Yet Another Voltswagen

Tell us about the project you do with the open inverter
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Ctwidle
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Yet Another Voltswagen

Post by Ctwidle »

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A few months ago I took the first step to a classic EV conversion when I bought a fully dismantled and partly restored ‘72 super beetle. Since then I have been an avid reader of all things EV and this forum in particular. When not reading or watching YouTube I have been prepping and painting the bodywork and restoring the suspension and brake components.

A couple of weeks ago I took the plunge with the purchase of a Lexus MGR which I can now confirm that it is a good physical fit in place of the original beetle transaxle with no structural modifications to the floor pan and I have started work on creating some mounts for it. Today I took delivery of a second hand partial Lexus harness with all the motor plugs intact and loads of other cables and fittings and a few minutes later a Prius Gen3 inverter arrived by courier. It’s missing all the bolts but it doesn’t look like it’s been opened.

I am thinking that a Leaf battery pack will be on my shopping list at some time which will be split into 2 packs - behind the rear seat and in the vacant fuel tank space. Voltage still to be decided. I’m currently undecided between a Prius or a BMW pedal - need a bit more work on the bodywork to see what will fit.

In the meantime I plan to prize the drive shafts out of the MGR and machine them down before welding a plate back on shaped to match the ends of the inner VW CV joints as I need to shorten the shafts by about 8mm each side. I had hoped that the inverter would have fitted on the left hand side under the rear seat opposite to the original 12v battery but a quick look makes that doubtful but I have a full engine bay to play with as well as the rest of the rest of the front boot/trunk. I’m thinking of KISS’S (keep it short and simple stupid) for this, my first, conversion so it’s slow charging only, no can bus requirements, and hopefully a plug and play front end will be available by the time I need it. No brake boost needed but I would like Regen from the rear to assist the front discs. AC is also on my wish list given that we are only a couple of hundred km from the tropics.

If Damian’s Blue Yacht or Zookeeper’s squareback demonstrate that the MGR isn’t up to scratch then I believe the rest of my package would still be viable for a different motor/transmission. The VW transaxle is totally dismantled and would probably be expensive to rebuild plus I like the idea of losing the clutch/flywheel/pedal etc.

So, many thanks to all the major and minor contributors to the forum for giving me the courage to move forward with the project. It wouldn’t be happening without your help!

Chris
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ZooKeeper
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Re: Yet Another Voltswagen

Post by ZooKeeper »

Hey Chris!

I KNOW the MGR is up to scratch, the question is at what voltage. Our VW's are much lighter than a BMW, but not sure they will do 70mph at Leaf voltages. However, we should be able to use the boost feature to rectify that and 50kw should be more than good enough for a 2000# VW :)
Huebner VCU controlling a Gen2 Prius Inverter powering an MGR
"Talent is equally distributed but opportunity is not." - Leila Janah
Ctwidle
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Re: Yet Another Voltswagen

Post by Ctwidle »

You’re very reassuring John! I fully agree the stats add up to it being viable but it would be nice to see some evidence of the long term durability.

My daughter (still in lockdown in London) is planning to inherit the beetle (pre rather than post mortem) and use it as a city commuter when she eventually gets back to Brisbane. Hence 100km/hr isn’t absolutely necessary.

In one of your videos you briefly showed a layout of your general wiring. I was wondering if a copy could be made available please?

For now it’s back to rebuilding the rear suspension so I can get some absolute measurements for the half shafts.

Chris
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Re: Yet Another Voltswagen

Post by ZooKeeper »

The diagram is also in the Wiki, but I dropped it into this thread as well.
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Huebner VCU controlling a Gen2 Prius Inverter powering an MGR
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vwbrady
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Re: Yet Another Voltswagen

Post by vwbrady »

welcome, fellow VW modder :) I am interested to see how the MGR works out for you performance wise. Good luck!
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Re: Yet Another Voltswagen

Post by Ctwidle »

Where do the weeks go? As this is also a complete bare metal, nut and bolt restoration it was never going to be quick. The advantage being that I have more time research the EV side of the project.

MECHANICALS
The floor pan is now sitting on its own wheels again with the MGR installed on its new mounts. There were no structural modifications to the Beetle ‘horns’ and the motor has just a slightly raised front and about a 10mm offset to the left. I was expecting to have to source some shorter ‘racing’ half shafts but with the rear suspension now rebuilt it has been possible to do some accurate measurements and the current plan is to shorten the right hand MGR stub axle by some 10mm (they can be prised out with little effort) weld on a 10mm plate which will then have a recess machined into it and 6 @ M6 holes tapped to match the original VW CV joints. The left hand will need to lose 20mm with a similar 10mm plate.
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Original engine mounts have been used so, as with the original Beetle motor, replacement couldn’t be simpler. Remove the electrical connections, disconnect the CV joints and there are just 4 bolts securing the motor to the body!


ELECTRICAL
The gen 3 Prius inverter case has been split and is awaiting its brain transplant. Although I have had lots of practice at basic soldering I do not wish to learn the intricacies of small scale soldering on this project so I will probably hand the task over to one of the technicians at my son’s workplace - time to call in some favours in return for many hours of landscaping over the last few years! He also has access to 3D printing.

NEXT STEPS
Now that the body is almost ready to be returned to the floor pan it is high time I put some effort into planning the two electrical layouts. Replacing a 50 year old wiring loom without the alternator, distributor etc isn’t the biggest of challenges. However designing a high voltage system is completely new to me and a challenge that I can see is fraught with lots of potential hazards so, first problem -what battery?
Until recently I had assumed that I would be able to source a used Leaf pack which could be split 50/50 between the luggage space and the fuel tank. Wrong assumption. The only ones I have seen have had a limited SoH, so, do I try for one of those with the expectation that when it needs to be replaced in a few years newer battery technologies might be available or look at a new pack and enjoy a longer period of reliability?
Despite pretty extensive reading on the forum I haven’t unearthed a thread that focuses on the basics of an EV. I realise that an enormous amount of development work has and is being done here so I would not want to take up anyone’s valuable time but I would appreciate any pointers towards some good sources for me to delve into.
One small step will be to revisit Prof Kelly’s safety YouTube video then find a power supply that’s powerful enough for me to get used to tuning a V1c board to the MGR without having the lethal potential of a full battery pack.
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Re: Yet Another Voltswagen

Post by Ctwidle »

Don’t know what I did wrong, they showed up in the preview!
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Ctwidle
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Re: Yet Another Voltswagen

Post by Ctwidle »

With things not looking too rosey with the Toyota MGR only seeming to want to provide a barely adequate amount of power it may be time to bite the bullet and look for an upgrade before I get any further down the track.
The Outlander rear motor seems to be a step in the right direction and a complete 2014 PHEV has just appeared in a wreckers yard near me. The front end is a mess but all the bits I could want are at the other end. Looks like I need to buy the whole wreck but that should give me motor, inverter, DC/DC, charge port, cables and battery. What more could a guy want? Well apart from a working gearbox, adaptor plate and coupling.
Couple of quick questions if I may.
I already have a Yaris inverter is this better option than the native one?
Is an Outlander battery pack reconfigurable and would it be worth doing so (provided it proves to be in good order)?
Chris
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Re: Yet Another Voltswagen

Post by Ctwidle »

Been a while since I updated this build thread but a lot of reading has been done. I would like to say learning but that might be stretching things! So a brief update. I didn’t get that outlander body but I did source a rear motor then found the inner cv joints were made of unobtainium so the beetle gearbox was rebuilt with just 2nd and 4th gears. An adaptor plate and coupler were made and bolted in. Then, after finding that it was not practical/possible to import a battery pack to Aus, I began the long wait for one to become available locally.
Two days before Xmas I scored an early present. Another 2014 ‘repairable write off’ Outlander PHEV was auctioned and I was the only bidder at Aus $1500. Didn’t meet reserve but the bid was accepted the next day. Borrowing a trailer and a 4wd got the beast back home with fuel, auctioneer’s fees etc bringing the total to $2k. Still a bargain for all the goodies I have been able to harvest. Another $100 for someone to degas the A/C (it goes through the battery pack) and the rest of the dismantling was quite therapeutic being able to rip things out and not have to worry about putting them back again!
The inverter and charger will fit above the motor and the battery modules behind the back seat. This means I can probably even reuse most of the original cables.
This morning I opened the pack and found the modules varied between 25v and 30v. I was initially disappointed but then calculated the cells were between 3.1v and 3.5v, not well balanced but I can probably leave that to Tom’s EVS-VCU to sort out. So SoC isn’t too bad but SoH for an 8 year old pack is anybody’s guess.
Time to order a VCU and start playing battery Tetris, then wonder how I am going to dispose of the rest of the vehicle!
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Re: Yet Another Voltswagen

Post by Ctwidle »

Progress has been made! I have ‘harvested’ quite a list of bits from the written off Outlander. If you have the space it seems like a great way to go so here is a list of goodies in no specific order: Battery pack inc CMU’s, contactors, main fuse and service disconnect and lots of bus bar copper. Rear motor, inverter and DC/DC with connectors. Charge port and interior cable (I’ve had to extend this to reach the Beetle’s fuel filler). A/C compressor (don’t know if I can fit this in the Beetle). I was about to order an OBD socket when I realised there would be one somewhere in the carcase. I might still harvest the front motor and inverter but I have no particular use for it. There is even a good chance that I will be able to recoup a few $ on the wheels, headlights, seats etc before the rest goes to the wreckers.
Motor attached to home made adaptor plate with support frame
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DC/DC on frame
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By putting DC/DC and inverter in same orientation as in donor I can reuse most connectors. Small plastic box will hold main fuse and service disconnect.
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I’m not expecting a lot from an 8 year old battery pack but it is fitting quite neatly behind the back seat.
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Preview is scrambled so I hope this looks OK.
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