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P85D Vbox guys -- anyone test to see if "Max Battery Power" changes anything?
- Thread starter LetsGoFast
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sataponw
Member
Max Battery Power mode heats up your battery so that it can produce higher output in a short burst. However it causes battery degradation and will reduce the longevity of your battery, so Tesla advises that it should be used sparingly.
ArtInCT
Always Learning
Hi Cynix: That is some interesting information. Can you please post a link as to where you read this from Tesla Motors? If you are on shore power, does the heating energy come from the shore power or the main traction battery pack? I will be getting a P90DL and would like to be "up" on the guidelines and warnings.... and how that actually works... thanks.
ARTinCT
Please see more information here: Max Battery Power setting in P90DL
I'm still waiting for v7.0 for my P85D, so I don't really have any first-hand knowledge
Please see more information here: Max Battery Power setting in P90DL
I'm still waiting for v7.0 for my P85D, so I don't really have any first-hand knowledge
i have 7.0 on my P85D and I'm pretty sure I haven't seen this option, I'll check again.
Please see more information here: Max Battery Power setting in P90DL
I'm still waiting for v7.0 for my P85D, so I don't really have any first-hand knowledge
I do not believe that that the warning is intended to say that it will reduce battery life or cause degradation to the cells. I believe they are simply saying that you will consume electrons at a more rapid rate and that the battery will enter reduced power mode faster due to overheating more quickly.
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I got it on 7.0 and tried it out, but my butt dyno didn't detect any performance difference.
wk057
Vendor & Senior Tinkerer
I disagree. Heating the cells while they're at high states of charge definitely does cause accelerated degradation. This is a well known fact of the cell chemistry. Unless the pack is below a safe operating temperature I would never heat the cells.
ArtInCT
Always Learning
Do you think that perhaps the MAX POWER function may take into account the current pack operating temperature and know, based upon that data point, that it does not have to heat the pack? For instance if the pack environment system was cooling the pack down already? Your thoughts? Or am I expecting too much from Tesla engineering??
But how hot. If it's no worse than a summer's day, then it's no worse than driving your car in LA vs Montreal.
wk057
Vendor & Senior Tinkerer
Based on other's posts it does seem to take the current temperature into account. I'm assuming max power is just a high pack thermostat set point.
Don't know. Doesn't matter though. Hotter at high SoC = more degradation. So, a pack in LA will degrade more than a pack in Montreal, although Tesla's heating and cooling system should negate a lot of this under normal conditions. The max power heating function seems to go beyond this.
Actually, Tesla/Panasonic's NCA chemistry is pretty tolerant of high temperatures... here's the research paper, examine the 2nd graph:
Development of High Power and Long Life Lithium Secondary Batteries
Note that the life cycle difference at 25 degrees C and 50 degrees C is roughly the same.
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Ldub22
Member
@Techmaven wins the thread nerd award for linking to a paper that I can barely understand outside of cunjunctions and punctuation!
;-)
wk057
Vendor & Senior Tinkerer
This paper has the same flaw that most battery related studies have. They simply charge and discharge repeatedly and think that's valid data. Unfortunately that's not how things work in the real world.
Instead of charging to 100% and then immediately discharging at a high rate, we tend to stay at or near 100% longer and discharge more slowly.
If you haven't watched this video, you probably should: Why do Li-ion Batteries die ? and how to improve the situation? - YouTube
Well, there are two different issues. One is what Tesla's statement actually says, which does not say that you will experience degradation. I'm pretty confident of that.
The second issue is the question of whether or not Tesla allows the batteries to heat beyond a point where the cells will deteriorate and whether or not Tesla takes state of charge and other operating parameters into consideration. Although I certainly agree that it is possible to overheat the cells, we actually have no evidence to suggest that this is what takes place when you activate the function. In fact, we have very little evidence to suggest much of anything about its function. It is well-known that LiIon batteries perform poorly at lower temperatures and that damage occurs most often at high states of charge and high temperatures. There is a lot of room in the middle.
Andyw2100
Well-Known Member
I'm wondering about the possibility of using the Max Battery Power option to preheat the traction pack when it is cold soaked. I started a thread to discuss that here:
Max Battery Power to Preheat Cold-Soaked Traction Pack? Possible? Pros? Cons?
Max Battery Power to Preheat Cold-Soaked Traction Pack? Possible? Pros? Cons?
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