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Old Dec 27, 2010, 07:42 PM
Nakelp
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Question
Eneloop batteries.

Whats the best settings to charge 8 pack (Tx batteries) of eneloop batteries.
each is 1.2 V 1900 Mah
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Old Dec 27, 2010, 07:49 PM
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1.5 amps max but I usually just recharge with the Tx wall wart charger overnight.

mw
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Old Dec 27, 2010, 08:39 PM
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Charge at 1 amp
Discharge at .5 amp

Cheers
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Old Dec 27, 2010, 08:40 PM
Nakelp
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Thx guys
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Old Dec 27, 2010, 08:41 PM
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Originally Posted by crusey_aus View Post
Charge at 1 amp
Discharge at .5 amp

Cheers
And what do you base your numbers on? Mine are based on actual use and recommendations by battery pack suppliers.

mw
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Old Dec 27, 2010, 08:49 PM
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Here's the Eneloop FAQ page:

[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, Sanyo or Sanyo NiMh battery chargers. We only warrant eneloop if used with an eneloop, Sanyo or Sanyo NiMh battery charger.]

And their charger page.

Make your own informed decision.
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Old Dec 27, 2010, 09:22 PM
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For AA's i would not charge them with more than 800mah I like using 600mah charge rate for all my AA's
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Old Dec 28, 2010, 08:49 AM
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1/10 C (200mA for Eneloops) or less is good for a balancing slow charge. I more often then not just use the stock wall wart TX or RX chargers for my Eneloops. You can tell when they're done charging when the cells warm up a little.

People have charged Eneloops up to a 1 C rate (2000mA) with good results, but I only charge them at up to a 1/2 C rate (1000mA).
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Old Dec 28, 2010, 09:02 AM
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Originally Posted by Wrend View Post
1/10 C (200mA for Eneloops) or less is good for a balancing slow charge. I more often then not just use the stock wall wart TX or RX chargers for my Eneloops. You can tell when they're done charging when the cells warm up a little.

People have charged Eneloops up to a 1 C rate (2000mA) with good results, but I only charge them at up to a 1/2 C rate (1000mA).
Have to second this post based on all the years of using rechargeables. Standard recharge batteries such as NiCD's, NiMH, LiION should be charged at 1/10th capacity rate to ensure long life and also even charge if charging a pack.
Charging at higher rates are quite often used - but care must be taken to not overcharge and therefore 'vent' the cell. Once this happens - you will have reduced capacity and reduced life.

The cells quoted - I may be blowing against the wind - but I would not charge at higher than 1/10th rate - that is 190mA ..... For quick charge a standard shop charger of 300mA would be ok but only for a max of 6hrs ... checking cell temp. after a couple of hrs.

It is true that modern cells can take higher rates better than cells of yesteryear - but why push the limits ?

I've kept to above for many years and had no problems.
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Old Dec 28, 2010, 10:10 AM
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With round cells heat is the enemy. I don't think it makes a whole lot of difference as long as the pack does not get hot. Warm is good at the end of the charge. Of course, a c/10 or equivalent such as using the wallwart overnight will keep the series cells balanced.

Let's not bother splitting hairs on this one. It's relatively simple round cell chemistry.

mw
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Old Dec 28, 2010, 10:28 AM
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This has been extensively tested. You can charge them at about 500 mA at a delta of 7 mV or about 700 mA with a 5 mV delta. They can get warm when charged but if they get hot they won't last long. So figure it out yourself!
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Old Dec 28, 2010, 10:56 AM
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200 cycles charged and discharged at 1C (2A) rate with 10 min. rest between .

http://www.candlepowerforums.com/vb/...37#post2785837

They still delivered over 200 cycles before starting to lose capacity.

Yes charging at 200 mA rate would yeild longer life (more cycles) and charging at 1/3 to 1/2 C ( 700 to 1000 mA) is more practical for many.

My RC transmitters get charged at 50 to 110 mA depending on the OEM wal charger which came with the radio.

My loose Eneloops get charged at 1A (1000 mA) in a Mahan c 9000 charger which is a 4 channel charger so each cell is charged seperately.

I have used a Energizer 15 min. charger in the past( not with Eneloops) and while it works it does reduce the NiMh cells life span but perhaps for some it is worth it. Here is a comparison of reasonable charge rates versus 15 min. charges

http://www.rcgroups.com/forums/showp...15&postcount=1

Snip

Quote:
I am a big fan of the Energizer 15 minute charger. I am amazed that the batteries don’t just melt down into a puddle and burn up. It actually does a very good job of charging in a very short time.

Charles, along with several others, pointed out that in order to enjoy maximum cycle life you need to charge at a slow rate. I contacted Energizer, and they pointed out that the 15 minute charger was a new product and they offer it for convenience. If you want long cycle life, you charge at a slower rate



The really nice thing about Eneloops is that due to their LSD rate they do not have to be fast charged at the last minute. Charge them up taking your time and weeks / months later they are still go to go.

Charles
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Old Dec 28, 2010, 11:05 AM
Nakelp
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Ok so I will just keep charging the pack over night with Futaba charger from the wall.
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Old Dec 28, 2010, 12:41 PM
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Good plan. I should mention that I only fast charge my tx packs when I've pulled an "aw ", forgot to charge the night before and want to keep flying especially with the slope gliders.

mw
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Old Dec 29, 2010, 02:19 AM
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They still delivered over 200 cycles before starting to lose capacity......
That I regard as very poor life ... honest. Stated life by manufacturers I have found when cells are treated kindly by charging at recc'd 1/10th rate last usually more than spec'd. I would suggest that I have achieved more than 1000 or more cycles on average from cells .... most likely a lot more.

2 things kill any rechargeable .... a) over charging ... basically leaving on charger too long, b) high rates of charge causing excess temp and venting of cells.

Me - I hate spending money ... so look after my cells to get max life possible.

My JR Propo and Futaba's in the 80's had same Tx packs through 80's and 90's ... with only 1 change of flight packs for each ... that's over 20yrs for Tx each and about 10yrs for flights ... I would suggest that exceeds 200 cycles by a very large margin.
TBH - it was only when I wanted to ressurect my JR recently after storage that I needed to change the pack again.
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