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Discussion Starter #1 (Edited)
I'm trying to figure out the best course of action to upgrade my current EV with more power. I have a 2011 Th!nk City with 44hp and 66tq. It's "ok" I guess in terms of drive-ability but it lacks enough power to maintain speed when trying to go up a hill or merge on the interstate.

I have two ideas in mind and I'm not sure which will provide the biggest bang for the buck or even be possible. Both ideas have the same premise; assume the car is just a rolling chassis, no electronics aside from the battery and possibly the charger. There are some inherent flaws in the Th!nk that I want to remedy by dumping all of the factory systems and starting over.

Option 1. Re-configure battery module to 120-144v and install HyPer9 motor and controller. This would require removing the AC, PS and Heater (which I'm ok with). Would likely mean I'd need a new on-board charger as well which adds to the complexity and cost. Will need to find someone who can help me reconfigure the battery pack. This should provide about 120hp and 170tq. A big upgrqade which would really help. Option 1 means tearing apart the battery, tearing apart the drive unit and losing accessories.

Option 2. Keep the original battery configuration and swap in a motor/inverter from a BMW i3. Because the voltages would be the same I could keep the PS, AC and Heater. I could keep the OBC and hopefully simplify the installation process. It's my uneducated theory that I would need an adapter plate to mount the motor and some custom wiring from the original battery to the inverter but other than a few input signals (throttle position, drive select, temp, ignition, etc) it would be fairly straight forward. worst case scenario I remove the entire drive system from the Th!nk and fabricate mounts and drive axles for the complete i3 unit so it doesn't have to be taken apart. Capable of 170hp 180tq. Option 2. means tearing apart the drive unit.

If I'm looking at this correctly I think option 2. would be the easiest and most straight forward. Even if the Th!nk batteries aren't strong enough to get the full power from the i3 motor it should still be more powerful than the Hyper9 which would aid in hills and interstate travel.


What am I overlooking? Dos anyone have any experience with i3 drive units?
 

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Hi Matt,

Take a look at this. Think City Batteries

It definitely looks like the pack can be reconfigure and you might be able to salvage the BMS.

You would have to replace the DC-DC converter and charger and any other system that requires high voltage.

But I'm not sure that would be the best option. I personally would go with the i3. Your still going to have problems with the systems as I assume (never good) that they require CAN bus to operate but that's a big assumption on my part.

If your think i3 your going to want to read this thread.
https://www.diyelectriccar.com/forums/showthread.php/diy-bmw-i3-controller-190418.html
 

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Discussion Starter #3
Thanks for taking a look at it for me. I was shopping on Copart for a totaled i3. I could just buy the entire vehicle for a few thousand and have everything I'd possibly need between the two. Honestly though it's probably cheaper just to go buy a used i3 and enjoy that. Maybe gut it out. Strip it down as much as possible. Put some actual rubber on it and track it on the weekends for fun.

I like this Th!nk but I feel completely in over my head. EVwest said they wouldn't even be able to to look at it for another 2 years and I will have moved on to something else by then.

why couldn't you live closer and take custom work on??
 

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Out of the two I'd definitely go with the i3 option. It would probably be easier (but by no means easy) and would definitely give you a better result.

Have you considered trying to keep the motor but feeding it more power, either with a new inverter or with a new "brain board" for the existing inverter? For sure the motor in there is a dinky little thing, but perhaps it could be pushed a bit harder. A couple of weeks after I got my Think back in 2012 I got the final firmware update which dramatically improved performance. So we know Think was working on increasing power up until they went bankrupt, and perhaps they left some more performance on the table. The nice thing is that it's an induction motor, so you don't have to worry about demag-ing if you go to far; as long as you don't roast anything you'll be fine.

I'm not saying THIS method would be easy either. But nothing you do is going to be easy.
 

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Discussion Starter #5
I'm a member of a Norwegian FB group for Th!nk owners and it seems the consensus is "why modify it?" They were able to set me up with all new suspension but when it comes to electronics everyone seems to be in the mindset that it's a faberge egg and just drive it as-is until it dies, which it will.

I thought of the car as a loaded golf cart. Very simplistic in design. I don't understand the need for a CANBUS system in the vehicle. I've built/modified golf carts that were super simple and this car doesn't look like it needs anything more than what those golf carts had.

If I were doing an ICE vehicle conversion I could buy a standard AC-31 package and have everything I need minus the battery and charger. I don't understand why this is any different.

If I were taking out EVERYTHING electrical and just keeping the battery pack and differential then why wouldn't an off-the-shelf AC motor kit just plug right in? I understand needing a different DC-DC and charger to go with the lowered pack voltage. I'm asking more specifically about the CANBUS thing.

I'm looking for the bare minimum a car needs to run and make decent power.
 

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You don't actually need to use canbus only if the donor car used it. And looking at the battery post the BMS looks like it was connected to a canbus. Which makes sense. The charger has to talk to each cell (through the BMS) to figure out what its status is. I know that's not exactly accurate description but you get the idea.

For my project I selected to use Chevy Volt parts. I made that decision due to cost. I purchase two chargers for just over 300 dollars. So I've got 6.6 kW of charging power. If i purchased something new with those spec (that didn't need canbus) it would be in the thousands. The down side is any modern car that you want to salvage parts from will most likely require some canbus programming or PMW signalling (or both) to make the parts function.

FYI....I purchased a Tesla Model S drive train for $1600. I only mention this as deals are to be had and you can build something cool on a relatively small budget.
 

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British slang, "torques". Is "tq" ft-lb, or n-m?

In any case, what's the present pack voltage, battery type, and stack configuration?

What motor does the car use, what type is it (AC, DC, BLDC) and what is its rated voltage and continuous and peak current ratings. How is it cooled?
 

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Think of the time and effort you will go through. I stopped building EV's when the Nissan Leaf came out. I couldn't build something for the same money even half as good. Check out prices of used EVs. You might be pleasantly surprised at what you might get. That said restomoding from a wreck might now be your best bang per pound. The Think is small. You may have to modify axles and such. Good luck.





I'm trying to figure out the best course of action to upgrade my current EV with more power. I have a 2011 Th!nk City with 44hp and 66tq. It's "ok" I guess in terms of drive-ability but it lacks enough power to maintain speed when trying to go up a hill or merge on the interstate.

I have two ideas in mind and I'm not sure which will provide the biggest bang for the buck or even be possible. Both ideas have the same premise; assume the car is just a rolling chassis, no electronics aside from the battery and possibly the charger. There are some inherent flaws in the Th!nk that I want to remedy by dumping all of the factory systems and starting over.

Option 1. Re-configure battery module to 120-144v and install HyPer9 motor and controller. This would require removing the AC, PS and Heater (which I'm ok with). Would likely mean I'd need a new on-board charger as well which adds to the complexity and cost. Will need to find someone who can help me reconfigure the battery pack. This should provide about 120hp and 170tq. A big upgrqade which would really help. Option 1 means tearing apart the battery, tearing apart the drive unit and losing accessories.

Option 2. Keep the original battery configuration and swap in a motor/inverter from a BMW i3. Because the voltages would be the same I could keep the PS, AC and Heater. I could keep the OBC and hopefully simplify the installation process. It's my uneducated theory that I would need an adapter plate to mount the motor and some custom wiring from the original battery to the inverter but other than a few input signals (throttle position, drive select, temp, ignition, etc) it would be fairly straight forward. worst case scenario I remove the entire drive system from the Th!nk and fabricate mounts and drive axles for the complete i3 unit so it doesn't have to be taken apart. Capable of 170hp 180tq. Option 2. means tearing apart the drive unit.

If I'm looking at this correctly I think option 2. would be the easiest and most straight forward. Even if the Th!nk batteries aren't strong enough to get the full power from the i3 motor it should still be more powerful than the Hyper9 which would aid in hills and interstate travel.


What am I overlooking? Dos anyone have any experience with i3 drive units?
 

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Discussion Starter #10
British slang, "torques". Is "tq" ft-lb, or n-m?

In any case, what's the present pack voltage, battery type, and stack configuration?

What motor does the car use, what type is it (AC, DC, BLDC) and what is its rated voltage and continuous and peak current ratings. How is it cooled?
there you go.
 

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