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I wish we had more V1G, aka grid-interactive charging. It's extremely unsexy, but upon further inspection it's surprisingly great. It doesn't add costly cycles

I wish we had more V1G, aka grid-interactive charging. It's extremely unsexy, but upon further inspection it's surprisingly great. It doesn't add costly cycles to the onboard traction battery, but it still can provide similar grid services (virtual spinning inertia, demand response, distribution network balancing, etc). Better yet it should be a software update for every existing electric car, even those without bidirectional hardware. Ideally I could tell my car, "always charge to [40]% immediately, then charge to [80]% by [8 AM] [Weekdays]." Then the car automatically participates in a fleet battery scheme, earning me money overnight by providing grid services. Bonus points if it also knows that I have TOU metering, and automatically optimizes for minimum cost.

labcomputer 2y ago
> Better yet it should be a software update for every existing electric car, even those without bidirectional hardware. Completely agree with everything you wrote, but also: It doesn't even require participation of the car! Plain old J1772 already provides the EVSE real-time-ish control over the charge rate. Some charging stations already exploit this to split power between two ports. When one car is plugged in it gets full current. Upon detecting a second vehicle, the EVSE signals the first to reduce current draw (and it must comply). In other words, every EV can be grid-interactive with just a software upgrade to the EVSE, or, failing that, replacement of the (much cheaper) EVSE.
mavhc 2y ago
https://octopus.energy/smart/intelligent-octopus-go/ https://octopus.energy/smart/intelligent-octopus-go/ UK power company offering that, if you have a compatible car/charger they can control for you
audunw 2y ago
Our power company ("Tibber") provides this as a service in their app for a bunch of different car models. Until recently this just let you avoid hours with more expensive electricity. But now you get an extra bonus on top of that since it lets the power company provide valuable grid balancing services. It's not sexy, but it's also not that hard to implement so I suspect this will become commonplace surprisingly quickly. > It doesn't add costly cycles to the onboard traction battery I guess for many people, NOT using V2G will be a net economic loss. For a big battery, and with 20%-80% limits, we are talking about extremely gentle cycles. The degradation is likely a drop in the bucket. Battery degrades with age as well as cycles. So after 20-30 years if you haven't used V2G you risk having an age-degraded battery that didn't deliver its full capability in terms of cycle life. Or the rest of your car has degraded before your battery did. For LFP it's even more likely that V2G will get you the most value out of the battery. If you go through a charge cycle every day or two on a Li-ion, I suspect V2G won't make sense since you're stressing the cycle life of your battery. The problem is we don't really know how long modern EV batteries will last, so it's impossible to know what the most rational choice is. We also don't know what the value of a degraded battery is in 15 years, and what the cost of a new one is. Since the economies of scale around battery recycling will be so massive in 15 years, it's possible that you get paid a fair sum for an old battery, and that getting a new battery will be fairly cheap. Or maybe not.
wcoenen 2y ago
I have a time of use contract with hourly pricing, based on the day-ahead electricity market. So I also wanted to schedule charging, but I was somewhat disappointed that - my charging station has no scheduling feature built-in - my EV does have settings for this, but they act more as a suggestion. It would often charge when I didn't want it to. Fortunately the charging station does support being controlled over modbus tcp/ip, so I was able to write some code and run it on a Rasperry Pi to control it. My control system fetches the prices and enables charging whenever they are below the configured maximum. However, I now find that (because of my obsession with optimizing this) it is still very far from a hands-off solution. I find myself doing this: - check electricity prices manually - check car state of charge manually - if prices are going to dip very low, figure out how much time will be needed to charge to 80% - if prices are high, figure out whether I need to do a minimal top up anyway and how much, based on how much I think I'm going to drive - choose a maximum price such that charging will be enabled during a sufficient amount of hours, based on the above The main thing that's missing to properly automate this is a way to retrieve the EV's state of charge. But a charging station for home use will typically only support a simple PWM signal to tell the car how much current it can draw. No other communication is possible unless the charging station supports ISO 15118. Mine doesn't :-(
- MrsPeaches 2y ago
  Very interesting! > I have a time of use contract with hourly pricing How did you get this?
  - wcoenen 2y ago
    I live in Flanders, Belgium. Half of households here have a digital meter by now, which makes such contracts technically possible. And the government has made it mandatory for the large energy companies to offer such a "dynamisch elektriciteitscontract". The reason for all that is to encourage more efficient usage of the grid and renewables.
- cl44s 2y ago
  Depending on your car Gridio [1] might work. It does everything you want it to do and can even split charging windows. [1] https://www.gridio.io https://www.gridio.io
thebruce87m 2y ago
I’m in the UK on octopus. They do exactly this. They charge in 30 minute chunks throughout the night - whenever suits them best. The reward is electricity at a quarter of the price during this period.

labcomputer 2y ago

> Better yet it should be a software update for every existing electric car, even those without bidirectional hardware. Completely agree with everything you wrote, but also: It doesn't even require participation of the car! Plain old J1772 already provides the EVSE real-time-ish control over the charge rate. Some charging stations already exploit this to split power between two ports. When one car is plugged in it gets full current. Upon detecting a second vehicle, the EVSE signals the first to reduce current draw (and it must comply). In other words, every EV can be grid-interactive with just a software upgrade to the EVSE, or, failing that, replacement of the (much cheaper) EVSE.

mavhc 2y ago

https://octopus.energy/smart/intelligent-octopus-go/ https://octopus.energy/smart/intelligent-octopus-go/ UK power company offering that, if you have a compatible car/charger they can control for you

audunw 2y ago

Our power company ("Tibber") provides this as a service in their app for a bunch of different car models. Until recently this just let you avoid hours with more expensive electricity. But now you get an extra bonus on top of that since it lets the power company provide valuable grid balancing services. It's not sexy, but it's also not that hard to implement so I suspect this will become commonplace surprisingly quickly. > It doesn't add costly cycles to the onboard traction battery I guess for many people, NOT using V2G will be a net economic loss. For a big battery, and with 20%-80% limits, we are talking about extremely gentle cycles. The degradation is likely a drop in the bucket. Battery degrades with age as well as cycles. So after 20-30 years if you haven't used V2G you risk having an age-degraded battery that didn't deliver its full capability in terms of cycle life. Or the rest of your car has degraded before your battery did. For LFP it's even more likely that V2G will get you the most value out of the battery. If you go through a charge cycle every day or two on a Li-ion, I suspect V2G won't make sense since you're stressing the cycle life of your battery. The problem is we don't really know how long modern EV batteries will last, so it's impossible to know what the most rational choice is. We also don't know what the value of a degraded battery is in 15 years, and what the cost of a new one is. Since the economies of scale around battery recycling will be so massive in 15 years, it's possible that you get paid a fair sum for an old battery, and that getting a new battery will be fairly cheap. Or maybe not.

wcoenen 2y ago

I have a time of use contract with hourly pricing, based on the day-ahead electricity market. So I also wanted to schedule charging, but I was somewhat disappointed that - my charging station has no scheduling feature built-in - my EV does have settings for this, but they act more as a suggestion. It would often charge when I didn't want it to. Fortunately the charging station does support being controlled over modbus tcp/ip, so I was able to write some code and run it on a Rasperry Pi to control it. My control system fetches the prices and enables charging whenever they are below the configured maximum. However, I now find that (because of my obsession with optimizing this) it is still very far from a hands-off solution. I find myself doing this: - check electricity prices manually - check car state of charge manually - if prices are going to dip very low, figure out how much time will be needed to charge to 80% - if prices are high, figure out whether I need to do a minimal top up anyway and how much, based on how much I think I'm going to drive - choose a maximum price such that charging will be enabled during a sufficient amount of hours, based on the above The main thing that's missing to properly automate this is a way to retrieve the EV's state of charge. But a charging station for home use will typically only support a simple PWM signal to tell the car how much current it can draw. No other communication is possible unless the charging station supports ISO 15118. Mine doesn't :-(

MrsPeaches 2y ago
Very interesting! > I have a time of use contract with hourly pricing How did you get this?
- wcoenen 2y ago
  I live in Flanders, Belgium. Half of households here have a digital meter by now, which makes such contracts technically possible. And the government has made it mandatory for the large energy companies to offer such a "dynamisch elektriciteitscontract". The reason for all that is to encourage more efficient usage of the grid and renewables.
cl44s 2y ago
Depending on your car Gridio [1] might work. It does everything you want it to do and can even split charging windows. [1] https://www.gridio.io https://www.gridio.io

thebruce87m 2y ago

I’m in the UK on octopus. They do exactly this. They charge in 30 minute chunks throughout the night - whenever suits them best. The reward is electricity at a quarter of the price during this period.