A Look at 15 Minute Charging

[Jackson]

Several years ago when I got a digital camera that used AA batteries, I began my research into the world of rechargables. At the end of my research, I decided on getting the Rayovac I-C3 charger and cells. My reasoning was that I would negate the self discharge problem with the ability to charge very fast. Plus, I thought, these batteries shouldn't suffer from the problems associated with 15 minute charging because they were specifically designed for that charge speed.

What I found was that the I-C3 system was more like a 30 minute charging system. The batteries were so hot at the end of the 15 minute charge, that they needed another 15 minutes to cool down. And, they had to stay in the charger for that extra 15 minutes.

One time, I was in a hurry and charged the batteries 15 minutes before I had to leave. I knew the batteries would be hot, but thought they could just cool down inside the battery case during the drive to my destination.

When I went to remove the batteries from the charger, I actually felt the outer cover pulling back. This is not something I expected from a cell engineered for 15 minute charging.

Here's a photo of the aftermath:


My cells never got close to the 500 or 1000 advertised cycles before the self discharge got bad enough that the cells would not work in my digital camera 4 days after a charge.

I only ever charged the cells in a charger specifically designed to charge them. I can't imagine how the Rayovac marketers could advertise in good faith that these batteries get 500-1000 cycles.

 

[Grog]

I've used the RS version of those, and they have worked great for the last two years. I use the cells in a radio receiver and run the heck out if it.

 

[SilverFox]

Hello Jackson,

Welcome to CPF.

It sounds like you may have faulty cells. The IC3 system incorporates a switch that is activated by the build up of pressure inside the cell. There is a correlation between internal cell pressure, temperature, and the cells state of charge. If your "valve" is a little slow to go off, it would result in high cell temperatures.

I believe Ray O Vac had some "issues" with this system, and it is no longer available. When everything works properly, it is a very good system.

With 2000 mAh cells, you may be able to get close to 500 cycles on the Energizer and Duracell 15 minute chargers, but the cycle life of 2500 mAh cells dropped to around 150 cycles.

Tom

 

[MorePower]

I believe Ray O Vac had some "issues" with this system, and it is no longer available. When everything works properly, it is a very good system.

The reason the IC-3 system is no longer available is mainly a matter of cost. It couldn't be sold at a price to compete with the Duracell and Energizer 15 minute systems. It was a very good system, but the cell design was fairly complex and therefore more costly to manufacture.

 

[SilverFox]

Hello MorePower,

Thanks for clearing that up.

Any ideas on why his cells are getting hotter than normal?

Tom

 

[Grog]

I will add, the only reason I bought mine was when RS put them on clearance, I was able to pick up the charger w-2AAs for $10 and a 4pk of AAs for another $6 (or something close). That being said, I got my money's worth.

 

[Avatar28]

Hello Jackson,

Welcome to CPF.

It sounds like you may have faulty cells. The IC3 system incorporates a switch that is activated by the build up of pressure inside the cell. There is a correlation between internal cell pressure, temperature, and the cells state of charge. If your "valve" is a little slow to go off, it would result in high cell temperatures.

I believe Ray O Vac had some "issues" with this system, and it is no longer available. When everything works properly, it is a very good system.

With 2000 mAh cells, you may be able to get close to 500 cycles on the Energizer and Duracell 15 minute chargers, but the cycle life of 2500 mAh cells dropped to around 150 cycles.

Tom

I used I think it was a Duracell 15 or 30 minute charger and I think that it completely killed my Energizer 2500 mAh cells. They only worked for a few tens of cycles after I started using it. It may only be one bad cell but I can't tell which one so I just threw the whole lot of them out the other day.

 

[MrAl]

Hi again,

As much as i hate to say it, i never believe anything Rayovac says anymore.
I dont trust anything their ads say because i have found just about
everything they say is based on something other than fact.
It started with their Renewal Cells, where they originally claimed 50 recharges,
and yes, you could get 50 recharges but only if you used the cell for two
seconds and then recharged it right after that (ha ha). If you used it the
way most people use cells (because after all they need to discharge the
cell to use it) then you get about 8 recharge cycles before they discharge
so fast you dont want to use them anymore.
When i saw their charger i immediately said "NO" because i wanted to see how
it faired in the marketplace over a few years before i started investing in
their stuff again. It has paid off to wait.
In general though for these unusual technologies i find it's best to wait to
see how they work out in the long run before buying into them, no matter
what the company is.
The reason behind this is because within a company the decision to
'ship or not to ship' comes long before there is even one working
product sometimes, or the decision comes based on a souped up
model. Unfortuntately, the souped up model is not what gets to market,
it's the cost reduced and feature cut version that does.
We got very lucky with the white LEDs though, as they worked out very well
in the long run while many other products did not.

It looks like maybe the other battery companies are following suite, so
i guess we'll see how their ads vs products work out in the future.

My philosophy now is that everyone should test their cells to see if they
really are up to standard, or at least close. Sometimes it even affects the
product itself when the cells are used in packs, which they almost always
are. With three 'good' cells and one 'not so good' cell, the device they are
used in might keep drawing current as the 'not so good' cell charge dies down,
and since the other three are still going strong, they reverse charge the
'not so good' one. If you knew ahead of time that one cell was much lower
than the rest you could use another 'good' cell from another pack (buy 4 more)
and stop this from happening.

 

[MorePower]

Hello MorePower,

Thanks for clearing that up.

Any ideas on why his cells are getting hotter than normal?

Tom

I don't remember the max allowable temp for charging cells with the IC-3 charger, but I do remember it was rather high. I'm pretty sure that the charger has a fan built into it which is supposed to turn on and help cool the cells. It's possible that the fan is kaput. I see from the photo that the cells are 2300mAh, which I believe is one of the later variations on IC-3 cells. The first were only 2000mAh. There were changes in cell design necessary to reach the higher capacity, so that may be a contributing factor as well.

The first thing I'd check is whether or not the fan on the charger is working.

 

[illumiGeek]

I have several of the older 2000mA IC-3 cellls and I have used and abused them heavily with excellent results. The newer 2300mA cells are crap. They can't deliver nearly as much current, and even in lighter load use they only had more capacity for about the first 10 cylces or so (if even that). After that they started losing capacity and shelf life rapidly, and now are practically useless.

Same for the Energizer 15 minute. My older 2200mA cells are still going strong after lots of use, but all my much newer 2500 cells have completely failed.

It's really a shame manufacturers have decided capacity is more important than quality. All the new high capacity AA cells I have tried are absolute crap!

Aloha, Tim

 

[Jackson]

The first thing I'd check is whether or not the fan on the charger is working.

The fan worked. It kicked on almost immediately and stayed on until the charge was complete.

 

[Avatar28]

Another thing is that I don't think it's possible to get anything like a full charge into any cell in 15 minutes. Even if you're trying to beat them half to death with the charge rate, I doubt you would see more than 80% charge with it.

Personally, I think you would be better off to just keep an extra set of charged batteries on hand. Eneloops work well for the purpose.

 

[DavidD]

SilverFox has tested the 15 min chargers and concluded that they charge to about 98%, IIRC. Not a totally complete charge, but very close. IMHO, 15 min chargers are handy to have around. I have the Energizer 15 minute charger.

I am also a big fan of Eneloops.

 

[Avatar28]

SilverFox has tested the 15 min chargers and concluded that they charge to about 98%, IIRC. Not a totally complete charge, but very close. IMHO, 15 min chargers are handy to have around. I have the Energizer 15 minute charger.

I am also a big fan of Eneloops.

Wow, then that's better than I had heard. I guess they must have significantly improved them over the early ones I heard of. Still it seems you must surely be beating the crap out of your batteries to get them to take a charge that fast.

 

[koala]

I am glad we don't have ebay chargers that claims 10 minutes charging. Imagine if they fail to terminate.

There's a company that makes 8 minutes charger!!! :thinking::shrug:

To achieve that 15minute charging is quite a feat. Amazing amount of current being forced in to your cells. These 15mins charging system is a good news to the companies that produce them. They'll cook your cells, so your cells die earlier and therefore you have to buy more.

As mention in previous posts, these cells are costly to make, so they require more resources that means it is bad for the environment. No doubt they are handy but I if there's really a need, I stick to the 30 minute chargers which is compatible to most NiMH cells.

Heat kills so keep the heat down.

 

[bob_ninja]

Wow, then that's better than I had heard. I guess they must have significantly improved them over the early ones I heard of. Still it seems you must surely be beating the crap out of your batteries to get them to take a charge that fast.

This pattern keep repeating. SilverFox's test showed only a slight lifespan decrease due to 15 min charging as opposed to slower rates. Meanwhile real life users keep getting far worse results and very short lifespans.

Seems that most/many battery makers simply lie and don't care. It started with a "slightly" exaggerated capacity and moved on to complete lies about lifespan, etc.

At this point there are only 2 companies that I would buy only LSD batteries from: Sanyo Eneloop and perhaps Maha's new LSDs. Sanyo has proven in Eneloop brand that it stands behind its claims. Maha of course has a good reputation for chargers, so I'll give them a chance. Everyone else is just pushing volume, quality be damned.

So much for quick charging. BTW, this also point to a big difference between 15 min chargers and a huge effect on cell lifespan. Seems this one really sucks. Others are probably much better.

 

[MrAl]

Hi again,

Tom had tested the 15 minute charger and he had results that showed
something like 150 charges with the 15 minute charger, but now that i
think about it im not sure what he used for the control in this experiment.
Perhaps if he reads this he can chime in and remind us all.

150 charges with the 15 minute charger, how many with a normal say
2 hour charger?

Also, i have used my 15 minute charger and it seem to work pretty well.
I also modified it to charge in 30 minutes and that allows higher internal
resistance with the AA cells, which some of my older cells required.
Here's the picture story:
http://mral.peu.net/index.php?page=EnergizerChargerMod

 

[bob_ninja]

I think it was the Energizer 15 min charger.
Actually after about 150 cycles the test cells were not dead. They still had plenty of life left. Which is in stark contrast to this case. Hence I am guessing that Energized charger is better. Also the cell types SF used were probably better.

Still a lot of people get far worse results in actual use.

Nobody did tests with slower chargers because it takes forever. You can only guess from people's reports. For instance, most people report their old NiMH 2 Ah and lower capacity cells still working fine after many years (using older slower chargers). These days many people report poor lifespan of new high capacity cells (2.5+ Ah). See the Energizer discussion that just will not stop. It is not just a single bad batch.

Is it due to 15 min chargers or due to poor cell design? Likely it is the combination of both. Hence Sanyo's new Eneloop batteries have both lower capacity (back to 2 Ah) and slower chargers (around 4 hours). I wonder why

I am sure that for SilverFox, you and other experienced battery geeks 15 min chargers work fine. The trouble is that higher capacity 2.5+ Ah batteries are fragile and 15 min chargers are certainly not gentle on them, resulting in premature failures if proper care is not taken. How many times do I retrieve a battery from a toy that is discharged too low? This is common for most people. You just cannot track all of them and ensure they don't go below 0.9V
Hence I use NiCd cells which can handle that abuse well and recover. My Enregizers didn't last even 100 cycles.

 

[lumenal]

Two quick comments :

From all I've read about 15 min. chargers here at CPF, including SilverFox's report, it seems 2000 mAh and under cells are more robust and will take to fast-charging better than the higher capacity cells, with thinner, more fragile construction.

Two of my nine chargers are 15 minute ones, so I try to read all the info available here. No fast-charging hi/cap cells here.

And as far as flaky 2500 mAh cells, I have a year old set of EnergyGeezer 2500s, which will hold a charge for 3 months or more, with very little self-discharge. Go figure... (Japans no less!) :huh:

 

[MorePower]

One thing to keep in mind is that the Rayovac 15 minute charger only charges Rayovac IC3 in 15 minutes. For all other brands and types, I believe it uses timed termination.