I love cameras and I love batteries ( batteries are very interesting ) . Now I only had one battery for my Canon 60D and I thought it time to get a back up battery for those times when the battery is low ( it happens ) . So I got on Google and YouTube to see what sort of informative battery reviews were out there ? I was a little disappointed to see so much opinion and speculation delivered so factually ( BS ) . Anyhow after a while I decided that I should just buy a Canon LP-E6 charger and gut it , turning it into a battery cradle for my Hobby Charger dis Charger . To test my idea I purchased the cheapest LP-E6 battery I could of Ebay . I charged the battery in a genuine Canon charger and after a short rest after completion the resting voltage was 8.22v . At this time I did not know at what voltage the 60D stopped working , so I discharged to 6v . The generic no name battery was advertised as having a capacity of 2200mAh ( cough - cough ) , but I was very interested to see what it could deliver . Discharging at some 200mAh to give the battery every chance to impress , the final result to 6v was some 1329mAh discharged ( A far cry from the advertised 2200mAh ) . At this point my curiosity got the better of me ! At what voltage does the camera stop working ? I never for a moment thought it would be close to 6v but what was it . I contacted Canon regarding a few questions and was directed to the user manual , which was of little help . So taking the bull by the horns I set my 60D to video mode and began to run down the battery till the camera stopped ( refused to work ) . With the battery out of the camera I measured some 6.59 volts , so I guess the termination voltage might be about 6.5 volts . So with their being little point discharging a battery past the cameras termination voltage ( the voltage at which the camera stops working ) I discharged the generic battery again but this time to 6.5 volts .. The resulting discharge was 1295mAh @ 200mAh . To be fair I also discharged my genuine Canon battery to 6.5 volts to see what the difference would be . The Canon battery is rated as being 1800mAh capacity , and discharging it @ 200mAh to 6.5 volts resulted in some 1359mAh discharged . ( Not that impressive ) Several questions come to mind . How old is my Canon Battery , just what process does Canon use to rate their battery ? Anyhow , I did this simply to put an end to speculation , guesswork , and general BS . So every now and again I will test a LP-E6 battery .. I would still like to know at what voltage level the camera stops working in the camera ? ( officially ) As it is some what important if one is going to test batteries , to see how much is actually available to the camera . Also the testing procedure ( By Canon ) where by they get 1800mAh capacity .. Discharge current and end voltage .. If say the camera does indeed stop @ 6.5 volts ( for many reasons ) , and Canon discharges to 5 volts to get their 1800mAh rating ... ( Well that's a bit how do you do )
Those are all good questions. I have read with lithium ion batteries the general safe minimum voltage is around 3 volts per cell. So in your case it would be 6.0V. Although you can discharge them more, it will hurt the lifespan of the battery in the long run. You should try to discharge your genuine canon battery to 6V as you did with the generic battery to see how many mAh it gave out.
Hello Phil ... A) There is little point discharging past the point the camera stops working as it is power your camera will never use . B) Usually 3 volt per cell is the minimum you would discharge to C) a lot of applications / systems / hardware now stop at a more conservative Voltage as the cells are more or less not performing that well bellow 3.5 volts . Obviously 2 cells are better than one and I don't know what the current demands are for the camera .. One could find out but it would be a tricky system where by one would gut a battery ... D) I would be very interested in Canons method of rating the battery Much easier if Canon just would let me know the details ... A lot of Li-ion are discharged to 2.5v ( 18650 ) to make more Capacity .. But most devices using them will not discharge lower than 3v or 3.5v per cell .. A lot of 2s ( 2 cell packs ) devices stop at 7 volts ( 3.5v per cell ) .. So what ever the battery can do bellow a cut off point is ? neither here nor there .. I would love to know if Canon discharges to 5v to make the capacity rating . Perhaps Canon wants to keep this stuff close to the chest ? , their battery prices are not really , how do I put it , ??
A bit of an update ... Canon Aust informed me that the low voltage warning is thrown up at 6.6 volts ( Under load of course ) for the 60D I await to see what the end voltage is ( camera no longer functions ) Also asked them about the process by which they determine battery capacity .. ( A interesting question to be sure )
Looking at this site: http://www.richtek.com/battery-management/en/designing-liion.html It would appear that battery capacity measurement is very dependent on discharge current so if manufacturers test them at unrealistically low current then they can easily come up with high capacity figures. Your tests at 200ma represents a discharge current of approx 0.1c so should be reasonably accurate but without knowing the average current that the camera is drawing then it will all be bit meaningless. Obviously the current drawn by the camera will vary according to what it's doing at the time and I would imagine could be over quite a wide range.
Sorry , its not meaningless ... Since I am comparing batteries ... What it is , is not 100% accurate in the sense of replicating the camera conditions .. But as far as comparing batteries ... ( ? ) You take away what you take away ... And its very hard to replicate camera conditions ... What am I trying to replicate ? A SLR taking photos Photos in continuous mode , And what about the lens ? Video mode / and again the lens ... ??????????????????????????? So we can only take it so far ! ( commons sense must prevail ) As for the battery test conducted by Canon for capacity / I did ask ..
Perhaps "meaningless" was the wrong word. I am not trying to denigrate what you are doing, I was trying to point out that even when comparing 2 different batteries because you get a calculated capacity from each of them at 200mA you may get completely different results at 100mA or 300mA. As for getting information from Canon as to how they do it, best of luck, I would imagine quite a lot of guesstimation goes into their method as well.
Ray-UK I have been testing batteries for about a decade now , and the difference @ 100 , 200 , 300 would be minimal . First let me say Canon Aust got back to me , and said that the camera stops working at 6.6 volts ... Hmmmmmm , I don't think the camera is going to throw up a low voltage warning at 6.6 volts and stop working at 6.6 volts .. So I don't think they have all their Oranges lined up correctly .. ( In this regard ) Back to the batteries : So far I am just exploring and trying to gather information .. ( The cut off voltage is important ) My initial discharge @ 200mAh was simply to give the batteries every chance to deliver .. The plan for the future , is to do 2 discharges ... One @ 200mAh and another @ 500mAh ... If the batteries deal with 500mAh well , then quite possibly kick it up to 1 Amp ... This is early days , and by no means definitive ... Next I think I have to contact Canon Japan and see if I cant get some info ...
