Eneloop Charging Question

[Dave Huck]

Hi folks,

Apologies in advance for any stupid questions, I'm a newcomer to recharging with "intelligent" chargers.

I just bought a few sets of Eneloop Pros in AA and AAA sizes. I also bought an Ansmann Powerline 4 Pro to charge them with. I've just put the AAs on charge to top them off but I'm confused by the Ansmann display, I selected a standard charge at 600 ma and the time display has been steadily increasing (started at 39 minutes and has steadily increased to over 2 hours.

The voltage is currently showing as 1.47 (increasing from an initial 1,41) with the mAh currently showing 1350 (increasing from an initial 900).

Two questions:

I thought eneloops were supplied fully charged? (these were supplied by 7dayshop and show as made 11/15). If so, how come they only read 900mAh on initial charging? I would have expected 85% of 2450?

Why has the Ansmann time display crept up and up while charging? I reread the manual and it's definitely time remaining.

I have a virgin set of AAA eneloop pros made in Feb 2016 (supplied by Maplin, £7.99 for 4 at the moment v. cheap!). I may test them out in a bit and compare.

Would be grateful if anybody could advise whether this is just a quirk of the charger (or user error...) or duff cells?

Update: The first battery now shows Full with the other 3 bays very hot and showing 1580 odd mAh. Definitely concerned that I have a bad set of batteries or a duff charger.. Unless it's designedone with an assumption of battery capacity is charge rate x 3?


Cheers

Dave

 

[ChrisGarrett]

Hello, welcome aboard.

Eneloops are supposedly charged up to only 70% (solar) at the factory, so they're not full by any stretch. That's a general speculation, as it could be slightly less, or slightly more.

2500/30%=750mAh.

We like to charge AA Eneloops at 1A, so the charger doesn't miss termination.

I don't know about your charger, but dV/dT (voltage/temperature) are the two methods that chargers may use to terminate charge. It sounds like you might have missed termination on those three bays.

Chris

 

[KeepingItLight]

I do not know anything about the Ansmann charger, but, based on its specs, it does look good. It has multiple termination methods, including one on temperature, so you probably did not harm your batteries.

The Eneloop Pro is rated for 2450mAh, so a 600ma charge rate is definitely a bit low. It works out to only about 0.25 "C." I like Chris' recommendation. Try a 1A charge rate. You could even go higher.

I recommend you perform a test cycle with all four batteries. That's where the Ansmann charges/discharges/charges all at once. Set the charge rate to 1A; discharge, nearer to 0.5A. Keep your eye on the Ansmann during the test. If you suspect your batteries are getting too hot, or if you have other concerns, don't be afraid to stop the test.

I suspect you will not have any problems. This test will allow you to gain confidence that your charger/analyzer is doing a good job and that your batteries are in good condition.

 

[archimedes]

I have used a Maha MH-C9000 for years, without any issues, until last week it apparently missed termination on all 4 bays for AA eneloops

Charge current was at 1000 mA.

Does that Maha have a temperature cutoff, as a backup termination signal ?

The cells were rather toasty (but not burning hot) when they popped out ....

 

[Dave Huck]

Thanks for the answers guys, much appreciated. The Ansmann seems a little restricted in the higher charging levels, you can only select 800 or 1,500 mAh. As suggested, I'll try a test cycle on 800 charge and 400 discharge and see what happens.

By the way, what charge rate would you recommend for the following cells in the Ansmann (options are 400/600/800/1500/1800):

AAA Pros

AA Standard Eneloops

AAA Standard Eneloops

I'll repost the results of this thread on the Brights section of British Blades, could be useful for UK based Ansmann owners.

Cheers!

Dave

 

[KeepingItLight]

Does that Maha have a temperature cutoff, as a backup termination signal ?

Sorry, that's something I do not know.

 

[markr6]

By the way, what charge rate would you recommend for the following cells in the Ansmann (options are 400/600/800/1500/1800):

Just my suggestions...

AAA Pros: 800

AA Standard Eneloops: 1500 (1000 would be nice. I've missed termination at 700 many times, so I'm hesitant to say 800)

AAA Standard Eneloops: 600 or 800 (leaning towards 600)

 

[Dave Huck]

Thanks guys, will try a test cycle on the higher charge rate and see what happens.

Markr, many thanks for the advice will use those charging rates and see how it works out.

Cheers

 

[acteng]

What charging rates do folks recommend for the Eneloop Lite cells?

I picked up some of these at IKEA -- the new LADDA ones in the brown wrapper appear to be Eneloop Lites.
At $1 each I can now start to replace all the alkaline batteries around the house in remotes, etc.
AAA = 500mAh and AA = 1000mAh. My charger is the BC-2000 / BT-C2000.