A 2011 Leaf with a 60 kWh battery pack and 400 km driving range

When introduced to the world the 2011 Leaf had a 72 mile driving range thanks to a 24 kiloWatt-hour battery pack (equating to 115 kilometers). While this was good enough for typical daily driving, humans of course want more driving range on our electric cars. Today it’s relatively easy to find a 60 kiloWatt-hour electric car for approximately the price of the 2011 Leaf, and many electric car owners are upgrading as a result. But that leaves behind plenty of good condition electric cars whose only sin is having a small battery pack.

In theory any of the electric cars could be designed to allow for battery pack upgrades. The manufacturers should have recognized that in N years battery capacity upgrades will be feasible, and electric car owners will want an upgrade. But few or none of the manufacturers have made that available.

Attached to the bottom of this is a video by an individual who claims to have done these things:

Installed a 40 kWh LEAF pack into a 2011 Leaf
Added a 24 kWh pack in the trunk area to run in concert with the main pack

The result is about 55+ kWh of usable capacity, and the dashboard reads nearly 400 kilometers of estimated range. For a 2011 Leaf that much range has got to be a jaw dropping experience.

Throughout the video the presenter describes what he has done. And it seems he is operating a business selling these upgrades to customers. His goal for this video was in preparation for a showing at the Frankfurt international motor show currently underway.

While he named a number of issues in the course of the video, the primary issue seems to be the hackery required for the car to recognize the larger battery pack. What he describes is that Nissan designed the system such that the battery pack is “paired” with the car using an identification code. When a battery pack is installed, if the car does not see the correct identification code the car displays an error message and refuses to operate.

Manufacturers designing systems that detect and reject replacement parts

This means replacing a Nissan Leaf battery pack is not like replacing the AA batteries in a portable radio. It’s more like the regime that Apple is beginning to enforce regarding battery packs on iPhones. In that case, it has long been possible to replace an iPhone battery with a 3rd party battery, so long as you’re willing to do some unsupported surgery to gain physical access to the battery pack. But with the iPhone Xs, XR and Xs Max, replacing the battery results in a warning message that the battery is unsupported and could cause damage. It turns out that Apple implemented cryptographic pairing between the iPhone and the battery for some unknown reason – it cannot be for the customer benefit – and it seems that Apple instead wants to prevent independent repair shops from repairing iPhones.

Apple’s most recent products are designed with “Security” chips that enforce cryptographic pairing between the security chip and other chips in the device. It’s claimed this is for customer security, so that nefarious 3rd parties cannot hack into a phone or computer to steal data. But it also hinders the ability of folks to repair or upgrade their computers or cell phones.

In the video the presenter talks about a similar issue. That there are devices available to Nissan dealers that can pair a battery with a Leaf. But an independent person does not have access to those devices.

The Right To Repair, and the Right To Tinker

There is a Right To Repair issue here – if we cannot repair or replace every part in our devices, do we truly own the device? Modern business practice in many cases is to instead make your customers captive to your service, and to limit their freedom of choice.

Shouldn’t it be possible for a Nissan Leaf owner to replace their battery pack? There have been generations of shade tree mechanics playing with cars in their garage, replacing engines and doing all kinds of modifications. They had every freedom to tinker with their cars. Why shouldn’t electric car owners have the same freedom?

For that matter, what kept alive the dream of electric cars were shade tree mechanics throwing away engines and installing electric motors into what had been gasoline cars. My former car, a 1971 VW Karmann Ghia conversion, is just one example among thousands. The value of tinkerers working in their garage is enormous. Tesla Motors would not exist today if it were not for a community of tinkerer/entrepreneurs who coalesced into the founding team of Tesla Motors. JB Straubel literally got his start in electric vehicles by tinkering with DIY conversion projects.

Fooling a 2011 Nissan Leaf to accept a bigger battery pack

The work-around discussed in this video is a “CAN Man-in-the-Middle” device. The phrase “man-in-the-middle” refers to a sort of security attack to insert modified messages in the middle of a computer-to-computer conversation. The attack works by inserting a 3rd computer in the middle between the two computers, forming a computer-to-MIDDLE-to-computer arrangement. The MIDDLE computer interjects information into the communication for some purpose.

This attack can produce negative results – for example if a man-in-the-middle service were to interfere with your attempt to log into a banking website. But in this case it is producing a positive benefit.

What he did was to study the CAN messages – CANBUS is a data communications protocol widely used in cars – between a Leaf battery pack and the car. His man-in-the-middle device replays those messages with a few changes necessary to fool the car into accepting the battery pack.

That – and some mechanical engineering – is what it takes to get a 2011 Leaf to do the seemingly impossible thing of housing a 60 kiloWatt-hour battery pack, and to support a 400 kilometer driving range.

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About David Herron

David Herron is a writer and software engineer living in Silicon Valley. He primarily writes about electric vehicles, clean energy systems, climate change, peak oil and related issues. When not writing he indulges in software projects and is sometimes employed as a software engineer. David has written for sites like PlugInCars and TorqueNews, and worked for companies like Sun Microsystems and Yahoo.