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Old 03-31-2010, 11:32 AM   #21
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Originally Posted by ERD50 View Post
You *may* be confusing SOC with battery voltage. I'd have to dig through their numbers a bit to be totally certain, but I'm pretty sure that 30% SOC ...
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SOC = State Of Charge. This is a standard term for battery. Let's take the common 12V battery in our car. The following numbers off the top of my head so they are close but unlikely exact:

SOC Voltage
100% 13.2
75% 12.0
50% 11.7
25% 10.9

At around 11V, the battery still has about 30% energy left in it, but the voltage is so low that starting the engine is almost impossible.
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Old 03-31-2010, 11:36 AM   #22
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More nitpicking: Sorry, you don't get to include the $10,000 cost of battery replacement in your 100,000 mile fuel cost. You already bought the car with its OEM battery for the first 100,000 miles. If you buy a second battery, that gets counted toward fuel for the second 100,000 miles. After all, you didn't need that second battery to drive the first 100,000 miles.
I agree with your logic as far as the first 100Kmiles is concerned. But at that 100Kmiles point, the Corolla is still fully functional. What do I do with the Leaf? In other words, what do I have to do to make the Leaf fully functional again? A $10,000 battery, right?
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Old 03-31-2010, 11:49 AM   #23
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I agree with your logic as far as the first 100Kmiles is concerned. But at that 100Kmiles point, the Corolla is still fully functional. What do I do with the Leaf? In other words, what do I have to do to make the Leaf fully functional again? A $10,000 battery, right?
You could look at it that way, but then the fuel cost for the next 100,000 miles would only be $3000. If a battery lasts for 100,000 miles, then the cost of driving 100,000 miles should only include the cost of one battery, not two. Let's say the Corolla has a 20 gallon tank and gets 30 mpg. If you fill the tank and then drive 600 miles, you will need to fill the tank again. Did it take 20 gallons to drive that 600 miles, or did it take 40, since you had to fill the tank again at the end of your trip?
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Old 03-31-2010, 11:49 AM   #24
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SOC = State Of Charge. This is a standard term for battery. Let's take the common 12V battery in our car. The following numbers off the top of my head so they are close but unlikely exact:

SOC Voltage
100% 13.2
75% 12.0
50% 11.7
25% 10.9

At around 11V, the battery still has about 30% energy left in it, but the voltage is so low that starting the engine is almost impossible.
That looks about right. I think the difference is that I doubt that accelerating an EV puts as big a demand on the batteries as starting a car puts on a starter battery. I'm pretty sure there is much more margin in the EV, or the batteries would die far too soon. In normal driving, you accelerate far more often than you start an ICE. That many hard cycles would kill the EV battery.

Some back-of-the-envelope #'s:

In mild weather, it might take 200A to turn over the starter; @ ~ 10V, that is ~2KWatts. Crank for 3 seconds, and that is a (3600/3) * 2KWatts = a rate of 2400KWHrs of energy. That's ~ 44x the capacity of the Tesla for > 200 miles. At 50 mph average, that is 4 hours of driving, so an average ~ 14KWhr draw on the Tesla batteries. Hard acceleration would be many times the average draw, but not 170x (2400/14), I'm pretty sure. I guess we could look up the peak VA on the Tesla to compare.


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Old 03-31-2010, 02:18 PM   #25
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GM offered EVs in CA because under CARB rules, they would not be allowed to sell cars in California at all if they did not deliver 2% (IIRC) of the CA fleet as 'zero pollution' vehicles.

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I still recall thinking when CARB rules came out: Eventually, the gummint (Federal or in this case Calif.) will come up with a mandate that the car companies will just say "forget you!". GM played the game and lost with the EV-1. All the others said "forget you!" It was kind of funny to watch - in a perverted sort of way. I think everyone thought that Honda or Toyota would come up with the mandated 0% pollution car and eat GM's lunch. Turns out GM ate it's own lunch while Honda and Toyota just sat and watched.

All the mandates in the world don't change physics and economics. You can't fool mother nature.
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Old 03-31-2010, 02:28 PM   #26
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I do think that a market will quickly develop for rebuilding / repairing batteries ...
I hope you're right.

The classic lead-acid battery has been around for so long, yet no technology exists for repairing it economically. The best claimed technology is the "battery desulfator charger". I have tried it on a dead battery and an almost dead battery. The results were disappointing.
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Old 03-31-2010, 02:36 PM   #27
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I hope you're right.

The classic lead-acid battery has been around for so long, yet no technology exists for repairing it economically. The best claimed technology is the "battery desulfator charger". I have tried it on a dead battery and an almost dead battery. The results were disappointing.
Aren't these new batteries made up of a bunch of individual cells that are soldered together? I'm thinking that the Escape battery, for example, is like 275 D size NiMh cells joined together.
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Old 03-31-2010, 02:40 PM   #28
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I think so. But when one fails due to age and use, most other would as well, or will soon.
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Old 03-31-2010, 03:34 PM   #29
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The classic lead-acid battery has been around for so long, yet no technology exists for repairing it economically. The best claimed technology is the "battery desulfator charger". I have tried it on a dead battery and an almost dead battery. The results were disappointing.
The U.S. Navy's submarine force has been using lead-acid batteries for a century. The latest technology consists of incremental improvements-- over a hundred four-foot-tall foot-square cells filled with the thinnest-possible spongiest lead plates, the lowest-resistance connectors, and an electronic monitoring system. Each individual cell even has an air-fed bubbler tube to keep the electrolyte thoroughly mixed.

These batteries are regularly beaten (operations & training) to the point where the electrolyte practically simmers. Electricians individually sample each cell's electrolyte specific gravities by hand (crawling around on top of the battery with only a couple feet of clearance below the deck), add water to the cells by hand, and clean the tops of the cells (exterior) by hand. Cells dying prematurely are jumpered out until the battery reaches minimum capacity, at which point probably after all of Electrical Division's personnel have been trained, accused of incompetence, correctively trained, persecuted, and then executed. Battery replacements are no fun but happen every 10-12 years.

When I arrived on my first submarine, its current generation of battery had been in use for at least 10 years and possibly longer. When I retired 20 years later there had been one upgrade in battery models. It probably took that long to be worth making yet another incremental improvement fleet-wide. AFAIK it's the same battery today, nearly eight years after I retired.

I bet DARPA and the Navy are spending millions on battery research. If there was a cheaper, higher-capacity, more reliable, longer-lasting battery then the submarine force would've switched over years ago. Today I don't have a lot of hope for the next three technologies-- NiMh, Li-ion, and metal phosphates. But give it another 20 years...
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Old 03-31-2010, 09:44 PM   #30
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If there was a cheaper, higher-capacity, more reliable, longer-lasting battery then the submarine force would've switched over years ago. Today I don't have a lot of hope for the next three technologies-- NiMh, Li-ion, and metal phosphates. But give it another 20 years...
That does not sound right to me. What am I missing?

Both NiMh and Li-ion are head and shoulder above the lead-acid battery. The power density of the Cobalt Li-ion is at least 4 times. NiMh is at least 2 times. Given the constrained space in submarines plus unlimited tax payers money, I would have guessed that not a single lead-acid battery could be found in today's submarines.

So is it an issue of reliability or lifespan? Or do Navy engineers use lead-acid batteries both as an energy store as well as ballast? Or maybe they just want to keep those poor battery technicians busy?
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Old 04-01-2010, 07:58 AM   #31
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I just finished reading a book in which the author tries to forecast what will happen with gasoline at $20/gallon. And while he makes a few stretches, I think eventually that price will happen. The only question is when.

So the electric car equations work differently with gasoline at $6, $10, $16, $20/gallon. At those prices the electric car starts to look a lot more attractive.
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Old 04-01-2010, 09:07 AM   #32
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So the electric car equations work differently with gasoline at $6, $10, $16, $20/gallon. At those prices the electric car starts to look a lot more attractive.
Europe has been in the $6-$8/gallon range for some time. Clearly, we should be seeing wide adoption of electric cars in Europe before we see any significant number of them here.

http://www.eia.doe.gov/emeu/international/gas1.jpg



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Old 04-01-2010, 04:47 PM   #33
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That does not sound right to me. What am I missing?
Beats the heck out of me, too, but I've learned not to bet against Naval Reactors' design engineers.

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So is it an issue of reliability or lifespan? Or do Navy engineers use lead-acid batteries both as an energy store as well as ballast?
I think it's a combination of reliability & lifespan, coupled with issues over max capacity and potential deep discharge. Heat discharge might be a challenge, although it seems easier to boost battery cooling if everything else gets 2x-4x better. Or perhaps it's just that the newer technologies are "too new" to have reliable longevity data.

One side issue was the Li-ion fire on an ASDS that essentially put the program out of business:
A six-hour blaze damaged a special-warfare minisub Sunday - Hawaii News - Starbulletin.com
Problems Persist for SEAL Mini-Subs

A nuclear submarine's battery stores quite a bit of energy. For reliability/longevity it's usually on trickle discharge when it's not supporting casualties, drills, and routine charges, and then recharged when it gets below a certain (fairly high) state of charge. Occasionally it's discharged a little more to keep it from developing a memory, but usually that requirement is met by "operating requirements". A casualty or a drill (like a reactor scram) can result in the battery discharging several thousand amp-hours at a rate of over a thousand amps, although watchstanders hope to succeed with a number of strategies to minimize both the discharge rate and the time.

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Or do Navy engineers use lead-acid batteries both as an energy store as well as ballast?
Plenty of other things the Navy prefers to use for ballast-- like weapons. The crew might also appreciate more food or berthing or exercise/entertainment equipment, too.

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Or maybe they just want to keep those poor battery technicians busy?
Nuclear-trained electricians are unbelievably expensive, and if a better battery could let the personnel branch cut a couple of billets per crew then they'd be all over it...
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Old 04-02-2010, 08:46 PM   #34
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Another view one often hears, is that by offering the subsidy the government increases demand, and that increases volume, and that accelerates the development of more cost effective vehicles. Sounds kinda reasonable, but look at the numbers:

Remember that the $7,500 credit goes to the buyer. The only thing the manufacturer gets out of that $7,500 is one more incremental sale. Do you really think that producing one more vehicle at marginal profits provides anywhere near the equivalent of $7,500 of development investment? If the govt was to spur development, why not just give the company some small fraction of that $7,500? It really seems like a waste of our tax dollars. It lets my neighbor buy some technology that he finds interesting, but isn't cost effective, on my dime. I (we) don't need that.

Look at some examples:

- I remember that VCRs were $1800 when they first came out. People who had to have the latest thing bought them at that price. No govt subsidy to the buyer.

- I remember when mobile phones were $4,000 (and high per minute rates). People who could afford them or felt they had a need for them bought them. No govt subsidy to the buyer.

- Computers, Laptops, iPods, GPS, and on and on and on. No govt subsidy to the buyer.

Yes, volume helped bring the prices down, but probably far more importantly, the supporting technology improved, and that allowed the prices to come down, and that spurred more volume. For example, laptops need faster, more efficient CPUs before they become small and cheap enough for more people to want to buy them (better CPUs mean smaller batteries, smaller fans, etc). But CPU technology could only progress so fast. Selling more of them wouldn't have had that much effect. Some things just take time. But the combined demand for faster processors, and all the push for improved semi-conductors of all types leads to improvements. It's a natural progressions, and I don't think the govt can alter that very much with buyer credits. At a minimum, there would be much more efficient ways for them to use those $.

And the main thing holding back EVs is battery cost/performance. But the battery requirements are very close to the requirements for laptops, cell phones, and other equipment. So selling a few more EVs isn't even a drop in the bucket to the entire industry-wide push for better batteries. It's such an indirect way to attack the problem that it is ridiculous.

In fact, I think I could make the opposing argument. If a company can sell these cars for $32,780, what incentive do they have to make them cheaper and actually compete with ICE cars? Maybe govt subsidies inhibit innovation? We've had govt subsidies for solar here since the 70's, and it still isn't cost effective for most cases.

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Old 04-02-2010, 09:03 PM   #35
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That does not sound right to me. What am I missing?

Both NiMh and Li-ion are head and shoulder above the lead-acid battery. The power density of the Cobalt Li-ion is at least 4 times. NiMh is at least 2 times. Given the constrained space in submarines plus unlimited tax payers money, I would have guessed that not a single lead-acid battery could be found in today's submarines.

So is it an issue of reliability or lifespan? Or do Navy engineers use lead-acid batteries both as an energy store as well as ballast? Or maybe they just want to keep those poor battery technicians busy?
The Navy is now using Li-ion for the Seal delivery vehicle for example. In fact, there was a recent problem with one that Nords may be aware of.

I doubt that any of the subs are using Li-ion on NiMH. I think they are still Pb-acid.
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Old 04-02-2010, 09:06 PM   #36
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FYI, see correction.

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That does not sound right to me. What am I missing?

Both NiMh and Li-ion are head and shoulder above the lead-acid battery. The energy power density of the Cobalt Li-ion is at least 4 times. NiMh is at least 2 times. Given the constrained space in submarines plus unlimited tax payers money, I would have guessed that not a single lead-acid battery could be found in today's submarines.
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Old 04-02-2010, 09:15 PM   #37
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That does not sound right to me. What am I missing?

Both NiMh and Li-ion are head and shoulder above the lead-acid battery. The power density of the Cobalt Li-ion is at least 4 times. NiMh is at least 2 times. Given the constrained space in submarines plus unlimited tax payers money, I would have guessed that not a single lead-acid battery could be found in today's submarines.

So is it an issue of reliability or lifespan? Or do Navy engineers use lead-acid batteries both as an energy store as well as ballast? Or maybe they just want to keep those poor battery technicians busy?
What you are missing is that the Navy is a conservative organization and and there are still safety concerns with Li-ion. If you over charge them or short circuit them they can turn into a bomb and that is a particularly bad thing on a submarine. Despite all the best technology and practices "bad things" still happen sometimes. I think that the space shuttle is evidence of that. But having said that an ex-submariner told me that they considered the (lead-acid) battery (because it can evolve hydrogen gas) and the electrolyzer the most dangerous equipment on the sub.
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Old 04-02-2010, 09:28 PM   #38
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But having said that an ex-submariner told me that they considered the (lead-acid) battery (because it can evolve hydrogen gas) and the electrolyzer the most dangerous equipment on the sub.
Yep. Torpedo room full of explosives, liquid fuel, and solid-fueled missiles, engineering spaces full of machinery separating hydrogen & oxygen from seawater, nuclear fuel and reactor coolant at high temperatures & pressures, 4500 psi air piping and 3000 psi hydraulic piping everywhere, a galley deep-fat fryer full of boiling oil...

... and the battery is still the most dangerous equipment on board.

The newer oxygen generator equipment seems to have dramatically improved in the last 10 years, but I think that was mostly a function of the old model's operations & maintenance costs. The operators got a lot better when the training commands shifted to computer simulators instead of the actual generators.
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Old 04-03-2010, 08:00 AM   #39
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Lead - acid batteries are still used in the telcom industry for power backup also.

Quite a bit of energy in one battery. I had a car battery explode when I started my truck. Acid everywhere! Don't know what happened. Wouldn't have wanted to be next to it when it went off.

But one gallon of gas has more energy than a few hundred pounds of batteries. Hard to beat.

If gas prices go up to the $20 a gallon level some day the fuel costs to produce electricity will go up with it.
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Old 04-03-2010, 10:17 AM   #40
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If gas prices go up to the $20 a gallon level some day the fuel costs to produce electricity will go up with it.
Yes, good point. Even Solar panels will go up in price, as it takes energy to make those. I have yet to hear of a solar-powered solar panel factory.

And, as they become more competitive, maybe govts will drop their 'cost shifting' subsidies, which will raise the 'price' to the buyer.

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