231–240 of 260 posts
Let's get ISO15118 working at scale before we declare it essential. I'm not aware of any EV for sale today that uses it for V2G. https://en.wikipedia.org/wiki/ISO_15118
https://zecar.com/resources/which-electric-cars-have-bidirec...
Earlier quoted context omitted.
But if that limitation is repetitive to the point of investing in infrastructure to use EVs, then some other large-scale investor will close that arbitrage opportunity. Basically, the next-day / week energy markets, where EV owners can compete, will be saturated by grid-scale battery operators. Renewables will leave large gaps for seasonal energy needs - for example two weeks of winter with no sun and no wind - but E…
I see, renewables will only leave gaps that fit your argument. You don't see any scenario where there could be brownouts during the day, say in the summer when AC usage is high? And no, using cars for grid-scale storage has not been tried multiple times. The technology has never been available/feasible at a large scale before.
There exist large scale trials for this idea, you never heard of them because (aside from the fact you are arguing on a subject you know little about) they failed or are barely limping along.
Earlier quoted context omitted.
But if that limitation is repetitive to the point of investing in infrastructure to use EVs, then some other large-scale investor will close that arbitrage opportunity. Basically, the next-day / week energy markets, where EV owners can compete, will be saturated by grid-scale battery operators. Renewables will leave large gaps for seasonal energy needs - for example two weeks of winter with no sun and no wind - but E…
It'll always be some marginal utility - the main purpose of the EV will always to be a car. You can use it to store energy purchased at non-peak hours so you can avoid using the grid at those times, something that'll probably raise peak prices, because if you need the energy right then, you really need it. So, EV owners may use their cars to help reducing their energy costs and supplementing their PVs and fixed batte…
Aren't people wary about using their very expensive car batteries for the grid? E.g. imagine you plug in your phone for the night, but instead of a single top up change it is now constantly discharging and charging again. Lifetime of pocket sized batteries is not too great even now, and in such scenario they will go bust 2-3 times faster, in year instead of 3 or so. Also discharge swings would be probably much bigger…
In short, no. I have a 10 year old Leaf that has been on a V2G trial for the last 3 years. (I also work for the company that built the charger.) The battery is not being deep cycled; it goes between roughly 30% and 90% state of charge. The trial has found no clear evidence that it ages the battery at all. In fact, it appears that this is better for the battery than regularly fully charging it and letting it sit. Calendar age appears to be the biggest cause of battery degradation along with deep discharging and rapid charging (which this isn't doing).
This feels gimmicky and fragile. If distributed / decentralized storage is required (sounds like a good idea overall) it is surely better to have stationary installations, with larger batteries and connectivity optimized for that purpose, not using the EV batteries currently developed for moving these two-ton exosceletons to random places... In fact you want to have the option to significantly reduce EV usage as othe…
I came on here to comment that if you do this, it requires that the EVs be connected to the grid. How is that going to happen during the day when a lot of folks are at work, or out and about, and there aren't that many public chargers? I don't think this whole EVs-as-grid-storage really makes sense. When the EVs go into the scrap market, the batteries will likely still have 80% of their range left (if not more, based…
This feels gimmicky and fragile. If distributed / decentralized storage is required (sounds like a good idea overall) it is surely better to have stationary installations, with larger batteries and connectivity optimized for that purpose, not using the EV batteries currently developed for moving these two-ton exosceletons to random places... In fact you want to have the option to significantly reduce EV usage as othe…
I came on here to comment that if you do this, it requires that the EVs be connected to the grid. How is that going to happen during the day when a lot of folks are at work, or out and about, and there aren't that many public chargers? I don't think this whole EVs-as-grid-storage really makes sense. When the EVs go into the scrap market, the batteries will likely still have 80% of their range left (if not more, based…
Also, some of us work from home, or commute by public transit, or whatever, and only use the car on weekends.
Earlier quoted context omitted.
Deep cycle lead-acid batteries are available around £100/kWh, and they'll last pretty-much as long as a LiFePo if managed sensibly.
Managing lead-acid sensibly in my experience means never letting levels go below 40%. Temperature too I suppose. I didn't know they could last as long as LiFePo though. Is this really true? If this is true, why don't we just use more lead-acid batteries then?
LiFePo has a very high maximum cycle count. But after ten years, they'll die anyway. The only way that you can actually achieve a cycle count as high as the specification says is if you're cycling the battery two or three times a day, which I can believe if you're doing grid-levelling, but not if you're providing backup for your solar panels.
For lead-acid batteries, be aware of the difference between normal lead-acid, which are optimised for standby operation, and deep-cycle lead-acid, which are optimised for long life under regular cycling. Normal lead-acid batteries will die very quickly if cycled - they're designed to be charged all the time, and drawn on for very short period, like a car battery or a UPS.
Deep-cycle lead-acid batteries age by cycling, in contrast to LiFePo, which age by elapsed time. Their maximum cycle count is much lower than LiFePo, but if you're cycling them every couple of days, like in an off-grid solar project, and you're avoiding draining them below around 40%, then they can last 10 years.
So, if you want to cycle your batteries two or three times a day, then LiFePo is going to last a lot longer than Lead-Acid. But if you're cycling every couple of days and limiting the drain, then they can last about the same amount of time. It depends on the usage.
What helps with Lead-Acid is because it is that much cheaper than LiFePo, you can buy a larger capacity Lead-Acid battery for the same or less money, and then for the same performance requirements that larger battery will be drained less and at a lower rate, and therefore be less stressed and even last longer.
I think we don't use Lead-Acid as much as we do for several reasons:
1. Lead-Acid batteries have a reputation of flaking on us after a depressingly short amount of time. But that reputation has been earned from normal Lead-Acid batteries, not deep cycle ones.
2. People get scared by the lead in them, and how lead is toxic and we should be stopping using lead in everything. But really, lead in these batteries is not a danger to us, and Lead-Acid batteries are one of the best recycling success stories in the world. That lead isn't generally getting out into the environment. LiFePo batteries are much harder to recycle.
3. Electricians recommend installing expensive stuff, because then they get a bigger commission.
4. Lead-Acid batteries are commodities, but LiFePo batteries are new and exciting, and have aggressive marketing.
5. Lead-Acid are bigger and heavier for the same capacity than LiFePo. So, a LiFePo installation is going to look prettier in a nice consumer unit and be easier to install. They're heavy enough as it is.
Earlier quoted context omitted.
Deep cycle lead-acid batteries are available around £100/kWh, and they'll last pretty-much as long as a LiFePo if managed sensibly.
> they'll last pretty-much as long as a LiFePo if managed sensibly [Citation needed] Typically lead acid lifespan is around 10x less than lifepo4, even if kept within spec. But in practice it's hard to keep them in spec too, shit sulphates immediately when you look at it wrong.
LiFePo is maybe 10x the lifespan of a normal Lead-Acid battery, if you're cycling it several times a day. A car battery for instance will not do very well in this test. But I'm talking about deep cycle Lead-Acid batteries, cycled every day or couple of days down to 70% capacity (so using 30%). This is a fairly typical workload if you're (for instance) using it as a backup for solar panels. Under those circumstances, the LiFePo battery will die from time elapsed probably about the same time as or maybe even earlier than the Lead-Acid battery dies from cycle count.
Earlier quoted context omitted.
> Buuuut... Delaying charging till later is free. This functionality is already there. > So each kwh cycled into and out of the battery costs 8 cents. This is quite much. If you add other infra overhead, feeding power back into the grid is not going to produce much revenue for the individual unless the selling price is maybe 20 cents above the price when charging. On the other hand, something that MAY make more sense…
> Still, though, for grid stability it is probably much better to use dedicated batteries as part of the grid itself than to use car batteries. Why? Every kwh we can store using car batteries is a kwh of dedicated grid storage we don't need to purchase. It can increase the speed we add new storage on the grid. It is a more efficient use of lithium and other precious metals. This "smart charge" or "flex EV" is the typ…
Then there are the efficiency downsides. Storage "at the edge" means more transmission infrastructure is needed, on average, compared to more centralized storage. Also, grid batteries can be optimized for number of charge cycles, not for charge amount per unit weight. Finally, servicing individual cars is probably more expensive than replacing batteries in a storage facility.
And this is before going into inconvenience aspects, such as risking that your car doesn't have a near-full charge when you need to go on an unexpected trip, or the hazzle of handling the payment agreements, etc, just for a couple of dollars per day in potential revenue.
In computer terms, it's kind of running mining software on your computer GPU at night. For those especially interested, it may be fun, but for the average consumer, probably not worth bothering with.
Earlier quoted context omitted.
I came on here to comment that if you do this, it requires that the EVs be connected to the grid. How is that going to happen during the day when a lot of folks are at work, or out and about, and there aren't that many public chargers? I don't think this whole EVs-as-grid-storage really makes sense. When the EVs go into the scrap market, the batteries will likely still have 80% of their range left (if not more, based…
Peak electricity demand occurs in the evening when people come home from work and start cooking and watching TV and giving the kids and bath and so on. Bring your car home, plug it in, and it supplies the grid at this peak time. Then it charges up again overnight when demand is otherwise low, and it is ready for you to go to work in the morning. As long as you have some charge left in your battery at the end of the d…