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Discussion Starter · #1 · (Edited)
So I have this Jeep XJ that i bought for 2k about 5 years ago from a family friend that was a metal worker(hence the custom back)
Wheel Automotive parking light Car Tire Plant


i had a donor ICE engine that I was going to swap it to. but the shop that I had it at took the jeep motor out, sold it, closed the business, and the owner moved across the country.

So i have a shell thats been sitting around for years, and i figured this would be a cool build.


My plan hasnt gotten very far yet but some of the ideas ive had so far are:
  • Build a battery box where gas tank is, up through the bed for easy access.
  • I would like a dual/tri motor with the "single gear transmissions" (i dont know the actual name)
  • I plan on building a Solar camper that will have panels on the roof and a large battery system so i would like to have a port on the back to allow the jeep access to the campers batteries to extend towing range
Your skill level with auto mechanics and fabrication

II have some mechanical experience, zero metal fabrication experience, some electrical experience. But ive always been kind of a jack of all trades and i pick up on things quickly with good instruction

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

looking for about 120 miles to start ( my daily average driving is just under 100 miles)

What level of performance you are hoping to get

Dont really need to go above 80mph, would like to be able to tow

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.
nothing yet

Any ideas, suggestions, product recommendations, instructionals, or just general feedback welcome.
 

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Discussion Starter · #5 ·
Towing power for what? You move houses for a living where you need three motors?

What are you towing (incl weight)?
In my post i talk about my plans involving building a solar powered camper with a large battery backup system, so im assuming thats going to be pretty heavy. I dont have anything picked out yet, as I am just in the starting phase.

but some quick weight estimates
Truck now as a shell: 2,000 +/- lbs
Camper: 7,000-10,000 lbs (this is based on a range of campers of different sizes, but doesnt include the weight of the batteries and solar etc)

is 2 or 3 motors a lot? the few swaps ive seen for these always have dual motors. and tesla uses dual and tri motor configurations in all vehicles. I just figured i needed that many for this plan.
 

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Tesla is a bunch of car guys who have no clue of what a truck is. They cite 0-60 times on the Semi...like a trucker GAF.

In my experience, towing more than 2x or 3x the truck weight is asking for trouble. I doubt your little sawed off Jeep was ever rated to tow more than 7000lb. As soon as you hit 2x, things can get squirelly pretty fast in curves going down steep grades with trailer push.

You clearly havent done the math on your solar powered camper. A set of foldout panels means next to no battery at all. LED lighting means you use maybe 40W of light for 8 hours...that's 0.33kWhr of battery...one Tesla module has you in lighting for 17 days...55lb. That's with zero solar. A PTC would nominally run 2kW for 12 hrs at night. That's 300lb of battery

Get the tow weight goal to a max of 4,000lb and target 3,000lb. Being sloppy with mass has no place if there's an EV in the equation.

Two motors if you need AWD, one is fine for highway work, gear it to top out at 80 is good.

Your problem will be cooling, not so much the battery...if you're not sloppy with the camper build.
 

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7000lb is doable, the Trailhawk trim XJs were rated for 7200, automatics in other trims 5000lb. But yeah, I wouldn't do it. I towed 4500 through the rockies in my 98 manual and it was... fine, but didn't love the downhill curves.
 

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is 2 or 3 motors a lot? the few swaps ive seen for these always have dual motors. and tesla uses dual and tri motor configurations in all vehicles. I just figured i needed that many for this plan.
All AWD production EVs use at least two motors, simply to have at least one at each axle; this avoids a shaft down the length of the vehicle, and avoids a differential between axles. A few EVs (and hybrids) use two motors at one axle - a single motor per wheel - mostly to allow them to independently control the torque applied to each wheel, partially to avoid the axle differential, and perhaps to get twice as much power using available motors and inverters.

Most DIY conversions use a single motor, even for 4WD, because the builders find that easier and probably less expensive.

Tesla has a single motor in 2WD models (assuming that they still sell some of the those), two motors (one per axle) on most AWD models, and three motors (one in front, two at the rear) in the highest-performance models (only the Model S Plaid so far, but planned for the Roadster and whatever else they might eventually build). The Semi - if it is ever produced - will have one motor per rear wheel... with the motors installed right in the beam axles.

In the Cherokee, do you intend to keep the beam axles front and rear, or are you planning (or willing) to replace that with independent suspension at front, or both? If you still have an original beam axle you can only drive it with one motor, so with both original beam axles you have two motors at most. Motors mounted on beam axles are possible, and would certainly work, but are not desirable in car or SUV. A beam axle with two separate inputs (pinion shafts) to connect two frame-mounted motor to one axle would be interesting, but custom, strange, and not worthwhile.
 

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Discussion Starter · #9 ·
In my experience, towing more than 2x or 3x the truck weight is asking for trouble. I doubt your little sawed off Jeep was ever rated to tow more than 7000lb. As soon as you hit 2x, things can get squirelly pretty fast in curves going down steep grades with trailer push.
Yeah I understand that. There's going to be a lot of other work done to the jeep increasing the weight of it.

You clearly havent done the math on your solar powered camper. A set of foldout panels means next to no battery at all. LED lighting means you use maybe 40W of light for 8 hours...that's 0.33kWhr of battery...one Tesla module has you in lighting for 17 days...55lb. That's with zero solar. A PTC would nominally run 2kW for 12 hrs at night. That's 300lb of battery
You're right I clearly haven't as I stated before that I haven't done any of the calculations on the camper yet. I was using the weight of the mid-size and the large airstream models as a basis for the weight.
The camper in my mind is going to have a fixed solar system on the roof of it and the battery packs in the camper are more so to extend the range of the Jeep while towing than they are to run the camper.



Get the tow weight goal to a max of 4,000lb and target 3,000lb. Being sloppy with mass has no place if there's an EV in the equation.
I don't think I will be able to get a camper in the size that I want / need at that low of a weight unfortunately


In the Cherokee, do you intend to keep the beam axles front and rear, or are you planning (or willing) to replace that with independent suspension at front, or both? If you still have an original beam axle you can only drive it with one motor, so with both original beam axles you have two motors at most. Motors mounted on beam axles are possible, and would certainly work, but are not desirable in car or SUV. A beam axle with two separate inputs (pinion shafts) to connect two frame-mounted motor to one axle would be interesting, but custom, strange, and not worthwhile.
My plan was to completely remove pretty much all of the components from the original Jeep including the straight axles and do independent suspension for each wheel. I figured that way I would have the room from the engine bay and transmission tunnel to mount a dual motor system.


Y'all, I have ZERO idea what I'm doing, I've just got a dream 😂😂
 

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I don't think I will be able to get a camper in the size that I want / need at that low of a weight unfortunately
Then you're probably pushing the design limits of the XJ for towing what you want. This isn't an EV problem in this case unfortunately. You have to take into account the other limitations of the vehicle for towing beyond powertrain.
 

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Braking, frame strength for the hitch, relative weight of the towing vehicle vs the trailer (The XJ is nice and light), strength of all the drive-line components under load. Keeping any fluids in the driveline cool, which is a little easier in the EV. Presumably you'll have trailer brakes as well. Sure I'm missing a couple things...
 

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Discussion Starter · #14 ·
Braking, frame strength for the hitch, relative weight of the towing vehicle vs the trailer (The XJ is nice and light), strength of all the drive-line components under load. Keeping any fluids in the driveline cool, which is a little easier in the EV. Presumably you'll have trailer brakes as well. Sure I'm missing a couple things...
So as far as frame strength and relative weight of the vehicle these are things that I had already kind of considered when I was trying to determine which route I was going to go as far as engine swap (I considered diesel and gas and more recently decided on electric)
With the Jeep being a unibody I was going to get a donor frame mounted underneath to add stability (also weight) And then the front and rear bumpers are already custom made steel heavy duty bumpers that add a considerable amount of weight. On top of that I planned on doing a steel exoskeleton and roof rack that are going to add weight too.

And so I've just got the body basically that I'm keeping and I'm going to be changing out everything else and upgrading and beefing up.

This is going to be a long-term build 😂


Here's a nice thread on XJ (non EV) towing: XJ towing capacity
Thanks I'll have to check that out.
 

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With the Jeep being a unibody I was going to get a donor frame mounted underneath ...

And so I've just got the body basically that I'm keeping and I'm going to be changing out everything else and upgrading and beefing up.
Ah, so you intended to build a custom truck, and set a Cherokee body on top of it. That's very different from converting a Cherokee, although the Cherokee body limits the truck to a size which is too small to reasonably tow several tons, on the basis of stability.
 

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Discussion Starter · #16 ·
Ah, so you intended to build a custom truck, and set a Cherokee body on top of it. That's very different from converting a Cherokee, although the Cherokee body limits the truck to a size which is too small to reasonably tow several tons, on the basis of stability.
So you're thinking the length of the XJ even if stabilized is still too short to be able to efficiently tow a camper of any reasonable size.

Well that's going to throw a wrench into my plan I'd say 😂😂
 

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Discussion Starter · #17 ·
Ah, so you intended to build a custom truck, and set a Cherokee body on top of it. That's very different from converting a Cherokee, although the Cherokee body limits the truck to a size which is too small to reasonably tow several tons, on the basis of stability.
Also the extent of how much of that extra stuff I do was depending on how much I needed to do like if I don't have to do that stuff I'm not going to

I think for now I'll focus on the truck, and then when it's done see what I can tow and go from there on the electric camper


Does anybody have recommendations on motors, batteries, controllers etc? Or a link to some good detailed instructions/check list for an ev conversation?
 

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It's all on here - several people have tried to organize "instructions", but everybody's requirements, vehicle, budget, resources, skills, tools, and regulations are so different it becomes more of a reference than a recipe.

Best thing is to dive through entire build threads to see what people did and try to understand why. Doesn't have to be the same vehicle, though it helps to look at Jeeps vs the Lambo conversion, for example.
 

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I'll pipe in to call attention to my hope that you're not planning on a "solar powered RV" situation.

It would be hard for solar panels to break even with the energy requirements of the added weight they bring.

You'd probably be looking at weeks to charge up your batteries with them. This isn't "park for a couple days to recharge my batteries, then drive 2 hours down the road" kind of thing.

Very rough ballpark, I'd say you'd be using 1000-2000kwh per mile of range when towing a trailer (versus 250-350-ish kwh per mile in a small, light car). The Jeep itself, hmm.. maybe 600 or so? If it's beefier like you plan, well, a van uses around 800-1000kwh/mile. Let's say you can get away with 600kwh/mile at 60mph (not 80, which will be like 1000). You want 120 miles of range. 600wh/mile x 120 miles = you'll need a 72kwh battery pack to do that. That's really, really heavy, and really bulky. Around 1000 lbs.

While towing, let's say 1500kwh/mile. ~48 miles. I dunno if you can even hop to the next campground with that kind of range.

Then, how much solar are you putting on your trailer roof? Being generous and saying 1000 watts? How many peak solar hours are there on an average day in your area? Maybe 3-5? Let's say 4. 4000 watthours per day.

You've got a 72,000 watt-hour pack, so, 18 days to fully recharge an empty pack. Which then gets you 48 miles down the road. Or, rephrased another way, 2.7 miles per day.

A far better use of money is to just buy a large gasoline generator, keep it in the trailer, and use that to add miles when you happen to be travelling with the trailer. Even a little minimal 2000 watt honda generator could be run 24/7 and at least get you charged back up in a day and a half.

Or, put another way since you say you want to use solar to help add range while driving... 1000 watts of solar, let's say you're in peak sunlight when driving. You're using 1500 watt-hours per mile. That's 90,000 watts to maintain speed. You're bringing in 1000 watts with your solar. Your solar is contributing just over 1% of your power requirements to maintain that speed. Is that significant enough to bother with? And that's noon sun. In morning or afternoon you're looking at maybe 1/400th of your power requirements. Might as well get out and push.

Every few months someone is dead set on an EV motorhome, or solar EV RV, and, I've never even seen anyone get started. I saw on Youtube once, one family built a solar EV RV, and they were getting something utterly comical like 12 miles range. They tried to sell it as "Oh it's good to just take your time and enjoy a slower pace of life" but to me, it looked like "Oh my god we spent all this money on this expensive project without thinking it through, and this is hugely disappointing but we can't admit that to ourselves, so, we'll talk about this failure as if it's a different kind of success."

I do want to see someone do it, I really do, but, the cost of hauling that much battery and/or that much solar is literally more than a lifetime of gasoline expenses. It never pays back the cost of building it.
 

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7000lb is doable, the Trailhawk trim XJs were rated for 7200, automatics in other trims 5000lb. But yeah, I wouldn't do it. I towed 4500 through the rockies in my 98 manual and it was... fine, but didn't love the downhill curves.
In the UK the 4.0 Auto XJ is rated for 3250kg which is 7165Ib's
Manual's seems to be rated a lot lower at 2500kg = 5511lb's
Jeep Cherokee (1993 - 2001) 4.0 Classic 5d Auto
3250kg​

Obviously we use a different hitch type Euro vs US - but it would be with the same frame/chassis. Don't know if there are axle differences between the man/auto? but if there are it would be simply to fit up-rated axles.
 
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