Supplimental battery

So, has anyone added a second battery to their car yet?

Seems to be a popular subject; I searched "LEAF extra battery" using the Google search option and came up with half a dozen relevant hits.

JohnBike said:

Seems to be a popular subject; I searched "LEAF extra battery" using the Google search option and came up with half a dozen relevant hits.

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The ones I found seem to be VERY expensive. one was over 12k for a 12 KW battery. for half that I could just go buy a new one from Nissan and cut it in half

Limey said:

JohnBike said:

Seems to be a popular subject; I searched "LEAF extra battery" using the Google search option and came up with half a dozen relevant hits.

Click to expand...

The ones I found seem to be VERY expensive. one was over 12k for a 12 KW battery. for half that I could just go buy a new one from Nissan and cut it in half

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You could buy a wrecked LEAF and just use the cells out of it for a trunk mount battery. You could easily make a 12kWh battery at the same 393.5 volts simply by removing the second cell in the cell pairs. You would need some kind of aftermarket BMS to control it, then simply run it in parallel with the existing battery.

TonyWilliams said:

Limey said:

JohnBike said:

Seems to be a popular subject; I searched "LEAF extra battery" using the Google search option and came up with half a dozen relevant hits.

Click to expand...

The ones I found seem to be VERY expensive. one was over 12k for a 12 KW battery. for half that I could just go buy a new one from Nissan and cut it in half

Click to expand...

You could buy a wrecked LEAF and just use the cells out of it for a trunk mount battery. You could easily make a 12kWh battery at the same 393.5 volts simply by removing the second cell in the cell pairs. You would need some kind of aftermarket BMS to control it, then simply run it in parallel with the existing battery.

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If only I knew more about electronics!

I'm seriously considering running another pack in parallel with the leafs pack. I know all the technicalities and dangers, but I'd love to hear your take on dealing with them.

I really don't know the easiest way to tap into the pack. Also needs to be heavy gauge tap, so that may be a factor.

It is far more complex than just that...

hillzofvalp said:

I'm seriously considering running another pack in parallel with the leafs pack. I know all the technicalities and dangers, but I'd love to hear your take on dealing with them.
I really don't know the easiest way to tap into the pack. Also needs to be heavy gauge tap, so that may be a factor.

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Please elaborate?

hillzofvalp said:

Please elaborate?

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Well---to start with, due to the weight increase, you'll need major changes to suspension, different tires----not to mention the complexities of electronic modifications. Not worth the effort, imho.

derkraut said:

hillzofvalp said:

Please elaborate?

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Well---to start with, due to the weight increase, you'll need major changes to suspension, different tires----not to mention the complexities of electronic modifications. Not worth the effort, imho.

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If I had a spare Leaf battery pack, I would re-wire the individual cells in each individual can.
Each can contains 4 cells, arranged 2 cells in parallel, with 2 pair in series.
If you were to rearrange them into 4 cells in series, you could make a supplemental pack with the same voltage as a full pack using 50% of the cells, resulting in a 12kW supplemental pack with 50% of the weight.

I think the suspension could handle that.
Might result in some increased tire wear, but would finally give me the 100+ mile car I was promised.
Add a dedicated Brusa to charge the pack, etc. and there you go.

Anybody got a pack from a wrecked leaf they want to play with?
How about one of those 2012's in New York that got flooded?
Still see them on the auction sites.

KillaWhat said:

How about one of those 2012's in New York that got flooded?
Still see them on the auction sites.

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I hear that the battery packs were removed before auction. Sold "as is".

derkraut said:

hillzofvalp said:

Please elaborate?

Click to expand...

Well---to start with, due to the weight increase, you'll need major changes to suspension, different tires----not to mention the complexities of electronic modifications. Not worth the effort, imho.

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I don't think it would be that bad, you've got a payload of 937lbs already so if you are going to make it a 2 seater that's 457lb that you can have to have 2 passengers and enough cargo for 2 people. If you are 250lbs plus and have a 250lb plus person you drive with a lot then it will be near the limit but still close to stock tire and suspension designs. There will also be some weight savings from taking out the back seats but this would probably be offset by building some kind of custom box/mount.

As for the electronic modifications the easiest way would be some sort of switch to trick the car into thinking it just has 1 battery. Run 1 battery down, turn the car off, reset the computer and start back up on the next fully charged battery. You could also in theory (especially if you are starting with a complete wrecked car) have the computers from 2 cars and only turn 1 on at a time.

The biggest concern I'd have would be with safety. If you're going to go through all this, and if you have the knowledge and tools to do it all you'd probably be better off getting a full leaf and putting it in to something old, aerodynamic and light like a CRX, insight, gutted out prius etc... and getting a much better range on the single battery, playing around with 2 low value maybe even free cars instead of cutting up one that will cost you at least $12000 to get (low value of 2011s). Even the 90s audi A4 has a better cdA than the leaf and you can find many of them with high repair bills that people will almost give away. I'm sure with no cooling needed and skinny tires you can get great aero out of it.

My aux pack would only weigh 200 lbs.. associated accessories would weigh < 100 lbs. no new tires or suspension. That was not the argument I was expecting.

hillzofvalp said:

My aux pack would only weigh 200 lbs.. associated accessories would weigh < 100 lbs. no new tires or suspension. That was not the argument I was expecting.

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Electrically speaking, if you run the auxiliary pack in parallel to the existing pack, all the computer should see is a pack with higher capacity. Now, whether or not that works with how Nissan has wired their pack is a different story, and it would require that your auxiliary pack runs at the same voltage as the main pack.

I don't think the car will see anything but "higher" efficiency. During charge mode, it might be confused, because it probably has a safety counter for that.

If you went down a mountain in aleaf, it wouldn't tell you that you can't drive anymore.. same thing with a parallel pack. It's only in the case when you charge at 50kW (and it takes twice as long to reach 50%) that the computer would freak out, if it has the safety mechanism. Solution: charge aux pack separate.

I am probably wrong. How did the ingineer system work? it charged the pack while driving? that's essentially the same effect as a parallel pack