 4 Brinkmann LED Flashlights which rarely have to get batteries changed. I've owned them for 3 years now and only had to change regular Alkaline batteries in one when it started to dim. Dimming is the only indication that the battery is starting to get low. The Eneloops will probably last many years if I ever do need to use them in the flashlights. Their LED lights are guaranteed for LIFE.

With the Eneloops having a Low Storage Discharge rate they will probably never reach 2 LED's on my DigiCam Tester with 5 LED's maximum and undergo a Discharge/Charge cycle. Thus, they will probably only undergo a full charge/discharge/charge Test Mode cycle only the once per year.

As a final note the 16 Eneloop AA batteries averaged 2021 mAh Capacity on their final Test Mode cycle a little over their official rating and the 8 Eneloop AAA batteries averaged 795 mAh Capacity on their final Test Mode cycle, a little under their official rating.

The reason for discarding the AA's at less than 1900 mAh Capacity and the AAA's at less then 750 mAh Capacity is that they must work in sets usually of 2 or 4 and, if any had too low a Capacity, the usage time of the entire set would be penalized. Once placed back in storage there is no way to identify which specific cells have low or normal capacity. They are really not that expensive. Since they have a Low Storage Discharge Capacity, I don't expect to lose more than 1 or 2 per year.

 

[SilverFox]

Hello Mitch,

Missing the end of charge signal probably does more damage to NiMh cells than anything else. The battery manufacturers (including Sanyo) recommend charging in the 0.5 - 1.0C range for reliable termination. Slow charging is also recommended at 0.1C for 14 - 16 hours. The charging range from 0.2 - 0.5C does not give a reliable strong end of charge signal and should not be used with chargers that rely on a drop in voltage (-dV) or change in cell temperature (dT/dt) to terminate the charge.

With the Eneloop AA cells, 1C = 2000 mA, 0.5C = 1000 mA, and 0.1C = 200 mA.

It is not clear why Sanyo chargers don't follow the Sanyo battery recommendations, but we are looking into this.

Here is the Sanyo AA Eneloop data sheet. You should take notice that they only list two charging rates... 200 mA for 16 hours, and 2000 mA for 1.1 hours with proper charge termination. I happen to believe that the 1.1 hours is a bit too long, but it would be a good safety time out.

Your charging rates will work, for a while, but they are not recommended.

Tom

 

[Mitch470]

Eneloop Charger Specifications

Hello Mitch,

Missing the end of charge signal probably does more damage to NiMh cells than anything else. The battery manufacturers (including Sanyo) recommend charging in the 0.5 - 1.0C range for reliable termination. Slow charging is also recommended at 0.1C for 14 - 16 hours. The charging range from 0.2 - 0.5C does not give a reliable strong end of charge signal and should not be used with chargers that rely on a drop in voltage (-dV) or change in cell temperature (dT/dt) to terminate the charge.

With the Eneloop AA cells, 1C = 2000 mA, 0.5C = 1000 mA, and 0.1C = 200 mA.

It is not clear why Sanyo chargers don't follow the Sanyo battery recommendations, but we are looking into this.

Here is the Sanyo AA Eneloop data sheet. You should take notice that they only list two charging rates... 200 mA for 16 hours, and 2000 mA for 1.1 hours with proper charge termination. I happen to believe that the 1.1 hours is a bit too long, but it would be a good safety time out.

Your charging rates will work, for a while, but they are not recommended.

Tom

Tom,

Here are the Eneloop Charger Specifications for their own chargers:

and

Thus, for AA Eneloop charging they recommend: 300 to 550 mA. I am using 500 mA. For AAA Eneloop charging they recommend: 150 to 380 mA. I am using 200 mA. My rates appear to be between rates used in their own chargers.

If I am using rates too low, so are they. Go to this site:

http://www.eneloopusa.com/eneloop.html

"Yes, temperature does have an effect on eneloop's performance. If it is too hot, the high temperature could cause the battery to discharge at a more rapid rate."

"Though it is possible to charge an eneloop battery in a "Quick Charger", it is not recommended. We recommend charging eneloop batteries in a NiMh charger that is 2 hours or more. Charging eneloop batteries in a "Quick Charger" can reduce the overall life of the battery. "

The safety practice of only charging 4 cells at once and terminating all cells within 15 minutes of 3 being terminated at 1.52V would appear to prevent accidental overcharges no matter what the case.

The Specification Sheet you referred to shows the POSSIBILITY, not desirability of charging at 2000 mA for 1.1 hour and 200 mA for 16 hours for an Eneloop AA battery. In practice I am charging an AA at 500 mA and it takes about 4 hours.

The problem may lie in the instruction manual for the MH-C9000 which does stipulate industry standards for STANDARD NIMH's - not the new Low Storage Discharge types. I have a hunch by next year the instruction manual may change in some respects with both Standard and LSD NIMH's having slightly different specifications for charging.

 

[Turak]

I have been reading/talking about the slow versus fast rates in many threads.

It seems that many may be 'misinterpreting' the fact that just because a chart or application guide shows a couple of the 'possible' charge rates ... these are assumed to be the 'recommended' rates.

MAHA is one of the few charger manufacturers that I now see 'recommending' the .5C-1C rates ( funny it used to be .3C or higher...hmmm) which I have a feeling has to do with some of their chargers (i.e. 401S, ealy MH-C9000's) having trouble terminating. Funny though since the 401S actually had more trouble at the higher rates than the lower...while the early MH-C9000 had trouble at anything below .5C (from what I read, never had a rev F unit).

The ONLY rate that I see 'recommended' by almost every battery manufacturer is the 16 hours at .1C rate.

The other thing that they all seem to agree on is that heat is bad for a battery. Although they disagree on 'how much' heat.....sheesh.

Higher charge rates ultimately mean more internal heat for the battery.....even if the rate is terminated properly the very center of a battery experiences more heat than any portion. It is very easy to hit 130'-160' in the center of the battery, while the outside only reaches 110' - 120'. This alone can cause premature thinning/deformation of the separator and is at least one of the causes of the higher self discharge rates seen in the higher capacity cells.

I think I summed up the slow versus high rates pretty good in another thread with the following statement...

If the charger you are using can RELIABLY terminate the charge at the lower rates (.2C to .5C), then there is absolutely no harm. In fact it is better for the overall life of the battery (less internal heat generated). BUT.....if your charger seems to have trouble at the lower rates (i.e. earlier MH-C9000's, BC900 (v32 fw), etc)), then you would want to stick with the higher rates (.5C to 1C).

Just for the record...

I have both the BC900 (actually 2 of them, v33 fw) and a MH-C9000 (rev. G fw). Both of them terminate extremely well at the lower rates.

Silverfox is totally correct though, in that .... it only takes the charger missing termination one time and you will at the very least lose some serious life cycles off of the battery you are charging, and at the worst you could cook it to death.

On another note ... I am noticing that how well a battery terminates seems to have A LOT to do with different manufacturers (Duracells seem to terminate better than the same capacity energizers), battery age (newer cells typically terminate better than older cells), battery capacities (higher capacities have more trouble at the low rates). More testing on this stuff is definitely needed.

 

[Mitch470]

Resolution of ZERO Voltage NIMH and 1.2V Eneloop NIMH

I thought through this apparent contradiction between the larger currents (.2 Ah x 16 hours) and the current I am using .5 Ah x 4 hours for the Eneloop AA cell.

The larger current is for a new ZERO VOLTAGE NIMH to be used as a FORMING CHARGE. These Eneloop AA batteries start with 1.2V and an initial capacity of 1200 mAh right out of the package. When they come off the assembly line, they start at ZERO Voltage. The customer does NOT see it directly off the assembly line.

Thus, the Maha instructions are correct for a ZERO VOLTAGE NIMH as a forming charge. To apply a FORMING CHARGE to an Eneloop with one volt or more is to significantly REDUCE its ability to maintain a charge for a long period of time. However, a Forming Charge would be correct for an Eneloop AA cell with zero volts right after it is manufactured.

Thus, it is correct to apply 2000 mA for 1.1 hours or 200 mA for 16 hours to zero voltage NIMHS or Eneloops coming off the assembly line. For the consumer Eneloops NEVER start with zero volts.

If our Eneloops ever drop below .9V, they are FINISHED. Discharge Mode on the LaCross drops the voltage to ONE Volt and then raises it to 1.52V. If you use the MH-C9000, Disharge Mode will drop it to ZERO VOLTS and ruin an Eneloop. Personally, I would never use Discharge Mode on the MH-C9000 for Eneloops and never use Refresh Mode on the BC-900.

Using the LaCrosse BC-900 Version 33, which is the one I use, applying 500 mA for 4 hours to an Eneloop AA cell with ONE Volt gets it to 1.52V correctly. It then drops to 1.4V after disconnection.

For Eneloop AAA cells the correct application if the battery starts with at least 1V should be 200 mA for 4 hours. It also then rises to 1.52V and drops initally to 1.4V after disconnection.

Another consequence of this situation is that the Refresh Mode should never be used on Eneloops. It SHOULD be used on zero volt NIMHS when new.

All rechargeable cells should be charged in twos or fours so that the odds of missing an end point are significantly reduced. When one or three cells reach an end point, the remaining cell should be watched carefully and removed from the charger if it still remains charging after 15 minutes with 1.52V or higher.

 

[TorchBoy]

Re: Resolution of ZERO Voltage NIMH and 1.2V Eneloop NIMH

I thought through this apparent contradiction between the larger currents (.2 Ah x 16 hours) and the current I am using .5 Ah x 4 hours for the Eneloop AA cell.

The larger current is for a new ZERO VOLTAGE NIMH to be used as a FORMING CHARGE. These Eneloop AA batteries start with 1.2V and an initial capacity of 1200 mAh right out of the package.

What on Earth are you going on about? Current is measured in A (or mA) not Ah, 200mA is not a "larger current" (but is the IEC standard current - for the IEC specified 16 hours - for testing the capacity of Eneloops), if you have a zero voltage NiMH it's almost certainly seriously damaged, Eneloops out of the packet are 1.3 to 1.31 volts, and they have about 1500mAh, using the standard IEC test will not destroy an Eneloop, and neither will discharging under 0.9V (although it may cause damage if the discharge is deep enough). Did I miss anything? :shakehead

 

[-QT-]

Re: Resolution of ZERO Voltage NIMH and 1.2V Eneloop NIMH

If you use the MH-C9000, Disharge Mode will drop it to ZERO VOLTS and ruin an Eneloop.

The initial Maha MH-C9000 discharged cells to 1.0v at rest. All versions since discharge to 0.9v under load. No version has ever discharged cells to 0v.

 

[VidPro]

Re: Resolution of ZERO Voltage NIMH and 1.2V Eneloop NIMH

I thought through this apparent contradiction between the larger currents (.2 Ah x 16 hours) and the current I am using .5 Ah x 4 hours for the Eneloop AA cell.

The larger current is for a new ZERO VOLTAGE NIMH to be used as a FORMING CHARGE. These Eneloop AA batteries start with 1.2V and an initial capacity of 1200 mAh right out of the package. When they come off the assembly line, they start at ZERO Voltage. The customer does NOT see it directly off the assembly line.

Thus, the Maha instructions are correct for a ZERO VOLTAGE NIMH as a forming charge. To apply a FORMING CHARGE to an Eneloop with one volt or more is to significantly REDUCE its ability to maintain a charge for a long period of time. However, a Forming Charge would be correct for an Eneloop AA cell with zero volts right after it is manufactured.

Thus, it is correct to apply 2000 mA for 1.1 hours or 200 mA for 16 hours to zero voltage NIMHS or Eneloops coming off the assembly line. For the consumer Eneloops NEVER start with zero volts.

If our Eneloops ever drop below .9V, they are FINISHED. Discharge Mode on the LaCross drops the voltage to ONE Volt and then raises it to 1.52V. If you use the MH-C9000, Disharge Mode will drop it to ZERO VOLTS and ruin an Eneloop. Personally, I would never use Discharge Mode on the MH-C9000 for Eneloops and never use Refresh Mode on the BC-900.

Using the LaCrosse BC-900 Version 33, which is the one I use, applying 500 mA for 4 hours to an Eneloop AA cell with ONE Volt gets it to 1.52V correctly. It then drops to 1.4V after disconnection.

For Eneloop AAA cells the correct application if the battery starts with at least 1V should be 200 mA for 4 hours. It also then rises to 1.52V and drops initally to 1.4V after disconnection.

Another consequence of this situation is that the Refresh Mode should never be used on Eneloops. It SHOULD be used on zero volt NIMHS when new.

All rechargeable cells should be charged in twos or fours so that the odds of missing an end point are significantly reduced. When one or three cells reach an end point, the remaining cell should be watched carefully and removed from the charger if it still remains charging after 15 minutes with 1.52V or higher.

some of what your saying here is confusing sounding at the least.

* you can charge enloop 2000ma AAs in the 900 at 500ma, it usually terminates properly on good cells at that rate. it is a bit low to insure termination EVERYTIME, it has worked fine everytime i have done it.

* dumb (slow) charging doesnt terminate it stays at the low rate, below specs for overcharge , so there is not a huge pressing need to terminate at full charge, its within spec for overcharge.

* the basic idea here being represented and understood is that on a fast charger you want to be fast enough to incurr termination everytime, on a slow dumb charger termination isnt AS nessisary. But on a fast charge if it does not terminate, it goes over the overcharge specs. the occurance of non-temination is not normal, it happens Rare and causes problems.

* you can Zero out an enloop, and it doesnt KILL it, and certnally doesnt damage it immediatally. what you can't do, or want to seriously avoid, is reverse charge.
When you pull a battery out of a SERIES device and it READS 0V chances are it DID reverse charge, and that does do major damage. but taking them to 0V without reverse charge has proved to be of no significant consequence YET. yet meaning i have only done it so many times. after many CONTROLLED zeroing out of enloops i have found Zero evidence of a capacity reduction.

these "smart charging' machines do not take the cell to 0v ever during a discharge, or a refresh or a forming or anything. almost all of them stop at .9v or 1v in some way or another, and working properly they do that everytime without failure , about the only thing they Will do 100% of the time without failure

* how does a forming charge that still terminates at the .9v or 1v, or that stays within the overcharge rate spec damage the cell? can you explain that? a forming charge is nothing more than a dumb slow charge that stays within spec for the overcharge rate. i have found ZERO evidence that a forming charge does any damage at all? mabey your explaination is just confusing?

*How is refreshing the cell going to damage it, the refresh cycle while totally unnessisary usually, does nothing more than work the cell the same way it would if you discharged it in a device then recharged it, but in a totally controlled manner ??? other than the overcharge state it keeps getting to before it terminates, it is not any different than USE.

* then you indicate you use a TEST cycle? ok so refreshing cycle is going to damage it, ok so refreshing is unnessisary at the least. but a test cycle does a single full refresh? which is it? will you stop cycling needlessly or not ? or is test cycling concidered a valuable assett even though refreshing isnt?

* the 1.52 (or whatever) volts of the termination point is not a Fixed ammount, termination does not occur Always at 1.52v it can occur at many different displayed voltages depending on when the V-drop occurs, which can depend on many factors, like charge rate, temperature and the state and age and type of the cells??

there are many things your saying that are confusing, i have specifically tested some of them, because i needed to test for my uses. i think you need to clarify things.

Silverfox is a very patient person, even patient with me he is usually %99.98 correct, even if the truth sucks

 

[Mitch470]

Proper Charge Current?

some of what your saying here is confusing sounding at the least.

* you can charge enloop 2000ma AAs in the 900 at 500ma, it usually terminates properly on good cells at that rate. it is a bit low to insure termination EVERYTIME, it has worked fine everytime i have done it.

* dumb (slow) charging doesnt terminate it stays at the low rate, below specs for overcharge , so there is not a huge pressing need to terminate at full charge, its within spec for overcharge.

* the basic idea here being represented and understood is that on a fast charger you want to be fast enough to incurr termination everytime, on a slow dumb charger termination isnt AS nessisary. But on a fast charge if it does not terminate, it goes over the overcharge specs. the occurance of non-temination is not normal, it happens Rare and causes problems.

* you can Zero out an enloop, and it doesnt KILL it, and certnally doesnt damage it immediatally. what you can't do, or want to seriously avoid, is reverse charge.
When you pull a battery out of a SERIES device and it READS 0V chances are it DID reverse charge, and that does do major damage. but taking them to 0V without reverse charge has proved to be of no significant consequence YET. yet meaning i have only done it so many times. after many CONTROLLED zeroing out of enloops i have found Zero evidence of a capacity reduction.

these "smart charging' machines do not take the cell to 0v ever during a discharge, or a refresh or a forming or anything. almost all of them stop at .9v or 1v in some way or another, and working properly they do that everytime without failure , about the only thing they Will do 100% of the time without failure

* how does a forming charge that still terminates at the .9v or 1v, or that stays within the overcharge rate spec damage the cell? can you explain that? a forming charge is nothing more than a dumb slow charge that stays within spec for the overcharge rate. i have found ZERO evidence that a forming charge does any damage at all? mabey your explaination is just confusing?

*How is refreshing the cell going to damage it, the refresh cycle while totally unnessisary usually, does nothing more than work the cell the same way it would if you discharged it in a device then recharged it, but in a totally controlled manner ??? other than the overcharge state it keeps getting to before it terminates, it is not any different than USE.

* then you indicate you use a TEST cycle? ok so refreshing cycle is going to damage it, ok so refreshing is unnessisary at the least. but a test cycle does a single full refresh? which is it? will you stop cycling needlessly or not ? or is test cycling concidered a valuable assett even though refreshing isnt?

* the 1.52 (or whatever) volts of the termination point is not a Fixed ammount, termination does not occur Always at 1.52v it can occur at many different displayed voltages depending on when the V-drop occurs, which can depend on many factors, like charge rate, temperature and the state and age and type of the cells??

there are many things your saying that are confusing, i have specifically tested some of them, because i needed to test for my uses. i think you need to clarify things.

Silverfox is a very patient person, even patient with me he is usually %99.98 correct, even if the truth sucks

VidPro,

I have a few questions. What is the proper mA current to apply to AA Eneloops to charge them? Why does the Eneloop Charger use a low mA rate? Eneloop chargers use 300 to 550 mA for AA cells. Is only the MH-C9000 qualified to charge the AA Eneloops? I happen to use a LaCrosse BC-900 Version 33. Those 2 chargers operate quite differently.

You mention the use of high mA currents to prevent overcharging. What is wrong with charging 4 batteries and just manually terminating the last to show its full by just removing the battery at 1.52V to prevent a missed termination?

Does any form of charging really matter much? Do they all accomplish the same result?

 

[VidPro]

Re: Proper Charge Current?

VidPro,

I have a few questions. What is the proper mA current to apply to AA Eneloops to charge them? Why does the Eneloop Charger use a low mA rate? Eneloop chargers use 300 to 550 mA for AA cells. Is only the MH-C9000 qualified to charge the AA Eneloops? I happen to use a LaCrosse BC-900 Version 33. Those 2 chargers operate quite differently.

You mention the use of high mA currents to prevent overcharging. What is wrong with charging 4 batteries and just manually terminating the last to show its full by just removing the battery at 1.52V to prevent a missed termination?

Does any form of charging really matter much? Do they all accomplish the same result?

proper ? oh oh, is there such thing when there are many methodologies/alogrythms. Proper is more based on the design/type of the charger, and the intention of it.
if you go all cheap, proper would be to keep the rate low, make a dumb cheap charger keep the rate really low, and everything will work out ok, because you dont go over specs. then have a very sensitive termination, which can sometimes fail and leave you with a 20% charge battery.

proper for a "smart charger" or fast charger is to insure that pressure temperature or voltage drop are monitored, and it stops at overcharge.

Proper for a 350ma charger would be to monitor temperature, which is almost impossible due to changes in ambient temps, or use a Voltage 0 detect instead of a voltage drop. if the charger looks for the voltage to stop going up, instead of start going down , then it can terminate easier at lower charge rates. that should be very good, but it can fail too, just like anything. stuff like that can fail by terminating EARLY, the battery not fully charged.

about anything will charge a enloopy, and most of the things sold and recommended wont damage it, and rates vary from 230ma (averaged) which is a very slow rate , to excessive speeds like 8000ma , which arent good for anything except speed.

the 900 and the 9000 are different, but not that much different, they have the same basic functions, just applied differently by the programmer. one says tomAto one says tomato. you can do a slow or fast rate charge with either. just the 900 doesnt have timer termination for a 200ma rate, the 9000 can do a "forming" thing and terminate on time. the 900 really cant, unless you include charging to slow for termination. the 9000 doesnt get stuck with a 1/2 rate discharge function.

You mention the use of high mA currents to prevent overcharging. What is wrong with charging 4 batteries and just manually terminating the last to show its full by just removing the battery at 1.52V to prevent a missed termination

i mentioned high rates to insure termination which prevent overcharging or baking of a cell. but things are indeed happy to go slow TOO with a charger that works in that way.

these 2 things the 900 and 9000 are designed to terminate based on a voltage drop from what i understand, if they dont get it, they bake the battery. they dont terminate on the taper, the terminate on the drop, so you slam the battery (higher rate) till it gets that drop, because just tapering off to 0 change isnt the way they work.

There is Nothing wrong with terminating the charge at some set voltage, but i assure you it will not always be 1.52 volts for 99% charged cell, some cells you can pull at 1.55 and they are only 80% charged, in TIME i would bet that the enloops will start acting aged , lots of time.
Also when the cell is not vibrant, when the resistance of it is lower, terminating at some set voltage the cell would not be fully charged.
for example if you let that cell park unused for some 6 months, and come back to it, it will terminate at a higher voltage.
some cells terminate before that, like at 1.47 , and again at some rate of charge. the rate can cause or not cause the overcharge state to occur at different votages, it is a unreliable method to assume completion at that point, and by removing the battery it will not "finish off" with the topping charge.
AlTHOUGH
there is nothing wrong with terminating any of them at say 1.4v and continuing to top it off very slowly. in my opinion that would be Much better than the present "smart" methods. Or just having it at 80-90% and using it that way. there is nothing wrong with Not reaching overcharge states, i dont like overcharge states, and neither does the battery.

the wrong occurs when it sits on the fence of the overcharge state, at an overcharge rate, and just heats up.

Yes all charging methods charge up the battery, so yes they are all the same, but some do more or less damage to the cell, between charger damage, and reverse charge damage in series configurations, that is probably MOST of the reasons a cell doesnt do 1000 cycles, but more like 150-200.
if you can stop all charger damage, and reverse charge damage, then you have happy long living cells. probably somewhere in Pleasantville or the emerald city that can happen

 

[Mitch470]

Thanks

proper ? oh oh, is there such thing when there are many methodologies/alogrythms. Proper is more based on the design/type of the charger, and the intention of it.
if you go all cheap, proper would be to keep the rate low, make a dumb cheap charger keep the rate really low, and everything will work out ok, because you dont go over specs. then have a very sensitive termination, which can sometimes fail and leave you with a 20% charge battery.

proper for a "smart charger" or fast charger is to insure that pressure temperature or voltage drop are monitored, and it stops at overcharge.

Proper for a 350ma charger would be to monitor temperature, which is almost impossible due to changes in ambient temps, or use a Voltage 0 detect instead of a voltage drop. if the charger looks for the voltage to stop going up, instead of start going down , then it can terminate easier at lower charge rates. that should be very good, but it can fail too, just like anything. stuff like that can fail by terminating EARLY, the battery not fully charged.

about anything will charge a enloopy, and most of the things sold and recommended wont damage it, and rates vary from 230ma (averaged) which is a very slow rate , to excessive speeds like 8000ma , which arent good for anything except speed.

the 900 and the 9000 are different, but not that much different, they have the same basic functions, just applied differently by the programmer. one says tomAto one says tomato. you can do a slow or fast rate charge with either. just the 900 doesnt have timer termination for a 200ma rate, the 9000 can do a "forming" thing and terminate on time. the 900 really cant, unless you include charging to slow for termination. the 9000 doesnt get stuck with a 1/2 rate discharge function.

You mention the use of high mA currents to prevent overcharging. What is wrong with charging 4 batteries and just manually terminating the last to show its full by just removing the battery at 1.52V to prevent a missed termination

i mentioned high rates to insure termination which prevent overcharging or baking of a cell. but things are indeed happy to go slow TOO with a charger that works in that way.

these 2 things the 900 and 9000 are designed to terminate based on a voltage drop from what i understand, if they dont get it, they bake the battery. they dont terminate on the taper, the terminate on the drop, so you slam the battery till it gets that drop, because just tapering off to 0 change isnt the way they work.

There is Nothing wrong with terminating the charge at some set voltage, but i assure you it will not always be 1.52 volts for 99% charged cell, some cells you can pull at 1.55 and they are only 80% charged, in TIME i would bet that the enloops will start acting aged , lots of time.
Also when the cell is not vibrant, when the resistance of it is lower, terminating at some set voltage the cell would not be fully charged.
for example if you let that cell park unused for some 6 months, and come back to it, it will terminate at a higher voltage.
some cells terminate before that, like at 1.47 , and again at some rate of charge. the rate can cause or not cause the overcharge state to occur at different votages, it is a unreliable method to assume completion at that point, and by removing the battery it will not "finish off" with the topping charge.
AlTHOUGH
there is nothing wrong with terminating any of them at say 1.4v and continuing to top it off very slowly. in my opinion that would be Much better than the present "smart" methods. Or just having it at 80-90% and using it that way. there is nothing wrong with Not reaching overcharge states, i dont like overcharge states, and neither does the battery.

the wrong occurs when it sits on the fence of the overcharge state, at an overcharge rate, and just heats up.

Yes all charging methods charge up the battery, so yes they are all the same, but some do more or less damage to the cell, between charger damage, and reverse charge damage in series configurations, that is probably MOST of the reasons a cell doesnt do 1000 cycles, but more like 150-200.
if you can stop all charger damage, and reverse charge damage, then you have happy long living cells. probably somewhere in Pleasantville or the emerald city that can happen

Vidpro and SilverFox,

Thanks for all the discussion. It appears that any reasonable way to charge Eneloops will make most of them last 2 years at which point all will be discarded including batteries and chargers. At that time it is highly probable the next generation will be out and all of them will make it to the junk heap - not from overcharging or too many cycles - but from OBSOLESCENCE.

 

[TorchBoy]

Re: Thanks

I have really old NiMHs (1800mAh) that I still use. They are not obsolete, and they still work very nicely, with an average 1719mAh when I last tested them.

And you really don't need to quote huge long posts if you're not actually replying to specific points made in them. Thanks. Like this:

* you can Zero out an enloop, and it doesnt KILL it, and certnally doesnt damage it immediatally. what you can't do, or want to seriously avoid, is reverse charge.
When you pull a battery out of a SERIES device and it READS 0V chances are it DID reverse charge, and that does do major damage.

I presume you're drawing a distinction here between zero volts under load and zero volts without any load?

 

[Mitch470]

Re: Thanks

I have really old NiMHs (1800mAh) that I still use. They are not obsolete, and they still work very nicely, with an average 1719mAh when I last tested them.

I, personally, always go for the latest technology. Its my hobby. Thus, I discard most every hi-tech toy I have in 2 or 3 years including my PC, TV's, batteries, battery chargers, GPS unit, radios, flashlights, camera, etc.

 

[TorchBoy]

Re: Thanks

... GPS unit

Send your next one my way. :thumbsup:

I've found, like many others it seems, that older NiMH cells have very low self discharge... just like the latest LSD NiMH cells, strangely enough. It makes me wonder just how new the technology inside Eneloops really is. How much is just marketing? Either way, both my old cells and my Eneloops are likely to be around for many more years.

Since you're OK with high turnover, do you prefer the higher capacity cells?

 

[Mitch470]

Re: Thanks

Send your next one my way. :thumbsup:

Since you're OK with high turnover, do you prefer the higher capacity cells?

I send all my old toys to my 6 grandkids. I was using Maha 2700 mAh NIMH's but gave them all away and am only using Eneloops for now. If they increase their capacity, I'll give away the AA - 2000 mAh's and the AAA - 800 mAh's. If a more advanced charger appears, I'll give away my BC-900 but NOT for the MH-C9000. I'd need the next generation charger to dump this one. I still use my Ansmann Energy 8 for C, D and 9 volt NIMHs.

For non-rechargeables I only use Lithiums rather than regular alkalines. I don't care even if it costs slightly more. If 4000 mAh Lithiums came out and were also rechargeable, I'd dump all my present batteries.

I have a hunch that the next generation chargers will have different routines for Hybrids versus Standards built into their systems and will handle all sizes of AA, AAA, C, D and 9 Volt.

At the moment I'm anxiously awaiting the introduction of the Garmin 750 GPS to be available in one week.

I just spent 2 days getting my Anycom Bluetooth Stereo speaker working in my living room with transmissions coming from my Dell PC in my Computer Room.

 

[TorchBoy]

Re: Thanks

I have a hunch that the next generation chargers will have different routines for Hybrids versus Standards built into their systems ...

How would anything differ? The same routines work well for both.

 

[VidPro]

Re: Thanks

I

I presume you're drawing a distinction here between zero volts under load and zero volts without any load?

zero volts , is zero load unless they are in series, and then it is heading into reverse charge if there is still a load .
yes, i totally make that distinction, reverse charge VERY BAD, using a single one up all the way not big problem

like say in a zebra light, or single AA light, or single battery digicams, or single minimag solitares stuff like that , should not KILL the cell to have accidentally flattened it.
although as some people mention , some chargers wont accept it till you unflatten it, that doesnt mean its dead yet, it just needs a bit of charge so the "smart" charger isnt so dumb about it the smart charger probably figures its a short or dead.