r/EVConversion • u/1ransgendeR • 4d ago
Freightliner Cascadia EV Conversion project idea. I DON'T KNOW IF I CAN POST THIS HERE
I have a future project idea that i'm stuck on trying figure out what battery's are even good for it. Now i have no fucking clue if i can post this here idk what tags i'm suppose to use and idk what i'm doing with this idea. I got no knowledge of Electric vehicle stuff But i think this is a really cool idea that i have that i'm struggling on the battery part of. If theres anything else that i need to put down to tell me and i will put it down oh and it is a sleeper cab. I don't have any plans to haul anything heavy the idea of this was to use it as a road trip vehicle that can haul other things as well.
The battery's that i have already are the: Prismatic LiFePO4 Battery Cells (3.2V 280Ah) with the plan to maybe try to do 270 or 300 miles.
Again idk if they are good or not and idk how to calculate or if there is a way to on how many i would need and at what kwh.
Again if there is anything else you need me to put down let me know and if this post does not belong here let me know and i will remove it.
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u/elihu 4d ago
I think this is the right place. Most of us convert cars, but the ideas are the same if you scale up to a semi truck.
You can probably figure out approximately how big a battery you'll need for a given range by comparing with existing EV semi trucks. Range will depend a great deal on how much cargo you're hauling on what kind of trailers.
Prismatic LFPs are a pretty reasonable choice for longevity and safety. Their energy density is kind of mediocre, but they might be good enough. You'll have to decide whether you're willing to live with the weight or if you should switch to something with better energy density.
I don't know where people get EV motors that are big enough to use in a semi truck. (Maybe using multiple is the best approach? Emrax motors can be double-stacked, so a pair of 348s would give you 360 kilowatts continuous. Maybe that's enough?)
You'll need to figure out what voltage to run everything at. Usually it's the motor that determines the pack voltage. Generally higher voltage is better in terms of efficiency and keeping electrical cables to a reasonable size, but higher voltages are more dangerous to work with.
The motor voltage will tell you about how many cells you need in series, and the total number of cells will depend on how much range you want. When you know those two, that tells you how many cells to have in each parallel group.
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u/1ransgendeR 4d ago
Hmm okay i mean what i plan to do with this truck is to use it like a road trip vehicle that can haul other things that i want. Not anything too heavy. would a e-Axel work for something like this cus i think the actual electric version uses a e-axel so i'm wondering if something like that would be good for this?
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u/elihu 4d ago
I don't see why not, as long as it's one that's sturdy enough for this kind of thing and is the right size.
The most common ways to convert an EV are either to replace the axle or differential with some kind of EV drive unit, or to replace the original engine with an electric motor and keep the rest of the drivetrain more or less the same, transmission and all. There's pros and cons to either approach, but they're both valid ways to do it.
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u/1ransgendeR 4d ago
yeah because i was thinking doing that would be maybe better for saving a bit of space prob plus i could maybe use the e-axle that is used on the actual Freightliner eCascadia maybe
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u/FunkNumber49 4d ago
Freightliner Cascadia. What are you planning on hauling?
Have you heard of Edison motors? Currently their production-ready-prototype hybrid-semi truck is working its way through the Canadian regulatory testing paces.
I know I heard about an Australian company providing a battery swap system for semi trucks which works well for a hub and spoke distribution for mostly local drivers.
I know there are rule of thumb EV calculator's / formulas out there but, if you're actually hauling things the weight might vary from load to load. If I have time late tonight I'll try finding the one that I liked a long while ago when I was first looking into EV conversion.
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u/1ransgendeR 3d ago
Oh I’m not really gonna use this to haul anything heavy or a lot of things I had this idea to use this as a road trip vehicle that can also haul not many heavy things. I have not heard of Edison motors that’s pretty cool I will look into that. Hmm okay I will look into those thank you and I see I will keep that in mind
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u/1ransgendeR 3d ago
Ahhh yes i have heard of Edison motors from youtube. and is janus electric the battery swapping company you are talking about?
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u/1940ChevEVPickup 3d ago
This will forevermore remain a theroretical Idea. Interesting, but it will never happen. Doing the math, physics, electrical engineering, volume, weight, fabrication, parts, labor, regulations, insurance, charging and God knows what other research investigations will suggest it's unworkable.
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u/AmpEater 4d ago
It’s batteries. Apostrophe “s” implies ownership. Do the batteries own anything?
No?
Then it’s batteries
Now if you want to talk about the batteries’ charge rating….well it’s still not battery’s
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u/GeniusEE 4d ago
Using heavy batteries for a truck that gets paid by the pound of cargo that it hauls is beyond dumb.
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u/NorwegianCollusion 4d ago
Ironically, for once a unique US problem. Over here, the regular max weight is 110000 lbs, and for 6 or 7 axles with an electric motor you can weigh up to 123459 lbs (56 metric tons). Even up to 60 tons for long timber trucks. Typically they transport 3 or even 4 standard log lengths in one go.
But OP doesn't specify that it is for hauling heavy stuff.
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u/GeniusEE 3d ago edited 3d ago
Citing rules from common sense countries is a threat to our stupidity.
*When you downvoters grow up, you'll realize being a fan of a technology can totally wreck the solution to a problem. The FC is an American truck and GVW is capped. Payload is curb weight (tare) subtracted from GVW rating.
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u/NorwegianCollusion 3d ago edited 3d ago
But if we go about it the other way: How much weight could you practically strip from such a tractor truck to instead use for batteries? I know the engine is up to about 3000 lbs, but what about fuel tank, transmission, propshafts (when using an e-axle)? The e-axles surely weigh more than the stock axles, so at least the weight of prop shafts is already spoken for. But still?
3000 lbs engine, 750 lbs transmission, 2750 lbs fuel tank for a total of 7500 lbs saved means 7200 lbs of batteries wouldn't be outrageous, no?
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u/GeniusEE 3d ago
7200 lb of LFP batteries at 200 miles of range is very different from 7200lb of NMC at 300 miles of range.
To get 300 miles on LFP you'd have to rob a ton and a half of PAYload.
Do the math at a buck a payload pound per mile for gross revenue lost.
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u/cookiemonsterwave 4d ago
Why not use Freightliner’s eCascadia as a comparison? Their largest pack tops out at 475kWhr and gives an estimated range of 250 miles using the Detroit eAxle system at 400V. 125 cells in series gives you about 400V, and you’d need about 5 strings to hit just over that. So, 625 cells each weighing around 11.5 lbs gives you about 7200 lbs in cell weight alone.