Reverse Engineering A Nissan Leaf Battery Pack

Batteries wear out. If you are an electric vehicle enthusiast, it’s a certainty that at some time in your not-too-distant future there will be a point at which your vehicle’s batteries have reached the end of their lives and will need to be replaced. If you have bought a new electric vehicle the chances are that you will be signed up to a leasing deal with the manufacturer which will take care of this replacement, but if you have an older vehicle this is likely to be an expensive moment.

Fortunately there is a tempting solution. As an increasing number of electric vehicles from large manufacturers appear on our roads, a corresponding number of them have become available on the scrap market from accident damage. It is thus not impossible to secure a fairly new lithium-ion battery pack from a modern electric car, and for a significantly lower price than you would pay for new cells. As always though, there is a snag. Such packs are designed only for the cars they came with, and have proprietary connectors and protocols with which they communicate with their host vehicle. Fitting them to another car is thus not a task for the faint hearted.

Hackaday reader [Wolf] has an electric truck, a Solectria E10. It has a set of elderly lead-acid batteries and would benefit hugely from an upgrade to lithium-ion. He secured a battery pack from a 2013 Nissan Leaf electric car, and he set about reverse engineering its battery management system (BMS). The Solectria will use a different battery configuration from the Leaf, so while he would like to use the Leaf’s BMS, he has had to reverse engineer its protocols so that he can replace its Nissan microcontroller with one of his own.

His description of the reverse engineering process is lengthy and detailed, and with its many photos and videos is well worth a read. He employs some clever techniques, such as making his own hardware simulation of a Li-ion cell so that he can supply the BMS known values that he can then sniff from the serial data stream.

We’ve covered quite a few EV batteries here at Hackaday. Quite recently we even covered another truck conversion using Leaf batteries, and last year we featured a Leaf battery teardown. We’ve not restricted ourselves to Nissan though, for example here’s a similar process with a Tesla Model S pack.

Evolving our Ideas to Build Something That Matters

When Jeffrey Brian “JB” Straubel built his first electric car in 2000, a modified 1984 Porsche 944, powered by two beefy DC motors, he did it mostly for fun and out of his own curiosity for power electronics. At that time, “EV” was already a hype among tinkerers and makers, but Straubel certainly pushed the concept to the limit. He designed his own charger, motor controller, and cooling system, capable of an estimated 288 kW (368 hp) peak power output. 20 lead-acid batteries were connected in series to power the 240 V drive train. With a 30-40 mile range the build was not only road capable but also set a world record for EV drag racing.

jb-straubel-porsche
The “Electric Porsche 944” – by JB Straubel

The project was never meant to change the world, but with Tesla Motors, which Straubel co-founded only a few years later, the old Porsche 944 may have mattered way more than originally intended. The explosive growth between 2000 and 2010 in the laptop computer market has brought forth performance and affordable energy storage technology and made it available to other applications, such as traction batteries. However, why did energy storage have to take the detour through a bazillion laptop computers until it arrived at electro mobility?

 

You certainly won’t find that grail of engineering by just trying hard. Rather than feverishly hunting down the next big thing or that fix for the world’s big problems, we sometimes need to remind ourselves that even a small improvement, a new approach or just a fun build may be just the right ‘next step’. We may eventually build all the things and solve all the problems, but looking at the past, we tend to not do so by force. We are much better at evolving our ideas continuously over time. And each step on the way still matters. Let’s dig a bit deeper into this concept and see where it takes us.

Continue reading “Evolving our Ideas to Build Something That Matters”

After the Prize: What’s Next for the Light Electric Utility Vehicle

Winner of the third place in last year’s Hackaday Prize was [Chris Low]’s Light Electric Utility Vehicle. In case you think that once a Hackaday Prize is in the bag then that’s it and the project creator packs up and goes home, [Chris] dispels that idea, he’s invested his winnings straight back into his project and posted his latest progress on an improved Mk3 model.

Light Electric Utility Vehicle, 2015-style
Light Electric Utility Vehicle, 2015-style

We first covered the Light Electric Utility Vehicle back in June 2015 when it was first entered for the 2015 Hackaday Prize. The aim was to produce a rugged and simple small electric vehicle that could be powered by solar energy and that was suitable for the conditions found in South Sudan, where [Chris] works. The vehicle as we saw it then was an articulated design, with chain drive to bicycle-style wheels. The Mk3 version by comparison has lost the articulation in favour of rack-and-pinion steering, has in-hub motors instead of chain drive, and now features coil-spring suspension. You might comment that it has lost some of its original simplicity and become something more like a conventional electric UTV, but along the way it has also become more of a practical proposition as an everyday vehicle.

You can follow the entire build log on the Light Electric Utility Vehicle’s project page on hackaday.io, and below the break have a look at [Chris]’s video showing it in action. Continue reading “After the Prize: What’s Next for the Light Electric Utility Vehicle”

London Tries Smart Cities

What’s a smart city? According to Wikipedia, a smart city uses ICT (information and communication technologies) to enhance quality, performance, and interactivity of urban services while reducing costs and resource consumption. Hackers have been using technology to enhance all sorts of things for years.

London is joining forces with cities across Europe to demonstrate smart city technology, mostly in the Royal Borough of Greenwich. The project is in conjunction with the EU Horizon 2020 project, which is still soliciting proposals for funding. It seems like some Hackaday readers–especially in the EU–ought to have some ideas worth funding.

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Hackaday Prize Entry: Tearing Down A Tesla

We’ve seen a few people tear down the drive trains from electric vehicles like the Nissan Leaf, Prisuses, or the Chevy Volt. We’ve also seen someone tear down the battery pack found in a Tesla Model S. What we haven’t seen until now is a reverse engineering of the Tesla Model S drive train.

A fortuitous circumstance landed [Michal] the crown jewel of the Tesla Model S – the 310kW, 590Nm drive train. Exactly how and where [Michal] landed this gigantic powerful motor is a question that remains unanswered, and the question unasked. We might not want to know.

Now that he has a motor, the name of the game is figuring out how to drive it. Usually that means capturing data from the CAN bus and replaying that data. This isn’t what [Michal] is doing; instead, he’s using a motor controller he developed for the Chevy Volt and Toyota Prius. It’s going to be a lot of work, but that’s only because these gigantic EV motors and controllers are pretty rare on the used market now. Give it a few years, and the work [Michal] is putting in now will pay off in hundreds of DIY electric vehicles.


The 2015 Hackaday Prize is sponsored by:

Hackaday Prize Entry: An Electric Vehicle From Recycled Parts

In the future, just about everyone will be driving an electric car. We’re seeing the beginnings of this, and that means electrics and hybrids are showing up in junk yards. What does that mean? Tons of big batteries and powerful motors to build an electric vehicle from recycled parts.

A few years ago, someone exceptionally smart did the math on the environmental friendliness of different makes of vehicles from cradle to grave. The most environmentally friendly car to buy wasn’t a Prius, Leaf, or Tesla, but a used car; an old Civic or Rabbit. The logic makes sense – after two or three hundred thousand miles under its timing belt, the Civic or Rabbit has already paid the cost of forging the body and refining the plastic. Obviously, then, the most environmentally friendly car would be reusing the batteries and motor out of a newer hybrid.

For his Hackaday Prize build, [mauswerkz] is taking a 2001 BMW 330ci coupe and replacing the motor and transmission with some salvaged EV equipment. In this case, it’s the transmission and inverter from a Lexus GS450h and the batteries from a Chevy Volt ‘Extended Range’. Where the magical junkyard [mauswerkz] is pulling this equipment out of is anyone’s guess, but he did it. Maybe you can too.

So far, [mauswerkz] has the charger out of the Chevy Volt hooked up to the inverter and transmission from the Lexus and is making stuff turn. It’s only running at 200V instead of the final voltage of 650, but it’s enough for a proof of concept. Now it’s just a matter of stuffing everything inside the BMW.

Of course going to a junk yard isn’t the only way to get an EV. The more enterprising builder might want to build their own EV completely from scratch, starting with a block of foam. Yes, it even looks better than the BMW.


The 2015 Hackaday Prize is sponsored by:

Hackaday Prize Entry: Building A Car, From Scratch, Out Of Foam

Want an impressive example of what a few people can do in a garage? How about building an electric car, from scratch, starting with a gigantic chunk of foam?

The Luka EV from [MW Motors] had a few project aims: it should be all-electric, naturally, with a top speed of 130km/h or 80mph. It should have a range of over 300km, and it should look good. That last line item is tricky; it’s not too hard to build an electric car, but to make one look good is a challenge.

The design of the car actually started out as a digital file. A large block of foam was acquired and carefully carved into the desired shape. This foam is covered fiberglass, and parts are pulled off this fiberglass mold. This is a great way to do low-volume production – once the molds are complete, it’s a relatively simple matter to build another body for a second Luka EV.

With all the lights, accessories, windows, and trim installed, it’s time to put this body on a chassis. This was welded out of square tube and serves as a test rig that can be independent of the mess of fiberglass. In the chassis are batteries, suspension, motor controllers, and wheels loaded up with hub motors. It works well, even with one motor.

There’s a lot more to this project, including a great guide on building a road legal car in the UK. The team isn’t based in the UK, but it’s a much more friendly environment for ‘small series’ vehicles. The requirements are easy to meet – “have a horn”, for example – but there are a lot of them.

Already the car is beautiful, and that’s just with it sitting on a trailer. We can’t wait to see this thing hit the road.


The 2015 Hackaday Prize is sponsored by: