Your car as a powerwall - for the grid!


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DarkRaven

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Sep 2, 2017
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That idea isn't new though. I would bet that Tesla is working on something like this or is at least thinking about it as well. It is just a logical next step. Maybe not THE next step, but certainly one of them.
For the same reason we will have to focus on reusing electric car batteries after we don't want the car anymore. We are doing that now with crashed cars, in the future we will have to do it as we are now with old laptop batteries.
 

dougal

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Sep 13, 2017
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The point is that this isn't just an 'idea', itis an actual contract being offered.

Just as Nissan are already re-marketing used car traction cells as powerwall products. And Ovo, today, have a contract offer for using those specific units for time-shifting electricity for the grid.

The unfortunate aspect is that these offerings are tied to complete systems ofspecific proprietary hardware. Got to start somewhere!
 
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dougal said:
The point is that this isn't just an 'idea', itis an actual contract being offered.

Just as Nissan are already re-marketing used car traction cells as powerwall products. And Ovo, today, have a contract offer for using those specific units for time-shifting electricity for the grid.

The unfortunate aspect is that these offerings are tied to complete systems ofspecific proprietary hardware. Got to start somewhere!

I really want to be able to use my Mercedes B250e as home battery. It is 36kw/h and parked on the drive most of the day every day!

We get 10-12 power cuts a year and it would save me building a powerwall!
 

Crimp Daddy

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Feb 21, 2018
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10-12 power cuts a year is a substantial amount of power interruptions... I can see why you are so motivated to complete such a project.

Where I live power is so cheap and reliable that I am fighting with myself because as much as I enjoy batteries as a hobby, I will literally never receive an ROI on such a project. I would be building because I like it, not because I need it. To make matters worse, I am in an HOA and can't have solar panels. I am almost to the point I feel like giving up on such a project because I truly can't take advantage of it but it's still fun.

Moving back onto the point of this thread... I think it's a smart idea, but I have concerns about the wear and tear on the battery pack. Perhaps the extra cycles don't really pay off in the long terms, perhaps its a raw deal if the packs life is degraded to the point where it barely offsets the cost of a replacement, or reduced life on the car.
 

completelycharged

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New battery is around 5000, they will pay 350 to use your battery and shorten the life by X (to be defined)... which then leaves you needing to buy a new battery for the car earlier.

Given the cells in the vehicles have a cycle life of around 1000 cycles and, lacking any more details, ovo could cycle your battery 120 times in a year (2 charge discharge intervals of 1 hour each at 7kW on a 24kWh pack).

For a 350 payment to deplete 12% of a battery costing 5000 to replace seems like the consumer is not the one going to benefit.

The economics need to be looked at a very closely and considered before letting a 3rd party cycle your battery for a relatively small fee.... When more details are released it might be interesting or a caution for Leaf buyers if they can work out the economics...

Just like Renault charging a relative premium/high lease rate on the battery, only to take those batteries, re-package them and sell them again as home storage units...

I believe that the average consumer is being short changed at the moment on vehicle batteries due to lack of detail and understanding from all parties involved...

Using the battery for covering power cuts is completely different, very viable and sensible option, but I think the ovo setup is going to be grid-tie only. Apparently (from what I was told by Tesla rep last year) the powerwall in the UK is also grid tie only at the moment because of the regulations and requirements needed to get more than 3.7kW of capacity connected and this would otherwise hinder sales......
 

DK100

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Feb 18, 2018
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If you do not cycle the battery to the full extent, bud for instance keep it between 3,1 and 4,1 volt number of cycles goes up to between 5- 10.000 cycles depending of battery type and chemestry.
 

completelycharged

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EV battery voltages are already constrained below 100% DoD and the approx 1000 cycle life already takes some of this into account. The cells in EV's are a compromise for more energy density above cycle life.

You may well get 5,000-10,000 cycles at 10% depth of discharge. 10,000 cycles at 10% DoD is the same energy throughput as 1000 cycles at 100% DoD... or in EV terms around 1100 cycles at 90% DoD.

You can get a reasonable increase at 10-90% charge state quite easily, yes I agree, but the way the article is written and knowing the way the market works there is little long term incentive for a 3rd party to manage the battery for "your best interests".

http://batteryblog.ca/2014/04/nimh-2000-cycles/
http://batteryblog.ca/wp-content/uploads/2013/07/BAK_1-1600-Cycles2.jpg
 

Crimp Daddy

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Feb 21, 2018
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DK100 said:
If you do not cycle the battery to the full extent, bud for instance keep it between 3,1 and 4,1 volt number of cycles goes up to between 5- 10.000 cycles depending of battery type and chemestry.

That is generally already the goal for people in the know. Most of us here are well aware of that metric.

Most people buying these cars (the average consumer) are not battery enthusiasts and could easily fall into the trap of not understanding the economics or what they signed up for.
 
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CrimpDaddy said:
10-12 power cuts a year is a substantial amount of power interruptions... I can see why you are so motivated to complete such a project.

Where I live power is so cheap and reliable that I am fighting with myself because as much as I enjoy batteries as a hobby, I will literally never receive an ROI on such a project. I would be building because I like it, not because I need it. To make matters worse, I am in an HOA and can't have solar panels. I am almost to the point I feel like giving up on such a project because I truly can't take advantage of it but it's still fun.

Moving back onto the point of this thread... I think it's a smart idea, but I have concerns about the wear and tear on the battery pack. Perhaps the extra cycles don't really pay off in the long terms, perhaps its a raw deal if the packs life is degraded to the point where it barely offsets the cost of a replacement, or reduced life on the car.

i think its a bigger issue on cars like the Nissan Leaf than cars like my Mercedes which is actually a Tesla, as Tesla manage the thermals so much better than any other manufacturer out there.

there are Teslas out there with over a 50,000charge cycles and they still have 85%+ original range left. Comparatively there are Nissan and Renault packs now with less than half their original range.

no Tesla packs in existence have gone below 75% original capacity yet, which is testimony to the incredible job Tesla do managing their packs.

also power walk type application is childs play for a Tesla pack that can supply 200a at 460v peak to a pair of 450whp motors!
 

completelycharged

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Also one main element to consider in this is if the Nissan battery warranty does not allow vehicle to grid then who pays for an early battery failure ? The 3rd party would have the incentive to cycle your vehicle battery as much as possible to make as much money as they can if there is no economic cost factor to using your vehicle battery on a /$ per kWh throughput charge basis. If they have a per kWh payment to the owner then there are other battery chemistries that are far more viable than EV chemistry.

To me the whole scheme is a marketing ploy with the consumer indirectly paying for another "green" initiative.

On a payment per kWh throughput basis if a battery in a Nissan Leaf is viable then all of the powerwalls on this site should club together and offer up thier battery capacity as a service... someone should do this !!!!!! There is a lot of capacity being built by users on this site....

Just imagine, you car is bing used for Vehicle to grid and then... https://insideevs.com/nissan-issues-statement-on-leaf-30-kwh-battery-degradation/
 
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completelycharged said:
Also one main element to consider in this is if the Nissan battery warranty does not allow vehicle to grid then who pays for an early battery failure ? The 3rd party would have the incentive to cycle your vehicle battery as much as possible to make as much money as they can if there is no economic cost factor to using your vehicle battery on a /$ per kWh throughput charge basis. If they have a per kWh payment to the owner then there are other battery chemistries that are far more viable than EV chemistry.

To me the whole scheme is a marketing ploy with the consumer indirectly paying for another "green" initiative.

On a payment per kWh throughput basis if a battery in a Nissan Leaf is viable then all of the powerwalls on this site should club together and offer up thier battery capacity as a service... someone should do this !!!!!! There is a lot of capacity being built by users on this site....

Just imagine, you car is bing used for Vehicle to grid and then... https://insideevs.com/nissan-issues-statement-on-leaf-30-kwh-battery-degradation/

This is another reason to buy Tesla as their management is so impressive.
The battery on my Mercedes only charges to 27kwh under normal usage, and an over charge adds about 20 miles range and charges the 36kwh pack to 31-32kwh.
Tesla are very conservative about managing their packs which is why theirs last so long.

Regarding liability; the vehicle owner would be responsible for their own replacement packs which from Nissan / Renault are about 6500.

I certainly wouldnt sign up to this with a Renault or Nissan from the current range or even the new Leaf 2. They just arent there yet with their thermal and power management.

That said if I could get hold of a Nissan or Renault pack I think it would make a great powerwall if you keep it charged to 80% and discharged to about 30%. Power walls dont need anywhere near the current that cars do.
 

completelycharged

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This makes me laugh....

https://insideevs.com/nissan-introd...es-for-older-leaf-in-japan-from-new-4r-plant/

"The batteries will be produced at the new factory in Namie by reassembling high-performing modules removed from batteries whose overall energy capacity has fallen below 80 percent. "

Pay for a lot more old cells to replace the old cells you already have... and at half the price for a new pack I would doublt you would get close to half the cycle life.... so a premium on a per mile basis for old batteries compared to buying a new pack....

The consumer market needs to be educated..... and the cells sold off cheaper to DIY powerwall builders ! That would make a lot more environmental and economic sense ?
 
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Its a shame Nissan never offered a 40kwh Leaf in the UK, only option was a Renault Zoe and you HAD to lease the battery :(

The 30kwh just wasnt enough for me. The 36kwh pack on my car makes it almost exactly half a P75D model S. Same motor and controller which makes it more efficient and powerful than the DC motors on the Leaf.
 

completelycharged

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I would not touch a Leaf battery unless very cheap. First gen cells have bad chemistry and would be a waste of time, second gen seem ok but not great, 2017 looks like either they really messed up on the battery chemistry and it is an epic fail or they have an issue with the pack being over charged.

Zoe lease pricing made it more expensive per mile to drive a Zoe down the motorway than a 3ltr pick up truck.. let alone allowing the battery to be used for a 3rd party to hammer. I was considering a Zoe until I worked out the economics of the lease.
 

ant419b

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Jan 17, 2023
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This is another reason to buy Tesla as their management is so impressive.
The battery on my Mercedes only charges to 27kwh under normal usage, and an over charge adds about 20 miles range and charges the 36kwh pack to 31-32kwh.
Tesla are very conservative about managing their packs which is why theirs last so long.

Regarding liability; the vehicle owner would be responsible for their own replacement packs which from Nissan / Renault are about 6500.

I certainly wouldnt sign up to this with a Renault or Nissan from the current range or even the new Leaf 2. They just arent there yet with their thermal and power management.

That said if I could get hold of a Nissan or Renault pack I think it would make a great powerwall if you keep it charged to 80% and discharged to about 30%. Power walls dont need anywhere near the current that cars do.
I note your comment on using Renault batteries as a powerwall. I have just written off my Zoe and the 40kwh battery is fine. I can buy the battery back from Renault to use it to make a powerwall, but have no idea who can do this for me. Are you aware of where I might find this expertise?
 
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