Initial charge on Eneloops, charging strategies.

[Muse]

I just bought 2 four-pack Eneloop AAA's from Amazon.com and the initial charge on every one showed at 1.30v. I popped one into my Sandisk Sansa m250 MP3 player and only got 3 hours out of it before the player shut down. I popped in another Eneloop and got only 35 minutes or so.

Is this typical? The player should give 10 hours or better with a well charged cell.

Which cycle should I do in my La Crosse BC-900 charger? Refresh or Discharge? Should I use the lowest voltages (i.e. 100 ma discharge and 200 ma charge) while doing so?

 

[Marduke]

Re: Initial charge on Eneloops (AAA)

Eneloop ship only partially full. Just charge them up and enjoy.

 

[Mr Happy]

Re: Initial charge on Eneloops (AAA)

The AAA's may have been old--they may even date from 2006 (the AAA size is much less popular than AA). I would just charge them up and try again before worrying about refresh cycles, especially with such a low drain device.

 

[Muse]

Re: Initial charge on Eneloops (AAA)

The AAA's may have been old--they may even date from 2006 (the AAA size is much less popular than AA). I would just charge them up and try again before worrying about refresh cycles, especially with such a low drain device.

OK, thanks. I almost always do a discharge/charge cycle with my BC-900 instead of a Charge cycle so that I get a display of capacity. I keep records of capacity for all my rechargeables.

When charging AAA's in the BC-900 charger, I wonder if I should use the lowest rates (100/200) instead of the 250/500 many recommend for AA cells because of the charger's sometime problem of missing cutoff at top charge when using the low rates. I'm concerned that 250/500 might be too much for such small cells. I've been using 100/200 with 8 Rayovac Hybrid NiMH AAA's for a year or so, and AFAIK the charger has not missed a cutoff (?). Can someone speak to that? Thanks.

Based on the advice above, I changed the charger from Refresh to Discharge (using 100/200 rates).

 

[Marduke]

Re: Initial charge on Eneloops (AAA)

OK, thanks. I almost always do a discharge/charge cycle with my BC-900 instead of a Charge cycle so that I get a display of capacity. I keep records of capacity for all my rechargeables.

When charging AAA's in the BC-900 charger, I wonder if I should use the lowest rates (100/200) instead of the 250/500 many recommend for AA cells because of the charger's sometime problem of missing cutoff at top charge when using the low rates. I'm concerned that 250/500 might be too much for such small cells. I've been using 100/200 with 8 Rayovac Hybrid NiMH AAA's for a year or so, and AFAIK the charger has not missed a cutoff (?). Can someone speak to that? Thanks.

Based on the advice above, I changed the charger from Refresh to Discharge (using 100/200 rates).

Using the BC-900, to get a reading of capacity, you need to run a "test" cycle. "Discharge" will not give you the cell's stored capacity.

 

[SilverFox]

Re: Initial charge on Eneloops (AAA)

Hello Muse,

Although the BC-900 reportedly terminates properly at low charge rates, eventually charging at low charge rates will result in a missed termination and possible damage to your cells.

The usual recommended charge rate is 0.5 - 1.0C. For Eneloop AAA cells, that would be in the 400 - 800 mA range.

Tom

 

[Muse]

Re: Initial charge on Eneloops (AAA)

Hello Muse,

Although the BC-900 reportedly terminates properly at low charge rates, eventually charging at low charge rates will result in a missed termination and possible damage to your cells.

The usual recommended charge rate is 0.5 - 1.0C. For Eneloop AAA cells, that would be in the 400 - 800 mA range.

Tom

Thanks Tom. In the future I will charge at 500 ma (both AA and AAA). I don't know why the Discharge cycle would not give as accurate a reading of cell capacity as the Test cycle, but will do the Test cycle as recommended. If anyone can speak additionally to the subject, please do! Am I going to have less lifetime service out of my rechargables if I routinely do the Test cycle?

 

[Muse]

Re: Initial charge on Eneloops (AAA)

Using the BC-900, to get a reading of capacity, you need to run a "test" cycle. "Discharge" will not give you the cell's stored capacity.

The Discharge cycle gives a reading of stored capacity. You are saying that it's not an accurate reading?

 

[N162E]

Re: Initial charge on Eneloops (AAA)

Hello Muse,

Although the BC-900 reportedly terminates properly at low charge rates, eventually charging at low charge rates will result in a missed termination and possible damage to your cells.

Tom

Sorry Tom but, I have never heard this, seen it or experienced it. I have always used low rates and never had a cell "Eventually" miss a termination. Higher rates on the BC-900 mean more heat at the end of charge.

 

[Marduke]

Re: Initial charge on Eneloops (AAA)

The Discharge cycle gives a reading of stored capacity. You are saying that it's not an accurate reading?

The "discharge" starts with discharging the cell, and then charging it. The capacity displayed is how much energy went into the cell, which is an overestimate since not all of that energy is actually stored.

"Test" first charges the cell, then discharges, then charges again. The capacity shown is a measure of the discharge portion, which is an accurate representation of how much energy is actually stored inside the cell.

You do not need to always do a cell "test", so it does not use many cycles up. Just when you want to check the cell health. Simply charging a cell is sufficient most of the time.

 

[Muse]

Re: Initial charge on Eneloops (AAA)

The "discharge" starts with discharging the cell, and then charging it. The capacity displayed is how much energy went into the cell, which is an overestimate since not all of that energy is actually stored.

"Test" first charges the cell, then discharges, then charges again. The capacity shown is a measure of the discharge portion, which is an accurate representation of how much energy is actually stored inside the cell.

You do not need to always do a cell "test", so it does not use many cycles up. Just when you want to check the cell health. Simply charging a cell is sufficient most of the time.

Why is the capacity shown during a Discharge cycle not actually going into the cell? I do see that the capacities shown when using the Discharge cycle do look too high, often far to high to be believed. Why is this? Isn't the charger only counting energy going into the cell after the discharge process is complete?

 

[SilverFox]

Re: Initial charge on Eneloops (AAA)

Hello Fred,

I borrowed some "abused" cells from my neighbor and charged them up on the BC-900 at 200 mA. These were AA and AAA cells. 6 of 8 cells missed termination.

I take very good care of my cells and always charge AA cells at 1000 mA and AAA cells at 500 mA when I use the BC-900. At these charge rates, and with vibrant cells, I haven't had any problems with missed terminations.

I picked up some AAA cells that had open circuit voltages in the 0.2 - 0.8 volt range. The first charge on the BC-900 at 200 mA has all cells missing the end of charge termination.

I took some of these same AAA cells and tried them on my Schulze charger at 250 mA. All the cells I tried terminated early at that rate, but when I charged them at 500 mA they terminated properly.

If you don't think you are having any issues with proper termination while charging at 200 mA, your cells must all be new or they are in very good condition. As soon as the develop some additional internal resistance, your BC-900 will miss the termination.

If you would like to switch BC-900 chargers with me, I would be happy to put some of my very limited crap cells through your charger and document that your charger misses terminations too.

Tom

 

[SilverFox]

Re: Initial charge on Eneloops (AAA)

Hello Muse,

When charging you will always end up putting a little extra into the cells. At 1C, you end up putting around 105% back in. At 0.5C it goes up to around 110%. At lower charge rates you can get all the way up to 120%, but if your are seeing amounts greater than that it means your charger missed termination.

Tom

 

[N162E]

Re: Initial charge on Eneloops (AAA)

Hello Fred,

If you don't think you are having any issues with proper termination while charging at 200 mA, your cells must all be new or they are in very good condition. As soon as the develop some additional internal resistance, your BC-900 will miss the termination.

If you would like to switch BC-900 chargers with me, I would be happy to put some of my very limited crap cells through your charger and document that your charger misses terminations too.

Tom

Yes, this is all true. My cells are all in good condition. My question here is why would anyone continue to use known bad cells. Maybe I'm wrong but, one of the reasons I test is to find and eliminate failing cells before they create a problem. However, I am not believing that low charge rates will be the cause of missed termination in good cells.

 

[Muse]

Re: Initial charge on Eneloops (AAA)

Hello Muse,

When charging you will always end up putting a little extra into the cells. At 1C, you end up putting around 105% back in. At 0.5C it goes up to around 110%. At lower charge rates you can get all the way up to 120%, but if your are seeing amounts greater than that it means your charger missed termination.

Tom

Well, I hope I haven't already screwed up my "new" Eneloop AAAs. Just got two 4 packs from Amazon. I charged 4 of them (2 had crapped out early in my MP3 player), one was used for a while in it and the other I hadn't used yet) in my BC-900 using the Discharge cycle at the lowest dis/charge rate and evidently they all missed termination based on your criteria. The capacities shown in the BC-900 were from 1166 up to 1292.:mecry:However, the charger showed Full for all cells.

 

[SilverFox]

Re: Initial charge on Eneloops (AAA)

Hello Fred,

I agree that people shouldn't use crap cells, but this slow charge issue has to do with transforming good cells to crap cells.

You should really take this up with all the battery manufacturers. They are the ones that made the observation. I simply confirmed it...

It isn't always the case where a manufacturer will supply you with good information, but when they do, you get better results by following it. After spending years slow charging and being dissapointed with cycle life and other cell performance issues, I decided to follow the manufacturers recommendations and charge at their recommended rates. I have, for the past few years, enjoyed wonderful performance from my cells and they last much longer than my cells did when I used slow charging.

I wear out 40 - 50 NiMh cells in about 2 years. Prior to following the manufacturers recommendations, I would go through that many cells in under a year. I am very pleased with this. Not only do I save some money, but I am also seeing much better performance from my cells during the time they are in use.

I will never go back to slow charging.

Tom

 

[SilverFox]

Re: Initial charge on Eneloops (AAA)

Hello Muse,

Time will tell...

Tom

 

[Muse]

Re: Initial charge on Eneloops (AAA)

Hello Muse,

Time will tell...

Tom

I just charged the other 4 Eneloop AAAs I just bought but with these did a Test cycle using 250/500 dis/charge. The reported capacities are:

781
772
757
783

Big difference. I just hope the other 4 aren't already ruined. Too bad the electronics in the BC-900 are so weak.

Dan

 

[N162E]

Re: Initial charge on Eneloops (AAA)

Hello Fred,

I agree that people shouldn't use crap cells, but this slow charge issue has to do with transforming good cells to crap cells.

You should really take this up with all the battery manufacturers. They are the ones that made the observation. I simply confirmed it...

It isn't always the case where a manufacturer will supply you with good information, but when they do, you get better results by following it. After spending years slow charging and being dissapointed with cycle life and other cell performance issues, I decided to follow the manufacturers recommendations and charge at their recommended rates. I have, for the past few years, enjoyed wonderful performance from my cells and they last much longer than my cells did when I used slow charging.

I wear out 40 - 50 NiMh cells in about 2 years. Prior to following the manufacturers recommendations, I would go through that many cells in under a year. I am very pleased with this. Not only do I save some money, but I am also seeing much better performance from my cells during the time they are in use.

I will never go back to slow charging.

Tom

Hi again Tom

Once again, Thanks for more of an explanation than I probably deserve. I sincerely appreciate your experience and patience. I'm going to continue to slow charge and see how it goes.

Thanks again,

Fred

 

[N162E]

Re: Initial charge on Eneloops (AAA)

Big difference. I just hope the other 4 aren't already ruined. Too bad the electronics in the BC-900 are so weak.

Dan

Hi Dan,

What part of the BC-900 electronics do you consider weak?

Fred