[Driving] MG F - Outlander Rear motor and inverter.

Tell us about the project you do with the open inverter
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Re: MG F - Outlander Rear differential with Prius Gen 2 Inverter.

Post by Mouse »

Oh, I meant the CAD drawing of the plate you cut out and bolted to the motor and not the spline.
I got a Jimney clutch for making the spline coupling.
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Re: MG F - Outlander Rear differential with Prius Gen 2 Inverter.

Post by LRBen »

Mouse wrote: Sat Mar 27, 2021 7:56 pm Oh, I meant the CAD drawing of the plate you cut out and bolted to the motor and not the spline.
I got a Jimney clutch for making the spline coupling.
Oh yeah of course. Attached is the dxf file for the motor. When I got it laser cut I had to go through the m10 holes with a 10mm drill bit after just to take the burs off. Otherwise they are a little tight for m10 bolts. So it's a pretty close fit.
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motor plate cam 29th Jan.dxf
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Re: MG F - Outlander Rear differential with Prius Gen 2 Inverter.

Post by Mouse »

Thanks,
Do you have the shaft position in the model as well?
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Re: MG F - Outlander Rear differential with Prius Gen 2 Inverter.

Post by LRBen »

It looks like I lost a lot of my intermediate files from this process. Around that time I was switching from Fusion360 to Solidworks, then back to a Fusion360 trial account as Solidworks doesn't like .OBJ files.

But I did manage to find a file that has the shaft position. I think at that moment in time the scale was still off. So double check that before you send it off for any fabrication. It's either going to be before I scaled it up, so it will be too small by a factor of about 36. Or it was too big so I had to reduce it by 1%.
The downside of photogrammetry is the lack of scale information.
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Re: MG F - Outlander Rear differential with Prius Gen 2 Inverter.

Post by LRBen »

The motor is now attached to the gearbox and sitting in the subframe. With the gearbox mounted on one side all I need to do is to fabricate a mount for the motor side and probably put in a third mount in the middle to stop it twisting under torque.
PXL_20210401_160035643_2.jpg
As you can see from my professional augmented reality photo Im planning on using some box steel to sit on the original engine mount, then angle over to the motor mount which is further back. It should pivit on the mount mount and be held in place by the bolt at the front.

I'll see how that goes then I can get to work on the battery box. It is looking like I should be able to squeeze in two 60s strings above the gearbox and motor. Just need to find a place for the inverter then. The other alternative is to split the battery and put one string in the front of the car. But I would very much like to keep this all contained in the rear subframe.
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Re: MG F - Outlander Rear differential with Prius Gen 2 Inverter.

Post by MiBa »

Hi,
wrt. a Motor-Support
you might have a look here:
https://robotics.ee.uwa.edu.au/theses/2 ... ive-Ho.pdf

Chapter
4.6.3 Design and Construction of Primary Rear Support

This Master Thesis with calculations/simulations is for a Lotus Elise,
however it's more or less the same for your MG-F (except the ICE is mounted horizontal swapped)

Good progress
Michael
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Re: MG F - Outlander Rear differential with Prius Gen 2 Inverter.

Post by LRBen »

MiBa wrote: Tue Apr 06, 2021 3:06 pm Hi,
wrt. a Motor-Support
you might have a look here:
https://robotics.ee.uwa.edu.au/theses/2 ... ive-Ho.pdf

Chapter
4.6.3 Design and Construction of Primary Rear Support

This Master Thesis with calculations/simulations is for a Lotus Elise,
however it's more or less the same for your MG-F (except the ICE is mounted horizontal swapped)

Good progress
Michael
Thanks for the link. That was an interesting read. Its encouraging to see I'm going the same direction, I had similar ideas with the torque mount as well.
It was also interesting to see the performance figures as well. The MG F isn't quite as lightweight as an Elise but it's a good indication at least.
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Re: MG F - Outlander Rear differential with Prius Gen 2 Inverter.

Post by LRBen »

Made a start on the motor mount this week. Just roughing it out on some bits of metal I have lying around.
I was planning to use the original engine rubber bushing, but that has seen better days and new ones are around £50. I figure that vibration damping isn't as much of an issue when there isn't 2,000+ Explosions per minute happening. If it does seem to be an issue I think I can always add some thin rubber mats under the square tube. This way I think will be a little stronger as well. I will then also add another smaller brace on the bottom that will go to the original engine mount to the rear to stop the engine twisting under torque.
I am half thinking of running a bar across the top as well, but I think that is probably overkill.
PXL_20210410_153057733.jpg
On the electronics side this week I managed to get my teensy to read CANBUS messages from the inverter and spit out some serial messages. I need to do some further work to turn those messages into something coherent that I can then send on to the dashboard.

I am becoming more concerned about space as I get closer to fitting the batteries. I was very keen to try to fit everything all into the engine bay compartment. However I think I am going to have to try and fit the inverter in the fuel tank area on it's side, and I am not sure how that might affect coolant flow through it.
Alternatively I might have to accept that I will only be able to fit in a smaller amount of batteries than I was planning.
I am hoping to fit in a battery of 60s2p using the kokam cells, which would give a healthy 23.5kWh of capacity. However if I have to save space I could go 80s1p, which would still work with the prius DC-DC it seems, and I would still get 15kWh.
I could split the 60s2p pack. But space in the front is very limited. I think I could fit in about 40 cells easy enough, but anything more than that would start to get complicated and the grinder would need to come out. I also want to avoid the complication of a split pack, so I might make the compromise of lower range for the sake of simplicity.
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Re: MG F - Outlander Rear differential with Prius Gen 2 Inverter.

Post by LRBen »

Finished the motor mount this week and gave it a bit of paint. Doesn't look all that bad now. I think I'll put this back into the car now so I can work out exactly how much space I have for batteries. It's looking pretty tight height wise, but that is just rough measurements with the tape measure.
PXL_20210416_102939953.jpg
I was hoping to fit in two strings of 60s physically parallel to each other. However the engine bay is smaller on one side where the fuel tank filler went. So I can fit in two parallel rows of 40. So I could just throw in 80 for my 80s1p option.
I can also fit 40 cells in the front without that much hassle. Giving me the opportunity to do my original 60s2p plan. However that means two separate split parallel strings. To much effort for me.
I could also split the modules and try to rearrange them into 5s2p. But that's allot of effort. Or I could sell all these cells on and maybe buy something else that might fit easier.

I think I'll just go with 80s1p. Keep it simple, voltage is high enough for CCS one day if I go down that route. Then in the future I can drop the subframe out and throw in some future tech batteries with 100kWh in the same space.

On the electronics side this week I figured out how to turn Canbus messages into something coherent. So that only needs a little bit more work to finish off the code for that.

I also visited the scrapyard and picked up the wiring loom connectors for my brake vacuum assist pump and sensor. So I can finish the installation of that next week.
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Re: MG F - Outlander Rear differential with Prius Gen 2 Inverter.

Post by Bratitude »

mount looks good. hard to tell the angle, but form what i can tell it might be worth putting an additional link from the motor end of your mount to the front(?) of the sub frame/cradle. which is in the path of rotation
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Re: MG F - Outlander Rear differential with Prius Gen 2 Inverter.

Post by LRBen »

Bratitude wrote: Fri Apr 16, 2021 6:29 pm mount looks good. hard to tell the angle, but form what i can tell it might be worth putting an additional link from the motor end of your mount to the front(?) of the sub frame/cradle. which is in the path of rotation
I was planning on an additional link from the bottom bolt of the motor plate back to the original engine torque brace mount thing. Which is helpfully almost exactly in line.
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Re: MG F - Outlander Rear differential with Prius Gen 2 Inverter.

Post by Alibro »

Your mount looks similar to mine. 😉
The only issue I can see (and hopefully mine will be OK) is having a single pivot point for the motor. The torque could be pretty hard on motor mounts so some triangulation would help.
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Re: MG F - Outlander Rear differential with Prius Gen 2 Inverter.

Post by LRBen »

Alibro wrote: Fri Apr 16, 2021 7:51 pm Your mount looks similar to mine. 😉
The only issue I can see (and hopefully mine will be OK) is having a single pivot point for the motor. The torque could be pretty hard on motor mounts so some triangulation would help.
Yeah I did take pretty direct inspiration from your mount! I'm hoping the second mount lower down will help with the torque load.
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Re: MG F - Outlander Rear differential with Prius Gen 2 Inverter.

Post by LRBen »

So I've been looking at the space for batteries these last two weeks. Rough measurements with a tape measure suggest about 5cm height clearance between the top of the gearbox and the car frame above. Which should be enough for the tray which holds the box.

I did make an attempt to scan the subframe and engine bay using photogrammetry, however it's not an ideal candidate for it and I didn't really spend the time I could have in getting the perfect photos. I did get some models into CAD. But with the margin of error on the models, I figured I had about a 5cm height clearance...

Today I decided to do the cardboard mock up route, and I think that trying to get 80s in a box in that engine bay just isn't going to fit. At least not without laser scanning dimensions. It's not just height, it's also width and length. If I do get the batteries in then there is no way I will fit in the inverter in the same space.

So I think I might try to split up the batteries. It's not ideal, but I can split up batteries easier than splitting up the inverter.

I have a few options here. I believe I can probably fit between 20-40 cells in the fuel tank compartment in much smaller boxes. I can also fit 40 cells in the front spare tyre compartment. But I am not sure if the thin steel plate can support that much weight. I could easily brace it from the front subframe though.
I was thinking I could also cut out the spare tyre section out of the frunk. This would allow me to place a nice size battery box on the front subframe, nice and low. I could probably get all the batteries in one box then. It would help with the F/R weight distribution as well.
Down sides are that I would then be cutting up body work and so risk a more indepth inspection requirement. Although it doesn't seem to be all that structural since it already has a small brace at the bottom connected to the subframe, presumably to stop the weight of the spare tyre flexing it. So I could cut out the spare tyre shaped metal and replace it with some sheet metal across the top instead. That would leave plenty of space underneath for a battery box. It would also give me a chance to restore the front subframe which I have so far ignored.

Either way, the next actionable thing for me to do is to mount the inverter and junction above the motor and gearbox. Then I can make a start on wiring some parts up.
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Re: MG F - Outlander Rear differential with Prius Gen 2 Inverter.

Post by Alibro »

I'll be checking how many batteries I can get under the floor of my Freelander this weekend so I'm in a similar position also wondering about making minor changes to non structural parts, in my case the cubby hole at the rear.
I suspect if we get a jobs worth at the DVLA it could cause issues so I'm trying to avoid giving them any excuses to be awkward.

Don't forget to allow space for the connections and insulation.
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Re: MG F - Outlander Rear differential with Prius Gen 2 Inverter.

Post by LRBen »

I think you might be pretty safe blanking the rear water reservoir/cubby hole in the Freelander. Weld a bit of sheet over top of the hole and don't even mention it. Although you have a pretty nice and boxy fuel tank so there might be enough space there anyway.

I think I am going to go down this route. I took off some of the front panels today, and I'll have to drop the front subframe at some point anyway to give that a bit of a refurb. There is absolutely tons of space in the front if I cut out the spare tyre panel.
My initial idea is to cut it roughly where the red lines are, then add in a steel sheet across the top all at the same level. I can reinforce with a couple small bits of angle just in case the car did need the spare tyre holder to stay together. Then I'll have more than enough room below to put in a battery box. It will be nice and low to the ground and add some weight to the front which wouldn't hurt.

I removed the main radiator and will be using the metal coolant pipes that run front to back as extra protection for the HV lines. I'll add in a small radiator in the rear facing one of the air inlets for the motor and inverter cooling.
PXL_20210430_153551804_2.jpg
I did look a little bit at where the inverter would mount above the motors today as well, it's actually a fair bit bigger than I thought once you actually get it onto the rear subframe. There is more than enough space to put it there, but I was crazy to think I would be able to fit batteries in there as well.
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Re: MG F - Outlander Rear differential with Prius Gen 2 Inverter.

Post by Alibro »

I agree 100% about the fish tank in the back of the Freelander, I was thinking myself I could just remove it, put a plate across the hole and no one would notice. ;)
It's been a few years since I sold my F but my recollection is the spare wheel well is pretty flimsy and can barely hold itself up, never mind keep the chassis together so I can't believe it would make any difference to the strength at the car.
I read in one of the other threads that a guy cut the floor out of his car which caused issues with the authorities but I suspect our changes could only strengthen the cars so shouldn't cause problems.
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Re: MG F - Outlander Rear differential with Prius Gen 2 Inverter.

Post by LRBen »

Yeah the spare tyre holder is very flimsy, there is a brace at the bottom to stop it flexing forward. I expect this change will make it a good bit stronger.

I've got some more penetrating oil on order before I make a start on the front subframe bolts. I snapped one of the rear ones and I don't want to repeat that.

So today I made a start on figuring out how the inverter is going to sit on top of the motor. I decided on this orientation, seems to make the most sense in terms of how cables will be coming into the inverter. The coolant lines are also now helpfully all at the rear, right where the original header tank will be.
I also bought a London Taxi heater matrix today, just happened to be the first new radiator I found on Ebay that was small and cheap. The plan for that is to place it on the bottom left side of the subframe as you see it in the first photo. That area is where the side intakes push air into the engine bay and on that side there is a fan. So potentially I can also hook that up if I find that I do need more cooling capacity. The water pump will also go in that area.

PXL_20210501_152616613.jpg
PXL_20210501_152600001.jpg
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Re: MG F - Outlander Rear differential with Prius Gen 2 Inverter.

Post by Boxster EV »

Alibro wrote: Fri Apr 30, 2021 10:30 pm
I read in one of the other threads that a guy cut the floor out of his car which caused issues with the authorities but I suspect our changes could only strengthen the cars so shouldn't cause problems.
That was me and ultimately it didn’t cause any issues. Although, there is a risk attached, as unrealistically the generic rules state you can’t drill or cut anything in order to gain the needed 5 chassis points.

Totally depends on the pragmatism of the inspector.
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Re: MG F - Outlander Rear differential with Prius Gen 2 Inverter.

Post by LRBen »

Boxster EV wrote: Wed May 05, 2021 1:55 am That was me and ultimately it didn’t cause any issues. Although, there is a risk attached, as unrealistically the generic rules state you can’t drill or cut anything in order to gain the needed 5 chassis points.

Totally depends on the pragmatism of the inspector.
Yeah I was reading your thread with interest in that respect. It was part of the reason why I chose to try and avoid cutting anything. However unless I settle for throwing a Prius pack in the boot I don't think I have any choice now.

This week I have been finishing off the inverter mounts. I made a start on mounting the radiator but the welder ran out of gas so that will have to wait until next week. Top tip, flappy pad discs are amazing on the grinder, but they also work pretty well on skin. That lesson is going to sting for a few days.
PXL_20210508_170452543.jpg
So I finished cutting out the spare wheel compartment and took some measurements. The space I have to work with is around 700mm wide, 480mm long and 265mm high. The height could be increased a bit more potentially, and in the middle I could easily add another 250mm of height.
Still not a huge amount of space. I did work out that if I laid my cells on their flat sides in stacks of 20 then I could in theory fit in 60s2p if I reconfigured the modules.

While I was measuring up the module I noticed that almost all of them are around 5mm wider at the base than at the top. Some cells are noticeably thicker at the bottom. So I am hoping that laying them flat might help to reverse some of this gel flow.
PXL_20210508_170348472.jpg
PXL_20210508_170410047.jpg
I'm going to drop the subframe next week and make a start on refurbing that. I'm thinking I'll just get a box made up to the max space available and then that gives me options for module packaging.
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Re: MG F - Outlander Rear differential with Prius Gen 2 Inverter.

Post by paaa »

Thats interesting , I placed mine beside a template spacer I made and they were 1-2mm wider at base. Clearly they don't like being upright.
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Re: MG F - Outlander Rear differential with Prius Gen 2 Inverter.

Post by Alibro »

I discovered yesterday that measurements are great but there's no substitute for CAD modelling.
I spent a couple of hours building a cardboard mock up of my battery box and discovered it doesn't fit. In theory there's room but it would be VERY tight so I'm on v2 of it now.
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Re: MG F - Outlander Rear differential with Prius Gen 2 Inverter.

Post by LRBen »

I've been thinking about the batteries overnight. I have a couple options.

Don't take the risk, sell them on and buy in some OEM batteries. I bought them for a good price and have sold some spare cells to E-bike builders already. So I could make a few £ on each cell which would help pay for the more expensive OEM cells.
However doing some calculations on the space, it would be tricky to get high enough voltage from normal EV cells. Hybrid packs are an option worth looking into a little more.

The other option is to fit them flat side down, probably 80s1p so I have more cells left over. Maybe some sort of slightly extra compression on the lower parts and hope that encourages them to return to their original shape in time. Should be tons of space then so I won't have to rely on small margins.

I think I'll just make the battery box as big as I can in the subframe. Which leaves more options open as to how I mount these cells and in what configuration. For now I'm going to disassemble my boxes the kokam cells arrived in and store them all flat side down.
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Re: MG F - Outlander Rear differential with Prius Gen 2 Inverter.

Post by Alibro »

Would 1P give you the current you need?
If you're thinking of OEM modules then, as I'm finding the box really needs to be made to match the modules.
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Re: MG F - Outlander Rear differential with Prius Gen 2 Inverter.

Post by arber333 »

LRBen wrote: Sun May 09, 2021 8:09 am I've been thinking about the batteries overnight. I have a couple options.
I am sorry but i have one more observation for you. More a limitation... I noticed that when one of my cells burst open along the seams it was the lowest one that was under the 16S stack of cells. I think they also dont like to be weighed too much. I am relating this because now i use cells in stack of 8S with plywood plate between them to spread the weight evenly among 3 stack of 8S cells and their 8S top neighbour. I wasnt able to design any different method of flooring/shelf between the stacks so i hope they will be OK.

Otoh there are written standards for those kokam cells. Do you have the datasheet or test report? What is the model of the cell?
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