[ArieKanarie]

I wanted to confirm my suspicions so my dad and I went on to remove the two battery boxes which were mounted on the bottom of the car with just 8 bolts each.
We don't have a lift so we had to do it with some elbow grease.

First we had to disconnect the main battery leads and the communication cables before removing the 8 bolts per box (16 total).
With the "ignition" turned off I disconnected the communication cables. You remove them by just turning them loose and then pulling them out. A push and lock by twisting system. You take them off at the side of the battery boxes.
Then the main battery leads, they work just like pneumatic connectors. You pull the knurled ring towards one side and then the two ends seperare easily. I put duct tape on them to insulate them. There are 3 places to disconnect, two between the motor and the front battery box and one on the side of the front battery box.

I used thick 1000V insulated gloves and a face shield just to be safe.

After that we were able to remove the battery boxes.
For the first box we decided to fill up the gap between the floor and the bottom of the battery box, to gradually lower it per side, one pallet at a time. Then we lifted the box up with my dad's trusty International 633 to put it up on some stands for later. It's not the most graceful way, but we had to make do with the tools we had.
You need a 13 and 17 millimeter socket for these bolts.

We got the job done but thought we should try it in another way for the next box. So we decided to support the box on the lowest point the car could go and then lift the car up to pull the box out from underneath.
It worked well but had to lift the car up higher than we thought because the rear box has a different shape.
We succeeded and put the box on a pallet with some wheels underneath to move it around more easily.

The next post will be about opening up the first battery box to take a look inside.

 

[ArieKanarie]

The box had some sealant around the edge of the lid. We scraped that off and found 4 hex bolts to remove.
After that the lid came off quite easily. Don't do this on your own because of its size and the almost bare battery poles underneath.

The battery is a 100S 100AH Lifepo4 configuration. This front box holds 54 cells. As you can see, 2 cells had been replaced before.
I only measured the cells in the middle row for now, it was getting late and I just wanted to confirm my suspicions.
Out of the 13 cells measured, there were 2 cells with a voltage of 0.17 and 0.09. The others were at 3.33 or 3.28 volts. This confirmed my suspicions, these cells were surely dead. Not going to try and revive these.

Knowing what was wrong, we closed the lid. I will come back later and take the whole battery apart to measure each and every cell. I can't reach them all in this configuration so I will take them all out after taking pictures of the layout or I will try to measure them by disconnecting the balance wires at the BMS.
I have found several places that sell these cells, so I'm not worried about that.

Hopefully this will revive this car!

Next posts will be reserved for future updates.

 

[ArieKanarie]

Here are some extra random pictures:

 

[ArieKanarie]

Update of more than two weeks later:

I received my 3 capacity testers and took all cells from the first enclosure.

I designed and printed some parts to mount these to a board to hang on the wall.
While those were being printed, I already tested 11 cells and found 2 dead cells.
One cell was bulging and read 0.09V and the other was dead because of a terminal that was tightened too hard so it spun inside the cell.

Good news about the other cells though; All but one had 90Ah or more left! One was 84.5Ah and there were even some with 95Ah and 101Ah!

There are 16 new Grade B cells on the way to me. I already ordered them without knowing how many needed to be replaced because the delivery will take a long time. I want to drive this car as soon as possible and adding the cap. testing time to the delivery time will take too long.

I chose Grade B cells because of their price and because they will probably match just fine with the current cells that have degraded a little bit. No need for 100Ah+ cells with Grade A.

The cells are put in the box loosely without any padding. There is protection with glass fiber sheets between groups of cells. While it's not the best idea, I think they'll survive just fine with the mostly smooth roads we have here.

This is what the battery box looks like without cells. I taped each and every bms wire for insulation and labeled any wire that was out of the ordinary.

I put all hardware in a assortment box for easy storage. The busbars are stacked sheets of copper by the way.

Here's me hauling the cells to my own home to test. Wanted to spread the weight around the car

I charge each cell with 10A using a ISDT charger I had left over from a quadcopter hobby.

Because I don't want my new cells to break while tightening the bolts on the terminals, I am going to make a tool for these terminals to stop them from spinning. I will do that using a waterjet cutter at work.

Next update will probably be the opening of the remaining battery box.

 

[ArieKanarie]

Finally got around to mounting my discharge station

 

[ArieKanarie]

A small milestone has been reached; all the cells from the first battery box have been tested!
The results surprised me, in a good way.
Most cells have 90Ah+ left from the original 100Ah.
The average over 43 (45 cells minus 2 dead ones) cells is exactly 91Ah with a minimum of 83,5 Ah and a maximum of 104,5Ah.

This also meant that I had to open the second box for the first time to continue testing the left over 55 cells.

Directly after opening the lid I saw two things that kind of shocked me (not literally), TWO bolts that hadn't been tightened and one busbar that was replaced with a less than 1mm thick piece of aluminium!!

The cause of almost no power is now found and I am lucky nothing has been damaged because of it!
Luckily the new cells come with new busbars so I can easily swap them out.

 

[ArieKanarie]

I want to recreate the battery pack digitally for future reference and as a guide on how to put it back together.
The first battery pack has taken shape including busbars and HV cables.
BMS wires are next.
I won't add bolts, washers or cable connectors, those should be self explanatory.

Progress so far after 2 hours of drawing:

 

[ArieKanarie]

Colleague had a little extra space on a cutting job that would otherwise be unusable.
He made me two of the battery terminal tools from the designs I gave him a few weeks ago.

No more spinning terminals

 

[ArieKanarie]

Small milestone reached: all cells have been tested!
The average of pack 1 came out to 91,1 Ah
The average of pack 2 came out to 91,4 Ah
The total average came out to 91,3 Ah

There were 3 dead cells total.
Will replace the 3 dead cells and the 13 lowest.
Those 13 cells that will be replaced will not be tossed, I will keep them as backup and/or to build a house battery in combination with my solar setup.

 

[ArieKanarie]

Finally some good news;
The 16 cells I've ordered have arrived in my country!

The first 8 have arrived already (not sure why they wouldn't deliver all 4 boxes in one go).
7 are on 3.32V and one 3.28V. I will first do a capacity test on these new cells before throwing them in the car.
I also need to charge each cell to the same voltage to prevent high current flow when connecting them all together.

The packaging was great and didn't suffer any damage. The cells are not bulged and seem to be fine.

At this point I'm going to open some compartments under the hood to hopefully identify more parts.
Doing this now while the battery is out of the car would reduce the change of me damaging myself or the components.
The car has been standing still with the ignition on, so all energy should be drained from capacitors.


Glad to be able to work on this car again after waiting for those cells to arrive!

 

[ArieKanarie]

I had some days off so naturally you start building batterypacks for your car

Yesterday I went out and started working on the front batterypack.
All cells were sorted by number and then I took the ones that needed replacement and swapped them out for the new cells.

Then the rebuilding started. Luckily I had all wire locations written down, it helped me quite a few times!

That's pack one done.
Then today I did exactly the same thing but now for the rear battery pack.

Now that both battery packs are together again, I can put the lids back on and seal those shut with silicone.

These packs are left to dry now.
Tomorrow we will mount the packs under the car again. We'll do it differently than how we removed them, hopefully saving us a lot of hassle and force.

 

[ArieKanarie]

We managed to attach both battery packs to the car again using a pallet jack.
Using the pallet jack makes this whole proces so much better than our janky setup we used when removing the boxes!

Before reconnecting the battery boxes' connectors I measured if there was voltage between the last two connectors. When connecting there was no spark! I was quite scared of that to be honest, but we took some good safety precautions.

All connected now!

Then the moment I've been waiting for came...
I turned the key..


Nothing.



I saw a faint light on the dashboard and heard a very quiet alarm coming from the motor compartment.
I figured the 12V must've died while the battery was out.
Well, it was dead. We put it on a charger and after waiting for maybe 30 minutes the car was able to turn on and also move.
The charger was put in and we left it for a while.

After a while I noticed that the lowest cell measured was again cell 78, even though the cells had the same voltage when putting it in the battery boxes.
That was a bummer, there's still something fishy going on with the BMS or communication.
I am really lacking the skills to find out how to connect to the can bus and also to find out what is being communicating. (Please contact me if you have knowledge about this without using the obd2 port)

 

[ArieKanarie]

Even though the car still has issues, it does drive!
I tried it out in the small field my parents have.
Public roads will be avoided at this point because the car shuts off sometimes when a low voltage error occurs (even though the cell isn't low)

Something else I've discovered by accident while messing with the car's head unit is that I can reach the Windows CE desktop.
I'm going to investigate if I can pull information about the can bus from the programs running on the head unit or maybe something else.
It looks a little like this (all text is Chinese in my case though):

 

[Swing]

Great report!
Where did you find it, just online? (listed as a damaged vehicle?)

Perhaps you could replace all the BMS and possibly motor controller, to get rid of your remaining problems. It looks like a faulty BMS pcb indeed.

The repair work that has been done on it looks a bit scary, but at least it is easy to repair. You can just bolt in new cells, itś great.

Not to many Chinese EVs around here in the Netherlands, but I will also keep my eyes open for it.

 

[ArieKanarie]

Great report!
Where did you find it, just online? (listed as a damaged vehicle?)

Perhaps you could replace all the BMS and possibly motor controller, to get rid of your remaining problems. It looks like a faulty BMS pcb indeed.

The repair work that has been done on it looks a bit scary, but at least it is easy to repair. You can just bolt in new cells, itś great.

Not to many Chinese EVs around here in the Netherlands, but I will also keep my eyes open for it.

Yeah I've been thinking about it.
It would indeed wipe away my problems, but I am unsure about how much I would gain from it after spending a lot of money and time on it.

I like this little car a lot but maybe I could use the funds for a new bms and motor controller towards a second hand Leaf or something similar.

But it's worth researching, and I will.

 

[Swing]

Yes a Leaf is more reliable, and even offers an upgrade path through Muxsan company! But that is nothing DIY
How much did you spend now? I guess an Orion BMS could do the trick and is programmable in terms of CAN messages. But can't you find the BMS parts on Aliexpress?

Did you find the car on Marktplaats or so?

 

[ArieKanarie]

Yes a Leaf is more reliable, and even offers an upgrade path through Muxsan company! But that is nothing DIY
How much did you spend now? I guess an Orion BMS could do the trick and is programmable in terms of CAN messages. But can't you find the BMS parts on Aliexpress?

Did you find the car on Marktplaats or so?

Yeah I meant to maybe get a Leaf alongside this Zotye. So DIY is still available

€2750 - €2000 subsidy + €1000 on cells makes €1750 total.

I've found the manufacturer and several resellers of the parts, but they don't respond on emails sadly.

The car was posted in a Dutch FB group about converting cars. For a change something like this was for sale near me so I jumped on it.

 

[ArieKanarie]

It has been a while..

The car has been standing still for more than 2 months now sadly, because 2 of the 16 new cells were dead.

Finally, after waiting more than 2 months for new cells, I was able to swap them out.
I let both cells sit for a week without connecting the battery boxes to the car.

The voltages stayed the same so I can hopefully say with some certainty that it's not in the wiring within the battery box.

Yesterday I went ahead and installed the rear box again. I started alone but within minutes my dad was there to help, he likes to get involved with my projects and I like that.

Tolerances are quite tight which meant that the install took some time. Too much time actually, I planned on driving the car back home. But since the first box took so much time it was getting too late to install the other.

(Not sure if I've mentioned it before but I have to lift the rear this high so the battery box can fit below the rear axle)

The other battery box will be installed within a week, I need to find some time.
Will update when it's done.