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Marktm
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Posts: 317
Joined: Thu Jan 21, 2016 10:49 am
Delivery Date: 09 Jan 2016
Leaf Number: 022737

Re: Repurposing of LEAF batteries in secondary non-BEV applications.

Wed Nov 30, 2016 6:29 pm

edatoakrun wrote:
No, I'm still driving it.


I'm not hopeful that an affordable system that meets my needs (Leaf battery back-up for emergency off-grid) will be offered anytime soon. The Tesla Powerwall 2 appears to be headed in the right direction at a seemingly competitive price. However, not sure it is well integrated for emergency use yet - cannot find any real tech data on that.
2012 Leaf SL; 34,000 miles. 12 bars - Battery replaced November 1st, 2016.
4000 watts Grid-tied solar. 3000 watts (level II) off-grid solar Leaf charging capable.

edatoakrun
Posts: 4457
Joined: Thu Nov 11, 2010 9:33 am
Delivery Date: 15 May 2011
Leaf Number: 2184
Location: Shasta County, North California

Re: V to G and repurposing of BEV batteries in secondary non-BEV applications.

Sun Jul 23, 2017 9:26 am

V2G found to improve the lifetime of electric vehicle batteries

Intelligent use of vehicle to grid (V2G) technology can improve the battery life of electric vehicles according to a new study from the University of Warwick, potentially disproving a key criticism levelled at the technology.

Working with the Energy and Electrical Systems group of the university’s research division WMG and Jaguar Land Rover, Dr Kotub Uddin analysed advanced lithium ion batteries used in commercially available EVs over a two year period.

This allowed him to create what is thought to be one of the most accurate battery degradation models existing in the public domain to predict battery capacity and power fade over time, under various ageing acceleration factors including temperature, state of charge, current and depth of discharge.

Using this model, Dr Uddin developed a ‘smart grid’ algorithm to calculate how much energy a vehicle requires to carry out daily journeys, and how much energy can be taken from its battery without negatively affecting it, or even improving its longevity.

This algorithm was then applied to WMG’s International Digital Laboratory to see if energy from EVs parked on the University of Warwick campus could power the multi-use building.

The study concluded that the number of EVs parked on the campus (around 2.1% of cars, in line with the UK market share of EVs) could spare the energy to power this building. In doing so, capacity fade in participant EV batteries would be reduced by up to 9.1%, and power fade by up to 12.1% over a year...

Until now a general consensus had been in place that the increased cycles imposed on a battery by V2G would lead to more rapid degradation. However, the new study suggests that this process is more complex than thought and that in fact, it can be exploited to improve a battery’s lifetime..
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https://www.cleanenergynews.co.uk/news/ ... -batteries
no condition is permanent

User avatar
Marktm
Gold Member
Posts: 317
Joined: Thu Jan 21, 2016 10:49 am
Delivery Date: 09 Jan 2016
Leaf Number: 022737

Re: V to G and repurposing of BEV batteries in secondary non-BEV applications.

Sun Jul 23, 2017 1:37 pm



For MUCH more details on this study:
http://www.sciencedirect.com/science/article/pii/S0360544217306825

It is notable that part of the study assumptions is that "cheap" batteries will be used to store (renewable) energy during peak productions and then "trickle" charged to the vehicle when not being used. What I've found is that used Leafs are about the cheapest form of batteries that includes a high quality BMS . Eventually, the used EV battery market might impact this?

It would seem a more realistic approach would be to keep our existing generation/distribution systems fully loaded 24/7 by charging EVs off peak and eliminate the major inefficiencies of coal/nat gas generation turn-down. Then, judiciously feed back energy from these EVs as needed to "fill the gaps" of energy generated by the ever increasing amounts of renewable forms (and prevent peaking plants from being needed). I wonder if the results (better battery life??) would be the same under this more rigorous charging scenario?

It is possible that alternate methods are covered in the (many pages) of the study - I have only "skimmed" it at this time - but it is very interesting that it could be possible to minimize battery degradation with (really) smart grid controls.
2012 Leaf SL; 34,000 miles. 12 bars - Battery replaced November 1st, 2016.
4000 watts Grid-tied solar. 3000 watts (level II) off-grid solar Leaf charging capable.

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