[Daniel] was recently featured here for his work in improving the default charging mode for the Nissan Leaf electric vehicle when using the emergency/trickle charger included with the car. His work made it possible to reduce the amount of incoming power from the car, if the charging plug looked like it might not be able to handle the full 1.2 kW -3 kW that these cars draw when charging. Thanks to that work, he was able to create another upgrade for these entry-level EVs, this time addressing a major Leaf design flaw that is known as Rapidgate.
The problem that these cars have is that they still have passive thermal management for their batteries, unlike most of their competitors now. This was fine in the early ’10s when this car was one of the first all-electric cars to market, but now its design age is catching up with it. On long trips at highway speed with many rapid charges in a row the batteries can overheat easily. When this happens, the car’s charging controller will not allow the car to rapid charge any more and severely limits the charge rate even at the rapid charging stations. [Daniel] was able to tweak the charging software in order to limit the rapid charging by default, reducing it from 45 kW to 35 kW and saving a significant amount of heat during charging than is otherwise possible.
While we’d like to see Nissan actually address the design issues with their car designs while making these straighforward software changes (or at least giving Leaf owners the options that improve charging experiences) we are at least happy that there are now other electric vehicles in the market that have at least addressed the battery thermal management issues that are common with all EVs. If you do own a Leaf though, be sure to check out [Daniel]’s original project related to charging these cars.
The Nissan Leaf is the best-selling electric car of all time so far, thanks largely to it being one of the first mass produced all-electric EVs. While getting into the market early was great for Nissan, they haven’t made a lot of upgrades that other EV manufacturers have made and are starting to lose customers as a result. One of those upgrades is charge limiting, which allows different charging rates to be set from within the car. With some CAN bus tinkering, though, this feature can be added to the Leaf.
Limiting the charging rate is useful when charging at unfamiliar or old power outlets which might not handle the default charge rate. In Europe, which has a 240V electrical distribution system, Leafs will draw around 3 kW from a wall outlet which is quite a bit of power. If the outlet looks like it won’t support that much power flow, it’s handy (and more safe) to be able to reduce that charge rate even if it might take longer to fully charge the vehicle. [Daniel Öster]’s modification requires the user to set the charge rate by manipulating the climate control, since the Leaf doesn’t have a comprehensive user interface.
The core of this project is performed over the CAN bus, which is a common communications scheme that is often used in vehicles and is well-documented and easy to take advantage of. Luckily, [Daniel] has made the code available on his GitHub page, so if you’re thinking about trading in a Leaf for something else because of its lack of features it may be time to reconsider.
The only thing limiting the range on any electric vehicle isn’t really battery technology, but cost. Customers don’t want to pay more money for an electric car or van that does essentially the same thing as one with an internal combustion engine. This in turn limits the amount of batteries manufacturers put in their cars. However, with enough money, and thus enough batteries, electric cars can get whatever range you want as [Muxsan] shows with his Nissan e-NV200 that gets over 400 miles kilometers on a single charge.
The Nissan e-NV200 is a battery electric vehicle (also available as a badge-engineered Chevrolet van in North America) with a drivetrain from the Nissan Leaf. This means that all of the components from the Leaf basically plug-and-play in this van. [Muxsan] took an extra 45 kWh of batteries and was able to splice them in to the existing battery pack, essentially tripling the capacity of the original 24 kWh pack. Some work was needed to the CAN bus as well, and the car’s firmware needed to be upgraded to reflect the new battery pack, but a relatively simple modification otherwise, all things considered.
While watching the video [Muxsan] also notes how much empty space there is all around the van, and Nissan could have easily upgraded the battery pack at any time to allow for more range. It also took the car 10 hours on a 6 kW charger to charge completely, but that’s not unreasonable for 430 miles of range. If your high voltage DC chops are up to snuff, it’s not impossible to find old Leaf batteries for other projects, too.
Perching on surfaces happens electrostatically. The team used an electrode patch with a foam mounting to the robot. This allows the patch to make contact with surfaces easily even if the approach is a few degrees off. This is particularly important for a tiny robot that is easily affected by even the slightest air draft. The robots were designed to be as light as possible — just 84mg — as the electrostatic force is not particularly strong.
It’s estimated that perching electrostatically for a robot of this size uses approximately 1000 times less power than during flight. This would be of great use for surveillance robots that could take up a vantage point at altitude without having to continually expend a great deal of energy to stay airborne. The abstract of the research paper notes that this method of perching was successful on wood, glass, and a leaf. It appears testing was done with tethers; it would be interesting to see if this technique would be powerful enough for a robot that carries its own power source. Makes us wonder if we ever ended up with tiny flyers that recharge from power lines?
Dev boards sporting a powerful ARM microcontroller are the future, despite what a gaggle of Arduino clones from China will tell you. Being the future doesn’t mean there’s not plenty of these boards around, though. The LeafLabs Maple has been around since 2009, and is a fine board if you want all that Processing/Wiring/Arduino goodies in a in an ARM dev board. The Maple has been EOL’d, and that means it’s time for a few new boards that build on what LeafLabs left behind.
The microcontroller inside this Maple Mini clone is the STM32F103, a 32-bit ARM Cortex-M3 running at 72 MHz with 128K of Flash and 20K of SRAM. That’s enough for just about everything you would want to throw at it. It also follows the pinout of the original Maple Mini, and the team also has a version that’s a slight improvement of the original Maple.
[Jay]’s Chevy S-10 electric conversion needed new batteries. The conversion was originally done with a bank of lead acids underneath the truck bed. With lithium battery factories so large they can boost an entire state’s economy being built, [Jay] safely assumed that it just wasn’t worth it to spend the money to replace it with a new set of the same.
You should remember the beginnings of this story from our coverage nearly a year ago. Being the kind of clever you’d expect from someone who did their own EV conversion, he purchased a totaled (yet nearly new) Nissan Leaf with its batteries intact. It took a little extra work, but after parting out the car and salvaging the battery packs for himself he came out ahead of both a new set of replacement lead acids and an equivalent set of lithium cells.
He has just completed the first test drives with the conversion, having built 48 Leaf cells into blocks resembling the volumes the old batteries occupied. He had to add some additional battery management, but right-off-the-bat, the conversion netted him more amps and 650lbs (295kg) less weight for the same power. Nice!
We linked to all the posts tagged leaf on [Jay]’s blog. There’s a lot going on, and the articles aren’t all linked to each other. It’s a really cool build and there are definitely tricks to learn throughout the whole process. If you have an hour to kill, [Jay] recorded the entire 26-hour process in a 66-minute video that is embedded below. It’s fun to watch him build up and mount the different modules and gives you a deep appreciation for his devotion to the project.
[Jay] got a pretty good deal on a low milage Nissan Leaf battery. Unfortunately, it came wrapped in a wrecked Nissan Leaf. There are more and more electric cars on the road each year, and that means there are more cars coming off the road as well due to accidents. Electric cars are specifically designed to protect their batteries, so as we’ve seen before with Tesla vehicles, a salvage car often will still contain a serviceable battery pack. [Jay] used this knowledge to his advantage, and walks us through his experience buying, testing, and dismantling Hoja, his very own salvage Leaf.
[Jay] set up an account on Copart, an auto salvage auction website here in the USA. “Live” online Auto auctions tend to work a bit differently than E-bay, so [Jay] walks us through the process of buying the car, and gives some tips for getting through the process. [Jay’s] particular car was delivered to him on a trailer. It had been rear ended so hard that the rear tires were not usable. The car was also electrically dead. Thankfully, the electrical problems turned out to be a discharged 12 volt accessory battery. A quick charge of the accessory battery caused the Leaf to spring to life – and display a ton of trouble codes. [Jay] cleared the codes with his trusty OBD II scanner, and the car was ready to drive, at least as much as a wrecked car can drive. It did move under its own power though – with the rear end riding on dollies.
Now that the battery was known to be good, [Jay] set about liberating it from its crushed Leaf cocoon. Nissan’s service manual assumes one would be doing this with a lift. [Jay] had no such luxuries in his driveway, so he used 3 floor jacks to lower the 600 lb battery and dollies to pull it out from under the car.