Leaf range extension, just thinking

It occurs to me that this is a "don't diddle with the Nissan stuff" way to add energy capacity:
Pull out back seats and put in around 500 pounds of LFP cells. Add BMS, charger, and inverter. Plug in Phil's modified Panasonic EVSE.
"Nice to have" perturbations:
1) charge Nissan pack while driving
2) charge LFP pack from Nissan side of the J1772 port
500 lb of LFP should provide about 20KWH of energy. Getting it into the Nissan pack would entail losses in both the inverter and Nissan charger. Maybe 10% in each? Maybe 16KWH of usable energy? At 4.5 miles per KWH, that would be about 72 additional miles.

I'm not yet ready to pull the seats out of my brand new Leaf, but I'm intrigued with the idea. I'm forced to compare my 90-100 mile Leaf to my 120-150 mile conversion (with about 40 KWH worth of TS-LFPs) and the Leaf is coming up short.

Can anyone shoot down these ideas? Other comments? Has anyone else proposed doing something like this?
Are my guestimates on the charger and inverter losses about right?

I have used the Leaf to haul 12x48lb boxes (576 pounds) plus about 400 pounds of driver and passenger; the Leaf seemed to handle that weight ok.

I've been thinking along the same lines, though I was hoping to use the trunk rather than remove seats.

I think the connector will have to be other than the charging port since the car won't move with the connector clipped in. Try it--there is a safety device. So Nissan or someone will have to design an auxiliary "power in" connector to the power train.

150 to 200 mile range would be much better. Right now the LEAF is only a daily commuter. I don't like sweating the last 20 miles, turning off the AC, driving in the slow lane at 55 to 60 and have everyone pass me.

We may have to wait for the LEAF generation 2, or when someone creates a battery replacement with 150 to 200 mile capacity.

DrRocket said:

I've been thinking along the same lines, though I was hoping to use the trunk rather than remove seats.

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I fear weight distribution would suffer too much with ~500lb above or behind the rear axle

I think the connector will have to be other than the charging port since the car won't move with the connector clipped in. Try it--there is a safety device. So Nissan or someone will have to design an auxiliary "power in" connector to the power train.

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I'm not surprise; I wouldn't expect "charge while driving" to be easy.
I believe, at 220v, the charger charges at about 12-14 miles per hour. If one COULD charge while driving, it would add 25-30 miles to the range assuming moderate ~50 mph driving. Then the energy to add another 25-35 miles while stationary charging.

150 to 200 mile range would be much better. Right now the LEAF is only a daily commuter. I don't like sweating the last 20 miles, turning off the AC, driving in the slow lane at 55 to 60 and have everyone pass me.

We may have to wait for the LEAF generation 2, or when someone creates a battery replacement with 150 to 200 mile capacity.

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Probably so. :-(

You could probably bypass or disable the safety interlock, however you probably can't get enough power through the J1772 charge plug to power the car to keep up with your power draw unless you are driving slowly. The DC fast charge port would probably be a better choice, and more efficient.

wow, this has been discussed a MILLION times and it simply is not feasible. the max you can charge will only gain you 10-12 miles of range PER HOUR. unless you have a real long and slow commute, it will not work.

you would have to look at a manual tie in to the pack, which i am guessing will take a TON of knowledge and more money than its worth.

what is wrong with driving slowly? is it really that awful to get home 10-15 minutes later?

Let's wait for generation 2 of the LEAF. The following quote is from the May edition of Car and Driver magazine.

"A123 (a battery manufacturing company) is aimed at optimizing the battery's power, energy, and life through the use of nanostructured materials that provide a high surface-area-to-volume ratio. Experimental solid-state (also known as thin-film) cells increase the surface area even more. The potential energy density of these micron-thin ribbons is four-to-five times that of today's Li-ion batteries. As with integrated-circuit manufacturing, the cell materials are deposited one thin layer at a time in a vacuum. The result is an incredibly light, dense cell."

DaveinOlyWA said:

wow, this has been discussed a MILLION times and it simply is not feasible. the max you can charge will only gain you 10-12 miles of range PER HOUR.

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Not through the DC fast port. Since you can recharge a LEAF to 80% in 30 minutes you can put enough power through it to keep you driving at normal speeds.

ERG4ALL said:

Let's wait for generation 2 of the LEAF.

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That's no fun.

If you are willing to give up the trunk capacity and your back seat, turning the four door sadan into a two seater, if that's worth it to you then maybe. I'm no engineer so I have no idea of the technical feasibility of it though there is surely a point of diminishing returns with added weight eating up the added capacity. I'm guessing we need a more dense battery pack to add more capacity without the scale tipping in the negative due to adding weight. I'm betting Nissan worked very hard to find the economical sweet spot between drag, weight and battery capacity.

Adding more capacity may simply result in trading our current gas guzzlers for future electric guzzlers. Having to pay attention to wind drag and optimizing MPKw seems like a good thing for a growing planet. For now, I"m embracing the limits, at least to some extent and seeing how I can go further on less. Who knows how long that will last as this car is fun to drive fast!
g

This sounds to me like what the original Prius plug in conversions did. I think they used contactors to parallel the additional battery pack to the Prius OEM battery. Or maybe they disconnected the OEM battery with one set of contactors and connected the conversion pack in its place with another set. Not sure, but it was something like that. I followed that stuff for a while, until I became convinced that pure electric was better.

Something similar to the Enginer plug-in packs for the Prius would work.. a DC-DC booster just supplements the main battery pack, extending the range. It just connects in parallel without changing any of the hardware of the car. It probably would confuse (even further) the range calculations of the Leaf.

http://www.enginer.us/

The 8kwh kit is $5500, it should give an extra 32 miles of range.

Herm said:

Something similar to the Enginer plug-in packs for the Prius would work.. a DC-DC booster just supplements the main battery pack, extending the range. It just connects in parallel without changing any of the hardware of the car. It probably would confuse (even further) the range calculations of the Leaf.

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Yeah, I was aware of the Enginer kit; it was probably the basis of my idea for a second battery pack almost independent of the native pack.

Elsewhere, it has been suggested that typical inverter losses are around 30%. That's a big burden for my scheme.

To those pointing out that the potential range increase by going through the Nissan charger are minimal, I can only suggest that they read my posts. If charging can be done while driving, a range increase of around 30 miles seems possible and reasonable. If one wanted to charge ONLY while driving and be satisfied with the ~30 mile range increase, only 200-250 pounds of battery would be needed. That, in addition to halving the battery cost, might make siting in the trunk viable.

Somehow dumping energy directly into the native battery via the $700 optional port has a lot of merit. I did not order the external charge port. Has anyone used (or even seen) a level 3 charger?

To the guy that thinks Nissan has done it perfectly, I say "hogwash". Had Nissan just devoted another 300 pounds to battery, we would have 150 mile range. Then, we would want 200 mile range .

I like my Leaf. It's performance is good and it drives very nicely. The remote access is truly WONDERFUL. Only it's instrumentation and range are lacking.

Another 300 lbs of batteries would have substantially increased the price, probably into Volt territory. I think another 10-15% of battery would have been a good idea which would have allowed more people to get closer to the 100 mile range. Because of human nature I think a lot of people fixate on that number. Of course that would also mean the car might not come under $30K with the rebate. It's all a trade off. There is certainly room for design improvement in lighter weight materials and better aerodynamics that could have gotten more range from the existing pack. The LEAF is too tall and too heavy but over all a good first effort.

JRP3 said:

The LEAF is too tall and too heavy but over all a good first effort.

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I agree. The first Leaf I saw was mine when I took delivery. It was MUCH larger than I expected. And I was surprised to see exterior mirrors on it. I expected video rear view to save exterior mirror wind drag.

That may not be DOT compliant, and supposedly the strange headlight design pushes the airflow past the mirrors smoothly.

JRP3 said:

Another 300 lbs of batteries would have substantially increased the price, probably into Volt territory. I think another 10-15% of battery would have been a good idea which would have allowed more people to get closer to the 100 mile range. Because of human nature I think a lot of people fixate on that number. Of course that would also mean the car might not come under $30K with the rebate. It's all a trade off. There is certainly room for design improvement in lighter weight materials and better aerodynamics that could have gotten more range from the existing pack. The LEAF is too tall and too heavy but over all a good first effort.

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I think Nissan did a good job of picking a lot of compromises to keep the price down.
Sure I would like more range and less weight, but I wouldn't have bought the car if it cost any more than it does.
It does seem taller than I need, but for those 6 foot four people it is probably just right.
If I had the ability to redesign it, I would lower the roofline 3 inches, and do something to make the headlights less "bug-eye". Overall though, I think it gets high marks for being a very functional and comfortable car.

My first reaction when I saw the post yesterday was to snort and think, "How does he plan to cool the charger and inverter?"

Ray

mckemie said:

Yeah, I was aware of the Enginer kit; it was probably the basis of my idea for a second battery pack almost independent of the native pack.
Elsewhere, it has been suggested that typical inverter losses are around 30%. That's a big burden for my scheme.

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30%?.. nah!.. perhaps a cheap $100 12v to 120VAC inverter.. but a good high power DC-DC inverter is about 95%, some 98%. Not cheap since its a custom application. Dont want to use an inverter? then use the exact same cell chemistry Nissan is using and 96 cells in series.. perhaps when used Leaf packs come in the market (replaced by 2013 150 mile upgrades) you will be able to scarf up used cells in good condition.. add a BMS and a case and you are set. The future for do-it-yourselvers looks bright

You would have to bypass a lot of safety features in the L3 port to use it while you are driving, much much easier just to tap the two main power cables coming out of the battery.

mckemie said:

To the guy that thinks Nissan has done it perfectly, I say "hogwash". Had Nissan just devoted another 300 pounds to battery, we would have 150 mile range. Then, we would want 200 mile range .

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Probably so, but you quickly run into diminishing results.. most people dont drive that far very often, some never do. An extra 7kwh would give you a "real world" (for speedy CA drivers) range of 100 miles, about 110lb plus BMS and steel case.. the Leaf should be able to handle that. Perhaps it may be easier to slow down to 55mph, you wont get rammed from the back, the speed differential is not that great. As an example: You are driving along at 20mph, are you really going to run into some guy stopped in the middle of the street?

mckemie said:

Has anyone used (or even seen) a level 3 charger?

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Please be patient. They will be available 'soon', to use Nissan's favorite word. I was told that ECOtality's last residential install would be Sept. 30, 2011. Then I believe they will begin installing the DC fast chargers (could be sooner though), so all this talk about 'extra' batteries will be moot. If you DC charge less than 7 times a day, it will not degrade the battery pack according to Brendan Jones, VP of Nissan Sales.

TEG said:

JRP3 said:

Another 300 lbs of batteries would have substantially increased the price, probably into Volt territory. I think another 10-15% of battery would have been a good idea which would have allowed more people to get closer to the 100 mile range. Because of human nature I think a lot of people fixate on that number. Of course that would also mean the car might not come under $30K with the rebate. It's all a trade off. There is certainly room for design improvement in lighter weight materials and better aerodynamics that could have gotten more range from the existing pack. The LEAF is too tall and too heavy but over all a good first effort.

Click to expand...

I think Nissan did a good job of picking a lot of compromises to keep the price down.
Sure I would like more range and less weight, but I wouldn't have bought the car if it cost any more than it does.
It does seem taller than I need, but for those 6 foot four people it is probably just right.
If I had the ability to redesign it, I would lower the roofline 3 inches, and do something to make the headlights less "bug-eye". Overall though, I think it gets high marks for being a very functional and comfortable car.

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my wife and I are both 6'3" and with our two kids/car seats we can just fit in the car comfortably. Any smaller/shorter and we would not have been able to make it work. I would have been willing to pay more for some added battery capacity but I'd get even more excited by having the option to go with premium sound. It's not like you can go and just upgrade the sound system at car toys, it's all so integrated with the car specific electronics that you are a bit locked in. Having to drive a little slower to get the most out of the battery is fine with me, just let me crank the tunes! ... that's the one thing I really miss about my TDI Jetta!
g