Question on charging Sanyo 2700's with Eneloop charger

[Wicho]

Well, I just got my order of 12 Sanyo 2700's. I charged them in my Eneloop chargers (the first generation ones withe the sliding cover) until the green light went out, and got about 1.5 hours of Turbo Mode on my Fenix L2D Q5's. Hmmm...

So, do you think the batteries didn't completely charge? Should I run them through two charge cycles, or is this charger smart enough to completely charge them and then turn itself off?

I know, I should buy a C9000 - I'm planning on it next week, but in the meantime...according to (I think Silver Fox's) charts, I should be getting around 2 hrs 15 minutes on Turbo on these cells in my lights, yes?

Thanks for your help,
Wicho.

 

[SilverFox]

Hello Wicho,

This thread may help you out.

Tom

 

[Wicho]

Thank you!

 

[Bones]

So, do you think the batteries didn't completely charge? Should I run them through two charge cycles, or is this charger smart enough to completely charge them and then turn itself off?

There's a post in the thread that SilverFox referred you to that does indicate your charger doesn't completely charge higher capacity cells Wicho.

I noted in a subsequent post that I've never seen mine run longer than 7 hours; making me suspect it is timing out.

Unfortunately, I don't have any high capacity cells with which to confirm this suspicion.

Perhaps you could test this for us all by fully discharging 4 of your 2700mAh cells, and then monitoring their charge.

I would suggest doing an initial check at 6 and 1/2 hours, and then monitoring the charge periodically from then on, especially around the 7 hour mark.

If it terminates the charge by timing out at around the 7 hour mark as I suspect it will, then it is definitely undercharging your cells.

Since it charges at 300mAh, it can only apply a 2100mAh charge to your 2700mAh cells in 7 hours. Perfect for Eneloops, but not nearly long enough for your higher capacity cells.

As well, if it is timing out, then you should be okay with unplugging the charger to reset the timer, then restarting the charger and letting it terminate automatically.

Please note that although this charger does seem to terminate very reliably, it would be still be prudent to monitor the second charge just to be sure.

Once you get a feel for how it is handling the second termination, then you can adjust your attention to the charge accordingly.

There are inefficiencies involved, so I'm not sure how long the second charge should take, but I would expect at least another three to four hours.

Please be sure to let us know your findings.

 

[Wicho]

Bones,

I will do what you mentioned and report back. I'll have to do it starting tomorrow morning since I like to sleep at night, not watch batteries. Plus, my wife thinks I'm weird enough as it is. :laughing:

 

[Bones]

Bones,

I will do what you mentioned and report back. I'll have to do it starting tomorrow morning since I like to sleep at night, not watch batteries. Plus, my wife thinks I'm weird enough as it is. :laughing:

Thanks Wicho.

Our reputations do seems to suffer from our little obsessions though.

There's a post somewhere on this forum of a member testing the temperature of a cell by sliding it around on his tonque.

It was only after the fact that he thought about how this might have looked had he been observed by another member of his family...

 

[radellaf]

I would recommend using your lips rather than tongue, they are more sensitive for one thing. Tongues should be reserved, in battery terms anyway, to check the status of 9V batteries.

300mA is not going to kill 2700mAh cells. I mean, sure, best to be there to watch it (and tell us what you observe), but 6-7 hours overcharge at that rate isn't somethng I'd worry about if you don't keep doing it.

2100mAh total charge isn't likely to put a full charge on a 2000mAh eneloop, either. At that low a rate 2400-2600 would be needed. Even at 1C, at least 2200. Assuming the eneloops were 2000, rather than 1850 or whatever they tend to be. 113% for 1850... I wonder if it isn't running a little "hot" vs the 300mA spec.

Does it rly time out that soon? Well, it's certainly safe then...

Anyone tested the 2-cell plug-in Eneloop charger? That's what I have two of, though I bought a friend two of the 4-cell ones for her two offices.

 

[tslrc]

I was also curious, so I tested charging 4 new Duracell AA 2650's in the NC-MQN05U - here are the test results:

I first discharged them on the C-9000, then waited an hour.

Charged on the MQN05U for 7hrs. 56mins.(2380 mAh) until the green light went out then waited 30 minutes

Plugged it back in and it charged for another 1hr. 36mins. (480 mAh) until green light went out.

Total time = 9hrs. 32mins. for a 2860 mAh total charge.

The batteries were only slightly warm after the first charge, but were rather warm at the end of the second charge, warmer than I expected but I had no way to measure other than holding them.

About 1.5 hrs. after the above charge, I then discharged at 500 mA on the C-9000 when I got home from work and found the following:

1 1.29V 2452 mAh
2 1.30V 2486 mAh
3 1.29V 2450 mAh
4 1.29V 2409 mAh

Obviously the 2860 mAh total charge that went in above is quite possibly only for one of the batteries, as some surely terminated earlier than others.

 

[tslrc]

Added discharge results to my last entry.

 

[Wicho]

Well, I charged my Sanyo 2700's in the Eneloop charger yesterday morning - the green light went off somewhere between 7 and 8 hours later. Couldn't watch it that last hour because I had to leave the house. I had two chargers going with a total of eight batteries and they both did the same thing.

After I got back home, I disconnected the chargers and then plugged them back in for another three and a half hours - the light was still green when I unplugged them. I needed the batteries so I wasn't able to find out how much longer it would have taken for the green light to turn off.

I'm trying it again this morning and will let you know what happens. I will say that yesterday evening my lights ran much longer than the first time during my night ride.