brainhouston
Active Member
Forgive the newbJason is screaming and pulling out his hair at this very moment.
No idea what this is about hehe
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MAIN BATTERY FAILURE
- Thread starter jasonbrown1437
- Start date
No idea what this is about hehe
Forgive the newb
No idea what this is about hehe
Replacing Tesla Model S Battery Modules Isn't A Viable Long-Term Solution
That's according to a Tesla and EV expert.
carbuzz.com
aesculus
Still Trying to Figure This All Out
So is the secret not to put in new cells but good used cells that closely match the good cells in the battery?
ucmndd
Well-Known Member
brainhouston
Active Member
Gruber seem to think so...
How then Tesla makes refurb packs??
Are they putting new modules in there?
For the most part they repair things not related to the cells/modules. If a cell/module fails they recycle the pack. (On the recent call they mentioned that they are recycling about 50 packs per week.)
No.
ucmndd
Well-Known Member
Give them a call and ask them how that's going for them.
See post #25 in this very thread. Lots of reasons packs "fail" that don't involve cell failures.
When they DO involve cell failures, they either remove modules from 16 module packs to make 14 module packs, or recycle the pack.
brainhouston
Active Member
im genuinely curious tho...
from technical/electrical point of view, why mix n match doesn't work? is there diff rate of charge/discharge depending on age?
is bms not able to balance a slightly weaker/stronger brick?
from technical/electrical point of view, why mix n match doesn't work? is there diff rate of charge/discharge depending on age?
is bms not able to balance a slightly weaker/stronger brick?
Interesting. Aren't they supposed to disclose that that pack is a remanufactured pack or not?
And then, how about those packs sold ~$23K when the customers are told they are brand new (non-remanufactured) packs?
Would you happen to know?
aesculus
Still Trying to Figure This All Out
I appreciate the responses from @ucmndd about how Tesla refurbishes the packs. I suspect this is driven from an economic standpoint (ie finding and fixing non cell issues is generally cheaper than fixing cell issues). But it seems that it COULD be possible, when appropriate, to fix the cell issues when that is the sole problem. In this case Gruber could be right in some cases, but for Tesla, this approach just did not make economical sense. It could also be that Tesla feels that a pack that experience cell issues once might have a higher chance of it happening again. This is not 100% the same as @wk057 was stating that the BMS adjusts the packs almost immediately, but just a likelihood that whatever caused a few cells to go bad could probably cause more to do the same.
Since none of us have the massive data about battery performance, that I expect Tesla has, we sort of have to take their word that they do what is most appropriate. But again, Grueber, in the right circumstances, could have a good approach too. Once size may not fit all but Tesla seems to have the size that fits most.
Since none of us have the massive data about battery performance, that I expect Tesla has, we sort of have to take their word that they do what is most appropriate. But again, Grueber, in the right circumstances, could have a good approach too. Once size may not fit all but Tesla seems to have the size that fits most.
ucmndd
Well-Known Member
I’m simply commenting on my understanding of the technical process, not how they determine/label whether something is “new” or “remanufactured”.
For example, an original 16 module 90kwh pack could be converted into a 14 module 75kwh remanufactured pack to be used as a warranty replacement in my car.
Yes, I agree with the warranty cases.
But I hope a pack that is not labeled as "REMAN" or doesn't have that designation in its part description is in fact a new pack. Otherwise, it would be deceptive to sell a remanufactured pack as new.
brainhouston
Active Member
i think i found my answer here:
teslamotorsclub.com
"Things will always be slightly off, and because these bricks are in a large series set these differences always result in a feedback loop that amplifies the differences over time no matter how small the differences are... and that's just how it is. You don't mix and match cells in series because current under load/charge is constant in a series string by definition. With mismatched modules you end up with the same current at different loaded voltages, resulting in unequal power/energy distribution throughout the pack, resulting in an imbalance."
Take out HV batt pack / cut out bad cell? (S P85+)
(1) Except as provided in paragraph (2) warranty period relating to an implied or express warranty accompanying a sale or consignment for sale of consumer goods selling for fifty dollars ($50) or more shall automatically be tolled for the period from the date upon which the buyer either (1)...
teslamotorsclub.com
"Things will always be slightly off, and because these bricks are in a large series set these differences always result in a feedback loop that amplifies the differences over time no matter how small the differences are... and that's just how it is. You don't mix and match cells in series because current under load/charge is constant in a series string by definition. With mismatched modules you end up with the same current at different loaded voltages, resulting in unequal power/energy distribution throughout the pack, resulting in an imbalance."
I really hate how much time I've had to waste explaining to people that fixing things at the cell level is not possible with these cars as a direct result of misleading (or even outright false) more-clicks-driven YouTube videos.
I think I need to give up. I think most people have enough posts of mine to reference at this point.
I think I need to give up. I think most people have enough posts of mine to reference at this point.
