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Hi Folks

I have a number of the above batteries that I use in my SB-600 plus some as spares.

When recharged, how long is it normal, for them to hold a charge?
If I take 10 flash pictures a week, how long should I expect between recharges?
Is it okay to charge the spares and just leave them in my bag until I need them?
Or should I only charge them just before I expect to use them?

I ask because earlier today my flash wouldn't live up to its name. When none of three sets of spares in my bag worked, I started to fear having broken my flash.

TIA
Bob in Bull Creek

They can lose up to 3% per day. 10 days = 30% gone. You need to recharge them the day before you need them which is a pain. The new Sanyo Eneloop AA batteries hold their charge for up to 6 months and are the best thing since sliced bread. They don't cost much extra. Do a search on this forum for more info/feedback on these batteries.

Yep. I used to only have 12 AA NiMH rechargeables of varying quality.

It seemed the ones that held their power best were some Powerbase 2100's that I bought in Apr 2004, followed by some Digitor 2000mah from DSE in prob may/June 04, and way way worse at self discharge are Duracell 2050mah nimh, that are truly useless.

There are now a few different low self discharge batteries coming onto the market.

Sanyo's Eneloop AA are rated at 2,000mAh.
Powerex Imedion AA are rated at 2,100mAh.

I recently bought 16 AA & 4 AAA Imedion from http://www.servaas.com.au and 4 Eneloop AA. I also bought some extra plastic battery cases and a Powerex C-9000 charger with many functions.

As a test I discharged some of the Imedions that were shipped to me charged & "ready to use" and got the following results for capacity - at a discharge rate of 500mAh, the capacities ranged between 1697 - 1754 mAh (took about 220 mins to discharge).

On a cyclical breakin using the charger, the final capacities shown were 2084 - 2131 with only the 1 battery being less than the rated 2100mAh.

This is in a sample size of 8 AA batteries thus far. So they were shipped from the factory, to Australia, and then held in stock & shipped to me and had heaps of power on board to power my flash.

I have another 5 of them as shipped in my SB-800 and it goes well, keeps up nicely. I have tested it both on the body, and just by manually triggering the flash via the flash button on the SB800 after setting it with manual settings to the point where it delivers max flash power.

Also - Jeff from Servaas offers a nice little discount for forum members - PM or email him & ask for the DSLRUsers forum price.

In short I'm a happy customer thus far.

I have 20x 2500mAh Energisers. I leave them in my bag for about 2 weeks before recharging or up to 2 months in the fridge (sealed in zip-lock bags). A month is about it for batteries at room temperature whether they have been used or not. I have never done any testing, so all that I can say is that on this schedule the batteries meet my needs.

Regards

Andrew

I only charge them when I need to use them

Lower mAh capacity rated NiMH batteries are more suited for high current drain use such as external camera flashes. The higher rated capacity cells have a thinner membrane inside that causes higher rates of self discharge and also higher internal resistance, meaning less ability to provide instantaneous power, and producing more heat which increases resistance again and also potentially reduce the cell's life.

I have sets of 1850, 2100, 2300 and 2500mAh cells, all Energizer branded (Sanyo-made OEMs). True to the theory, the higher rated cells discharge sooner, and I typically recharge them after ~1 month from their last charge if they've not been used. 2500s at 3 weeks start to become unusuable: from my "testing" of powering a torch. I keep a slip of paper with when I last recharge the cells, and they're packed in sets of 4 - and I have a voltmeter (~$20 from Jaycar or DSE) I use to keep track of the cell potentials.

I find that after 6 weeks, Sanyo Eneloop and my old Energizer 1850mAh NiMH (~5yrs old) holds their charge quite well (about 1.32V, they're about 1.38V newly charged). The worst are the Sanyo branded 2500s I bought in China/HK - they may be imitations as they no longer hold their charge after even 2 years of careful charging and occasional use, which is atypical of Sanyo cells as they're renouned to be among the best in the industry.

BullcreekBob wrote:When recharged, how long is it normal, for them to hold a charge?

Normal Ni-Mh batteries loose charge from 2-5% a day. After 1/2 to 1 month, they will be flat or mostly there anyway.

If I take 10 flash pictures a week, how long should I expect between recharges?

As per Nikon manual, constantly check battery level before an important shoot. Recharge battery when recycle time is longer than usual.

Is it okay to charge the spares and just leave them in my bag until I need them?

No, they will be flat anyway.
BUT, Eneloop is to this rescue!

Or should I only charge them just before I expect to use them?

Yes, that's what I do. But sometimes we are so busy that forget which one is charged.

<blockquote cite="=" onyx="">Lower mAh capacity rated NiMH batteries are more suited for high current drain use such as external camera flashes. The higher rated capacity cells have a thinner membrane inside that causes higher rates of self discharge and also higher internal resistance, meaning less ability to provide instantaneous power, and producing more heat which increases resistance again and also potentially reduce the cell's life. [/quote]

There is a lot of variation in quality onf NiMH cells, and this becomes evident in the discharge rate and also the number of cycles that they last for. I have tested the discharge rate of our Powerex 2700mAh AA batteries (not the low discharge IMEDIONs) stored in my office at room temperature for 30 and 60 days. I measured the discharge rate at 9% after 30 days, and 16% after 60 days. Batteries were discharged in a Powerex MH-C9000 to measure remaining capacity as a % of original charged capacity. These batteries were 18 months old and have seen 20 or so cycles.

I have sets of 1850, 2100, 2300 and 2500mAh cells, all Energizer branded (Sanyo-made OEMs). True to the theory, the higher rated cells discharge sooner, and I typically recharge them after ~1 month from their last charge if they've not been used. 2500s at 3 weeks start to become unusuable: from my "testing" of powering a torch. I keep a slip of paper with when I last recharge the cells, and they're packed in sets of 4 - and I have a voltmeter (~$20 from Jaycar or DSE) I use to keep track of the cell potentials.

Sanyo batteries are made in Japan. I believe the 2500mAh Energizer are now made in China. I expect your batteries that are holding charge are Sanyo OEM, and the ones that are not are a from a different manufacturer.

I find that after 6 weeks, Sanyo Eneloop and my old Energizer 1850mAh NiMH (~5yrs old) holds their charge quite well (about 1.32V, they're about 1.38V newly charged). The worst are the Sanyo branded 2500s I bought in China/HK - they may be imitations as they no longer hold their charge after even 2 years of careful charging and occasional use, which is atypical of Sanyo cells as they're renouned to be among the best in the industry.

There were several instances of counterfeit Sanyo AA batteries coming out of China, perhaps you have some of those!

If you use hundreds of flash shots per session, I would recommend high capacity batteries. If you want to be able to grab your flash and know it will work, choose low self discharge batteries (eneloop and IMEDION)

I have the energizer 2500 as well and they seem to work well. Only thing I've read is that the capacities over 2300 or so are overrated since they don't go to their peak capacity.

servaasproducts wrote:There is a lot of variation in quality onf NiMH cells, and this becomes evident in the discharge rate and also the number of cycles that they last for. I have tested the discharge rate of our Powerex 2700mAh AA batteries (not the low discharge IMEDIONs) stored in my office at room temperature for 30 and 60 days. I measured the discharge rate at 9% after 30 days, and 16% after 60 days. Batteries were discharged in a Powerex MH-C9000 to measure remaining capacity as a % of original charged capacity. These batteries were 18 months old and have seen 20 or so cycles.

Could you please clarify what you mean by "rate" here? The way it is written it suggests that after 30 days there were losing 9% per day and 16% per day after 60 days. I have a feeling that is not what you meant. Do you really mean that only 9% had discharged after 30 days and at 60 days they had only lost a total of 16%? If so, that's pretty good.

ATJ wrote:

servaasproducts wrote:There is a lot of variation in quality onf NiMH cells, and this becomes evident in the discharge rate and also the number of cycles that they last for. I have tested the discharge rate of our Powerex 2700mAh AA batteries (not the low discharge IMEDIONs) stored in my office at room temperature for 30 and 60 days. I measured the discharge rate at 9% after 30 days, and 16% after 60 days. Batteries were discharged in a Powerex MH-C9000 to measure remaining capacity as a % of original charged capacity. These batteries were 18 months old and have seen 20 or so cycles.

Could you please clarify what you mean by "rate" here? The way it is written it suggests that after 30 days there were losing 9% per day and 16% per day after 60 days. I have a feeling that is not what you meant. Do you really mean that only 9% had discharged after 30 days and at 60 days they had only lost a total of 16%? If so, that's pretty good.

After 60 days, I discharged the 4 batteries and measured the retained energy capacities as 2188, 2203, 2139, and 2150mAh. I then fully charged the batteries, and their capacities were 2557, 2625, 2561, and 2537mAh. Average capacity lost across all 4 batteries, after 60 days, was 15.4%. Yes, pretty good!

cant wait till the toshiba quick battery becomes available one day.... 80% charge in 1 min. not bad