LeftieBiker
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Re: New device boosts road time for Leaf by 50%

Sun Nov 26, 2017 2:30 am

We get the idea, actually. It would typically add very little range, and occasionally add about 10 miles, rarely somewhat more. The title is pure hyperbole, like a 140 mile 2011 Leaf.
2013 "Brilliant Silver" SV with Premium Package and no QC, and 2009 Vectrix VX-1 with 18 Leaf cells.

The most offensive, tasteless phrase in use here is "Pulled the trigger." I no longer respond to posts that use it.

Rxleaf
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Re: New device boosts road time for Leaf by 50%

Sun Nov 26, 2017 6:47 am

I believe the article says that battery pack lifetime will be extended by 50% due to a more efficient way of managing the battery balance and/or discharge.

So instead of a 5 to 8 year battery, you have a 7.5 to 12 year battery.

You will get 10% more range from the bottom end of the battery pack and maybe even the top end. That is use the full 24kw pack instead of 22.5kw.

The math works out. 24kw - 10% = 22.6wk, so about 10% more range.

Any engineers out there want to take a SWAG at it?

jjeff
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Re: New device boosts road time for Leaf by 50%

Sun Nov 26, 2017 7:48 am

Not that I want to feed the "arrogant" OP! who could have just said the article was about extending battery life not distance.....but that makes more sense, 50% increase in battery life and maybe 10% increase in battery capacity. I thought our Leafs had something similar, isn't that what the battery shunt graph is for on LeafSpy, showing which batteries were active and which ones were currently being shunted?
2012 SL purchased used 2/'16
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WetEV
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Re: New device boosts road time for Leaf by 50%

Sun Nov 26, 2017 7:50 am

Sounds vaguely like dynamic balancing. I heard about it years ago, not new.

The usual way battery packs in BEVs are balanced is "top balancing". While charging all the cells to the same voltage by using bypass resistors to "balance" the pack by switching in the resistors to discharge the cells that have higher voltages. While discharging, the pack takes the exact same current out of each cell, when the cell with the smallest capacity and thus the lowest voltage hits a lower limit the pack is empty. Notice that the cell with the smallest capacity sets the limit for the pack, and the cell with the smallest capacity is working the hardest and thus will have the most cycling wear.

Dynamic battery balancing, by one of several methods, keeps the voltage in the cells the same as they are discharged. This levels the cycling wear on the pack, and reduces wasted energy in balancing resistors, and slows wear and provides more usable capacity, especially as the battery pack ages.
WetEV
#49
Most everything around here is wet during the rainy season. And the rainy season is long.
2012 Leaf SL Red (Totaled)
2014 Leaf SL Red

SageBrush
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Re: New device boosts road time for Leaf by 50%

Sun Nov 26, 2017 8:50 am

Let's see ...

In a NEW battery,
wire in parallel
add a controller to each cell
add programming

All to solve a problem begat by poor QC and inadequate thermal control.
2013 Model 'S' with QC & rear-view camera
Bought off-lease Jan 2017 from N. California with 63.9 Ahr after 22k miles
Car is now enjoying an easy life in Colorado

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EVDRIVER
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Re: New device boosts road time for Leaf by 50%

Sun Nov 26, 2017 9:24 am

SageBrush wrote:Let's see ...

In a NEW battery,
wire in parallel
add a controller to each cell
add programming

All to solve a problem begat by poor QC and inadequate thermal control.


Exactly, an unreliable and labor intensive solution for a questionable savings and likely other issues. Classic "lab theory" project that is not grounded in real-world applications, If it were easy to embed this and practical then OEMs would do it without the extra hardware. Will make for pages of useless posts here however. Patented, that's the best part :lol:

WetEV
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Re: New device boosts road time for Leaf by 50%

Sun Nov 26, 2017 9:49 am

SageBrush wrote:Let's see ...

In a NEW battery,
wire in parallel
add a controller to each cell
add programming

All to solve a problem begat by poor QC and inadequate thermal control.


There already is a "controller" for each cell (or groups of cells), complete with programming. With a top balanced battery, the controller just measured the voltage and switches in a resistor when needed to balance the cell relative to the rest of the pack.

Regardless of how good of QC or thermal control, battery cells are not identical. By spreading rather than concentrating the wear, longer life can be achieved.
WetEV
#49
Most everything around here is wet during the rainy season. And the rainy season is long.
2012 Leaf SL Red (Totaled)
2014 Leaf SL Red

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Nubo
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Re: New device boosts road time for Leaf by 50%

Sun Nov 26, 2017 12:22 pm

DIY builders have been achieving essentially the same result for years in terms of the cells running out at the same time. It’s called “bottom-balancing”. Doesn’t require a truckload of relays. In fact no BMS at all.
I noticed you're still working with polymers.

LeftieBiker
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Re: New device boosts road time for Leaf by 50%

Sun Nov 26, 2017 1:12 pm

I believe the article says that battery pack lifetime will be extended by 50% due to a more efficient way of managing the battery balance and/or discharge.

So instead of a 5 to 8 year battery, you have a 7.5 to 12 year battery.


The 'Canary pack' degrades rapidly over time unless kept very cool. Unless this device can slow time, I don't see a big increase in longevity for pre 4/2013 Leafs.
2013 "Brilliant Silver" SV with Premium Package and no QC, and 2009 Vectrix VX-1 with 18 Leaf cells.

The most offensive, tasteless phrase in use here is "Pulled the trigger." I no longer respond to posts that use it.

SageBrush
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Re: New device boosts road time for Leaf by 50%

Sun Nov 26, 2017 2:19 pm

The LEAF pack is so bad, the charlatans are moving in.
2013 Model 'S' with QC & rear-view camera
Bought off-lease Jan 2017 from N. California with 63.9 Ahr after 22k miles
Car is now enjoying an easy life in Colorado

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