You could have rearranged the battery to ballance them out while you had it open. To those you removed, put them together in parallel, all positive and negative together while you change and discharge to repair them. Good job.
it is one big chain to make up 400v battery. It makes no difference where you place the weaker ones, from performance point of view. So rearranging would be just a waste of time and energy. Only difference is, that under heavy load(driving and fast charing whole day) the rear stack gets hotter.
Thanks for the video! Could have been better and more detailed though. Also in addition to the one mistake you mentioned I saw a couple more: Nissan dictates that the technician gets each module to within 2 mV of each other before starting the car. It has something to do with how the computer balances the pack eventually. Generally replacement modules are shipped with a 50% charge. The second mistake you made (and you did partly touch on this) is that you did not replace enough of the old modules. Since you were pressed for time in that shop I can understand the rush to get the car back together though. What I would have done if time was not an issue was to go back to the module supplier you found and buy as many modules as you need to replace them all, or as many as you can afford to. Weak cells and new cells seldom work very well together. Battery packs are just that way unfortunately. Last I checked new modules on Alibaba were about $360 each plus shipping. No idea what their capacity is though. But no doubt it is a lot more than what your old cells are doing now.
In reality, after driven with this 85% SoH combined with the 70% ones, they worked together very well. Stronger ones due to lower internal resistance automatically even make up for some of the weakness of others. This is why it did not really matter that I did not get them balanced so precisely. Under load and usage - it's such a big pack that stuff automatically balances out very quickly. The new modules always stuck out but the difference wasnt so huge, that charging would be issue. In the end, all this worked without any issues until I bought bigger battery and sold all these modules.
2:03 this looks exactly like my Nissan Leaf 40kWh Tekna from 2019: I have the same type of damage, but its only visible below 20% Leafspy SoC. I have contacted the dealership about this, who sold me the vehicle: claiming it had an good battery. But because of this heat damage, I can't use about 4kWh as it went into turtle mode at 12.4% Leafspy SoC. The dealership going do an battery test, and I will make sure to drop the car off with 15% or lower Leafspy SoC. Even when it means, driving circles around the car dealership area. To run down the battery even more, before dropping it off.
I would also recommend taking screenshots of the leafspy screen when under highspeed driving there's very visible ditch in the cell voltage columns and big number in the corner of min-max cell voltage difference. And do not say you took them but that "you let expert check and here's proof of some very shot cell modules in the battery" - and say you got shown how big the voltage difference is. And that is way above normal. I think the service manual test procedure is to put AC/heat on to full blast windows open, fullbeams on and let it run, and the difference should not be more than 40mv.
@@gelisob I did, but the Nissan dealership doesn't take any Leafspy screenshot seriously. So I'm going be dropping the car of with 15% Leafspy SoC, maybe even a little lower. And before doing, I will also do some more aggressive driving. As during my testing, I had the voltage difference rise up to 612mV before Turtle Mode kicked in. And I was at 12.4% Leafspy SoC when that happened. I reached during aggressive driving aka highway speeds, going full throttle. It showed at 20% already more than 100mV difference, but that was while using full throttle. I recorded the graph from Leafspy actually, so that I could see it afterwards. But I think, when I drop the car while Leafspy already showed the heat damage aka weak cells. Then Nissan battery test, should show it as well. I have heard, the outcome is very similar to Leafspy. www.speakev.com/threads/finding-out-the-real-usable-capacity-aka-weak-cells.179769/unread
This pack is long sold, but the benefit was to restore it's general state. The pack was at around 75% but because of the weak cells - it made everything suffer in cold and when used at higher speeds. The weak cells voltage sagged down and then battery controller decided that too much of the back is below norms and stopped working. So the benefit was, that it was back to usable 75% or a little more.
The screenshots are from widely used Leaf Spy app. Has free version. Only on Android. You need compatible OBD2 bluetooth/wifi adapter too. Can be found around 10$.
Average person probably does not drive 300 000km in few years, so, that kind of maintenance is not needed then either :) And this is the worst EV, other EV's have battery cooling solutions that prevent such uneven heating to happen.
Modern EVs have battery cooling / heating functions to manage temperature and maximise battery life / performance. No longer an issue, unless you want to buy super-cheap, used, semi-broken EVs to repair!
![62kWh isolation problem [part 1]](http://i.ytimg.com/vi/Ug9YdxXqkJ4/mqdefault.jpg)
Great video! Thanks for sharing your experience Gelisob! Greets from Białystok, Poland.
Great video! :) And wow that battery was rusty, I've never seen one that bad yet!
Thanks :) I'm guessing people in charge of salt on roads are more liberal here than they get to be over there where your cars are driving around :P
@@gelisob it's weird, doesn't in Finland, or Norway use salt as in Eesti? Even in Belgium they use it a lot on those few weeks going below 0.
You could have rearranged the battery to ballance them out while you had it open.
To those you removed, put them together in parallel, all positive and negative together while you change and discharge to repair them.
Good job.
it is one big chain to make up 400v battery. It makes no difference where you place the weaker ones, from performance point of view. So rearranging would be just a waste of time and energy. Only difference is, that under heavy load(driving and fast charing whole day) the rear stack gets hotter.
In Latvia in such cases (rusty bolts) etc we use "magic" Russian words which helps :D
Thanks for the video! Could have been better and more detailed though. Also in addition to the one mistake you mentioned I saw a couple more: Nissan dictates that the technician gets each module to within 2 mV of each other before starting the car. It has something to do with how the computer balances the pack eventually. Generally replacement modules are shipped with a 50% charge. The second mistake you made (and you did partly touch on this) is that you did not replace enough of the old modules. Since you were pressed for time in that shop I can understand the rush to get the car back together though.
What I would have done if time was not an issue was to go back to the module supplier you found and buy as many modules as you need to replace them all, or as many as you can afford to. Weak cells and new cells seldom work very well together. Battery packs are just that way unfortunately. Last I checked new modules on Alibaba were about $360 each plus shipping. No idea what their capacity is though. But no doubt it is a lot more than what your old cells are doing now.
In reality, after driven with this 85% SoH combined with the 70% ones, they worked together very well. Stronger ones due to lower internal resistance automatically even make up for some of the weakness of others. This is why it did not really matter that I did not get them balanced so precisely. Under load and usage - it's such a big pack that stuff automatically balances out very quickly.
The new modules always stuck out but the difference wasnt so huge, that charging would be issue. In the end, all this worked without any issues until I bought bigger battery and sold all these modules.
Great video.
2:03 this looks exactly like my Nissan Leaf 40kWh Tekna from 2019: I have the same type of damage, but its only visible below 20% Leafspy SoC.
I have contacted the dealership about this, who sold me the vehicle: claiming it had an good battery. But because of this heat damage, I can't use about 4kWh as it went into turtle mode at 12.4% Leafspy SoC.
The dealership going do an battery test, and I will make sure to drop the car off with 15% or lower Leafspy SoC. Even when it means, driving circles around the car dealership area. To run down the battery even more, before dropping it off.
I would also recommend taking screenshots of the leafspy screen when under highspeed driving there's very visible ditch in the cell voltage columns and big number in the corner of min-max cell voltage difference. And do not say you took them but that "you let expert check and here's proof of some very shot cell modules in the battery" - and say you got shown how big the voltage difference is. And that is way above normal. I think the service manual test procedure is to put AC/heat on to full blast windows open, fullbeams on and let it run, and the difference should not be more than 40mv.
@@gelisob I did, but the Nissan dealership doesn't take any Leafspy screenshot seriously. So I'm going be dropping the car of with 15% Leafspy SoC, maybe even a little lower.
And before doing, I will also do some more aggressive driving. As during my testing, I had the voltage difference rise up to 612mV before Turtle Mode kicked in. And I was at 12.4% Leafspy SoC when that happened.
I reached during aggressive driving aka highway speeds, going full throttle. It showed at 20% already more than 100mV difference, but that was while using full throttle.
I recorded the graph from Leafspy actually, so that I could see it afterwards. But I think, when I drop the car while Leafspy already showed the heat damage aka weak cells. Then Nissan battery test, should show it as well. I have heard, the outcome is very similar to Leafspy.
www.speakev.com/threads/finding-out-the-real-usable-capacity-aka-weak-cells.179769/unread
great vid...thanks
What kwh can delivery old pack and now many kwh delivery new repaired pack in spring time ? Want to know the benefits ;)
This pack is long sold, but the benefit was to restore it's general state. The pack was at around 75% but because of the weak cells - it made everything suffer in cold and when used at higher speeds. The weak cells voltage sagged down and then battery controller decided that too much of the back is below norms and stopped working. So the benefit was, that it was back to usable 75% or a little more.
What's the software you are using to view bad modules?
The screenshots are from widely used Leaf Spy app. Has free version. Only on Android. You need compatible OBD2 bluetooth/wifi adapter too. Can be found around 10$.
ELM 327 www.aliexpress.com
OBD II support all protocols
I thought EV's were cheap to maintain? This seems like a big deal and not cheap for the avg person.
Average person probably does not drive 300 000km in few years, so, that kind of maintenance is not needed then either :)
And this is the worst EV, other EV's have battery cooling solutions that prevent such uneven heating to happen.
Modern EVs have battery cooling / heating functions to manage temperature and maximise battery life / performance. No longer an issue, unless you want to buy super-cheap, used, semi-broken EVs to repair!
This is also like changing ICE engine