[andybp]

Most of this post is lifted straight from my thread on the Zroadster forum

Z3 EV Conversion

So I know Tom has been posting his EV conversion up here but since this type of project is likely to become more common I thought I'd give you my take on it I've been a petrol head forever and this is my first EV conversion but in the past I've done lots of engine conversions and general...

zroadster.org

 

[Electric Land Cruiser]

That's a really interesting way to couple the motor to the gearbox. Something that I've seen people talk about but that's the first time I've seen it done. Nice work. I gotta learn to weld aluminum...

How many kwh total is the plan for? What voltage?

 

[andybp]

That's a really interesting way to couple the motor to the gearbox. Something that I've seen people talk about but that's the first time I've seen it done. Nice work. I gotta learn to weld aluminum...

How many kwh total is the plan for? What voltage?

when I get the second pack in it will be 18.4 kwh 360v nominal I only travel about 5 miles per day any more than that and I use the Wifes car

 

[remy_martian]

So a 50Ah pack.

Which is a peak discharge of around 150A or 60kW of peak power. It'll likely barely climb a hill and barely make 100km/h continuous.

Sometimes the range comes for free when you want better than freight train acceleration.

But, all depends what you want. Definitely no longer a sports car, just looks like one.

I strongly suggest copious amounts of temperature sensing in the pack.

 

[andybp]

So a 50Ah pack.

Which is a peak discharge of around 150A or 60kW of peak power. It'll likely barely climb a hill and barely make 100km/h continuous.

Sometimes the range comes for free when you want better than freight train acceleration.

But, all depends what you want. Definitely no longer a sports car, just looks like one.

I strongly suggest copious amounts of temperature sensing in the pack.

The 530e BMW the packs are out of makes 68kW on a single pack so either your maths is off or BMW's and since I've driven it up a hill on a single pack I can tell you that it not only made it up but accelerated up with no issues or temperature spikes this is not me looking for an argument just reporting the facts

 

[remy_martian]

I'm guessing you have the phase change, refrigerant-based, battery cooler installed like BMW uses to achieve those power levels?

Cuz I didn't see an evaporator or refrigeration lines in your battery sandwich.

Of course it'll make it up the hill, even on air cooling...bring marshmallows if you did not install the BMW evaporators in your pack....not if, but when and your temperature sensor may not see a runaway in the core of a cell.

It's your build, of course, but there's no magic in BMW's cells. They resorted to phase change cooling to work a HYBRID (low capacity, high draw) application. If you don't have a refrigeration-based evaporator in contact with your modules, you will have a problem if you pull high continuous power, as in climbing a grade....maybe as lucky as killing the battery early in terms of cycle life.

 

[andybp]

You know what you may be right but it's not what you say it's the way you say it as I've seen from many of your other posts. And I'm too long in the tooth to get into a pissing contest with you I've got better things to do.

 

[remy_martian]

What's the plan now?

1. reinstall the most exotic battery cooling scheme available in a production car
2. add a lot more battery (and weight) to the car
3. Set limits in the inverter to where you'll have the best looking cart at the golf course

 

[andybp]

Your battery pack is f*cked because you relied on magic, sprinkled with arrogance.

What's the plan now?

1. reinstall the most exotic battery cooling scheme available in a production car
2. add a lot more battery (and weight) to the car
3. Set limits in the inverter to where you'll have the best looking cart at the golf course
4. keep crying into your milk

You really are a very small angry little man aren't you
I feel sorry for you

 

[brian_]

If anyone is interested enough to look, this is presumably the project:
Z3 EV Conversion
I skimmed through the first part, noting the interesting use of part of the Nissan Leaf transaxle housing as the basis for the adapter to mount the Nissan Leaf motor to the BMW Z3 transmission... but it's a 165-post thread.

 

[remy_martian]

With his hybrid battery capability mess, you'd think he'd be pissed off at the forum that let him get as far as he did.

The car is a POS if my analysis is correct - obviously is or he would have defended his choices rigorously and would not have had his little tantrum and gone back to his buddies at the forum that let him go down the garden path, thinking he was done and could gloat here. This was not a build thread, it was a "look at my skillz" post. It was a beautiful build, which sadly was done with a very bad assumption, imo.

Curiously, Damien and Gregski seem to also have this fantasy that it's magic "power cell" chemistry and not the whole system that lets Beemer do what they are doing in their hybrid.

We know Gregski has no evaporators in his pack - what do you want to bet Damien won't as well?

 

[remy_martian]

As far as shutting the thread down, there's a valuable discussion emerging on the BMW pack capability, so I'd suggest we leave it up.

This was not a build thread, but a potential mistake everyone can learn from. And how endorsements from "experts" can lead people to very expensive lessons in money and time wasting.

As I said, Damien's last video suggests he's drunk the Gregski BMW battery koolaide:

 

[MattsAwesomeStuff]

I purged and sanitized the thread so it has some semblance of value to readers still.

A few notes:

1 - I got to this thread a bit late to run damage control, sorry.

2 - Stop picking fights, take your respectives bullshit private if you have to.

3 - If I have to start throwing everyone in temporary timeouts like they're goddamn toddlers all the time you're probably going to have to find another person willing to admin the forums. I'm not paid to babysit. I'm not paid at all.

...

There's like 3 sentences of useful content in this whole thread, but, I left it for what it's worth.

These BMW packs are seeming to be a popular option of people starting builds, as yet unproven by anyone I've seen in a finished build. I think some skepticism is definitely of value here, especially with BMW's exotic handling of the power requirements. Since the OEM use of these packs was hybrid, and, I have a feeling hybrid in the sporty end (an HP booster), it's not clear to what degree the cooling is necessary in EV conversion use. Is it an added perk to get optimum performance out of the pack, or is it a necessity with many shortcuts taken that required it versus less exotic hybrid packs?

Damien has built a career out of proving naysayers wrong, and he's no fool, so, we'll see how well this goes on his experimental build.

 

[remy_martian]

Damien takes shortcuts to get things done. He's too top level to worry about details like longevity or a firefighter getting electrocuted after his no-battery-box car has run into a tree.

Getting packs for next to free is a disincentive to consider them anything but disposable. He's also one of the finest examples of the Heisenberg Uncertainty Principle. His "free" forklift motors are now $500.

He's shown a battery fire once already with his battery-building shortcuts. Gregski has been chumming up with everybody over on OIF - he's the one that started this BMW hybrid battery module endorsement and the one that threw out the enabler....the evap plates for those refrigerated battery modules.

Getting a car rolling is half the battle, which is when he's happy with calling a project done. Which is great - it's why he's so productive. He's also redone his builds several times and what do you want to bet those 360V Beemer modules will sit out in the open, like Gregski's are?

 

[UglyCarFan]

Thanks for your efforts. I spite of how irritating Remy can be, he does offer a lot of good advice. Now I have to read up on Gregski's evaporator idea! I'm still surprised by one factor on this, and other similar forums...very little discussion about various legal and financial ramifications of building and operating these vehicle creations in public. I used to participate on other forums, like DIY solar power, until I was completely flamed for bringing to peoples attention the FACTS about some of the 2020 NEC requirements, and what that might mean for people trying to install DIY batteries in their homes. I got fed up reading comments from people who would reply "f..k the insurance companies, I'll do what-ever I want". So, I just quit participating.

Insurance companies are scrambling to cut their losses in every way possible. Keeping that in mind, it would make a lot of sense to protect your investment, your project, your neighbors, and yourself by paying attention to things that many of us would never think of. The internet is a wonderful tool for learning, the problem being separating fact from fiction. Based on some scathing, withering comments Remy posted at various times, I choose to ignore "why" he does that, and look for things I can learn from his posts. As a result, I've elected to take time, and get some real world experience with an EV by searching for an inexpensive gen 1 Leaf I can actually drive. I already bought a 2011 Leaf with 27 miles on it, wrecked. So, lots of parts to keep a car on the road while I figure out how some of these systems work.

Hobbies are great, and for a lot of people, it might not matter if they ever get an EV conversion on the road. There is an old school hot rodder in my neighborhood that just loves to have people stop by his shop and shoot the breeze. For him, the fun part is going to swap meets, making something unique, helping others, etc. But his cars are not likely to burst into flames going up a hill, or leave him stranded in the middle of nowhere. He is also not likely to be sued by someone who took his advice, and then built something that is dangerous, and he won't die because he didn't use safety precautions while dealing with high voltage. Your mileage may vary.

 

[andybp]

With his hybrid battery capability mess, you'd think he'd be pissed off at the forum that let him get as far as he did.

The car is a POS if my analysis is correct - obviously is or he would have defended his choices rigorously and would not have had his little tantrum and gone back to his buddies at the forum that let him go down the garden path, thinking he was done and could gloat here. This was not a build thread, it was a "look at my skillz" post. It was a beautiful build, which sadly was done with a very bad assumption, imo.

Curiously, Damien and Gregski seem to also have this fantasy that it's magic "power cell" chemistry and not the whole system that lets Beemer do what they are doing in their hybrid.

We know Gregski has no evaporators in his pack - what do you want to bet Damien won't as well?

Ok this will be my last comment on this post that's if it doesn't get deleted
you make a lot of assumptions

What EV specific forum let me get as far as I did ? and also last time I checked I made my own decisions right or wrong (yes I know your opinion)

"The car is a POS if my analysis is correct" a personal attack and a personal opinion which I disagree with

"he would have defended his choices rigorously and would not have had his little tantrum" I don't have to defend my choices and I had no tantrum I simply chose to delete my posts
and not bother posting here so I didn't have to deal with you life's too short as I stated before but my post seems to have been deleted

"thinking he was done and could gloat here" I don't think I'm done nowhere near actually and as for "gloat " and ""look at my skillz" post " just more assumptions you know nothing about me

"It was a beautiful build, which sadly was done with a very bad assumption, imo." make your mind up you said it was a "POS"

 

[catphish]

While I don't know these specific cells at all, and I certainly wouldn't want to encourage anyone to push batteries beyond their documented limits, a modern lithium car cell can discharge at 5C peak (at least that's what my hybrid pack recommends). So a 50AH pack at 360V would likely be able to put out more like 250A (90kW) peak. In a light car, that's enough to enjoy yourself. Always worth trying to find the official specs for peak and continuous power though.

Sorry about your inverter, I'd suggest focusing on how you managed to blow up a the leaf inverter. At least the fuse did its job nicely.

 

[Electric Land Cruiser]

While I don't know these specific cells at all, and I certainly wouldn't want to encourage anyone to push batteries beyond their documented limits, a modern lithium car cell can discharge at 5C peak (at least that's what my hybrid pack recommends). So a 50AH pack at 360V would likely be able to put out more like 250A (90kW) peak. In a light car, that's enough to enjoy yourself. Always worth trying to find the official specs for peak and continuous power though.

Sorry about your inverter, I'd suggest focusing on how you managed to blow up a the leaf inverter. At least the fuse did its job nicely.

The Leaf motor/inverter he was using is rated for 80kw maximum.

 

[catphish]

The Leaf motor/inverter he was using is rated for 80kw maximum.

That makes sense, and in that case seems a reasonable match for the selected batteries and fuse. So the important question is why it exploded itself.