Energizer 15/min charger hacks

[mal]

Bought a Energizer 15/min charger some years ago and was quite happy with it. Used mostly to charge a 20 pack of a cheapy brand bought at Fry's called X1 and a few GP as well as the 4 batteries that came with the charger. Then over the last 6 months I started getting flashing reds from the charger. First with the X1's and then with the GP's and finally with the batteries that come with the charger. After searching this forum to find help I became convinced that it was because the batteries were not fully discharged. After discharging in a cordless phone with auto off I was able to get the batteries that came with it the charger to charge. But no luck with the other batteries I have. Maybe I should say rechargeable. All the batteries I'm talking about are NMH. Now the rechargeables that didn't come with the charger recharge fine in an old Rayovac PS1 I have. So I know they are not dead. But the PS1 takes a whole lot longer to charge and they don't charge very high. About 1.34v compared to the 1.42-44 that the 15/min did. So is there a way to hack this thing so it will charge my other batteries? I mean the only difference between the rechargeables that came with the charger and the others I have is some kind of special magnetic(?) band around the energizer 15/min. rechargeables that the charger is suppose to sense, right? I think I read that here back when I was making the decision what charger to upgrade to. Also is there a good but cheap discharger out there? I'm only seeing that feature on the very expensive chargers around here. Is the Energizer still the king of quick chargers? I don't have the time to cruise forums like I used to. Many thanks to all of you who contribute to this forum so dedicatedly. It's always been a great read. Sorry for there not being any paragraph space in my post. For some reason the post window keeps removing them when I preview my post. Mal

 

[Marduke]

The Energizer 15 minute charger is one of the most damaging chargers out there if used on a routine basis to charge your cells. The cells are most likely beaten to death already. New cells (such as Eneloops) and a modern smart charger is probably a wiser investment.

 

[Larbo]

The Energizer 15 minute charger is one of the most damaging chargers out there if used on a routine basis to charge your cells. The cells are most likely beaten to death already. New cells (such as Eneloops) and a modern smart charger is probably a wiser investment.

Please explain a bit about what info you have to support this claim. I bought one of these 15 minute chargers a few months ago and have 16 2450mah energizers to feed my TK40, I chose this partly because in a charger review in the forums here and it seemed to have pretty good specs...anyway with the lite use this torch gets cell life should not be a issue, besides I can always get more...Thanks lovecpf

Charger Reviews
http://www.candlepowerforums.com/vb/showthread.php?t=70935

 

[Marduke]

Please explain a bit about what info you have to support this claim. I bought one of these 15 minute chargers a few months ago and have 16 2450mah energizers to feed my TK40, I chose this partly because in a charger review in the forums here and it seemed to have pretty good specs...anyway with the lite use this torch gets cell life should not be a issue, besides I can always get more...Thanks lovecpf

Charger Reviews
http://www.candlepowerforums.com/vb/showthread.php?t=70935

The charger charges at ~4C, which is extremely high. Cells regularly charged at that rate will not last very many cycles before the frequent overheating leads to them having a high internal resistance and impedance, not to mention a much higher self discharge. Silverfox did some testing which showed this in greater detail. There is also MANY user experiences to cooberate.

While it is a decent charger while used OCCASIONALLY, it is NOT recommended to be used as your primary charger.

Seperate from the charger, the Energizer cells are also not very good. The old 2500's were HORRIBLE, and there are starting to be reports of the 2450's not being much better.

 

[Hondo]

First, I am no fan of really fast charging, I returned an Energizer 30 minute charger because of how hot the cells got during the charge, and won't even try the 15 min. version, I am never in that much of a hurry.

But, in all fairness, Silverfox's torture test of cells on the 15 min Energizer vs a 1C charge rate on, if I recall, a C9000, showed only about 20 or 25% less cycles until a significant loss of capacity for the cells charged on the Energizer. That was of course back-to-back cycles, and there could be more difference with more time between each fast charge cycle, no way to know without a much more drawn-out test.

Still, I don't like charging above 1C, and normally choose 0.5C or less when I know the charger is still able to terminate properly at a low charge rate. But a lot of the high self discharge stories I am aware of relate to the notorious Energizer 2500 batteries, and not so much the 15 min. charger.

As far as cells that have devoloped high internal resistance, the Energizer 15 min. charger is known to be quite picky about them and will error out. For that matter, really bad ones will error on my C9000, Duracell Mobile and Power Gage chargers, and a Rayovac smart charger that I have. Only my Lacrosse B700 will take them, and it still manages to find termination with them as well.

 

[Mr Happy]

Bought a Energizer 15/min charger some years ago...

The problem with the 15 minute charger is that it charges too fast. For long life, NiMH batteries should be charged no faster than about 1-2 hours.

What happens with the 15 minute charger is that the cells get hot and develop extremely high internal pressures. This can cause the cells to pop their safety vent and let gases escape. After repeated venting the internals of the cell dry out with the loss of electrolyte.

As they cells dry out they lose capacity and increase their internal resistance to the point where they are refused by chargers and cease to work well. This damage is irreversible and the only thing to do is replace the old cells with new ones.

If you buy new cells and don't want to kill them, a charger you could look at is the Duracell Mobile Charger. Also consider the new breed of PreCharged cells; they stay charged for months so you don't need to recharge them in a hurry.

 

[Larbo]

This unit has a small fan to blows from the bottom of the case over the batteries, they do get "warm" during some if the charge but not too warm you cant place the back of your hand on them. I think the next recharge I will use my Infrared thermometer and get a temp reading, btw charging times are about 22 to 23 minutes so it may be a bit easier on them, thanks for all the input :thumbsup:

lovecpf

 

[Ardillakilla]

I have a lot of cells that prematurely turned to "crap"--some even when they were quite new (and not Energizers). My first two chargers were fast chargers. The batteries got quite hot and some even vented or their covers warped from the heat. Needless to say, they have high impedance and the C9000 refuses to charge the majority of them. Now, I never fast charge batteries.

 

[MarioJP]

Not only did the Energizer 15 minute charger caused a great deal of grief. I never really got great use out of my cells effectively that i end up replacing them way too soon. All this time I could not figure out what was killing them until I found out from CPF that I should just get rid of the 15 minute charger and replace the cells that was used in this charger.

I will say that the only cell that manage to take the abuse from this charger, are my Duracell precharged cells.

They are slightly damaged but it stills hold its charge and still performing, but I will eventually replace them since the 15 minute charger tells me that these cells have develop a high resistance as it will no longer charge them.

And as cells getting hot?? They get really hot that the wrapper actually starts to melt. Sometimes I hear small popping sounds too. Now the higher capacity batteries have develop a very high self discharge to the point that you have to recharge them everyday lol.

 

[Mr Happy]

And as cells getting hot?? They get really hot that the wrapper actually starts to melt. Sometimes I hear small popping sounds too.

Like cooking sausages on the grill :devil:

 

[Larbo]

I guess time will tell, even if I get only 70 or so recharges out of them that puts me ahead of the game money wise (vs buying alkaline batteries) plus I can charge these from the car...live a learn.

 

[Egsise]

This unit has a small fan to blows from the bottom of the case over the batteries, they do get "warm" during some if the charge but not too warm you cant place the back of your hand on them. I think the next recharge I will use my Infrared thermometer and get a temp reading, btw charging times are about 22 to 23 minutes so it may be a bit easier on them, thanks for all the input :thumbsup:

lovecpf

I guess the fan keeps the surface of the cells cool, the cells internal temperature is the problem, right?

 

[Larbo]

OK here is the temperature result this evening,

Start of charging 74F
After 4 min 101F
After 8 min 108F
After 10 min 115 * Peak Temp
After 12 min 104
After 16 min 99
After 20 min 99 (Green Light) Charge Over

Granted this is surface temp and an hour or two charge would be easier on the cells these temps shouldnt be too extreme.

Not too scientific, but an idea of whats going on.:candle:

 

[Mr Happy]

OK here is the temperature result this evening,

Start of charging 74F
After 4 min 101F
After 8 min 108F
After 10 min 115 * Peak Temp
After 12 min 104
After 16 min 99
After 20 min 99 (Green Light) Charge Over

Granted this is surface temp and an hour or two charge would be easier on the cells these temps shouldnt be too extreme.

Not too scientific, but an idea of whats going on.:candle:

Granted 115°F doesn't seem too extreme, but it's not only the temperature. The high current also generates gas at the electrodes faster than it can be reabsorbed, which raises the internal pressure of the cell and sometimes pops the vent. Whenever the vent pops it represents an irreversible loss of electrolyte in the cell.

 

[Egsise]

I think that measurement should be done without the cooling fan, that would give more realistic numbers compared to 0.5-1C chargers.

 

[sparkysko]

Yeahhhh, don't use the 15 min charger. It made my eneloops vent.

 

[Mr Happy]

I think that measurement should be done without the cooling fan, that would give more realistic numbers compared to 0.5-1C chargers.

Can you spell KABOOM!?

 

[Egsise]

Yeap I think that could happen. :laughing:

On the other hand, if 0.5-1C charger would use similar cooling fan, the cells surface temperature would stay very close to room temperature.
So compared to that 15min charger IS very hard to cells.

 

[zipplet]

I have a GP fast charger that will charge 1-2xAA in 15-20 minutes or 3-4xAA in 40-50 minutes. I stopped using mine for general use once I got my LaCrosse BC-700 because of what I'd heard.

Surely enough, the 8 batteries I'd been using with that charger have since been tossed due to developing high internal resistance to the point that they would trip the overheat cutoff on the BC-700 halfway through charging.

It's true folks. Don't use a super fast charger as your general one, only as your "oh crud, Im going out in 1 hour and need some batteries" charger.

 

[clintb]

It's true folks. Don't use a super fast charger as your general one, only as your "oh crud, Im going out in 1 hour and need some batteries" charger.

That's the exact message people need to take away when reading about, or using, the 15 min chargers. MarioJP, you listening?

Tom (SilverFox) has done extensive testing on the effects of the 15 min charger; I think anyone considering using one would do well to read that thread and understand the tradeoffs. From his tests, cells charged exclusively on the 15 min would poop out after ~150 cycles. Think about it for a moment, that's 7.5A being crammed into a AA cell and it lasts for ~150 cycles. To me, that's awesome.