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I am signed up to take a course next month on how to use the laser cutter at the local maker place.

Perhaps it has the gas nozzle that is best for cutting bus bars.
 

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Linsight Designer
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Discussion Starter · #83 ·
Also, the EHW5/EHW5B series cells are the only ones with the crazy lifespan. Those are the cells you want, for longevity sake. Not the Panasonic Insight cells, as @mudder is quickly noticing in his testing when he says "capacity decreases ~5% after ~QTY600 cycles". That's HORRIBLE compared to the EHW5 cells.
See my reply to you in the other thread. In short, let's wait on valid data before we jump to conclusions on cycle life. It's ultimately moot; time will kill either cell type long before cycle count does.
 

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deleted comment here that I didn't mean to publish

See my reply to you in the other thread. In short, let's wait on valid data before we jump to conclusions on cycle life. It's ultimately moot; time will kill either cell type long before cycle count does.
Yeah and I mean 600 Cycles is probably 1 or two cycles per week for me... even with the hypothetical prius AC, age degradation might even outpace cycle degradation.
 

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Discussion Starter · #85 ·
Not sure why you'd say that?
My rational stems from your previous statement:
I can say with 100% certainty that the Insight modules are NOT ehw5 cells. And no, the W doesn't stand for welded. I plan to make a post in the "47AH fomoco" thread to straighten up several misconceptions you guys seem to be perpetuating on this forum.

Not sure why I'd help you, though, after the way you've treated me in a few threads so far. :(
When I made this statement, it was unclear if you were going to stick around this forum.
 

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Discussion Starter · #87 ·
Yeah and I mean 600 Cycles is probably 1 or two cycles per week for me... even with the hypothetical prius AC, age degradation might even outpace cycle degradation.
I 100% agree. I probably do less than 2 cycles per week... So QTY1000 cycles is ten years. I can live with 5% cycle-related capacity reduction over a decade... age-related capacity is certainly going to be higher.
 

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Instead of editing my post where I go into some of the differences of the 2 cells on the previous page, and no one seeing the addition, I'll just post this here.

Panasonic Insight cells are 3.7 volts nominal.
Blue Energy EHW5 and EHW5B cells are 3.6 volts nominal.
 

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From what I can tell, the EHW5 modules are rated for 300A, while the G3 cells are rated for 375A instantaneous and 150A (30c) continuous. The Cmax cells are rated at 100A continuous and 150A instantaneous.

Does that sound right? I'm just piecing this together from information online.
 

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Discussion Starter · #91 ·
Until recently, Blue Energy cells were only used in Hondas. Toyota has since started using a few Blue Energy cells, but we are several generations past the EH4 cells.
My understanding is that Blue Energy is 49% owned by Honda, right?
 

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Discussion Starter · #92 ·
From what I can tell, the EHW5 modules are rated for 300A, while the G3 cells are rated for 375A instantaneous and 150A (30c) continuous. The Cmax cells are rated at 100A continuous and 150A instantaneous.

Does that sound right? I'm just piecing this together from information online.
We need to decide what the term 'continuous' means in this instance:

1: Possible definition: "starting with a full cell, continuously discharging the cell until it is empty." In this case, it's possible the information you listed above is true. But note that assuming the cell is 5 Ah, and you pull it from 90% to 10% SoC, 'continuous' is only going to be 96 seconds long ( 5 Ah / 150 A * 3600 seconds/hour).

2: Possible definition: "continuously discharging the cell until it is empty, and then charging the cell at some lesser value (e.g. 100 amps) until the cell is full, and then repeating this cycle in perpetuity." In this case, none of these cells will 'continuously' handle the currents you list... they just get too hot. For example, 375 amps is going to generate 140 watts inside each cell due to ESR, which is going to cause it to heat up substantially. As a comparison, if we drop down to 100 amps, then the heat generated from ESR drops down to 10 watts... because ESR power loss is a squared function of current.

3: Possible definition: A hybrid of the first two cases... the cell is "continuously discharged" as in case #1, but then a long dwell period (or slow charge current) is placed between each discharge cycle. This allows time for the pack to cool down. The question then becomes "how many times can we pull 375 amps from the cell before the cell dies?" I imagine the answer is less than QTY100 cycles... that's a 75C discharge rate.

Obviously I can test whichever definition we ultimately come up with. My test equipment can charge at up to 270 amps, and I can discharge at up to 600 amps... so we can certainly test for anything. Of course, I don't see a reason to test at higher currents than the G1 Insight can actually create (i.e. 75 amps regen and 140 amps assist).
 

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Discussion Starter · #95 · (Edited)
Yes, why?
Just curious, as I had read that previously at some point. Seems odd Honda would sell their modules to a competitor (Toyota)... but obviously if they don't own 50% they don't have any say in who they sell modules to.

...

Update on the Panasonic G3 Insight cells:
Slope Plot Font Rectangle Parallel


No need to panic... while it looks like the capacity is dropping rapidly, note that the X axis represents 3+ years driving your car pedal to the metal (full assist and full regen all the time everywhere you drive). During that time, the cell capacity will drop ~3.2% due to cycle count. Specifically, if you linearize the data, you should expect to lose 0.221 mAh capacity per battery cycle... that's 0.00442% capacity reduction per complete charge cycle.

Caveats:
This testing is extremely abusive... we're completing one complete charge/discharge cycle (from 10% to 90% to 10% SoC) every 8 minutes, continuously 24/7. It would be impossible to replicate this condition in real-world driving conditions... but the whole point of this test is to 'quickly' determine how long a cell might last under the most extreme conditions.

Lithium cells tend to lose more charge initially than they do over the long term. It's likely we'll see capacity reduction taper off over the next thousand cycles.

Cycle count isn't the only thing that affects cell capacity. This test doesn't control for calendar aging, which includes ambient temperature affects, etc.

THIS IS NOT A COMPLETE ANALYSIS! This is preliminary data. It is too early to draw conclusions from the data.

The test I'm performing is not the same as is typically performed on cells. For example, the (actual) EHW5 long term cell test procedure continuously charges the cell at 40 amps, and discharges the cell at 40 amps, whereas my test is charging the cell at 52.5 amps, and discharging the cell into ~42 mOhm (~98 [email protected] volts, ~79 [email protected] volts). Specifically, my test is more abusive.

Summary:
So even though this isn't an EHW5 cell - which might or might not perform better - it still performs well enough for our G1 needs. I'll keep updating.
 

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Discussion Starter · #96 · (Edited)
And here's the 47 Ah FoMoCo module results over the same time period (there are fewer cycles because the cell capacity is much larger):
Rectangle Slope Plot Triangle Font


The linearized capacity reduction is -6 mAh/cycle (-0.0128%/cycle). We've lost around 550 mAh after QTY90 cycles. We expect the capacity to drop faster, due to this module's relatively lower cycle life (compared to EHW5 and/or Panasonic G3 Insight cells).

As above, the X-axis likely represents several years worth of driving... less if you have MIMA and drive hundreds of miles every day using constant manual assist/regen.

Same caveats as listed above, with one difference:
-The 47 Ah FoMoCo cell is recharged at 75 amps (versus 52.5 amps). Discharge current is identical.

...

Overall, both cells are performing well. I'm still certain aging will kill both cells long before cycle count does.
 

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Discussion Starter · #97 ·

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Discussion Starter · #99 · (Edited)
5AhG3 cell just broke QTY1000 cycles:
Slope Rectangle Plot Font Parallel


We've now charged and discharged 15 kWh through this single cell. That's equivalent to 720 kWh cycled through a 48S pack... which is equivalent to a non-MIMA car requesting continuous [email protected] kW for ~3600 minutes AND also continuous [email protected] for ~4300 minutes.

Assuming:
-you drive five days per week, 52 weeks per year.
-each day you use the equivalent energy consumed in four minutes at full assist/regen,

Then:
-QTY1000 cycles represents ~3.5 years of driving.
-after 3.5 years, cycling has decreased your cell capacity -3.5% (-175 mAh).

Note the slope has decreased (good):
[email protected] cycles, the per-cycle linear reduction was -222 uAh/cycle (averaged across all cycles)
[email protected] cycles, the per-cycle linear reduction is now -194 uAh/cycle (averaged across all cycles)

/////////////////////////////////////////////////////////////////////////////////////////////

47 Ah FoMoCo cell:
Rectangle Slope Plot Font Parallel


Note the slope has decreased (good):
[email protected] cycles, the per-cycle linear reduction was -6 mAh/cycle (averaged across all cycles)
[email protected] cycles, the per-cycle linear reduction is now -4.7 mAh/cycle (averaged across all cycles)

FYI: As mentioned previously, these lithium cells are heavily influenced by ambient air temperature. Today and yesterday were fairly hot, whereas the day before it rained in the afternoon... you can see how much it cooled down on the peak that has a trough in it (around cycle 85).

FYI: The 5AhG3 cell is less affected by temperature, likely due to how much warmer it's getting by itself (due to its smaller ampacity)... the the daily ambient temperature cycle might have less impact on the cell's own temperature.
 

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5AhG3 cell just broke QTY1000 cycles:
View attachment 98298

We've now charged and discharged 15 kWh through this single cell. That's equivalent to 720 kWh cycled through a 48S pack... which is equivalent to a non-MIMA car requesting continuous [email protected] kW for ~3600 minutes AND also continuous [email protected] for ~4300 minutes.

Assuming:
-you drive five days per week, 52 weeks per year.
-each day you use the equivalent energy consumed in four minutes at full assist/regen,

Then:
-QTY1000 cycles represents ~3.5 years of driving.
-after 3.5 years, cycling has decreased your cell capacity -3.5% (-175 mAh).

Note the slope has decreased (good):
[email protected] cycles, the per-cycle linear reduction was -222 uAh/cycle (averaged across all cycles)
[email protected] cycles, the per-cycle linear reduction is now -194 uAh/cycle (averaged across all cycles)

/////////////////////////////////////////////////////////////////////////////////////////////

47 Ah FoMoCo cell:
View attachment 98300

Note the slope has decreased (good):
[email protected] cycles, the per-cycle linear reduction was -6 mAh/cycle (averaged across all cycles)
[email protected] cycles, the per-cycle linear reduction is now -4.7 mAh/cycle (averaged across all cycles)

FYI: As mentioned previously, these lithium cells are heavily influenced by ambient air temperature. Today and yesterday were fairly hot, whereas the day before it rained in the afternoon... you can see how much it cooled down on the local maxima that was a trough in it (around cycle 85).

FYI: The 5AhG3 cell is less affected by temperature, likely due to how much warmer it's getting by itself (due to its smaller ampacity).
That's honestly insane. You could not feasibly even do this much in a day. Drain the pack sure. But charge at the 10kw, uhh no.
 
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