[JeffAU]

Hi, any thoughts on the Idea. Im new to the forum and the concept of doing an EV conversion. Im a former audio technician and have electronic trade in Australia. The more I read into it, it seems like the output of a controller/inverter is basically the same as an audio amplifier, just bigger and 3 channels (3 phase) instead of 2 (stereo). I feel capable of building this section of the controller and heatsinks, and liquid cooling as I also have plumbing experience (mainly at home but can solder quite well and seal/join copper pipes. Im just not good with the logic/brain board with all the programming etc.

I am also thinking of a 3 motor design (2 rear axle and 1 front - Im converting an old series 3 Land Rover and thinking of having on road all wheel drive as well as 4 wheel regen braking as well as leaving its original gearbox and transfer case in for off road mechanical 4 wheel drive so having 3 motors and 3 controllers provides good backup in case one or even two fail when off road. Ideally having 3 of each means I would like to keep the design as cheap as possible. Im even considering building my own motors and repurposing old front loader washing machine drum/barrels as waterproofing (with motors inside waterproof drum casing, and air intake, for additional air cooling, from up high or snorkel, connected via existing door seal to where front loader door was) for off road. I will post separately about motors when I have more details.

My thoughts on the controllers are to amplify the output of something like this:

I would need to check reviews about whichever smaller controller I use to amplify and make sure this and the amplifier I build supports the maximum speed/frequency I want the motor run at based on speed and number of coils in circumference /3 etc. as well as its quality/reliability.

Anyone tried this idea before?

 

[JeffAU]

Sorry If I’ve caused confusion about design of the car. All 3 motors will be under the bonnet. The 2 rear drive motors will connect to existing transmission and front drive motor will connect to front drive shaft where it connects to transfer case - this one will be belt or chain driven and this motor will only be powered when transfer case is in neutral and car is in matching gear for rear wheels (mainly on road but may be used to provide extra power/torque when mechanical 4 wheel drive is in use if this works , but probably won’t be the same gear ratio when in low range 4 wheel drive so not sure.

Sorry my design is complicated but will post separately when I have the design drawn up and motor type sellected.

 

[JeffAU]

Another question on this if anyone knows. Im guessing the smaller controller I use for this should be pure sine wave. Does anyone know if this applies to BLDC or EV inverters? Just been looking at mains/power inverters lately and pure sine wave definitely more efficient, and running when powering synchronous motors designed for mains voltage.

 

[Isaac97]

Hi,
I suggest you take a look at Eric Tischer's EV build. He took an industrial VFD and used it to power his large Siemens induction motor. The Electric Passat

Is there any reason you prefer 3 motors over a single one?

 

[JeffAU]

Hi,
I suggest you take a look at Eric Tischer's EV build. He took an industrial VFD and used it to power his large Siemens induction motor. The Electric Passat

Is there any reason you prefer 3 motors over a single one?

Isaac, Im thinking of building these motors:

Theyre only 45KW and I think my Landrover is going to need at least 100kw,

Rather than try to change the design to make it bigger, I figured, why have one when you can have three? - since Im building it myself on the cheap and will have the materials and tools anyway.

Also works better having balanced regen braking. I may just have one of the rear drive motors just switch on when its needed and save batteries by having rear driven one of these motors when not.

 

[Isaac97]

Oh, I have seen that article. Doubling or tripling them might work alright.
At those power levels you definitely need sine wave controllers. Either look at Eric Tischer's site or check out OpenInverter.

 

[brian_]

It appears that the plan is to use a small motor controller to drive a higher-capacity inverter - that's fundamentally unworkable. What you need to drive the inverter power stage is a pulse train for each phase to switch the IGBT devices on and off in pulse width modulated fashion, not an analog sine wave. Yes, you can treat this like an analog input to a switching-mode power amplifier, but that's a pile of unnecessary complication.

I suggest just buying one of the DIY inverter kits (so you don't need to design the controller, since that's what you're not familiar with) and building the whole thing.

 

[JeffAU]

Thanks for the help and info. Was looking into Paul Holmes original AC inverter design which I came across on the instructables, but little info available on these now so I should look into it further or go with an alternative kit. Was considering a single nissan leaf motor and inverter for a little while but not redily available here in Australia and the only wreck I came across at auction went for $7000 although that was repairable write off - so gone back to the plan of building my own inverters and motors and sorcing bateries from alibaba.

 

[Isaac97]

It appears that the plan is to use a small motor controller to drive a higher-capacity inverter - that's fundamentally unworkable. What you need to drive the inverter power stage is a pulse train for each phase to switch the IGBT devices on and off in pulse width modulated fashion, not an analog sine wave. Yes, you can treat this like an analog input to a switching-mode power amplifier, but that's a pile of unnecessary complication.

Absolutely -- I may have misinterpreted Jeff's idea. My understanding was that OP wants to use the brain of the sine wave controller and just replace the powerstage -- Eric Tischer did that with an industrial VFD and an IGBT power stage back in 2008 or so.

 

[brian_]

Absolutely -- I may have misinterpreted Jeff's idea. My understanding was that OP wants to use the brain of the sine wave controller and just replace the powerstage -- Eric Tischer did that with an industrial VFD and an IGBT power stage back in 2008 or so.

That would make sense, if the controller logic is appropriate to drive the chosen power stage, but that wouldn't be "amplifying the output" of the complete controller, so it wasn't what I assumed. Jeff - any clarification?

 

[JeffAU]

Sorry for the delay and confusion. I thought inverters work on the same theory as audio power amplifiers and basically turn a small sine wave created by the logic board and turn it into a much larger one in terms of watts or kilowatts. There is obviously more to driving a 3 phase motor to a loudspeaker coil.

Im basically looking for a low cost conversion for my recently purchased 1978 S3 Land Rover, especially where I am in Australia where the US$3000 conversation kits you see on eBay quickly turn into AU$5000 or more by the time you add shipping. Also, although Nissan Leafs have been sold in Australia since around 2010, finding used motors and wrecks are extremely rare and the only salvage vehicle I found at auction went for $7000

I think I’ve found a good source of batteries on Alibaba with good reviews and also received good feedback on the diysolarpower forum. I’ll post more about this in batteries section when I have more information on these when I hear back from the supplier.

My design has been changing from week to week but Ideally I would like to keep its original syncro gearbox and transfer case and add a main electric motor where the ICE used to be with or without the clutch - ideally without if this early syncro gearbox (Land Rover’s first) will handle gear changes with a stationary electric motor - I’ve got this idea from another article on this forum about clutch-less design.

I would also ideally like to add a second electric motor to the front drive shaft. It will most likely be added where the front drive shaft connects to the transfer case as the other end is moving with the suspension. This motor would be either belt driven (transfer case or CVT type multi-chain) or if its a double ended type and strong enough Ill add it in line and find a shorter drive shaft from another vehicle and leave a gap for it. This motor will be for on road all wheel drive (I plan to leave the original transfer case with low range to keep the vehicles off road capabilities but this front motor could be switched on momentarily as a boost of power for difficult off road situations but will be at a faster speed due to gear ratios) The main purpose of the front motor will be for 4 wheel Regen braking through as I think this is a lot safer and effective.

I’m now pretty much sold on Damien’s (EVBMW) Prius Gen 3 Dual Motor kit that is a new logic board for the original Prius inverter now as the Prius and it’s motors and inverters are one type of vehicle that is very easily sourced in Australia - they have been a vehicle of choice for taxi companies here for a long time now and you can even get a roadworthy vehicle for under $2000 now. Im thinking of getting a wreck at auction as I can get other useful bits such as the air con, accelerator pedal control and wiring - not sure about the batteries, I hear they are NIMH so will have to be a separate pack if they are any good. Probably good as a separate emergency battery to get out of trouble if my main battery goes flat though if they are still good.

I would be keen to hear if anyone here has had any experience with the Prius electric motors out of the trans-axles. I hear they are more difficult to work with due to being built in but confident about making a new casing - preferably waterproof if necessary. If I do go with the vehicle design with the extra front motor I’m not sure If I’ll try to split the two motors and use MG2 for main drive and MG1 for the additional front motor or buy 2 separate sets of these and kits and just use one complete set of these for each drive. Depends on power requirements as my vehicle is a fair bit larger and definitely a lot less aerodynamic than the Prius and I hope to use it for towing occasionally.

 

[MattsAwesomeStuff]

I’m not sure If I’ll try to split the two motors and use MG2 for main drive and MG1 for the additional front motor or buy 2 separate sets of these and kits and just use one complete set of these for each drive. Depends on power requirements as my vehicle is a fair bit larger and definitely a lot less aerodynamic than the Prius and I hope to use it for towing occasionally.

Nope. Don't do that.

The motors are all enclosed, fairly compact, into a gearbox. They are also not equally sized. You're going to need geardown for them anyway.

I'd keep the transaxles the same.

I wish you luck but I think you're biting off more than you can chew in terms of complexity here. And, you haven't seemed to consider battery much. Occasional towing is hopefully just around a yard or parking help, with 3 motor and inverter systems and a heavy vehicle and a low budget, you're just not going to have much for battery range.

Do note that Damien's dual-motor controller is a master-slave, not a twin master. That is, the second motor is given a mirror signal to the master, if one's on, the other's one, you don't have independent control.

The Prius Gen 3 controller is good for like 700 hp peak, limited only by your ability to cool it. Power is not an issue, though battery drain at massive power draw will be.

You might also want to look at the GS450H motor/gearbox combo from the Lexus. It looks like a normal tranny and bell housing, but has the motors and gearbox inside, and it's a decent amount beefier than the Prius units, and a lot easier to integrate into RWD.

Alternatively, there's an "MGR" which is a little baby motor as a diff, so if you just need "some" extra power on all wheels you could try that.

Damien has working controllers for all of those.

 

[JeffAU]

Thanks Matt,

I might just start with a standard conversion of swapping out the ICE for a decent size motor and look at the additional front motor as an upgrade later on.

With the Prius Gen 3 dual Motor set up as one set of both motors connected just running as one main motor connected to input of the original manual gearbox, and just using a lower gear to drive, is there any info on continuous and peak power consumption, doing it this way? Also with Damien’s inverter controller, I would be keen to know if this can be driven with one of those motors only (whichever is the master) in times when only low power is needed to save battery range and the slave motor only turned on when the extra power is needed?

 

[brian_]

With the Prius Gen 3 dual Motor set up as one set of both motors connected just running as one main motor connected to input of the original manual gearbox, and just using a lower gear to drive...

There's no reasonable way to use the Prius motors outside of the Prius transaxle (which is a power-split transmission plus final drive). The output of the transaxle is already geared to run at the speed of the wheels, so no only would you not need the original Land Rover transmission, you would have a problem with the axles providing too much gear reduction, severely limiting the speed of the vehicle. You wouldn't use a lower gear; you would need a super-overdrive.

 

[JeffAU]

Another Idea I’ve thought of is simply using Damien’s Prius Single motor or dual motor controller board, with Prius inverter with a different 3 phase motor (or 2 smaller 3 phase motors if dual controller) other than the one out of the Prius. I guess with this there would still be need to be a master and slave?

 

[JeffAU]

I found this video extremely informative of how the gen3 transaxle works in the Prius

I think Damien found a way of tig welding planetary gear sets to make the whole lot turn together, so that both motors combine to run the same as one double motor. I just can’t find Damien’s article now and it might be somewhere here or on open inverter.

Then I would imagine it would be a case of making a suitable plate to connect to the transmission bell housing, with enough precision for the existing vechicle clutch to mesh with the flywheel next to MG1 (where the damper plate was in the Prius) or for a clutchless design, still connected in this way but taking the clutch and flywheel out and replace with a flexible drive shaft (to allow for slight inaccuracies in connecting the 2 units together) I think there is a spline shaft to connect to when you remove the transaxle flywheel (from a picture I saw)

 

[MattsAwesomeStuff]

The Weber videos are a treasure. Clear, concise, well-lit, well-shot, well-labelled, well-paced. Guy knows how to teach.

IIRC, MG1 normally runs in reverse, and is fed by the engine.

You have 2 choices, you can cut off a stub of the engine shaft and weld it in place, or, you can weld the planetary gears. If you do the former, MG1 will run at 2.5x the speed of MG2 I think, and it will overspeed. If you choose the latter, it's more difficult but it ensures MG1 and MG2 turn at the same speed, with neither running over their max speed.

The GS450H motor/gearbox is different. I believe you can weld the input spline and it works fine.

 

[JeffAU]

I think doing the later of welding planetary gears is a better choice. Im guessing theres no reason why it can’t provide an output to gearbox by means of connecting to where the damper plate was because in the Prius, MG1 was used as a starter motor this way. It all depends if the shaft of MG1 and everything in between the MG1 and MG2, once the planetary gears are welded, are strong enough to handle MG2 driving it this way as this was not an intention in the original design. This was designed to handle the ICE driving it the other way though.

 

[brian_]

...
Then I would imagine it would be a case of making a suitable plate to connect to the transmission bell housing, with enough precision for the existing vechicle clutch to mesh with the flywheel next to MG1 (where the damper plate was in the Prius) or for a clutchless design, still connected in this way but taking the clutch and flywheel out and replace with a flexible drive shaft (to allow for slight inaccuracies in connecting the 2 units together) I think there is a spline shaft to connect to when you remove the transaxle flywheel (from a picture I saw)

There is no clutch in a Prius or other Toyota/Lexus Hybrid Synergy Drive transmissions/transaxles.

 

[brian_]

I think doing the later of welding planetary gears is a better choice. Im guessing theres no reason why it can’t provide an output to gearbox by means of connecting to where the damper plate was because in the Prius, MG1 was used as a starter motor this way.

I don't understand what you are trying to do. The engine and MG1 are connected to a planetary gearset used as a power splitter, conceptually similar to the way the left and right wheels of an axle are connected to a differential. Just like with the axle differential, if the common shaft cannot turn (in the Prius that means the car is stopped), turning MG1 turns the engine, and that's how it starts the engine.

It all depends if the shaft of MG1 and everything in between the MG1 and MG2, once the planetary gears are welded, are strong enough to handle MG2 driving it this way as this was not an intention in the original design. This was designed to handle the ICE driving it the other way though.

MG2 drives the car by itself whenever the engine is not running - the mechanical output of MG2 doesn't go through the power splitter (the planetary gear set connecting the engine and MG1 to the rest of the system) or involve MG1 at all. I'm not suggesting this, but you could remove the entire power splitter gearset and MG1 and it would leave you with a single-motor (MG2) drive unit... although who knows what shafts would need to be left and spacers would be needed to keep the spinning bits in place.