Thought experiment - A Leaf with Lead Acid Batteries

[adric22]

Its just an interesting mental project. What would the Nissan Leaf be like with Lead-Acid batteries, or NiMh batteries?

Assuming nothing else changed in the car, I'd be interested to see people's estimates on how the change of battery chemistry would affect these things:

• Range
• Weight
• Battery life expectancy
• Cost of vehicle
• Cost of ownership after 10 years

I remember several years ago when I was designing my own EV I had to make the choice and went with Pb batteries simply because of lower cost. I realized that even if I had to change the batteries out after 3 years that I'd still be ahead vs. cost of Lithium. It would only be after buying the 3rd set of batteries that cost might begin to favor Lithium assuming the lithium lasted as long as were promised.

I can also tell you that not all Lead Acid batteries are created equal. For example my electric lawn mower originally came with a panasonic AGM battery pack. It lasted 5 years. I've been replacing the battery with cheap aftermarket batteries every since and I'm lucky to get 2 years out of them.

 

[Herm]

The life with Pb in the cooler states might be similar to what people are getting in Arizona

With nimh the pack will be 50% heavier, lower performance but I think the car would not have any problems.. perhaps it would need upgraded tires. Not sure about the volume that the battery pack would need plus it would definitely need active cooling.

 

[skippycoyote]

This is an interesting question. I have very little experience with NiMh batteries (considered them for my EV conversion, but they were too expensive), but here is what I figure with lead-acid batteries (what I actually put in my EV conversion).

•Range - decreased range due to increased weight of batteries. Even with 20 deep cycle batteries in prime condition, I usually could only go about 40-50 miles in my lead-acid EV. This was in a car with little driver ammenities to waste electricity (no A/C, no power windows or door locks, no power steering, no navigation package, no computer, etc.)
•Weight - increased weight due to lower energy to weight ratio of lead-acid batteries (unless you sacrified range and went with fewer batteries). The lead-acid equivalent to litium ion usually weighs 2-8 times as much.
•Battery life expectancy - reduced with lead-acid batteries. Greatly reduced in hot climates (not sure about cooler climates)
•Cost of vehicle - significanly less with lead-acid batteries (2K-3K vs 10K for battery pack)
•Cost of ownership after 10 years - Probably less, even with having to replace the battery pack every 3 years

So, I think lead-acid would give us a much cheaper car and cheaper cost of ownership, but at the "cost" of decreased range and shorter battery life expectancy. Plus, there are a few other concerns about lead-acid that I would like to add. First of all, deep cycle lead-acid batteries require more mantainance. In the Arizona summer heat, I frequently had to add water to the batteries. I wonder, however, if there are any maintenance free deep cycle lead acid batteries out there that might not require this. Another concern is the affect of heat on the battery life. I actually got 3 good years out of my lead-acid batteries (we were told they would probably last 2 years). I know that some owners are seeing gradual reduced capacity with their hot climate LEAFs, but in Arizona, the lead-acid capacity loss wasn't really gradual at all. There were a few times we had bad batteries, and replaced them one at a time, but when the pack got old, the vehicle went from "running fine" to "barely crawling at all" in a matter of days. The heat also made the batteries swell, so that when one of the batteries cracked, it wasn't very obvious. When we removed the batteries a few years ago, there were parts of the truck bed that had been completely eaten through. In hindsight, if I do this again, I'll put the batteries in a heavy duty plastic tub, not on top of a rubber mat. Also, I would be concerned about the hydrogen gas produced by the battery pack. In my EV conversion, they were in the bed of the truck and isolated from the driver. In the LEAF, the batteries are under the driver and passengers. It would probably require a more active venting system. Furthermore, the lithium batteries make better spatial sense in a LEAF. Since the individual modules are fairly shallow and small, they can be arranged in various configurations. Deep cycle lead-acid batteries typically need to be deep to provide for enough contact between the plates and the electrolye. I'm curious to know what other people think.

 

[Nubo]

I think it might be interesting to add a NiMH LEAF to the experiment. Particularly regarding battery degradation. I keep reading of RAV4-EV owners who claim that their packs are still like new!

I seem to recall that the Cobasys patents for the Ovonics NiMH will expire not to far in the future. Might we see a return to NiMH for mass-market EVs?

 

[TEG]

I think it might be interesting to add a NiMH LEAF to the experiment. Particularly regarding battery degradation. I keep reading of RAV4-EV owners who claim that their packs are still like new!

I seem to recall that the Cobasys patents for the Ovonics NiMH will expire not to far in the future. Might we see a return to NiMH for mass-market EVs?

I recall it was 2014.

I doubt we see a switch back to NiMH.
Lithium continues to improve such that it will likely be a better choice both on cost, and energy density (weight.)
Yes, the best of NiMH has good calendar life, but so much effort on Lithium R&D has been improving it rapidly.
Note, the price of Nickel has gone up substantially since the late 90's when we had NiMH EVs.

 

[TEG]

The super short / obvious answers:

• Range :: LESS
• Weight :: MORE
• Battery life expectancy :: LESS... particularly if you ever drive down to low SOC you start to kill your pack.
• Cost of vehicle :: LESS, although lead isn't as cheap as it used to be.
• Cost of ownership after 10 years :: Probably more as I would think you would have had to replace the lead/acid pack a few times by then.

The lead/acid pack would do best if you only ever did short trips and kept it topped off all the time in between.

 

[SteveInSeattle]

This thread has gotten me thinking, the reality is that many of us could get by with LESS range. I use my Leaf to commute 25 miles R/T to work. Had I had the option of a lower cost, lighter Leaf with lesser range it would have appealed to me. What would it have required in Pb batteries for the Leaf to have a 40 mile per charge range? I think many of the GM EV1 owners who had the early models were happy with their cars. I think Tesla is on the right track in offering optional battery back sizes and wonder if Nissan has any plans to do the same? The Mitsubishi i has about the size pack and range that would have fit my intended use.

 

[TEG]

...I think Tesla is on the right track in offering optional battery back sizes and wonder if Nissan has any plans to do the same? The Mitsubishi i has about the size pack and range that would have fit my intended use.

Keep in mind that Tesla's smallest pack is a lot larger than the LEAF pack.

Also, for the time being Tesla is only making "top of the line" 85kWh 300 mile Range Model S sedans.
The 230 and 160 mile range versions aren't available for a while.

 

[adric22]

This thread has gotten me thinking, the reality is that many of us could get by with LESS range. I use my Leaf to commute 25 miles R/T to work. Had I had the option of a lower cost, lighter Leaf with lesser range it would have appealed to me. What would it have required in Pb batteries for the Leaf to have a 40 mile per charge range? I think many of the GM EV1 owners who had the early models were happy with their cars. I think Tesla is on the right track in offering optional battery back sizes and wonder if Nissan has any plans to do the same? The Mitsubishi i has about the size pack and range that would have fit my intended use.

I've said it before, and I'll say it again. Had the Leaf been available with a smaller battery pack offering a realistic 45 miles, at a considerable discount, I would have bought it. I've also said before that I would be happy with a Chevy Volt with no gas engine, even if the EV battery was the same. (Although I bet you'd gain a few miles by eliminating the ICE weight) Again, I would only go that route if the car was probably $10,000 less than it costs now. So a Volt that costs me $22,000 (after tax credit) with 45 miles range and no ICE. I'd take it.

However, what would make that option even more desirable would be a battery pack that is split into two. That way you buy the car with the smaller pack, but later on if you decided you needed more range you could add the second battery pack to double your range.

As for my original post, I was waiting to hear what other's opinion was.. But here's mine. Assuming the car were exactly the same except for the battery pack. The battery pack would be the same size, but would have AGM lead-acid batteries. These would be more or less the same kind GM used in the EV-1.

• Range - Most important of all. I suspect it would be between 30 and 50 miles.
• Weight - I expect it would add a few hundred pounds to the car.
• Cost - I bet the Leaf could shave $8,000 off of the MSRP.
• Life Expectancy - I'm betting 3 to 5 years on the batteries.
• Cost of Ownership - If batteries are only replaced 1 time during 10 years, then the Lead-acid would be the cheapest route. If it required 3 replacements, then the Lithium would be the right choice - unless we determine the Lithium isn't holding up as promised.

All in all, I think it would still be a viable car. It would cost about $20,000 after tax credits. In CA or other states it might be closer to $15,000. But you'd have to calculate in replacing the batteries after 3-5 years. The replacement battery pack would probably cost $3,000.

 

[kubel]

I think it might be interesting to add a NiMH LEAF to the experiment. Particularly regarding battery degradation. I keep reading of RAV4-EV owners who claim that their packs are still like new!

I seem to recall that the Cobasys patents for the Ovonics NiMH will expire not to far in the future. Might we see a return to NiMH for mass-market EVs?

Large format NiMH batteries already exist. The swedes would be happy to sell us theirs.

http://www.nilar.com/applications/traction-batteries" onclick="window.open(this.href);return false;

 

[Herm]

I keep reading of RAV4-EV owners who claim that their packs are still like new!

I doubt it, they are the same people that 10 years from now will have vintage Leafs with no battery degradation.. the capacity bar indicator malfunctioned.

 

[TomT]

People sometimes see what they want to see...

I keep reading of RAV4-EV owners who claim that their packs are still like new!

 

[smkettner]

Can you quick charge AGM in 20 minutes in 120F heat?

 

[DaveinOlyWA]

Leaf had no place in EVs. Add fat as range; I wanted a highway capable EV with a50 mile range. I am happy

 

[DaveinOlyWA]

What would a LEAF wi th a 16 kwh battery cost?

 

[Nubo]

I think it might be interesting to add a NiMH LEAF to the experiment. Particularly regarding battery degradation. I keep reading of RAV4-EV owners who claim that their packs are still like new!

I seem to recall that the Cobasys patents for the Ovonics NiMH will expire not to far in the future. Might we see a return to NiMH for mass-market EVs?

Large format NiMH batteries already exist. The swedes would be happy to sell us theirs.

http://www.nilar.com/applications/traction-batteries" onclick="window.open(this.href);return false;

Yeah I ran across Nilar quite a few years ago now. I've never seen any evidence that they had a real, physical product in the field.

 

[LTLFTcomposite]

What would the range be if it had lemons, galvanized nails and pennies? :idea:

 

[Herm]

What would a LEAF wi th a 16 kwh battery cost?

Maybe $4000 less, if Nissan passed the savings on to the buyers... or you could just get an iMiev..

 

[ENIAC]

What would a LEAF with a 16 kwh battery cost?

Not sure, ask some of the Phoenix LEAF owners what they would take.

 

[KJD]

What would a LEAF wi th a 16 kwh battery cost?

It would cost almost exactly the same as this car.
http://autos.yahoo.com/mitsubishi/i-miev/2012/" onclick="window.open(this.href);return false;

The biggest complaint with the Leaf is lack of range. This would just make those complaints louder.

I would much rather see a Leaf with a 36kwh battery instead of a 16 or even a 24 like it has now.

kjd