Discharging M8 battery

[gurtch]

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I received my M8 around Dec 30th, and charged the battery. It has yet to run down. (The M8 shares duty with a 1DSII). In April, I am going to a dear friend's daughter's wedding. I want to be unobtrusive, and not compete with the Pro, so I plan on taking the M8, and shooting by available light only with fast lenses. I want to be sure the battery is FULLY charged, and know i should probably fully discharge it right before charging the day before the wedding. What is the best way to fully discharg. I thought I would disable the auto-shutoff feature, then turn the camera on and leave it sit. Then I thought I should turn it on and activate the playback to discharge it faster. If I did this woujld it "burn-in" the display if the same picture was there for hours? Any advice appreciated.

Thanks in advance

Dave G

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[pfogle]

Isn't the battery a Li-ion one? If so, they shouldn't be deep-discharged at all; they like to be topped up rather than discharged. There is no memory effect with Li-ion, unlike NiCd or NiMh, so there's no benefit to running it down, and if you let it get too discharged, it can fail altogether.

 

edit - the IDsII uses the NiMh battery, so has a 'conditioner' setting on the charger. This reflects the different technology between the two batteries.

 

Lithium-ion battery - Wikipedia, the free encyclopedia

[fjmcsu]

Even though it is Li ion, the manual states:a" new battery only reaches its full capacity after it has been fully charged and-by use in the camera -discharged 2-3 times" . I did it by leaving it on overnight a you suggested with the auto shut-off- off & did that procedure 3 times.That should do it. To date batteries are fine.

[scott kirkpatrick]

If you set the camera to stay on, and play, the screen will shut off after a while, but enough things will stay on that the battery will be drained, and then the camera will shut itself off before there is any damage to the battery. That takes at most an hour or two, especially if you haven't charged it since Dec 30. Then give it a full charge. This puts the camera and the battery in synch so that the two of them will give you a full effort. Then just top it off after every shoot from now until the wedding, and you should get your 400 or so exposures without any problems. Yes, deep discharges are harder on the battery then constant topoffs, but they are apparently needed once in a while. See another recent thread with "battery" in the title for more on this subject.

 

scott

[pfogle]

On reading the other replies, I can see your point - Li-ion batteries do usually take 2-3 cycles to reach maximum capacity. I had thought that this might have been done before shipping, but the documentation suggests that it hasn't, so the advice given to run it through a couple of cycles seems to be sound.

 

Sorry for any confusion caused.

[wlaidlaw]

Apple recommends a full discharge/charge cycle on their Macs when new and then between once and twice a year to "condition and calibrate" their Li-on batteries. I would guess that it might be a good idea to do this with the M8 batteries. I did both mine along these lines, following various recommendations on this forum and have had no trouble with mine since. I always swap batteries at the end of a day's use and charge up the one I have taken out. I have been doing this since first having Li-on batteries in digitals over about the last 6 years and have never had a battery problem.

 

Wilson

[gurtch]

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Thanks guys. It's lousy rainy weather here, so tonight seems like a good time to run down the battery, then recharge. I will top it off several times before the wedding.

Dave

[albertknappmd]

Here is a summary from a reference found in the DMR-M8 battery thread of 3/23/07....

Simple Guidelines

 

• Avoid frequent full discharges because this puts additional strain on the battery. Several partial discharges with frequent recharges are better for lithium-ion than one deep one. Recharging a partially charged lithium-ion does not cause harm because there is no memory. (In this respect, lithium-ion differs from nickel-based batteries.) Short battery life in a laptop is mainly cause by heat rather than charge / discharge patterns.
  
• Batteries with fuel gauge (laptops) should be calibrated by applying a deliberate full discharge once every 30 charges. Running the pack down in the equipment does this. If ignored, the fuel gauge will become increasingly less accurate and in some cases cut off the device prematurely.
  
• Keep the lithium-ion battery cool. Avoid a hot car. For prolonged storage, keep the battery at a 40% charge level.
  
• Consider removing the battery from a laptop when running on fixed power. (Some laptop manufacturers are concerned about dust and moisture accumulating inside the battery casing.)
  
• Avoid purchasing spare lithium-ion batteries for later use. Observe manufacturing dates. Do not buy old stock, even if sold at clearance prices.
  
• If you have a spare lithium-ion battery, use one to the fullest and keep the other cool by placing it in the refrigerator. Do not freeze the battery. For best results, store the battery at 40% state-of-charge.

[albertknappmd]

I forgot to mention the source of the above reference:

How to prolong lithium-based batteries ;)

[albertknappmd]

You will note that NO mention is made about the utility or necessity of charging and discharging the battery three times initially... Is this just digital lore ? :confused:

It certailnly is not based in Science but I would do it once at first so as to CALIBRATE your camera's battery meter and then do it every 30 cycles or so as suggested in the paper I posted.