Energizer is getting another call

[jcs71]

Well, friday night I was charging up some batteries on Energizer's family charger and the led display went out on it. So now I have no idea when the batteries are done charging. Man that sucks. I actually liked that charger.

It is a good thing I bought the combo charger with 2 LSD batteries when I bought those other packs of Duracell LSD's. Duracell's little charger takes about 6 hours to charge up batteries. It also has an led display to let you know when they are charging, the led is red, and when they are done, the led is green. It worked ok, but man are the batteries hard to put in this thing. It is very tight.

It is going to be interesting to see what Energizer does about this. If they just send coupons it looks like I will be able to stock up on Alkalines for emergencies.

I wish I had the money to get me a Maha C9000 or at least a LaCrosse BC900( I think that's the correct model#).

 

[Gator762]

If you do some research, the slower charge like your Duracell's is MUCH better. The fast chargers really take a toll on cells, and are not needed anymore with LSD cells. 200 MA/h is a good charge rate, so for a 2000 MAh cell, that's 10 hours to charge.

I have a BC-900, it's a nice charger.

 

[Curious_character]

If you do some research, the slower charge like your Duracell's is MUCH better. The fast chargers really take a toll on cells, and are not needed anymore with LSD cells. 200 MA/h is a good charge rate, so for a 2000 MAh cell, that's 10 hours to charge. . .

Can you please point me to a reference or two where I can learn why and in what ways the charge requirements are any different for LSD than for any other NiMH cells? I had been under the impression that they were exactly the same. Thanks!

c_c

 

[Marduke]

Can you please point me to a reference or two where I can learn why and in what ways the charge requirements are any different for LSD than for any other NiMH cells? I had been under the impression that they were exactly the same. Thanks!

c_c

They are not any different. The point he was trying to make is with LSD cells, they keep their charge for a long time, so you don't need to throw discharged cells on a quick charger when you need power just because your cells self discharged in storage.

 

[Black Rose]

200 MA/h is a good charge rate

Not according to Battery University (for a 2000 mAh cell).

 

[jcs71]

Thanks for the replies so far. I am glad that the Duracell is a better one. I am going to start saving up for a Maha or a LaCrosse.

 

[Gator762]

Not according to Battery University (for a 2000 mAh cell).

That's very interesting, and different than my experience, my BC-900 documentation, and what I've read here.

There's some contradiction at Battery University. You should use a fast charge rate, but should avoid heating the cells. A fast charge is gonna heat the cells. I'm a bit surprised as I'm sure he knows more about cells than I.


Someone here did a hardcore stress test rapid charging Eneloops and some other cells. Wish I remember the author. He found cells rapidly detoriated after as little as 30 cycles if I recall.

In my own experience, I've had many 2000-2200 MAh cells crap out to only 200-500 MAh. Generally I've used the Energizer 15 minute charger, only charging 2 at a time with good airflow around the unit. I've refreshed a bunch. The 100 discharge/200 charge rate has given me much better results than refreshing at higher rates. But it sure does take a awful long time.

YMMV.

 

[Gator762]

They are not any different. The point he was trying to make is with LSD cells, they keep their charge for a long time, so you don't need to throw discharged cells on a quick charger when you need power just because your cells self discharged in storage.

Exactly.

 

[Black Rose]

Someone here did a hardcore stress test rapid charging Eneloops and some other cells. Wish I remember the author. He found cells rapidly detoriated after as little as 30 cycles if I recall.

That was SilverFox, our resident battery guru.

Deterioration started to show at cycle 125.

After 150 cycles, the Eneloop went to battery heaven, since they already went through battery hell

There's a whole thread regarding the BC-900 vs MH-C9000 chargers, so I'm not going to go into that again :laughing:

 

[Mr Happy]

There's some contradiction at Battery University. You should use a fast charge rate, but should avoid heating the cells. A fast charge is gonna heat the cells. I'm a bit surprised as I'm sure he knows more about cells than I.

There is fast, and then there is too fast. The optimum time for a fast charge is 1-2 hours. 15 minutes is just way too fast.

Good cells don't get hot during a fast charge until the end of the charge time when they are nearly fully charged. The rise in temperature triggers a voltage response that tells the charger when to stop charging. This is a bit of a balancing act though, as the faster charge rates give a better end of charge signal, but it's bad for the batteries if the charger misses it. Slower charge rates give a weaker end of charge signal, but less immediate harm if it is missed.

Really good chargers may use more sophisticated methods to detect end of charge at lower rates, so they can be used more reliably without needing the higher charge currents. The Sanyo chargers like the MQN05 and MQN06 seem to be in this category.

 

[Curious_character]

Yes, I don't see anything in SilverFox's analysis which indicates that charging at slower than 0.5C (e.g., 1A for a 2000 mAh cell) is beneficial in any way compared to charging at that rate, which was the claim seemingly made earlier in this thread. Or did I miss something?

I don't believe any manufacturer recommends charging as fast as the 15 minute charger he used, except for cells specifically made for use with that charger. So I don't see why we should be surprised that it has a detrimental effect on cells.

c_c

 

[Mr Happy]

In fact, in this post I did a very crude test of charging an Eneloop at 150 mA vs 1600 mA. The results indicated that charging efficiency was just as good at 1600 mA as 150 mA, and may even have been slightly better. The test gave no reason to believe that charging at 150 mA would have an advantage.

 

[Gator762]

That was SilverFox, our resident battery guru.

Deterioration started to show at cycle 125.

After 150 cycles, the Eneloop went to battery heaven, since they already went through battery hell

There's a whole thread regarding the BC-900 vs MH-C9000 chargers, so I'm not going to go into that again :laughing:

Well thanks for your post... I tracked down this info from Sanyo's site looking for their charging recommendations, not knowing if LSD rules are different or not.

1. How long does it take to charge an eneloop battery in the eneloop 2-position compact charger?
   From 2 to 4 hours.
2. Can I use a "Quick Charger" to charge an eneloop battery?
   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. It is strongly recommended to use eneloop, GE/Sanyo or Sanyo NiMh battery chargers. We only warrant eneloop if used with an eneloop, GE/Sanyo or Sanyo NiMh battery charger.

So if the Sanyo charger is 2-4 hours, then that means their recommendation is probably a 500-1000 mAh/h charge rate. They do not recommend charging past 1000 mAh/h. Could be due to their charger design, I don't know. I'll start charging my cells at the higher rates now.

 

[Curious_character]

In fact, in this post I did a very crude test of charging an Eneloop at 200 mA vs 1600 mA. The results indicated that charging efficiency was just as good at 1600 mA as 200 mA, and may even have been slightly better. The test gave no reason to believe that charging at 200 mA would have an advantage.

Most of the discussion has been about cell life vs charge rate. There's a persistent claim that charging at lower rates and/or temperature will extend the cycle life. Personally, I've never come anywhere close to the rated cycle life of any cell -- all mine have either died of some more dramatic cause, or become obsolete and been replaced long before reaching that point. But a lot of people seem to think it's important to get, say, 1000 vs 500 cycles from a cell. I haven't seen any real evidence, though, that charging at less than 0.5C or so will extend the cycle life.

Charge acceptance is another matter. One reason for the relatively high recommended charge rates for NiMH cells is that at low rates the change in voltage or temperature indicating the nearing of full charge becomes too small for a charger to reliably detect. (That's why Maha, for example, recommends at least 0.5 C for its MH C9000 charger -- and even at that rate I've had it miss the end of charge indication and grossly overcharge AAA cells on several occasions.) Another, according to some manufacturers, is that charging is more efficient at higher rates (that is, you don't need to apply as much extra charge) -- but that's not usually a concern for most folks. What we really care about is how full the charger gets the cell, even if it takes a bit longer proportionally. But I've found quite a wide difference between (approximately 2 hour nominal) chargers in the amount of charge they'll put into a cell before terminating the charge. And I'd think it likely that even the same charger is likely to be better at determining the full charge point at one current than another, so charge a cell more fully at one rate than another. So apparent differences in capacity due to charge rate are more likely be due to the peculiarities of charger charge termination than any inherent property of the cell, unless you put a measured charge into known fully discharged cells as Mr Happy did.

c_c

 

[TorchBoy]

If you do some research, the slower charge like your Duracell's is MUCH better. The fast chargers really take a toll on cells, and are not needed anymore with LSD cells. 200 MA/h is a good charge rate, so for a 2000 MAh cell, that's 10 hours to charge.

If you want me to take your opinions seriously you would do well to use correct capitalisation for your units and use the correct units! Capacity is mAh, while charge rates are in mA or A, which is current. MAh is mega-amp hours and might be used to describe the capacity of a small hydroelectric dam (if anyone cared about the capacity of such a thing rather than the potential energy in joules it held). You didn't even use the superfluous but accurate mAh/h to describe the amount of capacity the charging would be adding each hour.

Anyway, if by "fast" you mean 1-2 hour chargers, it's rubbish that fast chargers are not needed for LSD cells. One, it's pointless to wait 16 hours when 2 will do the same job with no significant damage, and two, long slow charging can promote crystal growth which decreases capacity. I suspect because of this SilverFox says the fast rate keeps cells vibrant. The 15 minute chargers take a noticeable toll on cells, but LSD cells are among the most rugged of available consumer NiMH cells, and even then last 150 cycles, as has been mentioned above. The cost/benefit of that is something individual users would have to decide.

Sanyo ... their recommendation is probably a 500-1000 MAh charge rate. They do not recommend charging past 1000 MAh.

They do not. Get your units right.

 

[Gator762]

If you want me to take your opinions seriously you would do well to use correct capitalisation for your units and use the correct units!

If you want me to take your capitalization seriously you'll need to spell capitalization correctly.

Seriously thanks for correcting me for the proper units!

 

[TorchBoy]

If you want me to take your capitalization seriously you'll need to spell capitalization correctly.

:laughing: I actually wondered about that as I typed it, but decided to spell it in English rather than American. :nana:

 

[MrAl]

Hello,

jcs:
I have the Energizer 15 min charger and it only has one LED and that
makes it hard to tell if all 4 cells are plugged in right. I wish
it had 4 LEDs instead. I also wrote to the company to ask them to
update the charger to do one-half charge rate to be easier on the
cells and also to allow some cells with slightly higher internal
resistance to charge normally, but they rejected the whole paper
saying that they might already have that idea in the works (ha ha).

Gator:
Not sure what you mean by:
"The fast chargers really take a toll on cells,
and are not needed anymore with LSD cells."
I would say that just because we use an LSD cell
that doesnt mean we dont 'need' a fast charge,
does it?

Curious:
I had some problems with the Energizer 15 minute charger in that
it wouldnt charge some cells, so i modified it (thread here on
CPF somewhere with detailed instructions and plenty of pics)
to charge at one-half the normal rate (30 min charge instead of
15) and then realized that it's better for the AA cells
anyway, so now i do all my AA cells at the 30 min rate instead.
The cells stay very cool compared to the 15 min rate charging.

 

[Gator762]

Hello,

Gator:
Not sure what you mean by:
"The fast chargers really take a toll on cells,
and are not needed anymore with LSD cells."
I would say that just because we use an LSD cell
that doesnt mean we dont 'need' a fast charge,
does it?

Curious:
I had some problems with the Energizer 15 minute charger in that
it wouldnt charge some cells, so i modified it (thread here on
CPF somewhere with detailed instructions and plenty of pics)
to charge at one-half the normal rate (30 min charge instead of
15) and then realized that it's better for the AA cells
anyway, so now i do all my AA cells at the 30 min rate instead.
The cells stay very cool compared to the 15 min rate charging.

Mr. Al,
With LSD cells, why not keep a few spares charged? They don't drop like regular cells. I also have the Energizer 15 minute charger. I stopped using it now. With spares, it doesn't really matter if they take 15 minutes to charge or a few hours. Maybe some long term cases of travel. Short term travel I can bring a bunch of spares just as easy as charger.

Read my previous post about the Eneloop cells. I indirectly got the charging rates from the Eneloop charger, and the times it takes to charge their 2000 mAh cells. I've also learned from this thread. Charge too slow and you risk crystallizing NiMH. I haven't really researched or found if there is risk crystalling NiMH LSD cells, but the chemistry is the same. Search on NiMH charging here and I think you'll find many recommend between .5 C and 1 C for a charge rate. I am now experimenting with my BC-900 charger and rates myself.