Charging my new eneloops

[shadowbuds]

They're on their way soon and I know I don't need to charge them when they come. I have two chargers, one is my Duracell 15 min fast charger. The other is my Rayovac Hybrid charger which seems to charge hybrids in 4-8 hours. Which charger is best for my eneloops? Any insight will be helpful.

EDIT: Also, are there any side effects when charger eneloops in a solar charger? One more questions What is the nominal voltage for 1.2V NiMh Cells? Freshly charged mine reach anywhere from 1.4-1.49 and drop to about 1.39-38 after a day or two. Thanks!

 

[Fallingwater]

I was under the impression 15-minute chargers only charged the special cells in 15 minutes, and took their time to charge the others...

 

[SilverFox]

Hello Shadowbuds,

Eneloop cells are charged like any other NiMh cell.

Your voltage observations are "in the ball park."

Tom

 

[SilverFox]

Hello Fallingwater,

You are thinking of the RayOVac IC3 charger. It would only fast charge IC3 cells. All others would be slow charged.

The Energizer and Duracell 15 minute chargers will charge all brands, as long as they are healthy. When the internal resistance of the cell goes up, the 15 minute chargers reject the cell.

Tom

 

[Fallingwater]

It doesn't sound very healthy for the cells. Even my 30-minute charger cooks them, so much so that I'm looking for less ferocious alternatives... a 15-min charger would probably beat the hell out of them.

 

[shadowbuds]

I'll be sticking with the hybrid charger, thanks.

 

[SilverFox]

Hello Fallingwater,

Healthy cells charged on the 15 minute chargers do warm up, but their temperature seem to remain below 120 F. I just checked some and they were in the 110 - 115 F range.

Tom

 

[dano]

I charge Eneloops in a 3 hour charger, which I feel gives a good compromise between charge time, charge capacity (i.e. doesn't peak too soon) and cell heat.

I have botehr 15 minute chargers from Energizer and Duracell. The Energizer one is pretty forgiving, but cells get H-O-T. The Duracell charger is really picky, and will reject a lot of my AA cells, especially higher capacity ones (i.e. over 2000MaH) regardless of age.

I've been playing with one of those Sony CycleEnergy chargers that also has a reconditioning feature. It seems to do a good job, too.

--dan

 

[HarveyRich]

I have a T-8000 30 min charger purchased from Battery Junction. It has a fan which circulates air around the batteries when they are charging, which seems to keep the battery temperatures quite cool. It seems to work very nicely, especially given the quick charge time.

Harvey

 

[barkingmad]

You do (ideally) need to charge eneloops when you first get them - they are charged but not 100% (usually 75%+) - so useable but better to charge them first.

Would recommend the slower charger (3-4 hours) - most slow chargers seem to do a better job of charging to (near) full capacity.

 

[koala]

Please note that Eneloop is a 2000mAh cell. It is lower capacity than many cells in the market currently. Using ultra fast 15 minute charger will not be nice to Eneloops as they are made for 2500mAh cells and above. Generally you should avoid(IMHO) the 15mins chargers. They are cell killers. Stick to the 1-2hrs chargers.

 

[barkingmad]

I would only use a 15-minute charger if I absolutely had to - they often do not charge as fully and may well reduce the life of your cells. It's easier / better to keep a few extra spares and use a slower charger.

 

[SilverFox]

Hello Koala,

Actually, the 15 minute chargers are designed for the lower capacity cells. Mine came with 2300 mAh and 2400 mAh cells. The 15 minute figure is based on 2200 mAh cells.

The cycle testing with 2000 mAh cells did see some advanced aging with the 15 minute charge, however the difference was only about 25 cycles. A 2000 mAh cell charged 125 times on the 15 minute charger was very similar in performance to a 2000 mAh cell charged 150 times at 0.5C.

I feel that the advantage of having the ability to fast charge outweighs the loss of cycle life with lower capacity cells. I prefer to charge in the 0.5 - 1.0C range, but when I am in a hurry I throw my cells (including Eneloop cells) on the 15 minute chargers.

It is true that the 15 minute chargers don't fully charge cells, but 94% is pretty close. If you need a full charge, just leave them to trickle charge for about an hour.

Tom

 

[koala]

I see, so the US versions are a little different from the Australia ones. The ones I saw hanging on the shelf here is bundled with 2500mAh. I am abit old school when it comes to charging cells. Once I have matched a pair of cells, I baby them and treat them nicely.