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Dala's Leaf buildthread (2015 Nissan Leaf)

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  • Dala
    started a topic Dala's Leaf buildthread (2015 Nissan Leaf)

    Dala's Leaf buildthread (2015 Nissan Leaf)

    So I thought I might start a project thread on this car, that wasn’t supposed to be a project.

    I recently picked up a commuter, 2015 ZE0 24kWh Nissan Leaf, with 5k km on it. It has extremely low range, the guess-o-meter(GOM) on the dash says 160km, but as soon as you start driving it you are lucky if you manage 20km. Pretty shite for 15 000€ (Yes these cars are extremely expensive in Finland!)

    Due to this being an USA model imported to Europe, so I apparently don’t have any battery warranties in place. I also wasn’t fully aware that the battery was this bad, so if I could go back in time I would have never bought this car.
    But nevertheless, let’s stay positive and start fixing this car up.
    Here’s a picture of the bog standard car. Not much to say really. Was a wet day.


    The car seems to deplete about 3-4kWh of battery, and then promptly report it as empty. This is strange, since it’s supposed to be a 24kWh battery! Charging it back up also goes suspiciously fast, so something is indicating that one or more cells are dragging the whole pack down.

    It also goes into turtle mode from time to time, and with a handful of dash warnings and load reductions.


    So next order of business is to start diagnosing the battery. The CAN communication needs to be forwarded to a phone running the LeafSpy Pro app. This is achieved with a bog standard v1.5 ELM327 Bluetooth OBD2 dongle. Note that it has to be v1.5, the cut down v2.1 won’t work.
    So here are some screenshots from a fully charged battery. Notice anything suspicious?


    So as you can see, the cellpair 57&58 are down 150mV from the rest of the cells. The Nissan battery management system utilizes passive balancing of the lithium cells using shunt resistors. Unfortunately, these are not very beefy, and can only bypass a few mA when charging. So if any cells have drifted far enough, and ESPECIALLY when replacing cells, you need to pre-balance them before you insert them into the pack.

    So a manual rebalance of 57&58 seems like the best way forward. Later down the line I can always replace them, but let’s start with a rebalance.

    First thing to do is disconnect the 12V battery in the front, or else the control system will freak out when I start disconnecting HW stuff


    Next thing to disconnect is the fuse from the HVDC pack. The fuse is located under the floor, and can be accessed via a panel in the backseat floor.


    After pulling the fuse, it is now safer to work under the car, and next step is to disconnect the high voltage cabling from the pack. Notice that I’m wearing Class 0 high voltage gloves each time I’m near anything labelled orange.


    Started propping up the car high with multiple failsafes.


    Removed splash plates. There are three of them.


    Here are the battery high voltage connections and CAN cabling, disconnected them. They were quite hard to figure out how to open.


    I then put pressure on battery with some wood and four jacks, started loosening bolts. There were 18mm, 8 in total.


    Built a dolly to be able to slide the pack around. The battery weighs circa 280kg!


    Lowered battery onto dolly


    Then it was very easy to slide the battery out


    For some reason they don’t want you to be able to open it easily. It was glued shut, but with the help of some prying and cutting tools, it eventually came apart


    Here is the battery exposed. Several stacks of modules, totalling at about 400V DC. Safety first, so gloves on at all times now!


    I then started to charging. Decided to take it slow due to not knowing much about the Li-MnO2 cells (I'm more of an 18650 guy ) Since the cellpair 57&58 was at the absolute bottom of the stack, they will be extremely hard to get to. I don't want to disassemble the pack, so I improvised some sticky leads with hard drive magnets inside alligator clips. That way I can just lower them down into the pack, and they will stick to the terminals.


    I then hooked up a bench supply, set it to 8.4V and connected it to the outer terminals of the 2S cell. I am lucky that the rest of the pack is at 4.00V cell average, so I won’t have to worry about CC/CV switchover, just CC charging up to 4V (8V effective due to 2S). As charge current limiter, I set it to 0.3Amps, to keep temps and everything nice and smooth.


    I also disconnected some of the BMS leads, don't know if this was necessary, and hope I don't break the BMS by piggyback charging this way.

    After 18h of charging, the cells are up from 3.60V -> 3.95V, so just a few more mV to go!

  • SBC
    replied
    Originally posted by TheCaptain View Post
    My experience with Swedish people is that they are very good at speaking English so...
    Except that she was a Finn. She asked something in Swedish, so I just told her that I can't understand what she said, so she got all grumpy for some reason.
    I have no problem with my friends who are FennoSwedes, as they have every other word in Finnish

    Leave a comment:


  • TheCaptain
    replied
    My experience with Swedish people is that they are very good at speaking English so...

    Leave a comment:


  • SBC
    replied
    Last time I was anywhere near there, I was trying to buy cigarettes from some small store in Vöyri and I had hard time to find common language with the clerk. He refused to speak Finnish and I can't speak Swedish. In the end I got those cigarettes.

    Leave a comment:


  • Kaktus
    replied
    Hej Dala, this is a much more interesting read than I imagined! Well done on getting the Leaf recommissioned, good job showing us it actually can be done by an avid DIYer.

    Btw, didn't realize you're in Replot, might try and come over at some point for a wee chinwag when I'm in Finland next time visiting my parents up in Jakobstad.

    Leave a comment:


  • Dala
    replied
    Thanks guys

    I went and added the garage to the Plugshare map, in-case someone is close to getting stranded in the middle of the Kvarken world-heritage archipelago





    It sure is an EV dead-zone out here

    Leave a comment:


  • MHR1294
    replied
    Good luck man

    won't be long before more and more independents pop up for this!

    Leave a comment:


  • TheCaptain
    replied
    Congrats man and good luck with the company!

    Hope you have time to spare for wrenching on cars and telling us about it, I'd love to see an update on the Mazda and the Leaf!

    Leave a comment:


  • Dala
    replied
    I'm in the local paper!


    I'm currently in the process of starting up my own company, aiming to be the first in Finland to offer 3rd party EV battery service/swap/upgrades. It's gonna be a wild ride!

    Leave a comment:


  • MHR1294
    replied
    I didn't know there was only 3% between A and B! That's useful info for me The winter tyres on my Alto are B rated I'm sure of it.

    I drove an electric car for the first time at work the other week, it was a Renault ZOE. it's actually not weird to drive at all. I really liked it.

    That's good to make a charging point public! Nobody would ever do that here in the UK, they're all so selfish. lol

    Leave a comment:


  • Dala
    replied
    Originally posted by MHR1294 View Post
    So Italy cells are better? Maybe they've been subject to the Italian equivalent of the Italian Tune-up!

    I guess untested cells is too risky - they might be better but it's the "what if it isn't" that will be eating you?
    Yes, most likely gonna chuck in the Italy cell any day now, just waiting for the weather to turn completely.

    Status update on the Leaf. It's been cold here...

    I assembled the OpenEVSE unit. Now I need to decide where I mount it. I will most likely make it open to the public on all charging apps, since it probably goes in the middle of nowhere


    We have also had a fair bit of snow


    Due to all the cold and snow, I decided to get some proper snowtires instead of the all-season ones that came with the car.

    I settled on "Nokian Hakkapeliitta R3"
    in the format: 205/55 R 16 94 R XL


    This is the tyre that Nokian primarily recommends for electric cars, since it's a low rolling resistance and wont impact the range. On the sticker they are branded as B on the economy gauge. The efficiency step between A - B - C goes something like 100% - 97% - 90%, so there is a huge benefit from stepping up from C to B. From B to A the 3% efficiency step is not as noticeable.

    Leave a comment:


  • MHR1294
    replied
    it was only -5 here yesterday and we had some frozen rain. My mirrors nearly didn't fold out so I've left them out so they don't jam in the morning.

    So Italy cells are better? Maybe they've been subject to the Italian equivalent of the Italian Tune-up!

    I guess untested cells is too risky - they might be better but it's the "what if it isn't" that will be eating you?

    Leave a comment:


  • Dala
    replied
    Car is working fine in -21*C Hope it doesn't go towards -30 this winter...
    I now have some capacity numbers to share, and time to make a decision.
    Test, 5Amp discharge, from 4.1V -> 3.3V
    USA cell: 39,77Ah
    Italy cell: 43,30Ah

    So presuming I have an USA cell from the same batch, If I upgrade to the Italy cell, I'd get a 9% range increase! I could also try looking for better cells, but most people just sell untested cells :/ Hmm...

    Leave a comment:


  • MHR1294
    replied
    that looks like an excellent tool!

    It's going to get you exactly the results you want, which is ideal

    Leave a comment:


  • Dala
    replied
    This showed up in the mail.



    Now I can start capacity testing the big Leaf cells! I settled on the reasonably priced Antimatter charger/discharger. It can do 10A charge and 7A discharge. I started it a bit more gently, and the test is going to take some time. I set the upper voltage to 4.1V, and discharge down to 3.0V. If I had set the upper voltage to 4.2, it would ofcourse net more capacity, but as long as I do the same for each cell I test, I will come to a conclusion what cell would be best to use in the car.

    Leave a comment:

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