Use Lightning like a Power Wall? Peak load shaving, not backup?

[EaglesPDX]

9 10% delta cycles < 1 90% delta in capacity loss by a wide margin.

So Tesla's advice to leave plugged in all the time vs. wait until it needs a charge would reduce the rate of battery degradation to some degree.

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[jefro]

There have been many reports of Tesla's driving and extraordinary amount of miles and some got warrantied battery replacements.

I don't believe keeping a Tesla plugged in all the time would degrade the battery I think that it would in fact maintain it better. Tesla's use a lot of energy just sitting there trying to keep the computers ready to go. It's also considered better on the battery for certain conditions were thermal management is needed.
I do however maintain only a 70% maximum charge on my electric car. Unless you need 100% of the Ford F-150 EV battery you can safely set it to below 80% and possibly maintain a longer life.

 

[Mr. Flibble]

I do however maintain only a 70% maximum charge on my electric car. Unless you need 100% of the Ford F-150 EV battery you can safely set it to below 80% and possibly maintain a longer life.

I think I am going to do this with the Lightning when I get it. I didn’t do this with my Kia Soul, and it fried the battery. Though, because of the warranty I should be getting a better, and slightly bigger battery. So all-in-all I was kind of hoping for a battery failure to get the free upgrade…

However, the Kia can’t be set to “only” charge to 80% unless you have it set with a timer. I hope you can define the maximum charge on the Lightning.

 

[Sklith]

It will impact the lifespan of the truck battery. There are finite full charge cycles in a Li-ion battery (500?). You'll be adding 365 discharge/charges a year if you are powering the house at night with the truck.

Probably cheaper and more cost effective to buy some old cheap batteries for house backup.

The amount of abuse the vehicle's battery will take (9.2 kW constant discharge) while performing V2L is negligible compared to normal operations while driving (ranging from 380 kW discharge to 100+kW charge from regen in less than a second). For this very reason, batteries find their second life as energy storage in homes, and last a very long time. Not all charge/discharge cycles are created equal.

 

[Mr. Flibble]

The amount of abuse the vehicle's battery will take (9.2 kW constant discharge) while performing V2L is negligible compared to normal operations while driving (ranging from 380 kW discharge to 100+kW charge from regen in less than a second). For this very reason, batteries find their second life as energy storage in homes, and last a very long time. Not all charge/discharge cycles are created equal.

You know, that is a really good point.

I know that “failed” Nissan Leaf batteries can still be used as whole house backup batteries; especially if you chain a few together. That’s probably part of the reason they are so expensive at wrecking yards.

Wouldn’t be hard to have a way to auto flip the power to switch to the lightning. But it would kind of suck to have the power blip twice a day as you switched to and from the battery.

 

[Sklith]

Wouldn’t be hard to have a way to auto flip the power to switch to the lightning. But it would kind of suck to have the power blip twice a day as you switched to and from the battery.

Yeah, I'm really curious how this will work. If I need to buy a separate inverter to power my home I'll probably skip on getting it installed, that feels extremely wasteful to skip the onboard inverter the truck already has.

 

[TF1000]

Question for MickeyAO or anyone else who knows. Do EVs actually let you charge to 100% and discharge to 0%? I do not own an EV but a PHEV (Prius Prime). On the dash it says what % you're at and does go from 0% to 100% but there is also a little battery icon with lines at about 20% and 80% that the bar never exceeds either of these lines. I thought I had read that Toyota was conservative with battery management and never actually let you deplete to 0% or charge to 100%.

 

[Mr. Flibble]

Question for MickeyAO or anyone else who knows. Do EVs actually let you charge to 100% and discharge to 0%? I do not own an EV but a PHEV (Prius Prime). On the dash it says what % you're at and does go from 0% to 100% but there is also a little battery icon with lines at about 20% and 80% that the bar never exceeds either of these lines. I thought I had read that Toyota was conservative with battery management and never actually let you deplete to 0% or charge to 100%.

They don’t actually charge to 100%, or down to 0%. They have a hidden reserve. For example, my Kia has a 30.5 KWh battery, but only 27 KWh is used. This additional 3.5 KWh is a buffer to prevent damage to the battery. So it still has a charge even when it is listed at 0%, you just can’t use that charge. I believe it has a similar cap, but I am not so sure about that.

Good battery management software should allocate electrons to the battery to help keep its life longer. Though, batteries that are not cooled/heated (Nissan Leaf), or air Cooled (my Kia Soul), fare worse than liquid cooled (Tesla, Ford Lightning) as managing the correct heat amount is important.

 

[EaglesPDX]

The amount of abuse the vehicle's battery will take (9.2 kW constant discharge) while performing V2L is negligible compared to normal operations

Usage is usage. Finite number of charges/discharges (usually equal to 500 full cycles) is the rule for Li-on batteries. Using it to power the house at night and then driving it during the day is going to increase the number of cycles and reduce battery life.

www.batteryuniversity.com

For the car mfgs who are basing warranty on just driving usage, this puts them at risk for having to replace batteries under warranty.

 

[Sklith]

Usage is usage. Finite number of charges/discharges (usually equal to 500 full cycles) is the rule for Li-on batteries. Using it to power the house at night and then driving it during the day is going to increase the number of cycles and reduce battery life.

www.batteryuniversity.com

For the car mfgs who are basing warranty on just driving usage, this puts them at risk for having to replace batteries under warranty.

If you're at all concerned about the wear of a battery from V2L usage then I strongly suggest you never drive the vehicle a single mile. Usage is not just usage, the charge and discharge C rating of batteries are limits set to mitigate degradation, and approaching those limits have negative consequences such as promoting the growth of dendrites. Approaching the acceptable limits of a battery's C rating is the worst thing you can do to them, and driving in normal conditions does this far more than a slight power draw could ever do.

The degradation of a battery when drawing 0.07C (9kW of power in a 131kWh pack) is infinitesimally miniscule compared to the draw of 3.1C (414kW of power) and, which is much worse on a battery by the way, 1C(131kW) regen power into the battery all within an instant. Any power draw/charge which approaches the battery's limits are much, much much worse than low amounts.

Your "usage is usage" comment is the same as saying a car's engine will will fail at the same mileage whether or it's running at full load & RPMs or a much more moderately used one. The latter will almost definitely be the better for wear.

The reason why I feel so inclined to bring this up is V2L is an important step to cleaning up our electricity grid. Since we need energy storage to reduce our dependence on non-renewable energy such as peak-load natural gas plants, traction batteries in EVs can be a temporary solution until industrial-scale energy storage becomes financially viable. Until then, us EV owners willing to opt-in on this can get nice kickbacks from our electrical companies.

 

[Sklith]

I say V2L (Vehicle to Load) since it can be used universally for applications that pull from the traction battery at relatively low power, be that for charging other EVs, running appliances in a home, or contributing the the local utilities.

 

[jefro]

My two EV's don't have any hidden reserve. You can charge to 100%. The issue if going to 0 is kind of sketchy. Various things start to happen once you get close to some low point. Things stop working, things make warnings and the car will usually slow to a crawl and report all sorts of things. Then it will die.
My i3 had a REX and on a very cold day running heat and wipers and going up a long hill the gas motor wouldn't go into closed loop until it warmed up and also wouldn't go into full power. The car felt like it hit a deer and slowed to 5mph on a highway going up a steep hill. Skerd me and I sold the car. Why have a motor if it can't prevent this issue?
The F150 will also have some low number that it starts to warn you and eventually you need to take action near zero. It won't have any overhead above 100% I'll wager.

 

[jefro]

My two EV's don't have any hidden reserve. You can charge to 100%. ( I don't recommend doing it unless you need to) The issue of going to 0 is kind of sketchy. Various things start to happen once you get close to some low point. Things stop working, things make warnings and the car will usually slow to a crawl and report all sorts of things. Then it will die.
My i3 had a REX and on a very cold day running heat and wipers and going up a long hill the gas motor wouldn't go into closed loop until it warmed up and also wouldn't go into full power. The car felt like it hit a deer and slowed to 5mph on a highway going up a steep hill. Skerd me and I sold the car. Why have a motor if it can't prevent this issue?
The F150 will also have some low number that it starts to warn you and eventually you need to take action near zero. It won't have any overhead above 100% I'll wager.

 

[MickeyAO]

My two EV's don't have any hidden reserve. You can charge to 100%. The issue if going to 0 is kind of sketchy. Various things start to happen once you get close to some low point. Things stop working, things make warnings and the car will usually slow to a crawl and report all sorts of things. Then it will die.
My i3 had a REX and on a very cold day running heat and wipers and going up a long hill the gas motor wouldn't go into closed loop until it warmed up and also wouldn't go into full power. The car felt like it hit a deer and slowed to 5mph on a highway going up a steep hill. Skerd me and I sold the car. Why have a motor if it can't prevent this issue?
The F150 will also have some low number that it starts to warn you and eventually you need to take action near zero. It won't have any overhead above 100% I'll wager.

Tell me what the vehicles were and I might be able to tell you if they actually had a hidden reserve. the vehicle might say 100%, but the cell capacity and the xSxP configuration might say something different.

 

[jefro]

BMW i3 and Chevy Bolt.
I spoke with quite a few highly trained i3 techs (even German) and all of them said no reserve trying to fix an issue.
Every Bolt technical manual says no also.

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