Eneloop 2000mah - how to care? Especially if not used often/regularly?

[mouse07410]

I have AA Eneloops (2000mah) for TK-40 flashlight. That light is known to drain the batteries a little even when switched off. For now that flashlight is used mostly for emergencies, which means - not often.

It's been with new Eneloops (new, fully charged via Break-In mode in MAHA C9000) for a few months, occasionally turning the light on in Low mode. Finally the batteries got low, so I took them out to recharge.

First 4 I recharged in "Analyze & Refresh" mode. They all came out around 1800mah and 1.45v. I repeated "Analyze & Refresh" - pretty much same thing. A bit more capacity, same voltage.

I'm running 2nd 4 batteries in "Break-In" mode, haven't seen the final result yet, as of this morning capacity was about 2050mah, voltage 1.46v.

My questions are:

1. Is it normal that the voltage is so low after recharge? I expected/hoped it to be 1.5v...

2. What's the best care for these batteries, especially if they're not used often? Should I periodically (say every month, every three months) take the batteries out and recharge? In what mode?

I'm new to this, so need your help. Thanks!

 

[lightseeker2009]

The voltage is good. I won't worry about that. I also have a TK40 with Eneloops. I have a general rule that I follow that seems to work great. If I did not used the light a lot, I will charge the batteries only once in 4 months. The slow drain is really slow. At first I was worried, but not anymore. I only take out and charge the batteries if the light was used extensively while camping, fishing etc over a weekend.
Just enjoy the light.

 

[Bobby_C]

I agree with lightseeker.

The first set seems a little low on capacity. You might want to let them sit for a week or so and run it again. I ran my eneloops on my BC1000 and got between 2060 to 2010 mAh on all 8. Rechargeable NiMH batteries are rated at 1.2v but will peak at 1.4xv.

LSD NiMH batteries should be recharged every 6-12 months if not used. Regular NiMH batteries should be charged every month.

 

[mouse07410]

I see (sort of).

So, if I don't use this flashlight a lot - I should just charge (in the CHARGE mode of MAHA C9000) all eight Eneloops every 4 months or so. And if the light got used a lot - then also just charge the batteries.

That first set of 4 with the capacity a bit down - I'll let it sit in the flashlight for about a week. Then - should I run them through BREAN-IN, or again REFRESH & ANALYZE? Oh, and it's safe in the meanwhile to put all these 8 (with somewhat low capacity and with normal capacity) Eneloops together in this TK-40?

Also, I'm confused wrt. when do I want to use these modes: CHARGE, REFRESH & ANALYZE, BREAK-IN. Yeah, I realize that it's good to BREAK-IN new batteries and those that were not used for 6 months to a year - but where does my TK-40 fall in here?

Also, are all Eneloops (purchased fall of last year) LSD? Is it written on them somewhere, i.e. do I need to verify it?

 

[Bobby_C]

You can charge the Eneloops every 6 months to a year if it doesn't get used or just charge after it's used. You don't need to charge them every 4 months.

You shouldn't mix different capacity rechargeables in the same device. Ever. They should all be within 10% (generous) and all at the same charge level.

You only need the CHARGE mode for regular charging. REFRESH & ANALYZE should be done once a year or every other year on the eneloops, more often on regular NiMH rechargeables. BREAK-IN for new batteries but not really necessary.

Here's the eneloop site. There's info towards the bottom to identify which type of eneloops you have (new or old). They're all LSD.

 

[mouse07410]

Thank you! Based on the pictures on the Eneloop site, my Eneloops are old.

Now, I came home to see the final results of the BREAK-IN of the 2nd batch - and got scared:

1: 1.43v, 1916mAh
2: 1.42v, 1920mAh
3: 1.43v, 1911mAh
4: 1.43v, 1910mAh

Charge time on all 4 was 315 min.

What does it mean? Do I need to do anything with them (short of putting them back into TK-40)?

They were new - I bought them (and the flashlight) in October 2010. I did BREAK-IN on them back then, and put them in TK-40. Used the light very rarely. A few days ago when the capacity dropped and the light stopped working, I took them out to charge (1st 4 via R&A, did it twice, 2nd 4 - BREAK-IN). You know the rest from this thread...

 

[Bobby_C]

That seems ok. I've noticed that they don't like being cycled that fast. My first set came in under 2000mAh too. I waited a couple of days and they showed 2040-2060mAh.

 

[HotWire]

You are good to go. Use them and check them from time to time. A small voltage difference would be normal.

 

[mouse07410]

"Check them" - you mean by voltmeter, measuring the remaining voltage?

Tnx!