DIY Electric Car Forums banner
1 - 20 of 23 Posts

·
Registered
Joined
·
926 Posts
Discussion Starter · #1 ·
In starting this thread, I'm going to advance a possible solution to the problem of the limited battery resources being tied up in little used EV conversions and other projects. The wave of EV acceptance is growing at an amazing rate. And, it seems to be nowhere near reaching its crest. If people can't get an EV, they want to build one or convert an existing vehicle. Hence, this Forum. The problem is, in some of these builds and conversions, the batteries are not being used to their maximum potential. Unfortunately, this contributes to skewing the already limited battery supply to a situation of even more scarcity and higher prices. In part, this is normal Economics 101: excess demand, panic buying, hording. etc. Part of the problem is unique to today's batteries

First, some background. Skip this paragraph if you already know about battery life. Batteries as they exist today have a cycle life as well as a calendar life. The batteries die from normal degradation, over time. Seals fail, electrolyte leaks out, contaminants in the materials reduce capacity, corrosion sets in, etc. 8-10 years to a fixed reduced capacity seems to be the normal warranty for current OEM EV lithium batteries. Tesla thinks this might be closer to 25 years for some of their latest batteries. Elon Musk has talked about "million mile" batteries in the future. Let's hope this true and part of a trend for the future. The batteries are going to fail at some point, mostly unrelated to how little they are use. So, if the batteries are used in a little used classic car, or other little-use application, much of the lifetime battery storage capacity is wasted. In the big picture, this drives up the cost of batteries and reduces the number of them available for other uses. These are uses that could make better use of the lifetime battery storage capacity and hasten the reduction of petrochemicals as part of our energy future.

I propose an idea that has the potential of a win/win/win solution for this problem. Use the converted classic car(or other low-use battery application) as an addition to or a replacement for the Tesla Powerwall and the like. For now, let's call it the Powercar energy option. Off grid solar, wind, or microhydro? Use the otherwise little used batteries in the car for the primary or secondary energy storage. Grid tie solar? Use the car battery for night time use, back-up during outages, grid peak usage sell back, other uses? I suspect the technology is already available for this type of application. If not, somebody should build a safe, convenient way of doing this.

At any point, the unplugged erstwhile Powercar could be driven away to a car show, parade, or to buy a loaf of bread to impress your neighbors(if you're into that kind of thing). Are there tax incentives for the Powerwall? Could they be applied fairly and proportionally to a Powercar?

What do people think? Sounds like a win/win/win to me.
 

·
Registered
Joined
·
7,976 Posts
I think this makes sense. While V2G (vehicle-to-grid) makes little sense to me for a regularly used vehicle, it would make much more sense for a vehicle which is parked anyway. Of course, distributed energy storage might not be a great use of battery capacity, either, but if people are going to either convert rarely-used vehicles or install home energy storage systems, making the same battery serve both purposes certainly makes good sense.

As a practical use case, consider someone with two EVs, of different vehicle types (large and small, practical commuter and sports car, daily driver and RV, etc) which are not both driven at the same time - whichever one is not be driven is serving as stationary storage.
 

·
Registered
Joined
·
7,976 Posts
As for Elon Musk and the "million mile battery"... yeah, sure, let me jump in my non-existent US$35K Model 3, or my new Roadster or CyberTruck that was supposed to on the road a couple years ago, and let it drive me around in the "full self driving" mode (that doesn't actually exist) to think about that, while looking for the Semis that are supposed to on the road and working but haven't been built. I'm sure claiming a million-mile battery really helped Elon's stock price manipulation, but that's the only proven connection to reality.

At least in Canada, EV batteries are covered by at least eight years of warranty because the federal government requires that - all "emissions related" components must get at least 8 years, and hybrid batteries - and subsequently apparently EV batteries - fit that category. As usual, warranty coverage length is a business decision, not a purely technical assessment.
 

·
Administrator
Joined
·
6,443 Posts
I am a lot less sure about your ageing batteries
Batteries have a limited cycle life - for fairly straightforward physical/chemical reasons

Age???
With the materials used and the designs used I would expect age to be simply a non issue - maybe a problem after 20+ years

Back when I worked in the Automotive industry we would get complaints from the suits that things were lasting too long
the inference was that making them have shorter lives would mean cheaper

But it rarely worked that way!

The usual result was that if they lasted for the warranty period they would last a LOT longer

The famous bathtub shaped life curve

123288

Is actually very very rare
What normally happens is the infant mortality then the normal life is a slowly rising straight line

The one area where the bathtub was correct was rubber things that were flexed - like your cam belts
 

·
Registered
Joined
·
25 Posts
Regardless of the ageing battery issue, or non-issue, its a pretty interesting idea - use your electric non-daily driver as a powerwall. I mean, just for anyone to be able to plug their car into their house to provide lighting in the event of a power outage has some real value.

Maybe flick Jehu Garcia a line. He is a serial DIYer with a sizeable youtube channel and influence. He made his own "eSamba" vw bus and makes his own powerwalls too...
 

·
Registered
Joined
·
926 Posts
Discussion Starter · #6 ·
Batteries have a limited cycle life - for fairly straightforward physical/chemical reasons

Age???
With the materials used and the designs used I would expect age to be simply a non issue - maybe a problem after 20+ years
Duncan, a 20 year battery calendar life, I think, is a legitimate aspirational goal and maybe available in rare examples of existing high quality batteries. Today, with the available used batteries and the new ones from the Far East, a ten year calendar life seems like a more realistic figure. If I am designing, building, marketing, and selling DIY conversion products to customers, I want to be realistic about the life of the batteries they might use with those products. It's probably a good, realistic figure to use for people designing and doing their own conversions.

If the calendar life turns out to be longer than ten years, then that's icing on the cake.
 

·
Administrator
Joined
·
6,443 Posts
Duncan, a 20 year battery calendar life, I think, is a legitimate aspirational goal and maybe available in rare examples of existing high quality batteries. Today, with the available used batteries and the new ones from the Far East, a ten year calendar life seems like a more realistic figure. If I am designing, building, marketing, and selling DIY conversion products to customers, I want to be realistic about the life of the batteries they might use with those products. It's probably a good, realistic figure to use for people designing and doing their own conversions.

If the calendar life turns out to be longer than ten years, then that's icing on the cake.
For some US states the battery is considered part of the emissions equipment - so the WARRANTY is 10 years
That means that they are all designed for a 10 year warranty - which means a 20 year life

The "new ones" - aftermarket - are more like 5 years if you are lucky
 

·
Administrator
Joined
·
6,443 Posts
Where do you get this information? Is there some study that confirms this? I would like to reference this information when talking to people about battery life.
Here is one article
The battery is covered for 10 years or 150,000 miles - to do with the emission warranty

That is for California - but the car companies design cars to the hardest standards

Best would be looking up the actual California requirements - but I don't have time just now
 

·
Registered
Joined
·
25 Posts
For some US states the battery is considered part of the emissions equipment - so the WARRANTY is 10 years
That means that they are all designed for a 10 year warranty - which means a 20 year life

The "new ones" - aftermarket - are more like 5 years if you are lucky
20 year life??? I remember just recently helping my brother look at used hybrids, 20 years is not the case.
 

·
Registered
Joined
·
25 Posts
Here is one article
The battery is covered for 10 years or 150,000 miles - to do with the emission warranty

That is for California - but the car companies design cars to the hardest standards

Best would be looking up the actual California requirements - but I don't have time just now
Are you talking specifically about the batteries???

Car manufacturing is all about the bottom line $$$$. Thats all they are interested in, including doing the absolute minimum to get through the warranty period because aftermarket parts and service is where they make most of their money. Why else do we now have plastic suspension parts, in the case of ford link rods, not to mention generalised plastic supports throughout the engine bay which dont last. But hey, consumers have had a choice in the past where the likes of Hyundai offered cars with 10 year warranties. Turns out people with money like to change their cars quite often regardless and are just not interested in keeping a car for 10 years.
 

·
Administrator
Joined
·
6,443 Posts
Are you talking specifically about the batteries???

Car manufacturing is all about the bottom line $$$$. Thats all they are interested in, including doing the absolute minimum to get through the warranty period because aftermarket parts and service is where they make most of their money. Why else do we now have plastic suspension parts, in the case of ford link rods, not to mention generalised plastic supports throughout the engine bay which dont last. But hey, consumers have had a choice in the past where the likes of Hyundai offered cars with 10 year warranties. Turns out people with money like to change their cars quite often regardless and are just not interested in keeping a car for 10 years.
The warranty specifically covers the batteries for 10 years
Its a government (California) mandate - not a consumer choice - because its considered to be part of the "emissions control"
Other US states have 8 years
This means that the engineers have to achieve a 99% 10 year life
Think about it if 1% of batteries fail inside the warranty period then you would need a massive "cost saving" to make a profit
This means that they will almost certainly have a 20 year life for most of the batteries

The suits will be telling them to make it cheaper - but it has to last the 10 years
 

·
Registered
Joined
·
7,976 Posts
For some US states the battery is considered part of the emissions equipment - so the WARRANTY is 10 years
That means that they are all designed for a 10 year warranty - which means a 20 year life
It's 8 years for the same reason in Canada, and apparently federally in the U.S. as well... but a given warranty period certainly does not mean an expected (by MTBF, or any other measure) lifespan of twice the warranty period.
 

·
Registered
Joined
·
7,976 Posts
This means that the engineers have to achieve a 99% 10 year life
No, it does not. It means that the cost of warranty replacement of failed batteries within the 10 year period must be acceptable, compared to the alternatives. If replacing 10% of batteries is cheaper than making them all last much longer, then 10% failure will be the least expensive business decision.

Many years ago Chrysler had a horrible quality reputation, and decided to offer a 7-year bumper-to-bumper warranty (up from something like 2 years) to convince customers that it was safe to buy the things. They didn't change the vehicles, which continued to rack up repairs at the same rate - they just made a business decision to pay for more repairs to make more sales.

Warranty period is a business decision which affects technical decisions. It does not define component life.
 

·
Administrator
Joined
·
6,443 Posts
No, it does not. It means that the cost of warranty replacement of failed batteries within the 10 year period must be acceptable, compared to the alternatives. If replacing 10% of batteries is cheaper than making them all last much longer, then 10% failure will be the least expensive business decision.

Many years ago Chrysler had a horrible quality reputation, and decided to offer a 7-year bumper-to-bumper warranty (up from something like 2 years) to convince customers that it was safe to buy the things. They didn't change the vehicles, which continued to rack up repairs at the same rate - they just made a business decision to pay for more repairs to make more sales.

Warranty period is a business decision which affects technical decisions. It does not define component life.
Not in the world that I remember!
And that WAS my business
 

·
Registered
Joined
·
36 Posts
If people can't get an EV, they want to build one or convert an existing vehicle. Hence, this Forum.
While I can understand people doing an EV conversion as a fun project, or because they like the idea of an electric classic car, or as a research platform like Stanford's MARTY, I would have thought that the number of conversions done these days due to inability to acquire a working EV couldn't possibly make a noticeable dent in battery supply.

But I like Brian's focus on EVs (of whatever origin or energy technology) as grid storage. However I wouldn't be so quick to rule out daily drivers in that application.

In a future where the planet's billion vehicles are mostly EVs (whether battery or fuel cell), and each is driven at 30 mph for 12,000 miles per 8800-hour year on average, that's a duty cycle of 400/8800 ~ 0.05, leaving 0.95 for other uses.

If as a matter of convenience all billion parked cars somehow connect automatically to the grid, which then maintains say 30 kWh or 106 MJ above minimum charge per car on average, that represents a total grid storage of (0.95*106) billion megajoules or 100,000 TJ (1 TJ is a million MJ).

World energy consumption is around 15 TW, i.e. 15 TJ/second. Hence that capacity would in principle suffice to power the whole planet for 100,000/15 seconds or about two hours. Longer in neighborhoods where vehicle density is greater than average, shorter in neighborhoods where power demand is greater than average (and maybe those two fluctuations will cancel to some extent).

If the world's billion EV's account for ⅓ of the world's HV batteries, the other ⅔ being used as additional grid backup, that extends those two hours to six. So if we can rely on solar up to 4 pm, four of those six hours can be used to meet demand from 4 pm to 8 pm, and the remaining two hours for the rest of the night.

Or thereabouts. And if that's still not enough I would expect wind could easily make up any shortfall.
 

·
Registered
Joined
·
926 Posts
Discussion Starter · #17 ·
I would have thought that the number of conversions done these days due to inability to acquire a working EV couldn't possibly make a noticeable dent in battery supply.
In the case of the Leaf battery modules, they have become much more scarce and the prices have ~doubled, just in the past 6 months. Of course, not all of this is because of demand for EV conversions. Other on and off road conversion vehicle use, small back-up energy storage systems, and other uses have also contributed to the demand. The Leaf modules are easy to work with, relatively rugged and safe, and until recently, in good supply at a (little high, compared to other new and used batteries) but steady price. This is not the case now. I suspect other small format battery modules, like the Leaf ones, will follow this supply and demand cycle, as they initially become more readily available. This include new batteries from the Far East, if some entity can vouch for their quality.

Right now, the Model 3/Y battery modules in their box (it is difficult to separate them from the box, and they are very long) are available at a fairly reasonable price. People are still figuring out how to use these modules, in and out of their box. I suspect, with human ingenuity being what it is, there will be some very creative uses developed for this valuable resource in the very near future.

Overall, I think we are seeing the first skirmishes of the future new and used battery wars. Tesla and others know this with new batteries. That's why their going to such great extremes now to lock down battery raw material supplies.
IT'S ALL ABOUT THE BATTERIES, STUPID.

If as a matter of convenience all billion parked cars somehow connect automatically to the grid...
I just don't know if there is enough copper in the world to build out the massive infrastructure required to do this. Is cordless inductive charging a practical possibility? Do people have any ideas on what this kind of world would look like?
 
Joined
·
8 Posts
. Use the converted classic car(or other low-use battery application) as an addition to or a replacement for the Tesla Powerwall and the like.
I have used our converted 1999 Beetle as a power source during power outages for years now. We live in a rural area and in the winter get lots of outages, some 2-3 days long. The Beetle is a 96V system with 260ahr cells. I have a 1.8kw solar setup with 300ahr lead cells. The Outback solar charger will take up to 150 volts input so I just plug the Beetle pack into the outback and it charges the 48V lead pack. I know it would be more efficient to just power the inverter directly from the Beetle but the inverter is 48V. We bought a Kia Soul EV last year so the Beetle is getting stripped and the lithium pack is going to replace the lead in the solar system. The downfall of that is that during longer power outages I wont be able to drive into town and fill up the pack which has been very handy. It would be nice to have V2G in our area to make use of the Kia pack.
 

·
Registered
Joined
·
7,976 Posts
Not in the world that I remember!
And that WAS my business
Perhaps things have changed, and perhaps your business didn't include the many products which have lifespans far beyond twice the warranty period (which includes most consumer products, with warranty of few months or perhaps a year and lifespans of several years).
 

·
Administrator
Joined
·
6,443 Posts
Perhaps things have changed, and perhaps your business didn't include the many products which have lifespans far beyond twice the warranty period (which includes most consumer products, with warranty of few months or perhaps a year and lifespans of several years).
Quite the opposite!

In my experience by the time you have engineered it well enough to last the warranty period you end up with an actual lifetime that is a LOT longer
 
1 - 20 of 23 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top