Rechargeable AA batteries

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rayonline

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#130843 30-Sep-2013 12:42

Hi all - how have your experience been with NiMH batteries - not the so recent Enloop etc ones?

I imported them from the states with a Lacrosse charger that charges each individually and does a slow 200mA charge so they may take 18hrs to charge and other readouts like MaH that was charged or that it charges it up and then discharge them to calculate the MaH and then it fully charge it up for you so it's ready for your application.

In the past, never really gotten a good use out of them, I did buy 12x of them. I charged them overseas on the ferry fully, put them in my Garmin hiking GPS to navigate the city and in 3hr it was saying low battery. This was even in 2009.

More recently, I charged them and set and went to Palmerston North for a trip within 24hr, it was put into my SLR's external flash which I powered it up 2x but no flash taken, the red said ready. I forgot to charge my other batteries in my film SLR so I took these batteries from the flash and immediately it said low battery but it could take a shot.

I ran some real world tests than just using the charger to give me stats. If I charge them fully and use them on a discman the better pair may go for 15hrs. OTOH if I charge them and leave for 10 days they last 5hrs. Compared to my good Energizers even after 10 days they still go for 15hrs.

On one pair while after 10 days it lasted 5hrs, I charged this maybe 3 or 4 days ago. Today it won't even power up our Logitech TV remote.

Do rechargeables becomes this unstable over time? I have had these for 9yrs but my Energizers someone else bought there was a similar age but they are still going strong. Did I happen to just have bad batteries? These are all 12x that are like that. Most of them won't power up, the 2 or 4 may give 5hrs running off the Discman. But I never recalled I ever got a good use of them ever.

jarledb

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#905053 30-Sep-2013 13:10

Most NiMH AA batteries will live for about 300 charge/discharge cycles. After that you can just throw them away.

And as you have seen, NiMH batteries have a discharge even when they are not used. From what I understand you can expect a fully charged NiMH battery to be fully discharged about 30 days after charging them.

So to get the most out of the batteries its a good idea to charge them up just before you are going to use them.

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russelo

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#905063 30-Sep-2013 13:19

9years? Mine don't even last 4.
What's the battery brand?

muppet

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#905064 30-Sep-2013 13:20

From all the reading I've been doing (a lot, I just bought a MH-C9000) I thought that charging them between 0.5c-1.0c was much better for the batteries than a slow trickle charge.

It sounds like the batteries you have purchased are rather crap, sorry to say!

If you have the low-self-discharge (LSD) batteries they can keep ~85% charge over the course of a year. The high capacity ones don't keep charge that well, but even they should lose only ~1-2% a day (Though at first you tend to lose 5-10% in a day, then it slows)

I'd suggest investing in some new batteries. I recommend recharged.co.nz for quality batteries - I have nothing to do with them, just had great experiences with them over the last month.

EDIT: Missed the 9 year life of them! Throw them and get new ones!

rayonline

1734 posts

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#905090 30-Sep-2013 13:41

I got them from ripvan100.com, they were like these, well Sanyo was hot at the time online forums and they said these were unlabelled industrial types - 2800.

Even when we just got them. But we've never had a good use out of them even with my dSLR with the flash at the time after just buying them they may sit for 5 days and half the power is gone. But the charge does say it has inputted 2.8 or 3.2AH of juice in them take out the efficiency but yeah 5 days after half the total juice is just gone. But the reality was 50 photographs and the battery gets depleted. 25 or so the low battery comes on.

The ones that are good which we have for 8 or 9 yrs are just the Countdown supermarket Energizer 2450.

timmmay

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#905098 30-Sep-2013 13:44

Sounds like rubbish batteries. I have maybe 30 PowerEx 2800mah batteries and a C9000 charger (plus a C801), and about the same number of Eneloops, to use in my many hotshoe flashes and I've never had a problem. Eneloop do keep their charge longer, but the standard ones keep them a fairly long time too.

Charging a 1C isn't recommended, 0.5C (ie a 2 hour charge) is better. Much slower and I understand that it's difficult to detect when the battery's fully.

mclean

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#905141 30-Sep-2013 14:26

We also use Powerex 2700mAh for our office cameras, and a MH-C9000 charger. The present a lot are about 6 years old and still fine. Several times we've had cells appear to give up, but a refresh cycle has brought them back to life. The charger is a bit expensive but a good thing.

eracode

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#905167 30-Sep-2013 14:56

I have been using rechargeable AA's for years until recently, mainly in low power devices like AV remotes and the two ends of a weather station. Most of them are 4 - 7 years old.

In the end I just got a bit sick of the self-discharge effect and recharging etc. So recently when I saw 20 Sony alkaline AA's at PB Tech in Auckland for $9.99, I bought them and will replace the rechargeables as and when they next need charging.

I have recently done the same with 9v rechargeables that I was using in six smoke alarms. Rechargeables are not at all suitable in alarms mainly due to the self-discharge thing. I was having to recharge those every 3-4 months. Have now replaced them with 6 X $2.98 each Varta alkaline 9 volters, again from PB Tech.

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rayonline

1734 posts

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#905172 30-Sep-2013 15:11

I got a pair of Photo AA off my 35mm pocket film cameras that I used in the late 90s and they still work in my remote.

timmmay

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#905190 30-Sep-2013 15:36

My PowerEx cells are around 6 years old, 2800mah rated, still holding 2600mah of charge. I do refresh them every now and then, and I break them in once a year.

JimmyH

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#905289 30-Sep-2013 18:32

I have some Powerhaus AAs that I got in 1999, and they still work fine. Maybe I just got lucky with the brand, although they haven't been used hard.

You can get batteries that don't have the high self-discharge problem. Eneloop is one brand that offer this, I think there are others. However, the capacity can be a bit lower (2000 mAh from memory) and the price is a bit higher, compared to the normal ones.

rugrat

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#905356 30-Sep-2013 19:47

I have batteries more then 5 years and still going.

I use a MH-C401FS charger. Brought charger over 10 years ago.

I always use slow charge, as I think it's better for battery, and get more charges in it that way.

When brought charger it claimed it conditioned battery as charged, so no need to completely discharge battery, and recharge. It does it by pulse charging, and not doing a continous current. Wouldn't know if that lot of rubbish myself but had no problems.

Use normal batteries in low current devices like clocks, and remotes until recently, as when not being used much, found fully charged battery only hold it's charge for about 3 months, and got sick of recharging every 3 months.
Now only buy enoloop (pardon spelling) type batteries as get over 9 months between charges on low current devices.

stevenz

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#905792 1-Oct-2013 16:10

Any device in my house that uses AA/AAA batteries now has Eneloop rechargeables in it. Given that a lot of the devices sit idle, the retained power feature means they last a LOT longer.

The first set I bought about 5 years back are still in regular rotation and still hold a good charge. I use the "proper" Eneloop slow charger, which is pretty much an overnight job.

That said, even "cheap" rechargeables seem to last for at least 5 years and a fair number of cycles.

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