Ephemeris
Veteran Member
Why would the last 10% create the most heat? During this the current is reducing towards zero.
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Canon LP-E6NH Performance
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Victor Engel
Forum Pro
Probably it's accumulating more slowly but is adding to the heat already there from earlier charging, until the cooling to ambient temperature is faster than the warming from charging. This would be another reason to charge slowly instead of quickly. Heat could dissipate while charging. I have a feeling Canon have figured all those details out and taper off the charge appropriately.
Ephemeris
Veteran Member
So that would mean it's not creating the most heat.
The charge cycleooks pretty similar to the few suppliers I looked at that make the same cells. Canon don't make the cells.
I still haven't done an in camera charge to measure the final voltage that I said I would. I'll go do that now before I get busy.
Victor Engel
Forum Pro
I don't believe it's about the cells, but about the circuitry in the battery. The battery isn't simply a couple of cells connected electronically. There is also circuitry to control the charging. That's what I was referring to.
Ephemeris
Veteran Member
It's all about the cells and the charger is what controls the charging.
Victor Engel
Forum Pro
Hmm - I'll have to check on that. There are many threads suggesting to use official Canon batteries because they include circuitry to control charging.
That didn't take long. https://www.ifixit.com/Teardown/Canon+LP-E6+battery+pack+Teardown/133243
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Ephemeris
Veteran Member
That thread doesn't suggest that at all.
The charger is in control of charging the battery and is the controller. I can charge a canon battery in the same way through one of our rigs (banks of programmable supplies).
Being able to ask information from the battery is not the same as control.
The camera also has a control charger within it and why we can't simply give the battery 5/12/20 v from USB.
Victor Engel
Forum Pro
Not Canon but I'm sure Newell tries their best to duplicate the Canon features. My point was simply that it's not simply a battery of cells. There is also an integrated circuit involved that does more than just identify serial numbers and whatnot.
I have not done testing on these batteries other than measure voltage, nor have I taken one apart, so I'll bow out at this point. It seems like there are at least two people on this thread who can weigh in more knowledgeably about particulars.
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Victor Engel
Ephemeris
Veteran Member
That is not disputed. However, the charge controlled isn't the battery.
From your image they incorporate sensible features such as reverse polarity, over voltage, type, temperature.
We don't have any from Newell but we do have some of the 16.2Wh from Newelll. Apart from characterising them and I have as I have an interest in wraps and wrap membranes CT scanned. I also did a teardown on a Hahnel which started to cease working sometimes. It was repaired but I shared some images.
I have a team who work at the energy research accelerator at WMG, I act as oversite. We develop plant models, control models and hardware for them to carry out research. We certainly don't specialise in camera batteries.
One area that isn't well publicised is the performance of these 18500 cells under the pulse type loads, which are significant that our cameras try to demand, and that information as a function of temperature.
Amazing how these systems operate on a notional 25W power budget. I've thought that at some point the battery platform will need to change but they seem to muddle on.
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Victor Engel
R2D2
Forum Pro
Thanks Victor, I didn't have time to explain any more thoroughly (had to head to work). The heat accumulates the most by the end of the charging cycle. It's very bad to charge (or keep charging) a hot battery!
Discharge is even worse. The heat generated internally gets very high (due primarily to the increased internal resistance) as the battery gets depleted.
Good circuitry can reduce these issues, as you suspect.
R2
I have a bunch of LP-E6/E6N/E6NH. The oldest of the bunch is from my 5D mk II, about 14-15 years old, and it still seems to work reasonably well for me to retire it, or give it any downgrade. The only thing I care about is not to carry it as my only spare given everything eventually fails
I have a year+letter system, so my batteries have ended up as 2010, 2016, 2020, 2020A, 2022, 2022A. I have it labeled on the side facing the battery door when in camera
Ephemeris
Veteran Member
It won't be hot R2. The charge currents are small.
The current is tapered as per the expeditions of the cell manufacturer until the expected cutoff, probably around 30mA.
It is quite plausible the end of the cycle isnt the point of maximum temperature for a cell, and it would be unusual if it was. So I don't think this is the right way to view it.
If we notionally say we will pull 25W, or 3A and power will reduce the temperature of the battery should be thought about as a delta from its start point. So assuming it will be hot I also don't think is correct.
Good circuitry can reduce these issues, as you suspect.
R2
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Good judgment comes from experience.
Experience comes from bad judgment.
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R2D2
Forum Pro
Look at the last line in my post (which you ignored ;-) ). That of course describes Canon's circuitry (which prevents cooking of the battery during charging). However I've seen other 3rd party manuf that don't do so well!
In addition there are other factors that can come into play that will change the heat production curve of the charging cycle, such as immediately charging a hot freshly-depleted battery, or charging a battery when the ambient temperature is high. Every manuf I've seen recommends against doing either of these.
Look at any temperature test curves done on Li-ion batteries. You'll see that huge spike at the end of the discharge cycle. Or just feel the thing with your hand!
And cameras aren't the only devices that use Li-ion batteries. Look at the precaution list on the Li-ion powered flashes (those batts can get Very hot during discharge). Heat kills Li-ion batteries.
Again, "Good circuitry can reduce these issues," but also use your head, and follow instructions too. (I know you know this already, so my advice is directed toward those that might not).Good circuitry can reduce these issues, as you suspect.
R2
Cheers!
R2
Ephemeris
Veteran Member
I didn't ignore but the thermal shutoff didn't seem relevant at this point.
It describes a feature which says I won't charge if too cold or too hot. My Hahnel and Neewer both do the same.
So, as said we are talking about a delta in tenperature. Using the word hot I don't this is right.
Not charging when hot? Okay but that's not what I'm describing.
So, as a person that manages a team that work in a research facility in WMG, and act as there sign off I have some notion of this. At the end of a typical charge cycle we will reduce the current from the nominal, say 1C, down to something tending to zero. Why do you think that would cause a huge temperature spike?
Being warm at the end doesn't mean it wasn't warm earlier. Maximum power transfer occurs early not late.
This isn't the discussion.
Again, "Good circuitry can reduce these issues," but also use your head, and follow instructions too. (I know you know this already, so my advice is directed toward those that might not).Good circuitry can reduce these issues, as you suspect.
R2
Cheers!
R2
--
Good judgment comes from experience.
Experience comes from bad judgment.
http://www.pbase.com/jekyll_and_hyde/galleries
R2D2
Forum Pro
Thermal shut off isn't the only circuitry incorporated into the charger/battery circuitry (the current taper that you mentioned is too). Canon does a good job of this. Not perfect of course (otherwise you'd see unlimited charge cycles). But much better than some.
Mine as well. However I do have a "B&M Premium" LP-E6NH batt/charger kit that actually gets quite hot (which I refuse to use). Bad chargers are still out there!
I'm a pragmatist. You can use the term "temperature delta" if you like. However just feeling the battery can tell you a lot. It's like those weathermen who should just look out their door before telling us the weather. ;-)
That's what I am describing. My recommendations here mirror those of the manuf.
Don't charge when hot.
Sure, but don't present minutiae to the common man at the expense of practicality. These warnings that the manufacturers put out there are good to heed (unless you have reason for us to do otherwise).
You'll need to reread what I wrote. I'm talking about the discharge cycle.
Heat is the discussion. Li-ion batteries are the discussion. Photographers out there own flashes that use these batteries. The same warnings are relevant.
I don't know what kind of agenda you're trying to push, but arguing with sound advice appears counterproductive.Again, "Good circuitry can reduce these issues," but also use your head, and follow instructions too. (I know you know this already, so my advice is directed toward those that might not).Good circuitry can reduce these issues, as you suspect.
R2
Cheers!
R2
Maybe start over with the concept you're trying to get across?
R2
--
Good judgment comes from experience.
Experience comes from bad judgment.
http://www.pbase.com/jekyll_and_hyde/galleries
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Victor Engel
Forum Pro
I looked for such a curve but didn't find one. I do notice my laptop warming up when it is charging. I've not noticed it with Canon batteries, but I don't have them sitting on my lap when they're charging either.
R2D2
Forum Pro
There are tons of resources out there that detail Li-ion charge/discharge/storage characteristics, including Ephemeris (when informative and not argumentative ;-) ).
There's a nice clear graph in the following brief of the charge/discharge cycle (yellow graph):
https://qmed.com/sites/default/files/Electrochem Li-ion Battery Temp Trends.pdf
This one delves a bit more deeply:
https://pubs.acs.org/doi/10.1021/acsomega.2c04093
Another good general resource is "BatteryU":
https://batteryuniversity.com/article/bu-808-how-to-prolong-lithium-based-batteries
R2
Ephemeris
Veteran Member
It has one source only of temperature information. And that isn't specifically a cell node, or electrolyte etc, it's external. I didn't say thermal was the only features, I've listed other features in other posts. We were talking about heat.
I have spotted since my post a 3 way Neewer charged O have. USB C input, little LCD display. It's a 2 pin device so can't have a way to measure temperature, my others have 4. Hadn't noticed this before. Sorry for my mistake here. I was just playing with it chatting in a meeting and realised, hey only 2 pins.
This is what it is. The battery could be any temperature before any current is moved.
As a farmers son my opinion of the weather forecast isn't sat somewhere near those physicists that describe the universe. However, in the UK I think if I say tomorrow it will rain I'm only going to get short changed when it snows
Weather is really bad this year for the farmers.
I think we are talking about different things. The conversation is about thermal delta from passing current rather than the impact of charging when hot or cold.
So, let's iterate together that charging your batteries, using your batteries when hot, or cold don't help with performance or longevity. It could potentially be dangerous (thinking of your hot car post you mentioned).
The conversation is about charging tho?
As for discharge the maximum power transfer also isn't at the end. It may become it's maximum temperature but not the maximum rate of change of temperature (power).
We are talking about charging batteries.
I don't have agendas R2, and find that rather unkind.I don't know what kind of agenda you're trying to push, but arguing with sound advice appears counterproductive.Again, "Good circuitry can reduce these issues," but also use your head, and follow instructions too. (I know you know this already, so my advice is directed toward those that might not).Good circuitry can reduce these issues, as you suspect.
R2
Cheers!
R2
Would you prefer our expertise which suggests rather different observations to stay quiet? Surely that's not the point of this place.
Ephemeris
Veteran Member
It appears that discharge is what R2 was thinking about, but maximum rate of charge also won't be at the end of discharge.
There are a lot of thermal models used related to both the analysis of entropic charging but also being able to monitor/predict. For example in a car we implement certain cells discharging, other cells used in regen to better equalise the thermal energy within a pack. This is to improve performance rather than longevity
There is an open paper called something like thermal analysis of a fast charging method for high power lithium ion cells. That gives some description of ways in which thermal impacts to charging are taken into account when one wants to fast charge.
Victor Engel
Forum Pro
None of those show the graph I'm looking for: x-axis is time, y-axis is temperature using a Canon charger (or equivalent scenario). I see now, quoted, above, "end of the discharge cycle". I thought we were talking about the end of a charge cycle, not discharge cycle.
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