[WIP] Voltswagen T2 -76

[Cera]

Alright! With the stack on the floor finally, I'm trying to make sense of the control electronics next

With the plan of Leaf motor + inverter combined to Tesla M3 batteries, is it possible to use the Leaf charger/PDM? Also if it's possible to get Chademo working with non-Leaf batteries?

I looked at Resolve-EV and they stated it all needs to be Leaf hardware, including the battery. This sounds inconvenient seeing the weight and size, but I don't rule it out completely if the benefits in compatibility outrule the TM3 modules.

Zombieverter looks more attractive since I do like opensource projects. but haven't been able to find confirmation if that would work with this setup either?

Right now my main goal is to find a setup that would charge through Typ2 ~6kWh like the Leaf normal charger does, but ideally would want to have the possibility to upgrade to fast charging lateron (without having to replace half of the components) when the Version 1 of the build has hit the road.

EDIT: probably bit poor choice of words above, but.. I mean, I know both Resolve-EV and Zombieverter will spin the motor stack, but currently looking for information about how easily they communicate with non-Leaf battery options and Leaf PDM (inc. fast charging in the far future)

[johu]

Zombieverter will talk to the Leaf charger as well, no matter which battery is connected

[Cera]

56kWh-ish short module Tesla M3 battery pack arrived! Final price 6000e inc. shipping etc. That puts this into roughly 107e/Wh which doesn't seem to be too bad and these flat modules will be near perfect fit for the "cargo bay false floor" idea.

One module length 1370mm and width 340mm, T2 cargo bay dimensions:



Going forward. Slow and steady...

[celeron55]

I don't think Chademo with the Leaf PDM has been done yet using OEM CANbus control. Personally I'd probably just re-wire the Chademo contactors inside the PDM to be controlled directly by an external Chademo controller.

On the other hand the PDM probably just needs some BMS messages to enable Chademo. We're probably not far off from making it happen.

[Cera]

I don't think Chademo with the Leaf PDM has been done yet using OEM CANbus control. Personally I'd probably just re-wire the Chademo contactors inside the PDM to be controlled directly by an external Chademo controller.

On the other hand the PDM probably just needs some BMS messages to enable Chademo. We're probably not far off from making it happen.

Okay yeah. My main goal is to get Type 2 standard charging for v1.0 so Leaf PDM normal side should(?) work pretty easily for that.

Lateron v1.2 should have a fast charger of some kind. Since I have the Leaf PDM it makes most sense to me to use that, but I'm also trying to learn about other options available as I go along. So fast charging is not a priority for me yet.

[Bratitude]

dam those model 3 short modules looks so compact. i might just have to find my brat some.

I should have a VW transmission adapter plate design available very soon. my friend is currently measuring it on his haas cnc,

[Romale]

Hmm. Is there a specific reason why Leaf motor should be mounted "in front of axle" (as it sits in Leaf itself) when using the Leaf gearbox?

this is very important, since the native Nissan gearbox has an oblique tooth on the gears inside and with prolonged rotation in the opposite direction, axial pressure on the bearings will occur, which will lead to destruction. This is not just a theory, I have tested it on my own experience

[Cera]

Hmm. Is there a specific reason why Leaf motor should be mounted "in front of axle" (as it sits in Leaf itself) when using the Leaf gearbox?

this is very important, since the native Nissan gearbox has an oblique tooth on the gears inside and with prolonged rotation in the opposite direction, axial pressure on the bearings will occur, which will lead to destruction. This is not just a theory, I have tested it on my own experience

Interesting and thanks for the warning. Although I'd not think thrust to be the major issue here, I did some research on this and found that the gearbox does indeed have a splash lubrication system, where oil is circulated by the largest helical to a splash channel from which it drips onto the two smaller gears.


(screengrab from the wonderful Benjamin Nelson's teardown video)

Without finding a way to create proper lubrication to the smaller gears I do think indeed that prolonged use in reverse direction can very easily lead to bad things. Even a small oil pump would probably be sufficient though, but of course that adds uncomfortable amount of complexity.

[remy_martian]

It has nothing to do with lubrication, though lubrication is *also* an issue in extended backwards rotation.

The thrust vector of the gearshafts reverses 180 degrees. While that's survivable in reverse because of short time operation, prolonged operation with that vector reversed means heavy loads in the vehicle accelerating or moving at high speed are not correctly transmitted to the case. People do run in reverse with Tesla DU's, but it sounds like @romale has experienced failure with the Leaf design.

There's one way to prove or disprove that

[Cera]

It has nothing to do with lubrication, though lubrication is *also* an issue in extended backwards rotation.

Since the bearings look identical on the both sides and thrust is created to both directions in normal operation as well, I just don't see that as an realistic big issue though. Even if doubting it'd be, I guess one could easily just swap the bearings from one side to another (they do seem to fit) and be done with that as a possible source of trouble. I've taken mine apart briefly and they are the same on both sides.

However, running prolonged times in reverse will for sure look like it'll leave 2/3 of the gears without lubrication, which will likely lead to more heat (also carried by the gearshafts to the bearings), and eventually failure of the gearbox as DIY'ers like Romale have experienced. I have heard reports about Leaf gearbox breaking in reverse mounted orientation twice now, so it definitely doesn't like to be used that way, but I still think the main culprit is knocking out the lubrication system.

To be clear, I do not plan to mount this in reverse direction due to extra complexity I don't really need in my 1st build.

[remy_martian]

It's not just the bearings. It's how they are held, seated, & preloaded in the housing. I thought I made that clear:

"heavy loads in the vehicle accelerating or moving at high speed are not correctly transmitted to the case."

[Romale]

As for the Leaf motor, I know it says "140V to 420V" but what kind of voltage it does actually run nicely with?

I have good news on this score, yesterday I tested my buggy with a motor and a gearbox from a sheet using only a 32s (125 volts) battery from catl cells, I managed to travel 95 km/h by satellite and this was not the limit! the power was also excessive, I could easily slip on the asphalt

[Gliset]

One module length 1370mm and width 340mm, T2 cargo bay dimensions:

Did you consider putting the batteries underneath the car? Saves the space in the cab...

(Picture from TheSamba)

[Cera]

Did you consider putting the batteries underneath the car? Saves the space in the cab...

I did. There's a few reasons why I didn't go that way. Mainly:

- Our legislation about EV conversion builds states that "Batteries must be installed in such a way that they are securely mounted and will not come loose even in an event of a crash" which is much easier to pull off and "show proof of" when bolting them onto the inside floor than outside. It could be done outside the chassis as well, but that would necessitate planning and building uncomfortably complex mounting hardware.

- I do not plan on installing much permanent hardware to the cargo bay. My current plan is a hammock mounted to the corners of the ceiling as well as some very simple and lightweight comfort mods, so I don't particularly mind losing 8-10cm of the indoor space height, it doesn't effect my furniture plans at all.

- Since the batteries do cost a lot, I like the idea of weather sealing, bash protection, provided by the chassis floor itself. It'd surely be possible to build a secure weathersealed case that could tolerate small hits from the rocks too, but again, unnecessary complicated in my build.

TLDR; Easier this way.

[Cera]

Darn it'd be tempting to use the Leaf box instead of VW transaxle but the question of durability when running in reverse for prolonged times is still on the table.

In other news, I found a welder who's willing to tackle the bodywork. So yay for that!

[Bratitude]

..... This is not just a theory, I have tested it on my own experience
[/quote]

any more info? what happened? what vehicle/ how was it driven?
did the gearbox break?

[Romale]

any more info? what happened? what vehicle/ how was it driven?
did the gearbox break?

it was not a very heavy car (about one ton). after about a month of use, I began to notice extraneous noise in the gearbox, which quickly turned into a crunch. when I opened the gearbox, some bearings were blue from overheating and had a large backlash. this also caused gear wear and replacement of bearings with new ones could not remove the noise from gear wear.
I think it might be the grease.
try to find analogues of these bearings, but in a "closed" version with a rubber seal.
then they will be independent of the lubrication system!

[Bratitude]

it was not a very heavy car (about one ton). after about a month of use, I began to notice extraneous noise in the gearbox, which quickly turned into a crunch. when I opened the gearbox, some bearings were blue from overheating and had a large backlash. this also caused gear wear and replacement of bearings with new ones could not remove the noise from gear wear.
I think it might be the grease.

interesting, sounds like a lack of lubrication
there is a few port holes in the case, one of them looks like it might be a good spot to mount a oil feed, without having to modify the case physically. this would require then an external oil pump

try to find analogues of these bearings, but in a "closed" version with a rubber seal.
then they will be independent of the lubrication system!

iv seen photos of the inside of newer leaf gearboxes with sealed bearings instead of the open ones in the earlier years.

[Cera]

Yeah I'm thinking about external oil pump heavily at this point.

I still personally remain convinced that it's the lubrication that's causing the issues in reverse-mounted Leaf gearbox. I'm no engineer, but that's the only thing I can see clearly being "different" when running in opposite direction.

The bearings seem identical;

Yes the case might have some extra support more on the other side, or it might not. I haven't been able to locate anything clearly visible.

There's also plenty of reports about Leaf gearbox breaking in Leaf due to use of wrong kind of oil (apparently Dala even found out that replacing the OEM oil Nissan used in the first gen Leaf's with ATF can increase performance of the whole vehicle, as silly as it sounds: )

OEM oil has been known to cook the bearings in Leaf: https://www.speakev.com/threads/leaf-30 ... ox.160142/ and people are recommending oil changes periodically (or switching to different brands).

It just seems that Nissan hasn't really done great job with the lubrication to begin with, and to have it then mount in reverse and take away the little they have done, sounds to me like a recipe for failure.

That being said, I am thinking about external oil pump with good quality ATF to splash the oil into the feed channel up top might just be enough. I don't know!

Yes I still can't make up my mind about which gearbox I want to run with this or the VW one.

[motorcircus]

I'm using the Nissan Leaf EM57 motor with the transmission in my VW T2 conversion. Wish me luck!
The bus will be running in a couple of weeks and I will share you the results soon. Bear(ing) with me.

[Cera]

I'm using the Nissan Leaf EM57 motor with the transmission in my VW T2 conversion. Wish me luck!
The bus will be running in a couple of weeks and I will share you the results soon. Bear(ing) with me.

Darn I'm already jealous of your build threw you a message in FB, if you have any drawings/plans for the motor mounts, drive shafts and info who made them for you, I'm definitely interested

... Just in case I end up using the Leafbox too instead of the VW transaxle

[Cera]

Long awaited time. Chassis is finally on its way to a professional workshop.



Also loaded motor and transaxle to be delivered to machining shop as well for the shaft coupler. Old clutch plate for template.

[Cera]

Status update

[Cera]

Base coat painted





It'll certainly be more fun to build on clean chassis than the rusty one.

Although these "small details" need to be dealt with first:



Yeah the painter was faster than the guy with a masking tape, so they need to be cleaned before welding still. Oh well.

Also while digitizing old slide film, came across pictures of a familiar vehicle granddad doing some repairs. I'd estimate these to be from early or mid 1990's or so.

[johu]

You really stick to #1 rule and don't start with a rust bucket
That crusty business will be replaced?