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Discussion Starter #1
Hi All,

At BEVoB last week I spoke with a few people about adding additional batteries to the leaf to extend range.

I have been doing some research and producing an add on 'kit' looks do-able.

It involves:
  • Mounting the batteries, fuses and any other components into a box in the boot essentially lifting the boot floor. Need to look at the impact of the additional weight on the existing range, chassis, suspension, tires and weight distribution.
  • Charging from the existing onboard charger - I would also quite like it to work with chademo/dc charging
  • Modifying the existing vehicle systems into either recognizing the additional battery capacity or fooling them as required.
  • Looking at how this affects warranty and safety.
I thought I'd post rough specs to see what the general feeling is. If it looks viable (i.e. I'm not throwing time and money into a black hole) then I'll look at creating something to be sold on the website (indra.co.uk) with the view of it being supplied as a kit (fit it yourself) or as a fitted service for slightly more (we fit to your car).

I should stress that this would be a commercial venture, it would need to be profitable (but fairly priced) and would not be entirely open source. Obviously there would need to be some transparency if it was provided as a kit and I believe it is also useful for the owner to understand how it operates from a safety perspective.

Rough specs:
  • Additional 40 mile range (minimum actual).
Based on 300 wh/mile *40 miles =12kwh.
12KWH *0.8 (80% of battery being usable) = 15KWH
15KWH /395 volts (leaf fully charged voltage) = 38AH required
so I would plan to use 112 * 40AH LiFePO4 cells

The cells usually come in at least 10% above rated capacity so add that on to the total range - wont be advertised like that though ;-)
  • Charge from existing sources, J1772, mennekes and (hopefully) chademo - note that the charge time will increase as the battery is ~2/3 larger
  • Lose existing luggage space in the boot. anticipate 8 inches depth to be lost
  • Approx £5,000 - cant set this in stone just yet as I don't know exactly what is involved.
Thoughts?
 

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Discussion Starter #3
Hi Kevin,

I believe about 50 modules would be required to get the the right voltage.

Thats over $5000 before import tax, VAT etc....
 

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Discussion Starter #5
Great. I'll take a read :)

My thoughts on not using the space underneath were that it would effect aerodynamics, reduce ground clearance (a real consideration given the weight as well), be difficult to mount and not actually be that usable due to the shallow depth.

With using just the boot space there are no aerodynamic losses and there are plenty of potential mounting points with no fear of the batteries dropping out the bottom!

It would also mean that everything could live in one larger package giving less potential point of failure.

Cheers,

Mike
 

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Discussion Starter #7
Sure... but if you buy a wrecked Leaf here then none of that applies :)

Personally, I think using the same battery technology would be more attractive to end users because it would be much easier to maintain if you are no longer around.
Good point...

I'll happily consider the leaf cells if there is enough demand for us to look at this. My concerns are with availability, consistency of used cells, having to repackage them and then work out the BMS.

Brand new CALB or Sinopoly cells, (although a different chemistry) are readily available, standardised in size, relatively cheap and easy to package. The cell sizes have remained the same as the technology has improved. For example, the new New Sinopoly 200AH cells are the same size as the CALB 180AH and the old Thundersky 160AH.

This would be quite a big investment for indra to make - we need to purchase a leaf, the batteries, all the other ancillaries and then put in what will probably be several thousand hours of development to get it fully integrated.

On the support side of things, my intention is that this will be fully documented so support shouldn't really be required. once installed. However things can go wrong so as a worse case, if we were to go under then all of our development docs could be made publicly available - there would be no commercial interest in us keeping them!
 

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Discussion Starter #10
Non technical side point, would LEAF owners paying £5k for 40 miles more range send a bad message to Nissan and others regarding future pricing policy and upgrades to the car?
Another good point.

Potentially or it could drive competion. Someone with a current leaf may see a £5k upgrade as a better choice than an £8k trade in and then another £20k for a new model
 

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Sure... but if you buy a wrecked Leaf here then none of that applies :)

Personally, I think using the same battery technology would be more attractive to end users because it would be much easier to maintain if you are no longer around.
Only if you kept the modules intact. The modules are 7.5V at 65ah. You need 48 in series to match the Leaf battery pack. That's good in that you would be doing a 100% upgrade, but bad because I don't think you'd have space for them all.

The other option would be to split the actual cells out individually. 96 individual 3.75v 32.5ah cells in series would match perfectly to the existing battery, but only be 12kwh, be bulkier and heavier than the sinopoly cells, and not "swappable" with the existing modules, they would need re-working. I'd rather go for known new cells that won't ever need replacing or support.
 

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Non technical side point, would LEAF owners paying £5k for 40 miles more range send a bad message to Nissan and others regarding future pricing policy and upgrades to the car?
A valid concern, but Toyota charge £11,400 for a 4kwh lithium upgrade for the prius. £5k for 15kwh is a bargain in comparison!!
 

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The other option would be to split the actual cells out individually. 96 individual 3.75v 32.5ah cells in series would match perfectly to the existing battery, but only be 12kwh
That's 50% extra Leaf range using batteries that will be readily available for years from wrecked cars. When removed from the can the 96 cells would weigh 75kg and you could probably parallel the new pack with the existing pack with almost no development :)

As a customer of a niche product I want something I can maintain easily and given we will have a cottage industry rebuilding wrecked EV's I know where I'd put my money.
 

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That's 50% extra Leaf range using batteries that will be readily available for years from wrecked cars. When removed from the can the 96 cells would weigh 75kg and you could probably parallel the new pack with the existing pack with almost no development :)

As a customer of a niche product I want something I can maintain easily and given we will have a cottage industry rebuilding wrecked EV's I know where I'd put my money.
Sure, but if it actually comes time to replace some then anyone with a spanner can replace a prismatic cell, and any lifepo4 cell that will fit in the hole (of equal or greater ah) will work. Tabbed cells are a lot more difficult to work with :(
 

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Sure, but if it actually comes time to replace some then anyone with a spanner can replace a prismatic cell, and any lifepo4 cell that will fit in the hole (of equal or greater ah) will work. Tabbed cells are a lot more difficult to work with :(
Sure but 50% extra Leaf range for $2,616 (£1,556) might be worth a little inconvenience :)

The tabs also look pretty easy to handle if you have a can opener;

http://speakev.com/threads/leaf-battery-disassembly.1771/

I understand the appeal of using CALBs or similar but the economics of using refurbished Nissan/Renault modules is hard to resist and if I was developing a product like the OP proposes then I'd be worried someone would come in with a Leaf based solution and steal my market.
 

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@Mike Schooling using a tiny sample of EV geeks my conclusion is that some would be interested at £2K but none at £5K and therefore I think you have a challenge on your hands today. However, as the Leaf resale value drops I can see a market for upgraded cars with a warranty and a smaller market for pure add-ons like extra batteries.

Keep up the good work :)
 

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@Mike Schooling using a tiny sample of EV geeks my conclusion is that some would be interested at £2K but none at £5K and therefore I think you have a challenge on your hands today. However, as the Leaf resale value drops I can see a market for upgraded cars with a warranty and a smaller market for pure add-ons like extra batteries.

Keep up the good work :)
Hey, I said I was interested at £5k! Not sure if that means I'm not an EV geek, not interesting, or just ok to ignore?? :(
 
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