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Discussion Starter #1 (Edited)
Hi all,

I'm upgrading (not converting since it is already an E.V) the Think PIV4 also known as the 'Think City' or the 'Think Classic'.



These little 2 seater cars were build in Norway around 2001 and a lot of them went to the USA under the name ' Ford Think City'.. and they all came back in 2005 or 2006 when Ford decided that E.V's where (again) not the way to go...

https://www.youtube.com/watch?v=uJBlZzihc_M

A lot of these cars are scrapped in the past years so only a few are left (mainly in Norway).



Originally it's equiped with 19 Saft 6V Nicad cells, so nominal 114V/100Ah. Has a Siemens drivetrain, PTC heater and a lot of other common Peugeot/Citroen mechanical parts.

The batteries are inside a 87cm x 75cm centralized batterybox under/inside the floorpan.
I have removed the old Nicad cells and cleaned the batterybox from all unwanted metal to make room for a full 24kWh Nissan Leaf battery.
With 24 modules in one stack and some modified endplates each stack is 35cm x 86,5cm and two of these fit perfectly inside the box with some room left for relais etc. :)

Since the Siemens inverter can only handle upto 385V and the original DC/DC upto 290V I have decided to 'break' and parallel the Leaf pack into a 196V pack. So instead of 48 modules in series I will parallel each two modules to get 24 modules in series. (each module is allready 2S2P).

The original battery had a 'BMS' and a contactorbox with pre-charge and main relay and some other functionality like cabin pre-heater, delayed/timed charging etc. By keeping the voltage under 200V I can almost certainly re-use all this functionality and re-use all HV components.

Although the firmware/software of the Siemens inverter is locked with a code that Siemens has to provide I managed to crack the code and can now make modifications with Siadis, the Siemens MS-DOS software. This opens the possibility to change setings like max Amps, Volts, top speed etc.

Why upgrading to a bigger battery:

https://www.youtube.com/watch?v=JcuDCZMmCKg
 

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Discussion Starter #2 (Edited)
Breaking up the Leaf battery.

Since I have decided to break and parallel the Leaf pack from 48S into a 24S pack I needed to create new/other module connectors/busbars. Made from 1mm copper strips that came from an electric building/powerplant, cut into smaller 20mm strips of 120mm each, punched 4 holes of 7mm in each so i can parallel and series connect 4 modules.



Heres the first protoype build of one stack:



For the monitoring I'm using Zevan BMS modules. Two modules on each stack for 24 cells.

And two of these fit perfectly inside to original battery box:



Prototyping and testfitting a terminal cover made from 1mm plastic

 

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Very cool, I will need to re-arrange the Leaf batteries for my VWLT truck project too.
Since you're using a Leaf motor, I assume that you still want all modules in series - as in a stock Leaf - so you are only physically re-arranging the modules. To do that you will need some new connectors, but you won't need these 4-terminal paralleling bars. Right?
 

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Since you're using a Leaf motor, I assume that you still want all modules in series - as in a stock Leaf - so you are only physically re-arranging the modules. To do that you will need some new connectors, but you won't need these 4-terminal paralleling bars. Right?
Correct. I will be packing them into rectangular battery boxes with the aim of eventually having a 48kw, one on each side of truck, under the bed, perhaps on rollers. I may need the 4 bolt connectors as the form factor will be similar to the fellow above. I haven't got that far yet. I will make a heating and cooling system for them as well which is not hard for me as it is my trade.
 

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Discussion Starter #7
I got my Leaf pack from Norway and it had heaterplates on each battery stack. I think its a 'cold-weather' or 'winter' option in these countries when ordering a new Leaf.
 

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I got my Leaf pack from Norway and it had heaterplates on each battery stack. I think its a 'cold-weather' or 'winter' option in these countries when ordering a new Leaf.
What are the dimensions of the battery pack in the picture? I need to start planning the boxes for mine.
 

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Discussion Starter #9
What are the dimensions of the battery pack in the picture? I need to start planning the boxes for mine.
L865 x W340 x H260mm

I have used 25x25mm angled iron to build end 'plates' and have a support frame underneath the modules to let them rest on it. I'm going to fill up these spaces with high density styrofoam isolation plates of 25mm. Another option is to use these spaces to accomodate for heater or chiller plates. Maybe bent a 15mm copper pipe in meander pattern to allow for coolant ?
 

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What are the dimensions of the battery pack in the picture? I need to start planning the boxes for mine.
L865 x W340 x H260mm
The width (340 mm) and height (260 mm) are the size of a module; each module is 35 mm thick so a stack of 24 (half of the Leaf pack) is 840 mm (plus end plates and other hardware); the stock Leaf pack includes a stack of 24 like this under the rear seat. You need to allow room for the electrical connections, which I think are on the 340 mm long edge of the module.
 

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I will be packing them into rectangular battery boxes with the aim of eventually having a 48kw, one on each side of truck, under the bed, perhaps on rollers. I may need the 4 bolt connectors as the form factor will be similar to the fellow above.
If you have 48 kWh that's two full Leaf packs, or 96 modules. You can configure that as
  1. two 24 kWh 48-module sets in parallel, or
  2. parallel them in pairs at the lowest level like prensel has (so you would need the 4-hole connectors), and run 48 pairs in series.
The BMS approach chosen will likely influence that choice.
 

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If you have 48 kWh that's two full Leaf packs, or 96 modules. You can configure that as
  1. two 24 kWh 48-module sets in parallel, or
  2. parallel them in pairs at the lowest level like prensel has (so you would need the 4-hole connectors), and run 48 pairs in series.
The BMS approach chosen will likely influence that choice.
I will be starting with one, and will be using the OEM BMS with the possible exception of a bespoke battery heat/cool. I definitely like Prensel compact configuration.
 

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Hi all,




Although the firmware/software of the Siemens inverter is locked with a code that Siemens has to provide I managed to crack the code and can now make modifications with Siadis, the Siemens MS-DOS software. This opens the possibility to change setings like max Amps, Volts, top speed etc.
I may need your help in working with the BMS, if you are OK with it.. I'm far from a software guy unfortunately.
 

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Discussion Starter #14
I may need your help in working with the BMS, if you are OK with it.. I'm far from a software guy unfortunately.
I'm not using the original Leaf BMS but one from Zeva (zeva.com.au).
Its an almost plug and play system without software skills required

The original Leaf BMS seems to work ok though but not the complete CAN protocol is known yet or easy to find out within a reasonable amount of time. I gave up after a few weekends diagnosing the CAN traffic but couldnt find the info i definately needed to have.
 

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Discussion Starter #15 (Edited)
So after a few days of tinkering the new Nissan Leaf based battery pack is finally installed in the little Think. Its a perfect fit and after initial adjustments to the Simotion controller the car runs very well. Originally it runs at 114V and now with the 48 Leaf modules on 194V but still has about the same 'performance'...



It's time to speedup/tune things.. :)
After modifying the inverter's current parameter from 100A to 225A the power went up from 20kW to 48kW and there is room for more but my main fuse at 250A is the limiting factor.
At this time the tyres 'screem' when pulling out every corner which is rather funny.
Topspeed was originally set to 90km/h and is now around 150ish..

Next step is lowering the suspension a bit and changing brakes to a ventilated setup at the front and disks at the rear from a Peugeot 106 GTI.
 

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This little project is crazy fun! It must be like a gokart. I'd be scared doing 150kph in it though. How strong and precise is the suspension and steering? Do you have a photo of the underside of the car and where everything fits for interest please?
 

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Discussion Starter #17 (Edited)
How strong and precise is the suspension and steering? Do you have a photo of the underside of the car and where everything fits for interest please?
I have tucked two Brusa NLG511 chargers at the front where the original ConstantPower charger was. The rest is kept original.
The Zeva BMS is in the batterybox at the front. Modified the original batterybox loom so its just a plug-n-play install to the cars connectors.




The Think has standard Peugeot 106/Citroen Saxo front end rear suspension bolted to the chassis. So using the upgraded suspension parts from the GTI/VTS versions of these cars should be good enough. The Peugeot 106GTI has 87kW and max speed of 205kmh and about the same weight.
 

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Hi
With a light weight powerful machine don't worry too much about the fuses

If the fuse can withstand 250 amps for an hour then it will take 500 amps for a few seconds - and during those few seconds you will have to lift off!

I'm running a Chevy Volt fuse - 350 amps - but my controller is set to 1200 amps
 

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Discussion Starter #19
Hi
If the fuse can withstand 250 amps for an hour then it will take 500 amps for a few seconds - and during those few seconds you will have to lift off!
I'm running a Chevy Volt fuse - 350 amps - but my controller is set to 1200 amps
Okay thats good to hear. The Simotion inverter is according the specs capable of 282Amps so i guess thats the max it will draw regardless of any higher (if even possible) settings. At my setup with 192V it would be about 54kW which should be ok :)

I've looked through all settings in the inverters software and not all are clear to me for what they are or do. The one that i'm looking for is the 'ramp', like how fast does the current rise from 0A to 282A when accelerating. That should allow me to do some burnouts...
 
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