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So what do you get if you gas it at a standstill with the clutch down/trans disengaged? Still vibration?
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Jul 7, 2020 07:54
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cakesmith handyman posted:So what do you get if you gas it at a standstill with the clutch down/trans disengaged? Still vibration? Well I imagine you’d get a mess and a fire. 
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Jul 7, 2020 07:58
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bawfuls posted:The vibration remains even when the clutch is disengaged. I could have sworn this was not the behavior a year ago when I was troubleshooting but whatever. I'm inclined to live with it for the foreseeable future as I have for the past year. Long term I'll do a drivetrain refresh and go to a direct drive setup with a higher voltage motor that doesn't need the transmission. Have a look into the GS450h unit  .If the vibration persists with the clutch engaged, then the issue is wither with the clutch/flywheel assembly, the coupling to the motor not being concentric, or the motor itself ( bearings). Pomp and Circumcized fucked around with this message at 08:18 on Jul 7, 2020 |
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Jul 7, 2020 08:13
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cakesmith handyman posted:So what do you get if you gas it at a standstill with the clutch down/trans disengaged? Still vibration? Pomp and Circumcized posted:Have a look into the GS450h unit bawfuls fucked around with this message at 17:42 on Jul 7, 2020 |
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Jul 7, 2020 17:24
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Yeah, the open source tesla boards are easy and cheap to make. The advantage of the GS unit is the cost, all of my hardware came in at under £1000. Can't you connect the current motor directly to the differential via a custom driveshaft? What's the advantage of the transmission? As for the voltage, yes a higher voltage can deliver a higher current, especially at higher RPM as the back-EMF of the motor increases, but for lower RPM you shouldn't notice much difference. I didn't see the pack voltage which you are using, is it much lower than 350V? I'd have thought you'd see the same issues with the Netgain motors. Pomp and Circumcized fucked around with this message at 19:01 on Jul 7, 2020 |
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Jul 7, 2020 18:58
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My pack voltage is 114V nominal. This motor’s torque curve starts to fall off around 3800 RPM. If I mated directly to the driveshaft or diff I would have the equivalent of 4th gear all the time (not nearly enough torque at the low end), and not enough room at the high end for freeway speeds (motor is limited to 7900 RPM). So this motor needs the transmission to really be drivable. The tesla motor has ~40% more torque to begin with and the reduction gear is equivalent to something between my current 1st and 2nd gear. With a higher pack voltage the torque curve falls of at a higher RPM, and the motor can keep spinning to more the double the RPM to reach freeway speeds easily. bawfuls fucked around with this message at 19:33 on Jul 7, 2020 |
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Jul 7, 2020 19:23
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Ah yeah, this pack voltage is too low for OEM units. Tesla chargers can't even charge reliably below 260V. I had a similar dilemma for my build, I went with more cells in series rather than the arrangement you have. Something like a Volt pack would be well suited for your proposed application.
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Jul 7, 2020 19:31
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Yes the Volt pack is the cheapest way to get high voltages, though it is only 17ish kWh. Two of them in parallel would be great, if one can figure out how to sandwich it all in. The other good option is the LG CHEM modules which are used in I think the Chrysler Pacifica and some other places. The latter is what EV West has in their E36 along with a big Tesla motor (if you haven't seen Bream absolutely thrash that car on Hoonigan, I highly recommend it). https://www.youtube.com/watch?v=I89llX3HUWc
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Jul 7, 2020 19:37
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Battery tech is moving forward so quickly right now, the longer you can hold off on buying, the better.
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Jul 7, 2020 19:42
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Yup, that's pretty much where I'm at. Hoping to buy a house some time in the next few years here, then when I put solar on the roof I'll be able to repurpose these batteries for home energy storage (a much less demanding application) which would help justify the cost of a refresh on the car.
bawfuls fucked around with this message at 19:49 on Jul 7, 2020 |
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Jul 7, 2020 19:46
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Pomp and Circumcized posted:Have a look into the GS450h unit Hey, Pomp, are you aware of an aftermarket or open-source controller for the Lexus hybrid automatic trans? I find that unit very interesting. I watched some of damien Maguire's videos on it, but he appeared to be designing his own controller. I can solder and assemble, but design work is beyond my current ability. edit: ah, he seems to have made it available: https://evbmw.com/index.php/evbmw-webshop/toyota-built-and-tested-boards/gs450h-vcm-fully-built-and-tested Darchangel fucked around with this message at 21:09 on Jul 7, 2020 |
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Jul 7, 2020 21:06
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Darchangel posted:Hey, Pomp, are you aware of an aftermarket or open-source controller for the Lexus hybrid automatic trans? I find that unit very interesting. I watched some of damien Maguire's videos on it, but he appeared to be designing his own controller. I can solder and assemble, but design work is beyond my current ability. Er, yeah, I'm the guy who designed it. This is me: https://openinverter.org/forum/viewtopic.php?f=14&t=205&sid=e29599d1629298280896e78b4761748c Damiens controller is a modified version of mine (he modified my schematics to suit his style of controller), and the code is a cut and paste of my code. He mentions it here: https://youtu.be/frqUaxcMFaM?t=1142 I went into detail on this in my RX7 build thread. If anyone on here needs any more info on these units, it's probably best to ask in there to avoid derailing this thread too far (until bawfuls gets a GS unit, of course!). I'm happy to get involved with building custom controllers based on this for peoples projects, like I did for my RX7. Pomp and Circumcized fucked around with this message at 21:29 on Jul 7, 2020 |
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Jul 7, 2020 21:19
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Pomp and Circumcized posted:Er, yeah, I'm the guy who designed it. This is me: https://openinverter.org/forum/viewtopic.php?f=14&t=205&sid=e29599d1629298280896e78b4761748c LOL, small world. Your thread is probably where I got turned to Damien, or at least found his work on the GS450H trans through searching for it from your suggestion - it's probably just been long enough that I forgot what put me on the track. I'm not at the point where I can afford the EV stuff yet, but eventually, I'd like to EV one of my first-gen RX-7 shells. On the plus side, the longer I wait, the better/cheaper it gets to do it. I need a seperate motor I can run to the original rear, since the first gen is stick-axle, unless I want to dig in and convert to IRS to make a Tesla drive unit work, which is a whole 'nother mess. I'll note down all this in my "EV notes" on OneNote for future reference. It's the only way I can keep all my stuff organized. Sorry to contaminate your thread bawful.
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Jul 7, 2020 22:37
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Heh, no worries. Definitely better to wait, I imagine that 5 years from now, the second hand market will be flooded with cheap EV components, just like it is with Prius parts right now. For those in the US, Tesla units make much more sense. As you said, you can upgrade the whole rear end at once. Scarcity in Europe drives the prices up, sadly.
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Jul 8, 2020 00:16
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bawfuls posted:The car is fun but if I were to do it now knowing what I know I'd do it differently. I will probably strip it down and refresh it some time in the next 5 years, both to finally do all the body work stuff and upgrade the drivetrain. Hey Bawfuls, pulling this from the EV thread so i don't derail it any more. Could you go into more detail about what you'd have done differently? I'm super interested to hear what exactly you did and didn't like with the build after a long time with it
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Jun 12, 2021 13:26
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I kinda mentioned it on this page I think, but I’d switch to a small Tesla motor in the rear which would be direct drive and more than double the power. The current setup is roughly equivalent to the stock L28 engine but with EV responsiveness. Moving to a small Tesla motor would be the electric equivalent to common but not extreme engine swaps like an SR or something. So I’d scrap the stock transmission, differential, and axels. The stock axels don’t have CV joints so they are “clunky” which is much more noticeable with the electric motor than a loud ICE. Similarly this would eliminate the vibration I currently get from the flywheel/clutch assembly. This would require some significant fabrication work to mount the motor and possibly relocate some suspension bits. Then I’d need a new battery pack to run at 355V instead of the 114V I’ve got now, and I’d put that up front under the hood. At the time I started this project, there were good batteries for this available at EV West and on ebay, but now they are harder to find. (I need 355V but without the full size/weight/capacity of OEM packs). Hopefully in a couple years there are lots of crashed Mustang, ID.4, etc modules around to be salvaged. If I’m gonna go to the trouble of doing all that, I’ll also strip the car down and send the shell off to a body shop in TJ to make it pretty (when it gets repainted i will use the same color green). Then there’s little things like, with direct drive there’d be no need for a tach so I’d replace that with a big ammeter, and I’d want to do something with the shifter to make it into a Drive-Neutral-Reverse selector. Replace carpet, build a cooling loop for the new batteries, find a spot for another pair of bigger speakers, etc. And I should probably take the opportunity to rewire the whole car and exorcise the 40 year old electrical gremlins in the 12v system. This mock-up illustrates some of the challenges wedging a small tesla motor into the rear subframe of the S30: 
bawfuls fucked around with this message at 18:20 on Jun 12, 2021 |
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Jun 12, 2021 18:08
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Bumping this thread because today I did something fun/dumb/smart. I found a deal on some batteries for the eventual P H A S E 2 refresh referenced in my previous post. This represents half of the future pack. It is one full 16kWh pack from a Chrysler Pacifica Hybrid minivan (plus some spare bits and cells), I will need to source a second minivan pack at some point in the future. These are LG Chem cells with an excellent packaging setup and capacity for a relatively compact battery pack still capable of 400V to run a Tesla motor.  There are 96 prismatic lithium-ion cells in total here, so at 3.7V nominal each in series would give 355V. But that's only 16kWh, so I will double the capacity by adding another 96 identical cells. I could hypothetically run two parallel strings of 96 cells, but doing that requires twice as much BMS hardware to monitor and manage, and there are safety/reliability concerns to not running parallel at the cell level. So instead, I'll reassemble these cells into a string of 96 pairs of cells. The nice thing about the packaging here is that it's all modular so I can make strings of whatever length I want. Naked cell pairs and some separators in the box (these cells are all physically parallel and have their contacts taped up for storage safety at the moment):  Here's a couple empty cell separators, which snap together with metal clips at each corner. Two cells go between each one, and you can see the cooling fin in the middle as well. Thus one large face of each cell gets contact with the cooling fin. The bottom of the separators is an extension of these cooling fins, meant to mate to a chill plate to cool the whole pack.   Originally in the Pacifica, these cells are arranged into modules of 16 cells in series, with 6 such modules per van. Here's one of those modules:  I made a mock up of how 12 such modules could fit with room to spare in the engine bay of the Z. This is roughly 500lbs of battery, which turns out to be just about the same weight as the original L28 engine this car once held. I don't have the full Z chassis in CAD cause I don't have a fancy 3D scanner, but from two 2-D schematics we can get a reasonable idea of fitment (top and side views):   So the plan is to reassemble these cells into 4 strings of 24 cell-pairs, which will take the space of 3 of the modules in the above images. I'll wire these 4 strings in series, for 96 cell-pairs in series. For context, the bottom row of the below image from my hand to the right shows how long 24 cell-pairs will be.  I have a lot of things I want to refresh/improve with this upgrade, but I also don't want to have the car out of commission for longer than necessary. Hence my approach is to accumulate components over time as I find good deals, and do as much work on them outside the car as possible before taking the final plunge. As you can imagine there is a lot of work to be done to assemble this pack properly, in addition to acquiring the second half and disassembling/reassembling that one too. This pack cost me just about $100/kWh, which is less than 1/3rd the cost of most EV batteries available for the DIY scene. Pacifica packs are available pretty regularly from salvage for $300-450/kWh but I will keep hunting for deals while I work on this one and other bits of the project. bawfuls fucked around with this message at 01:34 on Apr 17, 2022 |
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Apr 17, 2022 01:20
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That's a good find. I know Battery Hookup was trying to get rid of some Jeep hybrid batteries, these look like the same unit.
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Apr 17, 2022 03:23
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Cool to see an update! I'd love to electrify one of my spare RX-7 chassis at some point, when the cost is reasonable (and I have time/space. Kinda looks like that will be a retirement project, though...)
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Apr 19, 2022 19:04
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Wow that's really neat, I had no idea they were basically just spicy Legos.
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Apr 19, 2022 20:07
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Yeah these particular modules are very lego-like, which is definitely part of the appeal. Others *cough*Tesla*cough* are far less so. For some builds that's fine, you can adapt the vehicle to accommodate the modules and have less finicky stuff to deal with.
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Apr 19, 2022 21:00
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bawfuls posted:Yeah these particular modules are very lego-like, which is definitely part of the appeal. Others *cough*Tesla*cough* are far less so. For some builds that's fine, you can adapt the vehicle to accommodate the modules and have less finicky stuff to deal with. I know i've likely posted in here before but I just want to reiterate how jealous I am of both the vehicle and your ability to accomplish this. I am pretty handy (in my head) but the thought of having to learn everything to convert a car to electric seems very daunting
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Apr 19, 2022 21:14
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It's not that hard! There are for sure more complicated and difficult projects in AI. Honestly the EV wiring is one of the easiest parts of this.
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Apr 19, 2022 21:16
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