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Discussion Starter · #1 ·
Hi all,

Just posted my New Member introduction here: Greetings from Germany

I’m considering to convert my 1997 Jeep Cherokee XJ (currently fitted with a 4.0 L Inline 6) to reduce noise, emissions and potential failure points in the system. Besides that, I’m just a passionate tech guy and love a good project. Depending on how feasible the conversion is and how it turns out, I’m then also considering to put together a conversion kit for the XJ as well as possibly starting a business to convert 4x4s to electric, but those are just some thoughts for the next years.

Your skill level with auto mechanics and fabrication

I'm a car mechanic, also working on all kind of projects continuously. I know how to use a welder… the tire carrier on the Jeep is DIY :)

The range you are hoping to get (how many miles/charge)

Looking at roughly 100 km (60 miles) to keep cost and weight down for the beginning, might want to increase that further down the line

What level of performance you are hoping to get

Don’t need to go fast (80km/h, 50mph), but I need torque for offroading and climbing mountain roads. Also, I still want to be able to tow small trailers (750 kg, 1650 lbs)

How much money you are willing to put into your project

As much as required, as little as possible.

What parts you've already considered, if any.

At the moment, I want to go for a 96V system… just to keep it safe

For the batteries, I would prefer to use OEM modules because of cost and their good packaging... for example the VW ID3 modules. While we’re at it, how would I connect, let’s say an Orion 2 BMS, to these modules (since the cells are packaged already)? Would I still need to get a cell package with the BMS itself?


For the motor, I’m really torn between DC (brushed) / AC (induction)..

DC because I can get used motors.. aiming for the ZAPI H2 controller, which also offers regen (which should be possible with non-advanced brushes on a stock 80 V motor)

AC because it’s more sophisticated, but since I want to run 96V, I would need to buy a new motor (all OEMs are high-voltage)


Besides deciding between DC/AC, I also need to figure out how to implement proper cooling while also protecting the motor from water and mud. Watercooling on ACs seems to be the easiest.. For the DC motor, I would build an encasement (inside aerodynamically optimized) with an integrated cooling fan

In terms of weight, I’ll actually end up lightening the Jeep. At the moment, it’s roughly 1,7t (3750 lbs)… with removing the engine (250 kg) and all the other stuff, I should end up at around 1,5t (3300 lbs) after the conversion.

I’m posting here to get help deciding between DC/AC mostly, as well as just hearing your opinion on the whole conversion, if it makes sense in your eyes, what you would make different or if you have other ideas/input.

Looking forward to your replies!

Cheers, Flo

P.S. Some pictures of the Jeep

Automotive parking light Tire Wheel Automotive side marker light Plant


Automotive parking light Tire Wheel Plant Automotive carrying rack


Wheel Tire Automotive parking light Automotive side marker light Vehicle
 

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Good luck! Check out my build as my chassis and goals are similar. If you really need your vehicle to live your life you might want to buy another one to drive or even convert instead. Sounds like you have a great lifestyle however!
 

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Discussion Starter · #4 ·
Good luck! Check out my build as my chassis and goals are similar. If you really need your vehicle to live your life you might want to buy another one to drive or even convert instead. Sounds like you have a great lifestyle however!
Thanks! Already lurking around in your build thread :D My idea was to basically build a test stand in the garage, putting together the entire system, preparing the coupling, all the mounts etc., and then just swapping things over within a few weeks. If that works, I don't need to have another car :)
 

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As a fellow XJ nut (1998, first owner), good luck and god speed. My plan is to keep my XJ stock ICE for long trips and add a converted vehicle for the nearby trips.
 

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Discussion Starter · #7 ·
As a fellow XJ nut (1998, first owner), good luck and god speed. My plan is to keep my XJ stock ICE for long trips and add a converted vehicle for the nearby trips.
Yes, I've also thought about that, but I prefer to have one vehicle to "do it all". Since I have quite some capacity in terms of weight, I could add plenty more batteries for longer trips later :)

Where are you thinking you're going to put the batteries?
For the beginning, the pack will sit in the engine bay. Depending on the motor, it's going to weigh around 50-80 kg.. so still 170-200 kg left for batteries to maintain the original balance (since I also have the tire carrier in the back, evens out the weight loss from the gas tank)
 

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DC will be the cheaper route most likely, but you have to replace the brushes from time to time which can be a hassle. Also generally requires a more robust cooling system.

With AC you get more modern features like regenerative braking. The best low-voltage AC option is a hyper 9 motor kit.

Either way, Tesla modules are your best bet for a lower voltage system with those range goals. You'll want to have at least 25kwh or so to hit your desired range. 5 Tesla modules gives you 28kwh, and that voltage matches the low-voltage hyper9. If you want to up the voltage a bit, you can use 7 Tesla modules in series for more capacity with the Hyper9HV.

The car I was originally planning on converting was a 96 XJ 2-door I bought for $1k sight unseen. The unibody rails were completely rusted away, unfortunate because it looked so nice. I love XJs.
 

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Your recommendation might work for a one-off, but this is a prototype, not a one-off.

Tesla S/X modules are a bad choice if he plans to offer kits in upcoming years, meaning a complete redo. The 10 year old Tesla module design will likely be discontinued in favor of their structural battery.

The 3/Y modules make more sense, IMO, where one module more or less does the job and they're being produced like jellybeans.
 

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Tesla S/X modules are a bad choice if he plans to offer kits in upcoming years, meaning a complete redo. The 10 year old Tesla module design will likely be discontinued in favor of their structural battery.
I agree - the traditional S/X modules are presumably still in production, but have already been replaced for the top version of the model range (the Plaid) with a different form factor using different cells grouped in a different number of modules... and that's even without using the long-promised 4680 cells or a structural battery design.

From the point of view of diversity of supply in the same form factor, the VDA 355 standard is about the only potentially long-term format (because it is an industry standard not unique to one EV manufacturer or module supplier), but in practical terms it may not be the most viable. Examples are the three modules of about 355 mm length offered by Zero EV and the "Energy" series of modules in the OX Drive line from Electric GT; the Jaguar I-Pace uses this format, as well as some Volkswagens or Audis.

The 3/Y modules make more sense, IMO, where one module more or less does the job and they're being produced like jellybeans.
Form factor of those modules is not conducive to putting batteries in the engine bay at all.
They will certainly be more plentiful than the old S/X modules, but yes... they are way too long for most potential locations in a conversion. The only place they would fit in an XJ Cherokee without radical lower body modification would be in the rear seat and cargo area, eliminating the rear seat and requiring a raised cargo floor. They would suit some vehicles with a high floor and lots of empty space under it (SuperfastMatt's Jaguar Mk V uses them), but not a XJ.
 

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One down each side of the driveshaft tunnel and you're done.

Edit: on the bottom of the vehicle, not inside it. Between the frame rails.
That sounds good, but check the dimensions of those modules, add allowances in all directions for structure and housing, then crawl under an XJ with a tape measure and look for the space without cutting structure or removing needed components of the vehicle... I don't think you'll find it.

If two of them would fit, then I agree that for a system needing either 23S to 25S or 46S to 50S of 3.7 V/cell battery a couple of Model 3/Y modules would be great.
 

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I'm forcing them to think "out of the box" - this is not a car conversion AND the low volatge means only two modules. Of course, if it fits. I'm thinking it should.

Integrating removed crossmember function into the battery box structure is easy -- there are two shear plates in a box.

There's plenty of other crap that can get stuffed into the engine bay and a frunk in a conversion could be a calling card.
 

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Yeah...so what?

One down each side of the driveshaft tunnel and you're done.

Edit: on the bottom of the vehicle, not inside it. Between the frame rails.
There is very little space there in a Jeep XJ. The vehicle is unibody/unitized construction, so the actual "frame" sectional height is only about 4" or so, with multiple stiffeners and mounts from the floor above protruding into this area. Also, if the 4wd is to be retained, which IMHO is the only point of owning a SUV and not a minivan, the bulk of one side of this under body area is occupied by part of the transfer case and the front driveshaft. On my big ugly offroad XJ I had trouble even getting a 2.5" exhaust pipe through the "empty" side, as I have full belly skidplates and did not want anything hanging down. Likewise, you wouldn't want your battery modules to hang down, as you probably don't want them damaged.

If a guys is willing to make significant body and structural modifications, one probably could cut the floor out of the cargo area and part of under the back seat, and build a new floor lower down, install the modules, and put a false floor over the top. Or clear out that space and install said modules from below. There is a crossmember in this area that the shocks attach too, and two other braces that are for stiffening the floor and holding the gas tank. All of this would need to be reworked, and at this point there would be no way you could consider this a kit.

Model 70, AKA Jeep XJ, unibody "frame" diagram.
 

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I'm forcing them to think "out of the box" - this is not a car conversion...
Of course it's a car conversion. In other places people call this sort of vehicle a "car", because that's what it is... specifically a station wagon with 4WD. It's not a heavy truck with straight frame rails sitting so high that you can crawl under it without jacking it up.

... the low volatge means only two modules. Of course, if it fits. I'm thinking it should.
Even one is unlikely to fit, but yes, if one fits it's possible that one would fit on each side... but the transfer case and front driveshaft make that very unlikely.

Integrating removed crossmember function into the battery box structure is easy -- there are two shear plates in a box.
Well, sure... you could also remove all structure under the floor pan and build a whole new structural box. That's one aspect of what I meant by "radical lower body modification". And the uninterrupted single module from front to back in the Model 3/Y pack means that the ends of a box acting as shear plates are only at the end, leaving a long span with no crossmember.

There's plenty of other crap that can get stuffed into the engine bay and a frunk in a conversion could be a calling card.
I agree - the other stuff that needs to be packaged is not a concern if the battery doesn't go under the hood.
 

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Sorry Brian. Too late to the party and you're regurgitating what's already been said, and the obvious.

You can't beat the post before yours - he even included the "frame" diagram
 

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Sorry Brian. Too late to the party and you're regurgitating what's already been said, and the obvious.

You can't beat the post before yours - he even included the "frame" diagram
Ah, if only I gave a shit what you think.

And none of this seemed obvious to you, remy...
 

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The "like" button got pushed by me before you posted. Then you liked it. That made it very obvious I agreed with what got posted. And then you did. A = B, A = C, therefore, safe to say... B = C

There was nothing more to say, though I suppose I could have paraphrased the excellent perspective, analysis, and resource that was provided with an agenda to steal some of the intelligence. But, not my thing. I was provoking thought, as I had stated, the thought process got laid out really well on why not. Even included the structural layout, with measurements 😳

After that excellent posting, restating what got posted already was a waste of electrons and pixels.

There are now several dead salmon floating down the Columbia after going through that power surge you engaged in 😂 .....Trying to show B < C when B = C

Pointless after the math was already done.
 

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Discussion Starter · #20 ·
Oh boy, you guys left me stuff to read :D

Let's get into your posts:

Regarding DC/AC, I'm aware of the more intense maintenance for DCs and the regen advantages of ACs. The con of ACs is the cost.. a solution would be to go for OEM parts, but then we're at high voltage again. I think the main factor is to determine how easy regen would be for DC motors. I know that the ZAPI H2 controller offers this option. And as far as I read, it's in general possible on a Series DC motor with interpoles, as long as the brushes aren't advanced (correct?).

Another challenge would be to find a sustainable source for used DC motors that I could overhaul and then use for the kits. And since the motor characteristics are leaning towards higher torque from low rpms, this seems to be the better choice for 4x4s. But I still have limited knowledge in these topics, so any advice is welcome.

Regarding the batteries: Seems like I need to do plenty of more research. The ZAPI H2 96V controller can handle 120V max. as well as 600A. So in my simple thinking, I would need to get a pack that sits at 120V when charged fully, correct? In terms of BMS, I've read many opposing arguments.. wether I shouldn't even have one (I would then need to have LiFePo cells).. if it's the right choice to get something off the shelf (Orion 2) or rather put one together myself...

Regarding the battery position in the car, I think the sensible choice is to first stuff the engine bay. With the motor and accessories out, I lose about 280 kg.. the motor would weigh 80 kg max., leaving me with 200 kg. Just for rough calculations, 4 Tesla modules weigh around 120 kg.. leaving 80 kg of capacity.. with the gas tank removed in the bank, this should balance things out and make the car lighter.. keep in mind, this is just a first step for about 100 km of range.
Putting batteries under the car is not really practical because of ground clearance, damage prevention as well as water protection.

Since we've already started talking about potential "business" decisions for a potential kit, let me give you some more ideas where this should lead to:
My identified niche would be the opposite of high-end, high power conversions like most companies offer by now. I'm aiming for good overall torque/performance, realistic range and interesting pricing. So why not set up a kit with a DC motor, 100-200 km of range and total cost of 10-15k.. at least that's my initial idea.

I know, a lot of chaotic thoughts, so please forgive me for that. I appreciate the effort for making informational posts, and am looking forward to new inspiration :)
 
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