03-13-2019 06:19 PM
Most manufacturers of devices made that utilize lithium/lithium-ion batteries suggest that batteries remain in their charger for longevity, or to leave the device plugged into an AC source.
What about Canon’s LP-E6N? Should I leave them in the charger, or once charged remove them and put them in my kit?
I’ve asked Canon Professional Services this question and usually get “uhhhhh...” for an answer.
What’s your recommendation?
03-13-2019 07:36 PM - edited 03-13-2019 07:37 PM
I have LP-E6N's as old as 5 years and they are all still serviceable. I charge them up, then write in my notebook when they were charged (I have 7 of them so I want to keep track). I then use them in the order charged (each has their serial number on the bottom). I have one battery (not the oldest) that seems not to reach full charge when the charger indicates 100% as it is not good for as many "clicks" as the others, but it is still about 90%. Mine don't sit unused for longer than about 2-3 weeks and then they are used in a camera till they are at least 50% discharged. So far I have been very happy with the service life.
03-13-2019 09:01 PM
Thanks for the reply.
I’ve been rotating mine by date of purchase. Haven’t noticed any decrease in life yet, but I’m trying to find out what is optimum.
03-14-2019 09:07 AM
Lithium Ion batteries don't like being stored fully charged or fully discharged.
I tend to shoot a lot of images with my Canon DSLR bodies and in my experience about 3 years of battery life is about it for me before they are degraded too far. I keep 3 in rotation for each body and for the most part they are not being stored unused for any period of time. I will typically run them down to around 25% capacity and then recharge them but they don't sit around unused for any period of time.
The biggest maintenance action to maximize LiOn battery life is not to store them for a long period of time either fully charged or fully discharged because either will significantly reduce service life. If you plan to leave one sitting for a long period of time, either charge or discharge to around 50% as appropriate and then if it is not being used for months periodically check the battery level and bring it up to around 50% charge before storing it. Note that different battery technologies have different needs so if you are using older gear with NiCad packs the use and maintenance is very different.
I would not store LiOn batteries either in their charger or in the device for an extended period of time. it will reduce battery service life and keep in mind that if something goes wrong these batteries can source extremely high current for a short period of time which is the reason why this type of battery (NOT specifically Canon camera batteries) have been responsible for a number of fires so you don't want a device failure causing a battery fire or a battery failure to cook the device and that includes a charger that malfunctions while you are away. LiOn batteries that are about the same size/weight as larger DSLR batteries are used in car "jump" packs and can provide over 300 amps of peak current to start the car.
These batteries are quite safe when used properly but never forget the amount of power they can produce and USE those protective terminal covers when the battery isn't in the camera or charger. They both protect the contacts and act as a safety device to prevent the battery from being shorted by an external item. The connectors are designed to be safe but the covers are needed when not in use. An electrician who should have known better suffered significant burns when he put an unprotected battery pack in his pocket and some loose strands of wire created a short between fairly well protected terminals. Back when NiCad batteries were still the norm, a police officer was signifcantly but not fatally injured when he put loose ammunition and a spare battery for his communications radio in his uniform pocket and when the shell shorted across the battery terminals it cooked off the explosive charge. Incidents like these are reasons why terminals are designed to not easily be shorted in normal use. Companies are making these products more fool-proof but society continues to produce more advanced fools
03-16-2019 08:49 AM
Given the number of notebook computer and tablet (with lithium batteries) fires caused by leaving the charger plugged in, I would only charge lithium batteries when I am present to keep an eye on the charger.
Not long before I retired from an IT position several years ago, one of the iPads we had assigned to a manager caught fire in his home, and nearly burned his house down. They had left the iPad on an ottoman with the charger plugged in, and then went out. The ottoman kept the fire from spreading further, but it was destroyed, and the livingroom had heavy smoke damage.
I've seen photos of other such fires, and will never leave a battery in a charger now if I'm not here to keep an eye on it.
03-16-2019 09:56 AM
Excellent point Albert!
An iPad battery is of fairly small/low capacity compared to a lot of the LiOn batteries we use so imagine what a big battery pack can do when something goes wrong-or you don't have to imagine but just take a look at the videos of some EV fires that are difficult to put out and keep out after their very large battery systems catch on fire.
LiOn packs are the most power dense of any readily available rechargeable battery system and the separator between individual cells in the pack is very thin and easily compromised and one way to do this is via overcharging which can happen if the charger fails. When this separator is breached, a fire is the likely result.
I suspect the Canon system charger included with our DSLR bodies is built far better (higher reliability plus better fail-safe features) than a lot of aftermarket systems but even so I wouldn't leave the pack charging when I wasn't around. It is also a good idea not to store all of your packs together because if one fails and starts to burn it will spread to the others.
This isn't meant to scare you away from using packs because millions of them are in use every day and a lot of them are abused in ways they should not be but still survive. I have them in test equipment, power tools, smart devices, and of course still and video cameras and don't worry about them creating an inferno. But having done many years of risk management consulting I like to manage easily controllable risks and the risk from leaving unattended battery packs on charge is a risk that is easily managed at no real cost. And car chargers are some of the worst with many of them having only the bare minimum of circuitry to charge a pack with no real safety features to protect things in case of failure. One of these that caused a vehicle fire depended upon the user to disconnect the charger before the battery became overcharged and its only protective system was relying upon the car fuse that fed the lighter/accessory plug socket. Charging a lithium pack in a hot environment is a very bad idea and you don't want to store them there either; cars quickly become ovens in hot weather.
Even when there are applicable regulatory safety standards they are often not enforced in the world of online retailing where gray market imports and counterfeit items are as common as the genuine market focused products in some product categories. This is another reason to be careful buying very low cost replacement battery packs instead of OEM; they may be OK or they may be more prone to catastrophic failure than the more expensive OEM packs. There is no doubt that Canon makes a decent margin on replacement battery packs but that cost differential over third party items isn't all profit-some of it is component and build quality.