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Discussion Starter #1
Does anyone know the exact dimensions (LxWxH) of OEM battery packs? Or can you point me in the right direction? I can't find them anywhere and I like to think of myself as a skilled Googler. I'll even accept metric if you have it haha.

Specifically I'm looking for the size of the following packs:

Chevy Spark EV
Fiat 500e
BMW i3

I'm sure they may vary by generation, but even a reasonable estimate would be nice.
 

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Spark EVs may still be available as used cars or in salvage. There are two very different battery packs, but they may be externally identical. Internally, the early ones have A123 modules while the later ones have LG Chem modules that are similar to those in the Volt... if using the modules in your own pack case, it's probably easier to get Volt modules.

I have collected some module dimensions, but no precise pack dimensions. Is the plan to use a complete intact pack? That has some advantages, but it's hard to fit a stock pack in a vehicle which is not designed for it, so the only builder that I've seem do it is Yabert in his Westfalia T3 with Chevy Bolt drivetrain (which has a Bolt battery pack which would be too large).
 

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Discussion Starter #5
Spark EVs may still be available as used cars or in salvage. There are two very different battery packs, but they may be externally identical. Internally, the early ones have A123 modules while the later ones have LG Chem modules that are similar to those in the Volt... if using the modules in your own pack case, it's probably easier to get Volt modules.

I have collected some module dimensions, but no precise pack dimensions. Is the plan to use a complete intact pack? That has some advantages, but it's hard to fit a stock pack in a vehicle which is not designed for it, so the only builder that I've seem do it is Yabert in his Westfalia T3 with Chevy Bolt drivetrain (which has a Bolt battery pack which would be too large).
Yes the idea is to use the whole, intact pack out of a salvage vehicle. It's a pickup so there's plenty of room for a modest sized battery (although frame or bed modifications may be needed), just want to plan ahead.
 

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Yes the idea is to use the whole, intact pack out of a salvage vehicle. It's a pickup so there's plenty of room for a modest sized battery (although frame or bed modifications may be needed), just want to plan ahead.
That makes sense. If you're hoping to fit the pack between the frame rails, it may be hard to find a pack to fit, since most packs are designed to fit between the rocker panels of a unibody structure, which are much further apart than the frame rails of a pickup. Where are you planning to put the motor? If you put it where the transmission was and so need to keep the shaft down the middle of the vehicle, it will be hard to fit in any single pack.
 

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The sheer number of Model 3s and soon, Ys showing up in wrecking yards are going to make tempting batteries and running gear for larger pick-up sized trucks and some vans. As brian points out, the stock battery enclosures are just too wide, as configured, to fit completely under smaller vehicles. And, the extremely long battery modules just about have to be mounted as they are in the stock enclosure- so it might as well be used as is, if it can.
Someone needs to figure out if the stock battery enclosure could be used as a stressed member in a frame system under a truck or van. If not, some kind of support system would have to be designed that would allow the vehicle frame to flex (as traditional ladder type frames do) without transferring much force to the battery enclosure. One good frame design might be to have the main frame rails (box or channel sections) moved to the perimeter to support and protect the sides of the battery enclosure This would also help preserve ground clearance and ride height. Typical cross members in the middle of the frame (now occupied by the battery enclosure) that provide lateral support, frame stiffness, and mounting points will have to be attached to the top( and/or bottom, if ground clearance allows) of the frame rails.
Ideas on using the running gear? You might get away with using stock 3 and Y parts on 1/2 ton (the lowest weight capacity designation in the US and other places for larger trucks and vans) truck and van applications. 3/4 ton, 1 ton capacity vehicles?
 

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Discussion Starter #8
That makes sense. If you're hoping to fit the pack between the frame rails, it may be hard to find a pack to fit, since most packs are designed to fit between the rocker panels of a unibody structure, which are much further apart than the frame rails of a pickup. Where are you planning to put the motor? If you put it where the transmission was and so need to keep the shaft down the middle of the vehicle, it will be hard to fit in any single pack.
From eyeballing it, it looks like the Spark battery is about 39" wide which is almost identical to the width of the interior of my frame rails - which is why I'm asking for exact dims. The motor is going directly on the rear axle. I want to have the battery between the axles, but there will be room up front if need be.
 

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Discussion Starter #9
The sheer number of Model 3s and soon, Ys showing up in wrecking yards are going to make tempting batteries and running gear for larger pick-up sized trucks and some vans. As brian points out, the stock battery enclosures are just too wide, as configured, to fit completely under smaller vehicles. And, the extremely long battery modules just about have to be mounted as they are in the stock enclosure- so it might as well be used as is, if it can.
Someone needs to figure out if the stock battery enclosure could be used as a stressed member in a frame system under a truck or van. If not, some kind of support system would have to be designed that would allow the vehicle frame to flex (as traditional ladder type frames do) without transferring much force to the battery enclosure. One good frame design might be to have the main frame rails (box or channel sections) moved to the perimeter to support and protect the sides of the battery enclosure This would also help preserve ground clearance and ride height. Typical cross members in the middle of the frame (now occupied by the battery enclosure) that provide lateral support, frame stiffness, and mounting points will have to be attached to the top( and/or bottom, if ground clearance allows) of the frame rails.
Ideas on using the running gear? You might get away with using stock 3 and Y parts on 1/2 ton (the lowest weight capacity designation in the US for larger trucks and vans) truck and van applications. 3/4 ton, 1 ton capacity vehicles?
I've got a smaller truck so Tesla battery packs wouldn't work, because you're right - too wide. Plus even salvage Teslas are all going for $10k plus, while I can get a non-wrecked Spark for $9k and a wrecked one for under $4k. They're just so much more popular than other OEM EV salvages - for obvious reasons. Maybe in a couple years Tesla salvages will be numerous enough to be cost-effective for smaller budgets?

Having the pack provide structure help is what I'm hoping. If I can get one to fit inside the frame rails, especially if a snug fit, I can remove the rear bracing (currently used for bracing, attaching the bed, and holding the spare tire) which would allow for a longer pack to fit. I think I would want to keep the bracing directly above the rear axle regardless. Here's a diagram of my truck's frame for reference.
120205
 

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From eyeballing it, it looks like the Spark battery is about 39" wide which is almost identical to the width of the interior of my frame rails - which is why I'm asking for exact dims. The motor is going directly on the rear axle. I want to have the battery between the axles, but there will be room up front if need be.
That's promising. The Spark EV pack is in the cargo area, instead of under the passenger area floor, so it is forced to be narrower, a good thing for this application. I was trying to think of other similar "compliance" EVs using the same design with simple pack (not, for instance, the multi-level thing in a Focus Electric) but none come to mind.

Someone needs to figure out if the stock battery enclosure could be used as a stressed member in a frame system under a truck or van. If not, some kind of support system would have to be designed that would allow the vehicle frame to flex (as traditional ladder type frames do) without transferring much force to the battery enclosure.
This is a good point, and I would be very cautious about appling torsional stress to the battery pack. A typical unibody is much stiffer than a truck frame, so a typical EV pack isn't twisted by body distortion.

One good frame design might be to have the main frame rails (box or channel sections) moved to the perimeter to support and protect the sides of the battery enclosure This would also help preserve ground clearance and ride height.
We discussed this is Yabert's T3/Bolt project thread. Stock packs are so wide that they generally don't fit between the rails of ladder frames (like a pickup), and so they need a custom structure; Yabert put his under the van's structure (and still had sufficient ground clearance) but had to modify the floor and structure for the taller part (normally under the back seat) of the pack. A custom perimeter frame for a pickup would work, but it would be a lot of effort.

For someone willing to build a custom frame (perhaps using the front section for the front suspension, but cut off around the cowl and custom from there back) I think a Bolt pack might work well for a pickup, with most of the pack under the cab and the taller section under the front of the box, still ahead of the motor and rear suspension. The Bolt drive unit would also be suitable for a compact truck, with the components on top of the motor unstacked.

Typical cross members in the middle of the frame (now occupied by the battery enclosure) that provide lateral support, frame stiffness, and mounting points will have to be attached to the top( and/or bottom, if ground clearance allows) of the frame rails.
Crossmembers over top of the pack would be much better than under the pack for the purpose of installing and accessing the pack, although removable crossmembers might be possible.

The Ford Ranger EV had a nearly stock frame with an enormous pack filling the space between the frame rails from almost the front axle to just before the motor (which was transverse on the axle line). To make that possible, EV-specific crossmembers arched high over the pack, lining up with transverse slots in the top of the pack. It was also the higher-riding 4WD version of the chassis, and the pack hung down lower than the conventional components.
 

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From eyeballing it, it looks like the Spark battery is about 39" wide which is almost identical to the width of the interior of my frame rails - which is why I'm asking for exact dims. The motor is going directly on the rear axle.
Are you direct driving the pinion or what's your plan there?

Drive ratio relative to motor rotor and axles?

What motor are you using?
 

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Discussion Starter #12
Are you direct driving the pinion or what's your plan there?

Drive ratio relative to motor rotor and axles?

What motor are you using?
My plan right now is to basically transplant everything together. So if I got a Spark, I'd use the batteries, motor, etc. and likely just replace the entire truck rear axle assembly with the Spark axle assembly - motor and all. Obviously there will be some modifications needed to make it work especially when it comes to suspension. Not going to change anything with regards to how the OEM stuff functions - trying to keep it simple.
 

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My plan right now is to basically transplant everything together. So if I got a Spark, I'd use the batteries, motor, etc. and likely just replace the entire truck rear axle assembly with the Spark axle assembly - motor and all. Obviously there will be some modifications needed to make it work especially when it comes to suspension. Not going to change anything with regards to how the OEM stuff functions - trying to keep it simple.
That is exactly the approach which Yabert took with his Westfalia van and Bolt donor. It seems to have worked well for him. :) The battery pack which could fit between the truck's frame rails are just small (in energy capacity and power output), and the corresponding motors are mostly relatively low power, limiting their usefulness in a pickup truck... but the Spark EV is an oddball in that it has higher motor power than other small EV cars.

If using a drive unit like that in essentially any modern EV, the rear suspension would need to be either independent or a de Dion axle; in the Ranger EV Ford took the de Dion approach, which is the easiest to adapt to the truck's frame and existing suspension hangers.
 

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Discussion Starter #14
Found the Fiat dims. 72" x 42" which is way too large in both directions lol.

Down to the BMW or the Chevy I guess.
 

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Eyeballed the BMW pack. There's a diagram that shows where the battery is in relation to the wheels, seats, etc. From that, I was able to get the exact measurements of the wheelbase (101.2"), tire diameter (27.3-27.8, depending on model), and, rear hip room/seat width (50.4).

The length is approximately the wheelbase, minus 1/2 of both wheels (one tire diameter), minus about 4-8 inches of wheel well gap and some extra body length. I'm guessing 65-70" which is pretty long.

The width is approximately equal to the rear seat width - possibly slightly smaller. I put it at 48-52" to be safe.

Unfortunately, the extremes of both estimations are still too large for my project. Looks like I'm down to the Spark, which is significantly skinnier than the BMW.

Currently, I have a Spark measurement of 59"Lx39"Wx13.5"H from a source that I'm not sure is good. Going to do some estimating so see if that's close and hopefully dig up another source.
 

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Someone needs to figure out if the stock battery enclosure could be used as a stressed member in a frame system under a truck or van.
The new super strong bonded battery cell enclosure/ honeycomb-like battery box design, as outlined during the latest Tesla Battery Day, makes this even more of a possibility. I hope, for us DIYers, Tesla makes the battery box easy to separate from the rest of the vehicle's structure. Or, it's designed so enough of the structure could be retained or easily modified(welded, bonded, etc.) to support the suspension, motor(s), and other components under a variety of body types.
Yes, the much vaunted "skateboard"!
 
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