[D&VsEVJeep]

My first real 3D printed part for the Jeep... Fit perfectly. This is the coupler/adapter between the stock transfer case and the Cascadia Motion Speed Reducer... I hope it will hold up to the torque from the e-motor...

Finding space for batteries...

BTW...that was just a joke about the 3D printed part being actually used on the jeep... Just a fitment test before making a real one...

 

[remy_martian]

The batteries in the engine bay can't lay flat?...every bit helps with lowering CG....

 

[asymptonic]

The batteries in the engine bay can't lay flat?...every bit helps with lowering CG....

Maybe? The motor mounts include on the space pretty awkwardly as I've found. I've been able to get a pretty dense layout with VDA355 but the MachE's are bulkier... These screenshots are super preliminary, so don't make fun of my awkwardly placed motor. In both screenshots the inward lumps are the original motor mounts.

VDA355:

Approximate Mach-E dimensions and layout. I think there is room to do them sideways but I don't have the batteries in hand so I'll defer to D&V on this.

Personally I'm waiting on someone to teardown the Ultium batteries from the Hummers that should be wrecked in 3...2...1...

 

[asymptonic]

Looking closer, is that a big chunk of square tube crossing the engine bay in place of the motor mounts in your mockup D&V?

 

[remy_martian]

The steering mechanism is generally immovable.

The old motor mounts are sawzall food.

 

[asymptonic]

Agreed but I do like to take advantage of non-hobbyist bits that were meant to take weight against torque if I can. Re: steering, the trackbar etc are below the battery for sure. Pardon my blobby CAD engine bay for the moment, still working with the surprisingly helpful iPhone scan. Side view of steering on the bottom right. The steering from the cabin is the extreme right of the earlier screenshot. All should be well clear as far as I can tell. This tracks with the 4.0 from my experience with the XJ which is pretty much the same setup as the TJ from this era. Part of my motivation for vehicle choice is to get a bunch of fresh parts for my XJ. , the oil pan drops down below the aft of the engine and gets closest to the suspension and steering, but the engine block attaches to the mounts quite a bit upward from that.

 

[remy_martian]

All I'm saying is you can lop off the engine mount ears if it gives you clearance to lower the heavy battery box CG. You can still pick up the same location on the frame to transfer that weight to the frame and front suspension.

The only bear is the damned steering box - I'm offsetting the battery box an inch or two (still in design) from vehicle centerline to get away from the steering shaft to achieve a lower CG.

A couple of inches of CG drop on a 400 pound box is huge for rollover moment in turns, or incline angle if you're crawling.

 

[asymptonic]

All I'm saying is you can lop off the engine mount ears if it gives you clearance to lower the heavy battery box CG. You can still pick up the same location on the frame to transfer that weight to the frame and front suspension.

The only bear is the damned steering box - I'm offsetting the battery box an inch or two (still in design) from vehicle centerline to get away from the steering shaft to achieve a lower CG.

A couple of inches of CG drop on a 400 pound box is huge for rollover moment in turns, or incline angle if you're crawling.

One hundred percent agree from a physics standpoint. The 90s jeeps all pretty much have the same over abundant engine bay volume fore to aft due to the inline 6 engine being a long nosy beast. The steering is way over to the side to clear the weirdly large intake/exhaust manifolds from the early 80s design and the steering box is right above the bumper (above the natural off-road clearance) and ahead of the engine. All this to say it's a lot of room to work with with the ICE removed.

 

[D&VsEVJeep]

The batteries in the engine bay can't lay flat?...every bit helps with lowering CG....

Yes...just didn't get to that yet. The engine bay is the "easy" part... I did have three modules in there in the beginning and three definitely won't lay down...

Looking closer, is that a big chunk of square tube crossing the engine bay in place of the motor mounts in your mockup D&V?

Yes...just a place holder for me to mate things to in Solidworks. I will remove the factory engine mounts to leave the flat "brackets" to make some kind of frame connected to the front round frame member to give me a good (flat) structure to mount things to...

 

[brian_]

Personally I'm waiting on someone to teardown the Ultium batteries from the Hummers that should be wrecked in 3...2...1...

Given the moments between Tesla Model S Plaids hitting the streets and the teardowns starting, it shouldn't be long for the Hummers. Rivians should appear any moment, too.

 

[remy_martian]

^ lol

The Ultium BMS is likely going to be encrypted RF, so look forward to either a hacking reflash of hardware that's there or replacing boards with ones we control.

That means, what you get for your money is a thermally coupled box of cells in a different form factor than what's already out there from Mustang, Bolt, Volt, iPace, etc. A measuring tape is likely the only useful tool on an Ultium teardown, imo.

 

[asymptonic]

Maybe. I'd bet GM cuts corners on BOM cost and doesn't encrypt due to the wireless being internal to an EMI sealed metal box. But I'd guarantee they didn't spend enough to stop anyone from just attaching directly electrically with a custom BMS as you say.

Margins on these guys are thin compared to the oversized empty boxes they call trucks that they like to sell, so I don't expect real security on these. (I'm in cryptography/security for a living for what little it's worth).

 

[asymptonic]

Way late addition: I take your point that there may be little benefit to Ultium cells if you're going to crack into them, but I had been reading that they may have been getting a bit better chemistry. For those of us that aren't as adept at delicate fabrication, the shots I've seen seem to indicate a manageable form factor with strong mount points that is at least worth considering. If the chemistry is identical to the others though I'm sticking to the more lego-like VDA355s from wherever. I love the great mounting and integrated dumb bms/thermocouple connectors on them.

 

[D&VsEVJeep]

@remy_martian Thanks for the push...

Side-by-side they just fit...

...and it gives me reserve space in case the battery modules next to the rear driveshaft are too close for comfort...

BTW...these are not the stock modules... I will reconfigure into two 8-cell pair "sub-modules" that will be interconnected...

Custom liquid cooling plate...

One port in...one port out... This is the sheet metal version... Also getting pricing on machined cooling plates from our supplier...

 

[D&VsEVJeep]

Shit...I just noticed the batteries are upside-down inside the box...

 

[D&VsEVJeep]

So...the project manager asked for a color render of the current model... She likes things colorful...

 

[remy_martian]

So, where I'd go from here is get the inverter out of the way and pull the battery modules back to the firewall to give yourself a bit more crush room in the event of a frontal. Makes for a slightly smaller polar moment as well if the project manager ever decides to enter it into Formula 1.

Lay the inverter down on the pack near the firewall. A bit lower CG from this as well or maybe same - hard to eyeball, even with the colors 😛

 

[remy_martian]

The modules I'd move first not the ones by the driveshaft..you can armor that area.

The ones in front of the rear bumper are a concern and need to vamos first, imo.

 

[remy_martian]

You also might want to experiment with moving the inverter under the pack, offset to the passenger side. With the pumpkin offset to the driver's side, it may go in there:

 

[electro wrks]

This article describe a conversion design very close to your design:

https://jalopnik.com/the-fully-electric-jeep-wrangler-concept-looks-like-it-1846262255