I'm seeing conflicting information about battery storage for the Nikon Li-ion batteries. The manual says to store the batteries fully discharged while other battery resources indicate significantly worse battery life with that practice.

This is what the Nikon V1 manual says on page 171 (it's the latest product and uses the current battery):
"If the battery will not be used for some time, insert it in the camera and run it flat before removing it and storing it in a location with an ambient temperature of 15 to 25 °C (59 to 77 °F; avoid hot or extremely cold locations). Repeat this process at least once every six months."

This website is a pretty goood resource and clearly indicates that batteries lose life if stored fully discharged. They also lose a lot of life stored at high temperatures, so this is the most compelling reason to avoid regularly leaving a camera in a hot car. This link provides the best information I have seen on batteries.
http://batteryuniversity.com/learn/article/how_to_prolong_lithium_based_batteries

My inclination is to believe that cool temperatures and batteries 40-50% charged would be the best approach for extended storage.

For regular use, charging or topping off immediately after use looks to make sense.


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Eric, The D7000 manual states the same thing on page 310.

But I cannot help but think this was some sort of miss translation or erroneous statement.

First, it seems contradictory to the statement on page xi of the V1 manual (page xiii of D7000 manual) that says that batteries are prone to leakage when fully discharged.

Second, it is contradictory to just about every recomendaton I know of or read about battery usage and storage.

I'll be interested in seeing what others have to say about this.

Pete

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Personally I keep them fully charged and spares stored in my camera bag. The first dslr I purchased was the D80 6, 7 years ago or something like that. I still have that origional battery and it still shows as new on the battery life meter in that D80 as well as my D300 and 700.
All my batteries are numbered and dated and when i pull them to charge/recharge I rotate them so not the same two batteries are stored as spares all the time.

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I wonder if it's not more about some "scare" on exploding Li-on batteries...?
The new Japanese regulation on smaller batteries, the in-flight requirements elsewhere, the temperatures recommendations, all those make me think that they recommend storing discharged batteries in cold places as many people can be quite careless (battery in bag in car in summer, etc.) and they might vote for a shorter battery life versus light minded storage to just be sure they won't be any accident in a sort of "caution principle"...?

Just a feeling...

Jacques

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From my 8mm video cameras to my Nikons, I have not really worried about my maintenance regimen with Li-ions and have suffered no ill effects. Prior to a shoot, I check battery levels to see if they are charged enough. If not, I top them off.

Since buying my D100 in 2002, my batteries are all working well, so I would rather replace them as necessary as opposed to being tied down to a regimen. Fortunately, since my last three cameras use the same batteries, I have backups in case one or two go bad.

Scott Chapin
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Eric - the only cautions I am aware of in Li-Ons is to not leave them on the charger once they are fully charged. I didn't pay attention to this when I had a D100/200 setup; the EN-ELs didn't seem to suffer from any ill effects. There have been some months that batteries lay idle, I'm pretty sure they were fully charged - again, no negative performance in the field.

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I have had my D80 for about 5yrs with an extra battery and D300 for about 3yrs. I have not worried one iota about the care they are given. I use them, charge them & they all work great to this day. I am very satisfied with there life.

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Scott Martin Sternberg

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Good question. for what's it worth, I charge mine up and leave them in the camera or bag until they are near depletion and then charge then up.

If I may open another but related can of worms.

I used to hear that the best battery life was obtained by keeping batteries in the refrigerator. This may be a throw back to Alkaline batteries. I don't know. But for now, I just keep my batteries int he camera bag unless it will be in a very hot place like the car in the summer.

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I am very careful about Nickel batteries, strategically charging/discharging on a certain schedule.

Speaking about Lithium batteries only, Battery University says 40% charge and as cool as possible (as you said). This is what I've been following.

So I don't recharge until mine go below 30%.

There is no memory effect, so I doubt that not topping off would impact performance.

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I opened a ticket with Nikon Support and have asked for clarification.

It's hard to be able to judge battery life without testing for 500 recharge cycles or more. You can't reliably judge it by using the battery display in the camera. The Battery University website shows some gradual deterioration of all Li-Ion batteries with time and use. Charging at 50% levels appears to extend life - even if you run through 3 times as many battery recharge cycles.

Cool temperatures are best - even cooler than the 59-75 degrees recommended by Nikon. Freezing applies to other types of batteries and does not help Li-ion.

Most better chargers have cutoff technology that stops charging the battery once a full charge is reached. Your laptop battery uses that technology. If you do not have a charger that cuts off - or if your battery remains warm on the charger hours after completing charging, you need to be more careful.

The approach I use is to top off batteries after use, keep batteries inside at normal room temperature, and rotate batteries among cameras so that all batteries are used. I've got a couple of batteries from my D200 that are still performing fine.


Eric Bowles
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I think common sense and moderate temperature are the most important.
Don't forget a car trunk or glovebox can get might warm.

Bob

I have had a couple of responses from Nikon support related to my open ticket. The most recent was sending me a data sheet with care instructions for Nickel batteries saying they cover the EN-EL15. The instructions were from Matsushita Battery Industrial Co. and prepared in 2003. I responded that the EN-EL15 is a Li-ion battery not a nickel battery. Hopefully I will get response that makes sense soon.

Gives you a lot of warm fuzzies about Nikon's technical support.


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Eric, I have had an ongoing argument with Nikon for years about their instructions on the use and maintenance of Li-Ion batteries.

To put it bluntly, in my opinion, they have been and continue to be flat out wrong!

I have a trove of more communications with them than I care to count.

Somehow, I think their minds haven't left the 1980's.

I have contacted Li-Ion manufacturers including Sanyo, Hitachi and Duracell.

Here are the facts about Li-Ion batteries as I understand it from these companies.

1. Storage - Store Li-Ion batteries in a cool place with somewhat under a 50% charge.
   
2. Li-Ion batter manufacturers typically ship Li-Ion batteries with about a 40% charge. If that's good enough for them, it sounds reasonable that we should essentially adopt that for our storage of the batteries.
   
3. Li-ion should never be discharged too low, and there are several safeguards to prevent this from happening, the main one being the battery's own protection circuit.
   
4. If somehow you manage to deep discharge an Li-Ion battery to low, the protection circuit will put the battery into sleep mode, rendering the battery useless. Most chargers are not capable of waking up these batteries. They are as good as dead for most people at that point. For long term storage the battery needs to be charged to 40%-50% to prevent the battery from entering sleep mode.
   
5. Li-Ion batteries don't need to be fully charged to work well.
   
6. Li-Ion batteries don't have a memory like the old NiCad batteries, so, if desired you can top them off without reducing their life.
   
7. Li-Ion batteries start dying the minute they're charged for the first time. As long as they aren't abused, they will last about 500 cycles.
   
8. Because of the protection circuit, it's tough to overcharge Li-Ion batteries. Think about all those Li-Ion batteries in laptops which are constantly plugged in.
   

Ned

Nice summary of the key points. The only difference I have seen is a reported 2000 cycles if you recharge the batteries at 50% rather than letting them drain fully.

I finally got some useful information from Nikon. I've attached the EN-EL15 battery data sheet from the manufacturer - Sony. It does not address long term storage, but everything else looks consistent with our thoughts about travel, safety, temperatures, etc.

http://www.nikonians.org/dcfp/user_files/218721.pdf

I agree with you - Nikon seems to be publishing 1980's battery advice in their manuals.


Eric Bowles
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Attachment #1, (pdf file)

Eric, I should have been clearer, but I wanted to stay brief, something I don't do here as much as I should (LOL), even though my articles are, as my editors impose word limits on print and online articles. After all, they're selling advertising and articles and columns can't interfere with that.

With regard to the 500 vs. 2,000 cycles, my practical experience, and from data I've seen published, is that at 100% depth of discharge (Actually it's not 100% as that would render the battery useless, but typically somewhere between 95%-93% where the protection circuit stops discharge screaming, "no mas" and the battery is functionally dead until you recharge.) you get 500 cycles, typically.

I doubt there are many who will replace their batteries with a fresh set when they reach 50%. I know I rarely do, if I'm out shooting all day, even though I know it will prolong the number of cycles I can get from the batteries. Many don't even have spares. I think most people probably average about 75% discharge and can expect 700 cycles at that point.

I have tried to get to the right person at Nikon about this problem of misinformation, but so far, I don't think I have, as I've gotten no where. I'm hoping at the next PDN PhotoPlus Expo in NYC, I can get to the right person, or at least get their contact information. I'll be setting up an appointment with Nikon there. It's a good place to talk as upper level Nikon USA personnel are available, and typically a few from Japan too.

Ned
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