This --> <-- close to ordering a Leaf but have to ask

[GRA]

Since the 90's the additional saftey features added increase car weight, and comforts such as better radios, homelink, etc. all increase weight as well.

I found it somewhat surprising when I discovered that the Prius C weighs 700 pounds LESS than the LEAF.. As I recall, this is a little more than the weight of the entire battery pack, so I'm thinking that even the LEAF could stand to shave off a few pounds. I'd concede an extra 200 pounds for better build quality in the LEAF (how many people make that argument!), but that's still a fair bit of extra heft..

I would also add that I've seen plenty of NiMH batteries fail, sometimes in as few as 2,000 miles (Vectrix electric scooter) and certainly in timeframes less than 10 years even in properly designed applications. Proper cooling system design, system sizing for the application, good charge/maintenance control and vehicle usage all come into play when talking battery chemistries in an EV. I've so far been impressed with how well the batteries have held up in my LEAF and certainly expect them to be "functional" for me (at least 50 miles freeway range) until it's time for me to consider retiring in another 15 years..

The Prius C is shorter than the Leaf, and has a less powerful (read lighter) motor. Direct comparison is with the regular Prius.

Re Lithium battery life, Mitsubishi says they expect the i's battery to degrade to 80% in 5 years, 70% in 10. The Coda's LiFePO4 is supposedly more durable; Coda claims only 7% degradation after 100k miles, although what kind of cycles in what kind of conditions is unstated.

 

[Sc0rPs]

You make some good points, however as mentioned the real EV applications of NiMH has shown zero degradation with well over 150k miles on them, then the range provided by them is 150 miles. Then few years later Oshinsky introduces a NiMH pack doing 300+ miles on a charge in a vehicle which should take care of most people's 'range anxiety'. Never got that, it's not like gas vehicles were unlimited either...

So it does come down to size, and I believe it was 15% and not 50% capacity difference in favor of lithium, however the real win comes down to how soon you need to replace them. If the lithium dies even after 10 years that's quite the expensive replacement, plus evironment unfriendly chemistry of the dead batteries to be recycled. As opposed to environmentally friendly NiMH using older generation tech but still going at 100% after about 14 years now.

That is my primary concern, I want the best battery for an EV and worried I will need to replace the lithium ones every 5 - 10 years.

However I decided to go for it, and probably place my ordering this weekend. I figure when the lithiums do go south I can replace with NiMH... increase the range.

I'm in Canada, the cost of a Leaf is right below 39k, while in the US is 34k. I'll have to see if I buy one from the states will the incentives still apply, or will the dealer match the price...

It will be interesting how long they engineered the batteries in the leaf (or other EVs) to last in years. Really, I am guessing 10+ I think we are all being very conservative and guessing they will die quite fast. As for the NiMH comparison, its not quite fair. You cannot compare say the EV1's range with NiMH or a Rav4's range to the Leaf. Smaller car, lighter weight, only 2 seater (the EV1), better aerodynamics (much to do with the car's size) and so few accessories/saftey improvements.

If you put the same size/weight NiMH in the leaf today, I bet your average range would be 50 vs 73 (using EPA numbers). Since the 90's the additional saftey features added increase car weight, and comforts such as better radios, homelink, etc. all increase weight as well. NiMH just doesn't have the energy density and range would suffer greatly. No one would buy a 50 mile range (epa) EV. I know for sure that the faster you charge a NiMH the shorter its life (you can easily cut your life in half). I would say it would definetely rule out Level 3 charging but I am unsure about the Level 2 usage, how much kWh charger could it take before the battery has fits. Li-ion really doesn't care how fast you put energy in it, only heat.

I am fairly certain you can make the extra room if really needed, the improvements did not really add to vehicle weight, materials and perhaps some safety features may have though. I believe it all comes down to quality of the NiMH, there has been advances since the Rav4 but bottom line is they're still running solid even today and at 100%. On the other hand lithium batteries have a limited run, may not care for quick charges but they are decaying and will die. Which is the point I have been trying to make, a NiMH (outdated type) has been running a Rav4 since about 1998. Lithium is banned from air transport, starts to degrade the moment it is made and above all unproven. I just don't want to be having to buy another battery pack every 5 - 10 years...

 

[Pipcecil]

I am fairly certain you can make the extra room if really needed, the improvements did not really add to vehicle weight, materials and perhaps some safety features may have though. I believe it all comes down to quality of the NiMH, there has been advances since the Rav4 but bottom line is they're still running solid even today and at 100%. On the other hand lithium batteries have a limited run, may not care for quick charges but they are decaying and will die. Which is the point I have been trying to make, a NiMH (outdated type) has been running a Rav4 since about 1998. Lithium is banned from air transport, starts to degrade the moment it is made and above all unproven. I just don't want to be having to buy another battery pack every 5 - 10 years...

Technically, the current basic forms of Li-ion and NiMH are the same age, both were developed as stable battery cells in the mid 1980's. NiMH had a longer history starting from the last 1960's but didn't get into its current form into the 1980's with commercial cells going in the early 1990's. Li-ion started development in the 1970's, first commerical in mid 1980's and consumer in the late 1990's. So really, saying that Li-ion is "unproven" is farily incorrect as the original inception was over 40 yeras ago - thats quite a bit of time to get the chemistry and kinks worked out. As for the transport, the US is just dumb, most modern countries don't have this problem but the US can't seem to understand it. Li-ion can have thermal runaway, which can cause explosions, but chips inside the batteries prevent this from occuring. So yes, Li-ion can explode, but the explosion rate is probably just as likely to happen than the actual plane exploding from bad fuel (and yes the cheaper the battery the more likely it will happen if the manufacture skimps on this saftey issues).

Believe it or not, most battery techs have been around for a very long time, we just improve them until they become feasible for consumer use (by cost, safety, size, and weight). Most have been around for 50+ years. I would easily say Li-ion is just as proven as NiMH as both almost have the same commerical life time on the market.

 

[Herm]

I believe it all comes down to quality of the NiMH, there has been advances since the Rav4 but bottom line is they're still running solid even today and at 100%.

are you sure the battery in a RAV4EV with 125k miles is still at 100% in capacity and power?.. internal resistance will increase in these batteries, limiting your power but not your range. The nimh cells used by Toyota and Honda in the hybrids do show decreased capacity after a few years..

There are lithium-ion batteries with guaranteed life of 15 years, they are used in satellites.

 

[DaveEV]

I found it somewhat surprising when I discovered that the Prius C weighs 700 pounds LESS than the LEAF..

The Prius C is shorter than the Leaf, and has a less powerful (read lighter) motor. Direct comparison is with the regular Prius.

Definitely.

Prius C: 2500 lbs
Prius: 3042 lbs
Prius Plug-in: 3165 lbs
Camry Hybrid: 3190 lbs
LEAF: 3354 lbs

So the C is over 500 lbs lighter than the Prius and 850 lbs lighter than the LEAF. Toyota did an amazing job packaging and shrinking the hybrid drivetrain in the Prius C. I think the real question should be "Why is the regular Prius so heavy?"

I'd like to see the LEAF drop a couple hundred lbs. But then I'd like to see the 80% charge range increased out to 100 mi LA4 so that one has close to 100 mi EPA range on a 100% charge when needed... I wouldn't mind another 30-40 kW of power while I'm asking, too.

 

[garsh]

I think the real question should be "Why is the regular Prius so heavy?"

Actually, I have to ask, "Why does the heavier Prius get better mileage than the lighter Prius C?"

 

[Herm]

probably aerodynamics are to blame.. its hard to make a short stubby car sleek. The standard Prius is very close to perfect, its hard to improve on it.

 

[DaveEV]

probably aerodynamics are to blame.. its hard to make a short stubby car sleek. The standard Prius is very close to perfect, its hard to improve on it.

Yep, aero is the biggest difference between the two, and if you compare the hybrid components on the C to the liftback they've been downsized in every way. If it had the same drivetrain it might produce better EPA numbers overall, but that would increase cost and weight.

Light weight = good city economy.
Good aero = good hwy economy.

If you look at the EPA numbers the C is better than the liftback in the city and lower than the liftback on the highway.

In real life, people seem to be easily beating EPA numbers in the C, though, without significant hypermiling techniques. Early magazine/blog reviews seem to confirm this and those drivers tend to hammer on the cars.

 

[GRA]

probably aerodynamics are to blame.. its hard to make a short stubby car sleek. The standard Prius is very close to perfect, its hard to improve on it.

Yep, aero is the biggest difference between the two, and if you compare the hybrid components on the C to the liftback they've been downsized in every way. If it had the same drivetrain it might produce better EPA numbers overall, but that would increase cost and weight.

Light weight = good city economy.
Good aero = good hwy economy.

If you look at the EPA numbers the C is better than the liftback in the city and lower than the liftback on the highway.

In real life, people seem to be easily beating EPA numbers in the C, though, without significant hypermiling techniques. Early magazine/blog reviews seem to confirm this and those drivers tend to hammer on the cars.

All correct. Regular Prius Cd is 0.25 IIRR, Prius C is 0.28. So the regular Prius is rated 51/48, and the Prius C is 53/46. Since car mag types have been reporting 55+ for the Prius C without really trying, this confirms that the new, more conservative EPA ratings understate the actual mileage achievable even more than the previous ones (which I've regularly exceeded for decades). You've got to wonder who the people are who complain that the current and just previous EPA ratings are too liberal, when even leadfooted car magazine editors can exceed them. Are the complainers driving around with passengers sitting on top of bricks, trunks full of sand or cement and six bikes on the roof?

 

[Sc0rPs]

You all might find this interesting:

3500 lbs., with a 660 lb. battery pack. Still the wrong battery, since it only has a lifespan of 5 to 10 years and 80,000 to 100,000 miles.

Nickel is cheaper and longer-lasting, and less heavy in practice. A 30 kWh NiMH pack weighs 1000 lbs., the 20 kWh you can access in the LEAF weighs about the same per kWh (30 lbs. per kWh) but costs more and doesn't last as long. Nissan plans to recycle used batteries into new batteries, enabling lower cost and eliminating the need for new mining of the metals in the battery.

 

[Pipcecil]

Something is wrong with that math. NiMH is way heavier. The 660 pounds in the leaf is everthing included (shielding, protective structure, etc.), was that included in the weight of the NiMH or was it just the cells? Gotta compare apples to apples. NiMH, no matter how you slice it will always be heavier. Its chemistry and math and there is no way around it. Its pure logic.

A fairly simple test you can take: Get a good NiMH AA battery like Envelope, which is THE best for charge times, capacity, and everything else (awesome batteries). Now get a AA size Lithium-ion (cobalt) battery. The Li-ion has more capacity but lets pretend it didn't. Weight them. The Li-ion will be about 20% less. An even simpler test is purchase some good AA NiZn batteries (NiZn has density bettery than NiMH but less than Li-ion). Get a camera or some other device that uses AA's (lots of em). With 4 AA's in a camera you can feel the extra weight and heft from the NiMH. They are just that heavy.

If NiMH was better in density (equal or less weight) then all your electronics would use it. Do you think Apple would stick that huge battery in the iPad only to go with a more expensive, heavier battery that gave no benefit to more power? It makes no sense. If weight is not much of a factor, NiMH is still good (think of a roomba), but Li-ion chemistry is just lighter per power output and when weight makes all he difference (cell phone, laptop, tablet, power tools, and cars) Li-ion is the way to go.

Also, something to consider. Just because Li-ion CAN be crappy and stop working in 2-3 years, so can NiMH cells. My energizer crappy NiMH AAs lasted less than 2 years, what a load of crap considering I barely used them and the cells went bad. My Envelope ones? 2 1/2 years and counting.

 

[Sc0rPs]

Something is wrong with that math. NiMH is way heavier. The 660 pounds in the leaf is everthing included (shielding, protective structure, etc.), was that included in the weight of the NiMH or was it just the cells? Gotta compare apples to apples. NiMH, no matter how you slice it will always be heavier. Its chemistry and math and there is no way around it. Its pure logic.

A fairly simple test you can take: Get a good NiMH AA battery like Envelope, which is THE best for charge times, capacity, and everything else (awesome batteries). Now get a AA size Lithium-ion (cobalt) battery. The Li-ion has more capacity but lets pretend it didn't. Weight them. The Li-ion will be about 20% less. An even simpler test is purchase some good AA NiZn batteries (NiZn has density bettery than NiMH but less than Li-ion). Get a camera or some other device that uses AA's (lots of em). With 4 AA's in a camera you can feel the extra weight and heft from the NiMH. They are just that heavy.

If NiMH was better in density (equal or less weight) then all your electronics would use it. Do you think Apple would stick that huge battery in the iPad only to go with a more expensive, heavier battery that gave no benefit to more power? It makes no sense. If weight is not much of a factor, NiMH is still good (think of a roomba), but Li-ion chemistry is just lighter per power output and when weight makes all he difference (cell phone, laptop, tablet, power tools, and cars) Li-ion is the way to go.

Also, something to consider. Just because Li-ion CAN be crappy and stop working in 2-3 years, so can NiMH cells. My energizer crappy NiMH AAs lasted less than 2 years, what a load of crap considering I barely used them and the cells went bad. My Envelope ones? 2 1/2 years and counting.

You do make some good points, I am not 100% on the math either but pointing out practical comparisons may not be best either. When comparing an Eneloop to Lion AA your comparing a 'Low Discharge' (means it holds it charge losing maybe 2% per month when not in use) to a regular rechargeable type. What we would need is to compare the weight of two regular rechargeable batteries with same mah ratings, there is both offering up to 3,000 mAh for AA batteries.

You're also right, plenty of NiMH batteries that failed, but that was due to quality of the battery. As a more practical example the NiMH packs in Rav4 EVs (14 years old) are still going solid, another good practical example in the NiMH is hybrids like the Prius - that is a much larger and better example. Not a single NiMH battery has failed in a Prius and they have been sold since 1997. The only time one had to be replaced is because of an accident.

I think there is enough evidence to prove NiMH is a far more robust battery that would outlast the car itself, when Lithium degrades the day it is made. The ones in the Leaf will last 5 - 10 years and may even start losing capacity before that depending on conditions such as charging capacity, weather.

I am not pro any battery, I just want one that will last and even if NiMH requires more space so be it. Please do keep in mind that the lithium packs in EVs such as the Volt is capable of 100 miles if allowed to deplete completely (btw NiMH does not suffer memory loss, you can deplete them). If you deplete Lithium you could 'brick' your battery pack, basically useless see 'Brick' & 'Tesla' in a google search. Not sure on the Leaf, but if I need to spend $10,000 every 5 - 10 years to replace my batteries when there is a battery I wouldn't it has to make you wonder. In fact, by 1996 they already had a NiMH battery pack capable of a 300 mile range.

 

[Stanton]

At first I followed this thread with some curiosity; now I can't believe we're actually arguing whether NiMH or LiOn battery technology is a better choice for EVs:

1) NiMH is WAY heavier than LiOn for the same energy density
2) LiOn is better on cycle counts, discharge rates, etc.
3) LiOn is SAFER (chemically speaking) than NiMH

We're not going to be spending anywhere near $10k to "replace" Leaf battery packs in 10 years (even if the whole thing fails--which I doubt). There's a reason every (new) EV is using LiOn battery technology: it's just plain better than anything that has come before it!

 

[DaveEV]

You're also right, plenty of NiMH batteries that failed, but that was due to quality of the battery. As a more practical example the NiMH packs in Rav4 EVs (14 years old) are still going solid,

Not sure where you got your data, but most of the RAV4 EV packs ended being replaced after 100-150k miles or so. Or like this one being auctioned off by pluginamerica which was "refreshed" after 50k miles or so.

another good practical example in the NiMH is hybrids like the Prius - that is a much larger and better example. Not a single NiMH battery has failed in a Prius and they have been sold since 1997. The only time one had to be replaced is because of an accident.

Totally not true, either. There's been plenty of cases where NiMH has failed - most notably in the Gen I Prius but it also happens on occasion on the Gen II Prius, too. Heck, there's a company that specializes in Prius battery pack replacements!

From a hybrid repair specialist: Gen 1 Prius Battery Failure, P3006

Based on experience within our walls and in discussion with technicians across the country, we can fairly call Gen 1 Prius battery failures “common” and even “predictable.” The youngest we’ve seen served 130,000 miles, some make it past 200,000 miles. Overall we’ve found 150,000 miles a reasonable expectation of how long the packs will last.

Look - I'm a big Prius fan (I own one) - but claiming that NiMH is 100% reliable and never fails is simply not true.

 

[Sc0rPs]

At first I followed this thread with some curiosity; now I can't believe we're actually arguing whether NiMH or LiOn battery technology is a better choice for EVs:

1) NiMH is WAY heavier than LiOn for the same energy density
2) LiOn is better on cycle counts, discharge rates, etc.
3) LiOn is SAFER (chemically speaking) than NiMH

We're not going to be spending anywhere near $10k to "replace" Leaf battery packs in 10 years (even if the whole thing fails--which I doubt). There's a reason every (new) EV is using LiOn battery technology: it's just plain better than anything that has come before it!

1) Next Gen NiMH is maybe 15% heavier, some argue same now but honestly not sure

2) Not so, NiMH sufferes no memory loss thus can be discharged completely with no ill effect

3) Also not true, Lithium is the battery that caught on fire in lap tops, also banned from air transport. Unlike NiMH which is 100% safe for travel and 100% recyclable.

I still hope you're right, in that Lithium will last longer than 10 years but Nissan themselves stated 5 - 10 then they will start to degrade, range will decrease. There may be a reason why the new EVs are using lithium but it may be to do with how unreliable Cobasys (maker of the large format NiMH) actually is, in fact a small car company and Mercedes both launched law suits due to Cobasys failing to deliver agreed upon large format NiMH batteries.

 

[davewill]

another good practical example in the NiMH is hybrids like the Prius - that is a much larger and better example. Not a single NiMH battery has failed in a Prius and they have been sold since 1997. The only time one had to be replaced is because of an accident.

Totally not true, either. There's been plenty of cases where NiMH has failed - most notably in the Gen I Prius but it also happens on occasion on the Gen II Prius, too. Heck, there's a company that specializes in Prius battery pack replacements! ...

Yep. Toyota just replaced the one in my 2005 Prius under warranty (I was just under the mileage limit).

 

[Sc0rPs]

You're also right, plenty of NiMH batteries that failed, but that was due to quality of the battery. As a more practical example the NiMH packs in Rav4 EVs (14 years old) are still going solid,

Not sure where you got your data, but most of the RAV4 EV packs ended being replaced after 100-150k miles or so. Or like this one being auctioned off by pluginamerica which was "refreshed" after 50k miles or so.

another good practical example in the NiMH is hybrids like the Prius - that is a much larger and better example. Not a single NiMH battery has failed in a Prius and they have been sold since 1997. The only time one had to be replaced is because of an accident.

Totally not true, either. There's been plenty of cases where NiMH has failed - most notably in the Gen I Prius but it also happens on occasion on the Gen II Prius, too. Heck, there's a company that specializes in Prius battery pack replacements!

From a hybrid repair specialist: Gen 1 Prius Battery Failure, P3006

Based on experience within our walls and in discussion with technicians across the country, we can fairly call Gen 1 Prius battery failures “common” and even “predictable.” The youngest we’ve seen served 130,000 miles, some make it past 200,000 miles. Overall we’ve found 150,000 miles a reasonable expectation of how long the packs will last.

Look - I'm a big Prius fan (I own one) - but claiming that NiMH is 100% reliable and never fails is simply not true.

Intersting, thanks for clearing that up. Looks like I read some biased web sites, was it just the gen. 1 Prius batteries or all?

 

[toasty]

do it