openinverter forum

I've been following your project for a long time. Unlike most people here, I don't think you should choose a car because it's in good condition and easy to convert. Converting a car is usually not cheap and rarely pays off from a commercial point of view. That's why it makes particular sense to choose a classic car that you can enjoy for a long time and doesn't have to be amortized. From my own experience, I know that the conversion part of the work involved in such a project is rather secondary and simple compared to the rest. So I really respect you for sticking with it. For comparison, it took me 2 years to complete the entire chassis with batteries, radiator, charger, brakes, drive unit, etc. Now I've been working on the bodywork for 3.5 years. viewtopic.php?p=35541#p35541The paintwork and interior are still to come. So you're well on schedule.

muehlpower wrote: ↑Sat Jul 12, 2025 7:22 am I've been following your project for a long time. Unlike most people here, I don't think you should choose a car because it's in good condition and easy to convert. Converting a car is usually not cheap and rarely pays off from a commercial point of view. That's why it makes particular sense to choose a classic car that you can enjoy for a long time and doesn't have to be amortized. From my own experience, I know that the conversion part of the work involved in such a project is rather secondary and simple compared to the rest. So I really respect you for sticking with it. For comparison, it took me 2 years to complete the entire chassis with batteries, radiator, charger, brakes, drive unit, etc. Now I've been working on the bodywork for 3.5 years. viewtopic.php?p=35541#p35541The paintwork and interior are still to come. So you're well on schedule.

Thanks for the kind words of encouragement. There are certainly days where I get a bit down at how much is still ahead of me. And there are days that I wish all of this pesky restoration work was done so I could get on to the fun EV conversion bits. Which is funny because this was a restoration project long before it was an EV conversion project. I bought the car specifically as a restoration project and only decided to convert it later. But those feelings don't last long. And the days where you can stand back and get the satisfaction of seeing another piece come together outweigh all of that. Plus, encouragement from internet strangers doesn't hurt

As for picking a car? I say to each their own. But I couldn't see myself doing it any other way than this

Back on its wheels for the first time in 6 years.

I'll put back in the steering column, steering box, tie rod ends, and so on as all of that will influence the placement of EV parts in the engine bay. Once I have that all done, I'll get a qualified automotive engineer in to tell me all the ways my plans are a bad idea

muehlpower wrote: ↑Sat Jul 12, 2025 7:22 am Unlike most people here, I don't think you should choose a car because it's in good condition and easy to convert. ...That's why it makes particular sense to choose a classic car that you can enjoy for a long time and doesn't have to be amortized.

Absolutely agree. Whatever you build is going to be your "thing" for years to come, build something you're going to continue to like and want to drive.

It’s time to lock in the final position of the motor in the engine bay and also figure out how to go about mounting the big three heavy bits - motor, battery, and inverter.
First, I’ll make a rectangular-ish frame out of 30x2.5mm box. I have the two lengthwise bits sitting on a wooden jig in the photos below. The wooden jig bits are roughly in the position where the widthwise bits of the frame will be. I’ll weld tabs to the sides of the frame so it can bolt to the original engine mounts (on the sides of the shock towers). I’ll also attach the frame to the bumper mounts at the front of the car (see the two silver bolts on the left). I’ll do this by extending out the bottom of the rectangular frame so it’s the full width of the frame rails. I’ll weld a bit of plate to the ends, drill holes in the plate and it will bolt on.

The frame will cantilever out from the engine mount toward the bell housing of the motor (towards the rear of the car). I’ll attach a big piece of angle iron to the front face of the bell housing and sandwich two rubber isolators between the other face of the angle iron and the frame. It’s probably not technically required to dampen the motor like this as it shouldn’t make much in the way of vibrations, but better to do it now than have to change it later.

The cantilevered part will only be about 150mm deep, so, not a lot. I think the box I have should be strong enough for this. It’s not only taking the bulk of the 90kg of the motor, but it also has to resist the twisting force the motor will put on it.
I need to be careful with the placement of the motor to not obstruct the steering. The center link runs across the front face of the motor and, as you steer away from center, it moves back a bit. So I’ll need to be sure that there is some clearance when the wheels are at full lock in either direction. I also need to leave a little space so I can pick up some of the lower holes in the bell housing for the mounting.

There is plenty of room above the motor for the inverter. I was slightly concerned that the diagonal struts would be in the way, but there’s plenty of headroom. I’ll probably run some angle from the box section straight up to pick up the mounting points on either side of the inverter. So the inverter will be mounted on the ‘hard’ mounted frame rather than the ‘soft’ mounted motor.

The battery box will be mounted on top of the frame in the center of the engine bay.

All of this may change of course when I get an automotive engineer in to look at my plans. For all I know this is a terrible idea and I’ll have to go back to the drawing board. I’ve lined one up and I think he’ll be able to take a look at this all in a week or so.

One other thing that occurs to me is that since the there's nothing in the engine bay, the front of the car is sitting up high. The motor is sitting on a trolley on the ground, so the angle between the car and the motor isn't right. I'll need to jack up the rear of the car to make it level to get the alignment right.
I’m also trying to lock down the design of the front battery box. One thing I underestimated is the size of the safety disconnect I got from a Hyundai Kona. It’s about 230x220x90mm. It also has an awkward bulge where the fuse is on the right. You can’t just cut out a hole for the disconnect plug/socket and use the six bolts to mount it. The fuse bit sits up proud from that face. At fist I though about making a little tub to recess the plug/socket bit. But I want this thing to be easily accessible in the engine bay. That means having it sit on the top face of the battery box, pointing up. That got me worried about water pooling in the recess. I’m sure it’s perfectly waterproof, but I don’t want to worry about having to mop water out of the recess in an emergency before pulling the thing out. So, I’ll just do the reverse. I’ll make a little bulge in the battery box lid to accommodate the fuse.

For the batery box itself, I’ll make a frame out of 30x3mm angle. I’ll fill in the sides and bottom with some welded-in sheet. The lid will be a piece of sheet that will bolt on using some rivnuts. I may or may not put a lip on it. I may also change my mind and have the sides bolt on as well. I’ll see how easy it is to fit everything in the box first without having access from the sides. I plan to mount the HVJB to the top of the battery box - directly on the lid.

I love it when a plan comes together
Any (awkward) pictures from the bottom? Also what rubber mounts are you using, the ubiquitous gearbox/engine mounts for the classic Land Rovers?
Also for the disconnect, is there no space at the front left or right? or would that be problematic as it should be mid-pack?

marcexec wrote: ↑Tue Jul 22, 2025 8:53 pm Any (awkward) pictures from the bottom?

Awkward undercarriage pics coming right up
That rib is what the old transmission mounted to at the back. It lines up amazingly well. I'll still need to move the motor rearward about 20mm, but it's still basically spot on.
The car is a little nose up at the moment, so the rubber thingy will move a little away from the tunnel.
I'm trying to take a pic here where the bottoms of the two frame rails are lined up. If you look closely you can see a little bit of the oil pan from the motor peeking out. Like I say, I'll have to move it back slightly, which will mean moving it down slightly, but I think I'll get away with this.

marcexec wrote: ↑Tue Jul 22, 2025 8:53 pm Also what rubber mounts are you using, the ubiquitous gearbox/engine mounts for the classic Land Rovers?

Yep, handy to get, should do the job just fine.

marcexec wrote: ↑Tue Jul 22, 2025 8:53 pm Also for the disconnect, is there no space at the front left or right? or would that be problematic as it should be mid-pack?

The internal cabling bit will be fiddly no matter what I think. I'll probably need to get more of the internal pack cables from BMW and chop them up to make the safety disconnect work. I'm more thinking about where's the best place to put the disconnect where it's accessible but not too much in the way. And which way to arrange things inside the pack to be space efficient.
I could possibly put it at the front, but it's pretty tight and I think it would be awkward to get out. I'll still have to put a rad in that space. Actually, now that I think about it, it won't work at all. It would need to be forward of that bit of wood as that's the front of the battery modules.
The only thing I plan to put to the right of the pack (at least for now) is the header tank for the coolant loop. So there is a fair bit of room there. That would allow me to make the pack less tall. I need to do a Jamie Jones on this, climb into the engine bay, close the bonnet and measure the clearance from the inside (minus the locking myself in part )
There's space to the left, but that's where my 12V batt, fuses, relays and so on will go.

chrskly wrote: ↑Sun Jul 06, 2025 9:28 pm
The original 200 cubic-inch I6 engine that this car had made about 120 horsepower (when it left the factory 60 years ago). I plan to use the inverter from a Toyota Prius when converting this car to an EV. The maximum current that this inverter can pump out is around 500A. Above that some safeties kick in and shut you down. When full, my pack will sit at almost 400V. That means the maximum power output of the inverter will be something in the region of 200kw (500A * 400V = 200kW). 200kw is equivalent to about 270 horsepower.

don't mean to rain on your parade but this inverter and seems like all Toyota inverters have some sort of 3500 torque number hard coded limit that we can't get around, so in my 1984 VW Rabbit I can't go faster than 52 MPH in it, I believe the 2007 Lexus GS450h inverter in my truck also has this hard coded 3500 limit however it is capable of much higher output, I plan to try a Toyota Camry inverter in my Rabbit soon to see what it outputs.

a shit never mind I think you are swapping the logic board and not using the Zombie

Gregski wrote: ↑Thu Jul 24, 2025 3:12 pm don't mean to rain on your parade but this inverter and seems like all Toyota inverters have some sort of 3500 torque number hard coded limit that we can't get around, so in my 1984 VW Rabbit I can't go faster than 52 MPH in it, I believe the 2007 Lexus GS450h inverter in my truck also has this hard coded 3500 limit however it is capable of much higher output, I plan to try a Toyota Camry inverter in my Rabbit soon to see what it outputs.

a shit never mind I think you are swapping the logic board and not using the Zombie

Yessir, that's Damien's dual-motor brain board in there.

With the tank at the back gone are you not worried about the shift in weight distribution? I plan on moving the 12V battery to the back on mine (secret project(jk), no thread yet) plus charger/DCDC to alleviate a bit.

marcexec wrote: ↑Fri Jul 25, 2025 3:50 pm With the tank at the back gone are you not worried about the shift in weight distribution? I plan on moving the 12V battery to the back on mine (secret project(jk), no thread yet) plus charger/DCDC to alleviate a bit.

Actually the opposite I have two BMW packs. One is going in the front and one in the back. The bare BMW modules weight 75kg total. A full 16 gallon tank would have weighed about 44kg by my reckoning. So I'll be adding at least 31kg to the back (assuming my battery box weighs the same as the tank, which it wont, it'll be more). So I'm wondering if I'll have to adjust the ride height on the back. We shall see

Plus the charger, rear hvjb, and various other small charging bits n bobs will go in the back.

D'oh! I had wrongly assumed they'd all be in the living room for V8s in the front

Now that I have my plans for how the battery boxes will be structured more or less decided, todays task was to confirm that what I decided is actually possible. I don’t want to get half way in to making the boxes then realise the cables won’t reach or I’ve made it 10mm too short or something.

First I gathered all of the internal cables I had from the two BMW packs and sorted them. I figured that I might need to swap some cables from one pack to the other to make this work (and I was right!).

The really long cable from one of the packs I had already cut and made into two cables with lugs on the end. This was so I could connect one pack to my HVJB during my bench tests. It probably would have been better to make the short one a little longer, but I don’t think it’s going to cause me any problems ultimately.
Front Battery Box

The front box will be three modules on top of three modules. The CSC units will go on the ends of the modules as I have plenty of width to do that and it saves me some height.

There will be room inside the battery box on top of the modules for the contactors, safety disconnect, vent, HV socket, and the LV socket. I’ll make some sort of internal bracket to hold the contactors of course.

In the pics below the front of the box is on the left and the rear on the right. The front being the bit that points towards the front of the car … in case that’s not obvious

The most negative side of the battery is on the top right module (in the picture). You can see I’ve used the little stubby cable to connect it to a contactor to see if it’ll reach. There’s not exactly a lot of length to work but I think it’ll do. The most positive side is on the bottom right module.

The saftety disconnect will be a mid-pack disconnect and will split the pack between the top left module and the bottom left module. It will be attached to the lid of the battery box, so, it’ll make opening the box a little awkward but I can live with that. I had considered putting a ‘bulge’ on the front left side of the pack to accomodate the safety disconnect, but then there’d be a lot of wasted volume inside the box. The contactors would still need the same amount of the height and they’d only be taking up a little bit of the overall space.

The HV and LV sockets can go on either side of the battery box. I’ve just put them on the left side here.

The vent can go almost anywhere as it sits on the outside surface. You just need a little hole behind it.
The HVJB will mount to the top of the battery box. So the disconnect needs to be placed in such a way as to allow space for it.
Rear Battery Box

The rear battery box will be two modules on top of four - the same as the OEM arrangement. Again, the CSC units will go on the ends of the modules as I have plenty of width but a limited amount of height.

The most positive terminal is on the rear right module on the bottom level and the most negative terminal is on the rear left module on the bottom level.

Again, the safety disconnect will be a mid-pack disconnect. It will split the pack between the top left and top right modules.
My first thought was that I’d need to extend the battery box forward to have space for the safety disconnect if I was keeping to a rectangular box type of shape. An alternative way to go would be to put a sloped face on the front of the battery box. If I cut off some of the (unneccesary) black plastic mounting tabs off the safety disconnect there should be space to do this.
As has been the way since I took my toys apart as a kid, when I put all of this back together again, somehow, I seem to have ended up with leftover parts. I have a couple of extra cables.
Some other things that I figured out doing this exercise #

The sense wires that come out of the module and go into the CSC stand up a good bit taller than the top of the module. Also, the plugs for the sense wires and the data wiring stand up a bit too. I had been measuring to the highest bit of plastic on the top of the module and hadn’t factored this in. I’ll need to leave a little more clearance between the bottom layer and the top layer of modules than I had planned. Not a big issue, but good that I discovered it now so I can leave a little additional room.

Each module has two bolt holes on either end. The plan was to put some stand-offs between the bottom level and the top level. But that would have the top level be supended by their ends only. I’ll still do this, but I’ll also put a sheet of aluminium or steel between the levels as well to spread the weight out a bit - so the module doesn’t have to support its own weight.

I’ll weld some nuts to the bottom of the battery box. Some threaded rod will screw into these and hold the battery modules in place. But, I’ll also put some little tabs on the inside of the battery box which line up with the top of the mounting holes on the top layer of modules. This way the modules will be supported at the top and won’t have to depend on the nuts at the bottom alone (as was the original plan).

Did some battery-boxin'.

This is the front battery box to go in the engine bay.

Made the bottom out of some 30mm x 2.5mm angle.
Then welded in a bit of sheet for the floor.
Then I welded nuts to the bottom, cut some lengths of threaded rod and popped them in there. (copying other people's homework here )
Here is the first layer of modules in.
I'm using some threaded spacer things from screwfix (@rstevens81 excellent suggestion). I needed to throw a few washers on there as well to get enough clearance for the second layer.
There'll be 30mm all around in between the edge of the modules and the wall for cabling and so on.
Pretty happy with the result so far. It's pretty compact, but feels sturdy. I'll break it all down again and start building the rest of the frame of the box. More angle iron for uprights, then another rectangle made of angle for the top (mirroring the bottom) only without the welded in bit of course.