Freelander 1 Freelander EV

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I put a few miles on the car over the weekend.

I always wanted this to be a practical workhorse that I don't need to be too precious about
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Every time I use it to tow a trailer it's another time I don't burn out a little bit more of SMBO's Kuga clutch.
 
The last few days I've been struggling to get my head around the BMS again. Although it probably won't be able be able to keep the pack balanced it's a good idea to have it working as I can use a simple Bluetooth dongle and App called LeafSpy to monitor the voltages of each cell. Having the BMS working means I'll be able to see if any cells are out of balance and if necessary I can intervene manually. I really should have had it sorted months ago but I knew it was going to be a pain so kept putting it off. I had it connected and working a couple of years ago on the bench but that was with all the modules in one place. Now I have some in the front, some in the fuel tank area and some in the boot so it's not so simple.
During the week I spent several evenings working on it and then pretty much the entire day today soldering testing, pulling apart and resoldering cause I messed up.
This was the mess I was in earlier.

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After many cockups, a few poor decisions and some generally dodgy workmanship I think I have it sorted.
Some time ago I made up a spreadsheet to give me the expected voltage at every connection for any given cell voltage. I was able to test all the voltages and even discovered a fault in the spreadsheet so tomorrow I'll sort out a 12V supply for the BMS, hook up the CAN leads and hopefully see the condition of the battery pack.

Wish me luck
 
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The last few days I've been struggling to get my head around the BMS again. Although it probably won't be able be able to keep the pack balanced it's a good idea to have it working as I can use a simple Bluetooth dongle and App called LeafSpy to monitor the voltages of each cell. Having the BMS working means I'll be able to see if any cells are out of balance and if necessary I can intervene manually. I really should have had it sorted months ago but I knew it was going to be a pain so kept putting it off. I had it connected and working a couple of years ago on the bench but that was with all the modules in one place. Now I have some in the front, some in the fuel tank area and some in the boot so it's not so simple.
During the week I spent several evenings working on it and then pretty much the entire day today soldering testing, pulling apart and resoldering cause I messed up.
This was the mess I was in earlier.

View attachment 317348

After many cockups, a few poor decisions and some generally dodgy workmanship I think I have it sorted.
Some time ago I made up a spreadsheet to give me the expected voltage at every connection for any given cell voltage. I was able to test all the voltages and even discovered a fault in the spreadsheet so tomorrow I'll sort out a 12V supply for the BMS, hook up the CAN leads and hopefully see the condition of the battery pack.

Wish me luck
I would not have the bandwidth or storage capacity in me head to work through that lot!
 
I would not have the bandwidth or storage capacity in me head to work through that lot!
If you can connect one wire you can connect two. If you can connect two wires you can connect five. If you can connect 5 wires....... you get the point.

It looks daunting and complicated but when you break it down it's just connecting wires. There are four rows of modules in the boot with 8 cells per row so 32 cells all together, I had to extend the wires and used two lengths of 25 way multicore so had 64 connections to make. Each one is soldered then insulated with lengths of two heat shrink, (to be sure to be sure).

My problem was caused by the numbering convention by Nissan, they count the most positive cell as cell 1 and most negative as cell 96. The lowest number cell in the boot is 41 so I started there when I should have started at 96. I figured trying to meter and count the voltage from cell 96 to 41 would be too complicated so I metered from the most positive end and managed to confuse myself completely. Eventually I dug out a spreadsheet I had created almost two years ago which gives the voltage at each cell for any given single cell voltage. Once I had this in front of me it all started to make sense.

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I got the connection numbers from the Nissan Leaf service manual and it worked before so I'm confident it is correct but another complication is at cell 48. There is an extra negative connection for cell 48 because the BMS is galvanically isolated between cells 48 and 49, to protect it from stray current drain when the HV service disconnect is pulled. Basically if this was not there the BMS would be shorting out the HV service disconnect, thereby maintaining the HV circuit, This would not only be dangerous but if there were a stray power drain it would melt the BMS.
My service disconnect and contactors break the pack at cell 41/42 so I have to try and figure out a way to ensure the BMS is never connected when the contactors are open. I'll probably use a relay to make/break the connection to cell 49 and ensure it is only ever active while the car is in drive mode.
 
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Regarding the bms breaking at cell 48, a suggestion has been made to move the neg contactor in the rear battery box (that is probably overkill anyway) to between cells 48 and 49. This should protect against accidental damage to the bms and would be fairly simple and easy to do.
Hopefully I'll get a chance to look at this tomorrow, today I spent the morning refitting the rear offside control arms and had a go at setting the tracking with the help of some string.

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Note the multiple plastic bags under the wheel to let it turn freely.

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From I first drove this car it has been pulling to the left and a couple of weeks ago with the help of a length of string I discovered the rear offside wheel was towing in a by a fair amount and the front offside was towing out. I tried to adjust the rear wheel first but (despite trying heat and abuse) couldn't get the adjuster to move so ordered a new track control arm and long bolt that I knew would be destroyed getting it out. Unfortunately the bolt was seized solid to the 2nd control arm so I ended up ordering a new one of those too.

After an hour or so working at it I have the tracking close but not perfect as it is still pulling slightly to the left but not as bad as before. At some stage I plan to get new tyres so will have the tracking set properly then.
 
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