# Meet Chick Magnet, 1948 Willys CJ2A gone electric



## eWillysBoulder (Nov 19, 2021)

Complete restoration on the 1948 CJ2A, kept the original transmission, clutch and flywheel. Motor is a NetGain HyPer 9HV with the X144 controller. Battery pack consists of 6 Tesla S modules in series for 30 kWh at 148V. I get about 50 miles of driving range (with the windshield down). Chick Magnet is an awesome four-wheeler:
Four-wheeling near Cliff Hanger trail and Four-wheeling near Ward, CO
I am having an overheating problem on the X144 controller when I drive on highways. Liquid-cooling the controller will be this winter's project.
Cheers


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## EV-FAN (May 17, 2021)

That’s awesome! Looks incredible. I envy your battery pack. We should organize an eJeep jamboree when I finish mine! Haha


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## eWillysBoulder (Nov 19, 2021)

EV-FAN said:


> That’s awesome! Looks incredible. I envy your battery pack. We should organize an eJeep jamboree when I finish mine! Haha


Thank you for the kind words, EV-FAN. The eJeep Jamboree is a great idea, count me in! Most of all keep me posted on your project and don't hesitate to reach out if I can help in anyways. Here are a couple pictures of my battery pack during assembly:


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## Electric Land Cruiser (Dec 30, 2020)

Does the Netgain motor regen? I would have expected more than 50 miles from a little guy like that on 30kwh. Either that or I need to seriously re-evaluate my estimates!

Do you have more photos of the build? I'd love to see it sometime. Should put together a DIY EV meetup in Colorado next spring, there are quite a few of us.


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## eWillysBoulder (Nov 19, 2021)

Electric Land Cruiser said:


> Does the Netgain motor regen? I would have expected more than 50 miles from a little guy like that on 30kwh. Either that or I need to seriously re-evaluate my estimates!
> 
> Do you have more photos of the build? I'd love to see it sometime. Should put together a DIY EV meetup in Colorado next spring, there are quite a few of us.


Yes I have three regen modes from the SME Compact Display: (a) regen from the brake pedal (it is like having power brakes!), (b) medium regen which is like one-pedal driving and (c) high regen which I never use because it locks the rear wheels if I let go the gas pedal (my Willys is a bit front-heavy). I live 2,300 feet above Boulder and the road is 8 miles long, so you can imagine the grade. I do use the regen a lot.

On the mileage, a 1948 Willys is not exactly a choice vehicle largely due to the flat widshield and the 3-speed gearbox. It weighs 2,500 lb. Until I correct the controller over-heating problem, driving on highways has been an issue. So I have not fully vetted the driving range other than estimating it from - say - 40% battery discharge to drive 30 miles. My observations so far seem to match all the calculations I did before getting into this. If you want a second set of eye balls, I would be happy to run an independent estimate for you.

Another concern is with the battery itself: I have six modules in series, connected by 1/8" thick copper bus bars wide enough to provide the same cross-section as 00 gauge wire. Nonetheless, when I draw too much torque (like driving in 50 mph headwind with the windshield up), my battery modules tend to get out of balance with a premature low-voltage alarm on the cells closer to the end connections. Once I ease on the torque demand, the BMS rebalances the modules nicely. I will correct that by reducing the maximum torque.

I like your idea of a meet-up!

Cheers,


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## eWillysBoulder (Nov 19, 2021)

Electric Land Cruiser said:


> Does the Netgain motor regen? I would have expected more than 50 miles from a little guy like that on 30kwh. Either that or I need to seriously re-evaluate my estimates!
> 
> Do you have more photos of the build? I'd love to see it sometime. Should put together a DIY EV meetup in Colorado next spring, there are quite a few of us.


Electric Land Cruiser, as you requested, here are some photos of the conversion.













































I started in June 2020 with the teardown of the rust bucket and finished in June 2021 with Chick Magnet the awesome four-wheeler. Since the NetGain motor is 108 HP whereas the original Go-Devil engine is 65 HP, I put disk brakes on the front wheels. I was so focused on the electric conversion that I neglected to rebuild the transfer case and it is biting me in the rear-end; one more winter project!

For the story, I was about to buy a Jeep Gladiator. Same budget! Well the Willys came out $20k cheaper but it was not a cheap exercise. My wife agreed that I should flex my engineering muscles and make the Willys electric rather than buy a new truck.

As you may guess from the front grill lifting with the hood, Chick Magnet is a battery-swapping EV. I can swap batteries under 15 minutes (except I can't afford a second battery yet so I use the old J1772 charger). Once I build a second battery, I will have enough storage to back-up my house for three days (with the clothes dryer and disco ball going). Ok, now we are talking microgrid, sorry.


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## eWillysBoulder (Nov 19, 2021)

EV-FAN said:


> That’s awesome! Looks incredible. I envy your battery pack. We should organize an eJeep jamboree when I finish mine! Haha


EV-FAN, one more thing, Chick Magnet has been team work:
My wife fully supported the endeavor. This is HUGE!
I had two engineers help me with SolidWorks to CAD the project. One is a seasoned professional, the other was an engineering student at CU-Boulder - great guy too.
I have two guys at a metal shop who did wonders.
Michael Bream and his team at EV-West helped me so much avoiding pitfalls.

By no means was it a one-man show.


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## 800a (Jun 18, 2021)

Awesome build! 
I'm curious about your motor mount. I like how you reused the original mount point and am thinking of something similar in my Scout. From the angle in the photos, I can't tell how it's connected to the motor. Do you have another close-up you could post?


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## gregski (Sep 6, 2011)

I'm a simple man, I see "*Chick Magnet*" I click


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## eWillysBoulder (Nov 19, 2021)

800a said:


> Awesome build!
> I'm curious about your motor mount. I like how you reused the original mount point and am thinking of something similar in my Scout. From the angle in the photos, I can't tell how it's connected to the motor. Do you have another close-up you could post?


IH Scout, great project! Good question on the motor mounting.
The motor is bolted to the adapter flange that bolts to the bell housing, that's it. The bottom red plate is also bolted to the adapter flange and to the front motor mounts, this way I maintain the triangular configuration of the power plant. Then I had an ah-ah moment and realized the motor was too cantilevered, I stuffed some rubber pads underneath it so it can rest on the bottom plate (most of the time, unless I shake the Willys too hard on the dirt roads). 
Making this a true home-grown project, I got a brace to bolt the front of the motor to the bottom plate but the brace is a bit too wide so I have not installed it yet. This is only one of several after-the-fact things I should have - could have considered earlier in the design phase. Just as it is installed right now (without the brace), it works fine. I feel the motor/transmission shaking a bit when I start driving uphill on a steep hill and from a stopped position on a paved road. On dirt hills, I spin the wheels when I shift into 2nd gear which impresses the neighbors.

Here are a couple of photos, sorry this is all I have:


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## eWillysBoulder (Nov 19, 2021)

gregski said:


> I'm a simple man, I see "*Chick Magnet*" I click


Bless your heart! The reason for the name is that my wife never refused a ride in the Willys, even before the conversion to electric when it was a rust bucket with no brakes.


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## asymptonic (Oct 14, 2021)

Electric Land Cruiser said:


> Does the Netgain motor regen? I would have expected more than 50 miles from a little guy like that on 30kwh. Either that or I need to seriously re-evaluate my estimates!


Same here. Planning on converting a 98 TJ, curb weight approx 3200lb, estimated final weight a hundred pounds less or so. Same brick shape, and yet I was seeing similar conversions with poorer DC motors with no regen get 80 miles on 25-30kwh batteries. I was aiming for 14 LG Chem 2.6kwh batteries, 36kwh for a range of around 100-120mi, but this gives me some pause.


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## remy_martian (Feb 4, 2019)

I like the built in pallet portion of your case design that enables a fast swap of battery packs


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## brian_ (Feb 7, 2017)

eWillysBoulder said:


> Another concern is with the battery itself: I have six modules in series, connected by 1/8" thick copper bus bars wide enough to provide the same cross-section as 00 gauge wire. Nonetheless, when I draw too much torque (like driving in 50 mph headwind with the windshield up), my battery modules tend to get out of balance with a premature low-voltage alarm on the cells closer to the end connections.


That doesn't make sense to me: with all modules in series, they are all passing the same current... so how could it possibly matter whether a module is at the end of a string or the middle? This sounds like a thermal problem (due to the position of the module in the middle of the stack or the end), rather than an electrical problem (due to the position of the module in the middle of the series string at the end). Is there enough coolant flow, and is it balanced between the modules?


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## remy_martian (Feb 4, 2019)

My money's on dead/fused cells in those modules.


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## eWillysBoulder (Nov 19, 2021)

asymptonic said:


> Same here. Planning on converting a 98 TJ, curb weight approx 3200lb, estimated final weight a hundred pounds less or so. Same brick shape, and yet I was seeing similar conversions with poorer DC motors with no regen get 80 miles on 25-30kwh batteries. I was aiming for 14 LG Chem 2.6kwh batteries, 36kwh for a range of around 100-120mi, but this gives me some pause.


I am by no means an expert. So far I am getting around 1.5 miles per kWh. A Tesla Model S seems to get around 3.5 miles per kWh (300 miles with 85 kWh). It sounds like you are in between these two bookends at 2.8 miles per kWh.


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## eWillysBoulder (Nov 19, 2021)

brian_ said:


> That doesn't make sense to me: with all modules in series, they are all passing the same current... so how could it possibly matter whether a module is at the end of a string or the middle? This sounds like a thermal problem (due to the position of the module in the middle of the stack or the end), rather than an electrical problem (due to the position of the module in the middle of the series string at the end). Is there enough coolant flow, and is it balanced between the modules?


Thank you for your very valuable input here. I do not have a heat problem and I have coolant in my batteries. Nevertheless I appreciate your comment, it sounds like I was looking at the problem the wrong way.


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## eWillysBoulder (Nov 19, 2021)

remy_martian said:


> My money's on dead/fused cells in those modules.


Thank you, I may take my battery apart this winter and re-check the connections. I wonder how I can test the cells, they all seem to hold the voltage when in steady state.


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## remy_martian (Feb 4, 2019)

When there are a bunch of cells, you can't do it without disconnecting the cell.

You might isolate the culprit parallel group by leveling all the cells to identical voltages, then doing a low current discharge (to eliminate the module interconnect loss variable) with the BMS (another possible culprit) shut down or disconnected.

For reference, I regularly get 4 miles per kWh out of the Bolt EV at 3600lb curb weight, heaters and AC off, 70 degree ambient.

Tires and their pressures are a big factor nobody's mentioned....


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## eWillysBoulder (Nov 19, 2021)

Here is the latest video of my September outing: 




Now waiting for spring temperatures to take Chick Magnet out again


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## eWillysBoulder (Nov 19, 2021)

remy_martian said:


> When there are a bunch of cells, you can't do it without disconnecting the cell.
> 
> You might isolate the culprit parallel group by leveling all the cells to identical voltages, then doing a low current discharge (to eliminate the module interconnect loss variable) with the BMS (another possible culprit) shut down or disconnected.
> 
> ...


Thank you for the valuable help.


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## mpgMike (Nov 9, 2021)

I'm aware of Kirchoff's Law, but reality begs to differ. Cell balancing offsets this observed anomaly. Having worked with lead acid batteries (and others), a 6-cell 12 volt automotive battery usually kills the middle cells before end cells. Kirchoff would like to suggest this is a fluke. However, it is the overwhelming norm. So, seeing different cell voltages in a battery stack would substantiate the observations I've seen, in spite of old-man Kirchoff.


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## brian_ (Feb 7, 2017)

mpgMike said:


> I'm aware of Kirchoff's Law, but reality begs to differ. Cell balancing offsets this observed anomaly. Having worked with lead acid batteries (and others), a 6-cell 12 volt automotive battery usually kills the middle cells before end cells. Kirchoff would like to suggest this is a fluke. However, it is the overwhelming norm. So, seeing different cell voltages in a battery stack would substantiate the observations I've seen, in spite of old-man Kirchoff.


The position is the middle differs in cooling. Middle cells dying first does not imply any deviation from Kirchoff's laws.


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## remy_martian (Feb 4, 2019)

Unless you have leakage current accounted for, Kirchoff might APPEAR to fail, but it is a LAW.


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## electro wrks (Mar 5, 2012)

Am I missing something in this picture? I see two different colors of coolant and no outlet for the top row of connections.


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## electro wrks (Mar 5, 2012)

eWillysBoulder said:


> Nonetheless, when I draw too much torque (like driving in 50 mph headwind with the windshield up), my battery modules tend to get out of balance with a premature low-voltage alarm on the cells closer to the end connections. Once I ease on the torque demand, the BMS rebalances the modules nicely. I will correct that by reducing the maximum torque.


Interestingly Tesla has chosen to put the two thermistors per module near these end connections, I believe attached to the most negative and the most positive cells. Or, is it the location of maximum current flow per conductor cross sectional area in the module design (not counting the whisker wires)? How much battery current are you drawing when this happens?


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## FelixPilot (6 mo ago)

eWillysBoulder said:


> View attachment 124990
> 
> Complete restoration on the 1948 CJ2A, kept the original transmission, clutch and flywheel. Motor is a NetGain HyPer 9HV with the X144 controller. Battery pack consists of 6 Tesla S modules in series for 30 kWh at 148V. I get about 50 miles of driving range (with the windshield down). Chick Magnet is an awesome four-wheeler:
> Four-wheeling near Cliff Hanger trail and Four-wheeling near Ward, CO
> ...


Awesome eWillysBoulder! Well done! I would appreciate any advice for my similar build...


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