Francisco's Electric Pajero

Post up a thread for your EV. Progress pics, description and assorted alliteration
francisco.shi
Senior Member
Posts: 550
Joined: Mon, 17 Sep 2018, 16:30
Real Name: Francisco
Location: Brisbane, Strathpine

Re: Francisco's Electric Pajero

Post by francisco.shi »

I have been a bit busy for the last two months so not much progress. I have however been doing some other stuff that I will eventually need like a way of lifting the battery into the car.
Battery lift table.
Battery lift table.
20210407_204845.jpg (1.65 MiB) Viewed 383 times
I have also been doing a bit of work on software to try to tune the inverter control loops.
I have added a function to record what us going on and added some trigger functions so I can get charts like these:
Sensor plot.
Sensor plot.
20210401_201324.jpg (1.26 MiB) Viewed 383 times
And some way to easily change parameters.
Parameter update screen.
Parameter update screen.
20210404_151524.jpg (1.29 MiB) Viewed 383 times
I have got the overcurrent tripping reliably now so
I a added some more batteries. I am testing at about 72v now. Still tripping on overcurrent but now it turns off if I get too much current in any of the phases.
I have also added a way to automatically adjust the gains depending on the battery voltage but haven't got the inverter tunned correctly yet so I can't tell how well the voltage compensation works.
The resound motor is a bit harder to tune because the impedance is much lower so it is much easier to get some overshoot in the current and trip.
User avatar
jonescg
Senior Member
Posts: 3807
Joined: Thu, 21 Jan 2010, 23:05
Real Name: Chris Jones
Location: Perth, WA.

Re: Francisco's Electric Pajero

Post by jonescg »

Nice battery bench! I just use a mobile table and the hoist does the work...
AEVA National Secretary, WA branch chair.
User avatar
coulomb
Site Admin
Posts: 4642
Joined: Thu, 22 Jan 2009, 20:32
Real Name: Mike Van Emmerik
Location: Brisbane
Contact:

Re: Francisco's Electric Pajero

Post by coulomb »

jonescg wrote: Wed, 07 Apr 2021, 19:23 Nice battery bench!
Indeed! And for those times when you don't need a battery lifter (pfft!), you can just fold it up and put it on a shelf! :shock:

Edit: are those pneumatic cables to synchronise the lifters, without the need for a helper?
Nissan Leaf 2012 with new battery May 2019.
5650 W solar, 2xPIP-4048MS inverters, 16 kWh battery.
1.4 kW solar with 1.2 kW Latronics inverter and FIT.
Patching PIP-4048/5048 inverter-chargers.
User avatar
coulomb
Site Admin
Posts: 4642
Joined: Thu, 22 Jan 2009, 20:32
Real Name: Mike Van Emmerik
Location: Brisbane
Contact:

Re: Francisco's Electric Pajero

Post by coulomb »

francisco.shi wrote: Wed, 07 Apr 2021, 19:01 I have added a function to record what us going on and added some trigger functions so I can get charts like these:
Nice. I always found tuning control loop gains to be a pain. Even simple loops where there is a well-known formula (which I've long forgotten). That looks really sophisticated.
Nissan Leaf 2012 with new battery May 2019.
5650 W solar, 2xPIP-4048MS inverters, 16 kWh battery.
1.4 kW solar with 1.2 kW Latronics inverter and FIT.
Patching PIP-4048/5048 inverter-chargers.
francisco.shi
Senior Member
Posts: 550
Joined: Mon, 17 Sep 2018, 16:30
Real Name: Francisco
Location: Brisbane, Strathpine

Re: Francisco's Electric Pajero

Post by francisco.shi »

jonescg wrote: Wed, 07 Apr 2021, 19:23 Nice battery bench! I just use a mobile table and the hoist does the work...
I tried that to start with but it was very unstable and difficult to move around. Using the hoist to lower the car into the battery was not very good. It is very difficult to move the car down accurately and then I have to move down a little then walk around checking the position adjust and then move down again. It was too cumbersome. Also my battery fits between the chassis rails so I need good position accuracy or else I can crush the side of the battery box without knowing.
So far I have only used the movable table with the empty box and the two motors (about 200kg) and it was not very stable. I don't want to try that with a 500kg assembly
francisco.shi
Senior Member
Posts: 550
Joined: Mon, 17 Sep 2018, 16:30
Real Name: Francisco
Location: Brisbane, Strathpine

Re: Francisco's Electric Pajero

Post by francisco.shi »

coulomb wrote: Wed, 07 Apr 2021, 20:13
jonescg wrote: Wed, 07 Apr 2021, 19:23 Nice battery bench!
Indeed! And for those times when you don't need a battery lifter (pfft!), you can just fold it up and put it on a shelf! :shock:

Edit: are those pneumatic cables to synchronise the lifters, without the need for a helper?
There are two hoses the black one is a high pressure hydraulic line so I can use either side to Jack up the table. The white hose is an air hose so the reservoir on both cylinders stay at the same level.
The cylinders are jot synchronised. They push with the same pressure. There are some guides with rollers to keep the table from rocking.
francisco.shi
Senior Member
Posts: 550
Joined: Mon, 17 Sep 2018, 16:30
Real Name: Francisco
Location: Brisbane, Strathpine

Re: Francisco's Electric Pajero

Post by francisco.shi »

coulomb wrote: Wed, 07 Apr 2021, 20:19
francisco.shi wrote: Wed, 07 Apr 2021, 19:01 I have added a function to record what us going on and added some trigger functions so I can get charts like these:
Nice. I always found tuning control loop gains to be a pain. Even simple loops where there is a well-known formula (which I've long forgotten). That looks really sophisticated.
Tunning is becoming a bit more difficult than I expected.
I still don't know why but if the motor is running slowly it is stable as the motor speeds up it starts to become unstable. I may need some help from some one with better mathematical skills and understanding of the control loops.
So far the problem is either too much overshoot (which causes it to trip) or going unstable when the motor is spinning fast (which eventually it also causes it to trip)
francisco.shi
Senior Member
Posts: 550
Joined: Mon, 17 Sep 2018, 16:30
Real Name: Francisco
Location: Brisbane, Strathpine

Re: Francisco's Electric Pajero

Post by francisco.shi »

I just did some weight measurements and was pleasantly surprised.
The old Pajero weights:
Front axle 1160kg.
Rear axle 1060kg.
Total: 2160kg.
Pajero EV (without batteries but with battery box and motors)
Front axle: 705kg.
Rear axle: 1060kg.
Total 1765kg.
Difference: 395kg.
Expected weight of batteries: 402kg.
So If I am overweight it will be very little.
T1 Terry
Senior Member
Posts: 1251
Joined: Thu, 30 Sep 2010, 20:11
Real Name: Terry Covill
Location: Mannum SA

Re: Francisco's Electric Pajero

Post by T1 Terry »

Wow, don't you think you might have gone a bit over top with the battery lifter? Our sizzor lift hydraulic table says it's rated to 350kg, but we've lifted 500kg with it on more than a few occassions ..... it does make a few noises when lifting that weight, but it does it, we just stay out of the pinch areas just in case :lol: This one is rated at 500kg so it might be the next purchase https://www.ebay.com.au/itm/New-LIFT-TA ... ctupt=true

We also use a modified motor cycle lifter for the real close to the ground slide in battery drawers, or to get the bigger battery packs up high enough to slide off onto the other lifting table, then use that to get them up to bench height .... cause I'm getting too old to be working much below waist high without suffering severe headaches from looking down for too long.

T1 Terry
Green but want to learn
francisco.shi
Senior Member
Posts: 550
Joined: Mon, 17 Sep 2018, 16:30
Real Name: Francisco
Location: Brisbane, Strathpine

Re: Francisco's Electric Pajero

Post by francisco.shi »

I have one of those tables but it is not very stable when lifted.
The battery pack in the Pajero is a bit big (1.2x1.9m) and every time I used the table to get it out I was very worried it would tip over.
Another problem I have is that the hoist has a cable that goes underneath so there is a ramp about 50mm high that I have to get over.
The plan is to put something to make the angle a bit more flat.
The battery and the motors are one piece so it has the battery weight plus another 140kg of motors. Total weight about 500kg. I also wanted large wheels so it is easy to maneuver.
As far as load capacity I think it will do 1000kg easily. Just in case I drop the car on top of it. :lol:
It is also a bit wide so that I could slide the pack on top for small adjustments.
So yeah. A bit of an overkill but it wasn't going to be much cheaper or easier to make something smaller or lighter. I did look on eBay and other options and I couldn't find anything better than the lift table I already have for a decent price.
Anything that was wide and long enough to be stable was over $3k
T1 Terry
Senior Member
Posts: 1251
Joined: Thu, 30 Sep 2010, 20:11
Real Name: Terry Covill
Location: Mannum SA

Re: Francisco's Electric Pajero

Post by T1 Terry »

Fair enough. Does it drop down low enough to get out from under the vehicle even though the whole unit with the pack on top would have to climb over the cable cover/ramp in the centre?
Maybe building a a platform the vehicle drives up on that is the height of the centre ramp so in effect the hoist becomes sub floor.
A previous life as a motor mechanic I've seen all the different variations of vehicle hoists and none do it all, even the individual wheel lifter type, a big open area under the vehicle, but hopeless if you need to remove the wheels or drop the diff assembly wheel to wheel out :lol:

T1 Terry
Green but want to learn
francisco.shi
Senior Member
Posts: 550
Joined: Mon, 17 Sep 2018, 16:30
Real Name: Francisco
Location: Brisbane, Strathpine

Re: Francisco's Electric Pajero

Post by francisco.shi »

Yes. It drops enough. It has about 400mm of travel. And even if it didn't the hoist can still go up a fair bit. I didn't want to have too much travel because that makes the table taller and to get the battery to go into the car I only really need about 150mm of travel that I can not do with the hoist. The plan is to use the hoist to get it close then use the table to move around and then slowly move the battery up with the table.
T1 Terry
Senior Member
Posts: 1251
Joined: Thu, 30 Sep 2010, 20:11
Real Name: Terry Covill
Location: Mannum SA

Re: Francisco's Electric Pajero

Post by T1 Terry »

Had a similar type of lifter we used for installing gearboxes in the buses down in Tassie when I was working in a bus yard down there. It had a mega single ram in the centre with sliding steady telescope "Acrow-prop" arm at each corner. The idea was to lift up to the required height and then adjust as required to get the tilt and roll using the "acrow-props" so the transmission would slide the input shaft smoothly into the clutch so the bolts could be fitted and tightened. The problems they had before the invention of the transmission lifter was hanging the gearbox on the input shaft and buckling the clutch plate. Getting this monster into the pit was a bit of a problem, getting around it once it was loaded up with the bus back over the pit was a whole different story .... no bus lift hoists at that bus yard, just over 50 buses and me the only mechanic .....

T1 Terry
Green but want to learn
francisco.shi
Senior Member
Posts: 550
Joined: Mon, 17 Sep 2018, 16:30
Real Name: Francisco
Location: Brisbane, Strathpine

Re: Francisco's Electric Pajero

Post by francisco.shi »

I did a bit of work on the inverters this weekend and got a bit of progress. I found the reason for the difficulty in the running was because of a bug in my PID code. I got that sorted and that fixed the overcurrent tripping problem caused by the overshoot. I then started having some desat protection problems which were caused by the inverters not getting enough voltage on the 12v supply. Each inverter consumes about 1.5A just for the gate drive. The problem was that there was too much voltage drop between the battery and the inverter PSU. I was getting about 10.5v from a supply of 12.5v. I increased the wire size and replaced some of the connectors. That solved the problem. Being more confident that things were not going to blow up I upped the voltage from 38v to 76v and then to 150v.
After the voltage increase I started getting some overcurrent trip problems again (at the higher voltage) looking at the data logged from the inverter and it seems that some times the processor stops. I have not put any effort in optimising the code so I need to do a bit of work to see what it is going on.
I was a bit concerned that the resound motor would have too little inductance and was going to get a very high ripple current but that does not seem to be the case.
Inverter 1 settings.
Inverter 1 settings.
20210411_133917.jpg (1.51 MiB) Viewed 248 times
Inverter 1 log.
Inverter 1 log.
20210411_133902.jpg (1.42 MiB) Viewed 248 times
Inverter 0 settings.
Inverter 0 settings.
20210411_133911.jpg (1.42 MiB) Viewed 248 times
Inverter 0 log.
Inverter 0 log.
20210411_133838.jpg (1.24 MiB) Viewed 248 times
Inverter 0 is the rewound motor. You can see from the current waveforms how the current drops quicker when the transistors are turned off.
I am not expecting the freezing of the processor to be a difficult problem to fix. It is probably just a matter of optimising the code and removing some debug stuff.

I am getting excited. The project is getting to the almost drivable stage.
I will need to start building the battery pack very soon.
I already got the cell boards and all the cells.
I have started working on a jig to assemble the battery pack and have hit some unexpected issues with the busbars linking the 3 modules. I have also managed to fit 82kwh instead of the original 70kwh. So should get a bit more range.
I have gone from a 3P to a 4P arrangement and will end up with 96S. The good thing about working with 96S is that I can use parts from any other EV including the charger.
On the subject of chargers, I found a 7kw liquid cooled charger. If anyone is thinking of building a high voltage conversion let me know if you want to get the charger when I order mine.
francisco.shi
Senior Member
Posts: 550
Joined: Mon, 17 Sep 2018, 16:30
Real Name: Francisco
Location: Brisbane, Strathpine

Re: Francisco's Electric Pajero

Post by francisco.shi »

I have progressed a bit further with the inverters. Yesterday I got to a point where the inverters were tripping it looked as if the processor was crashing or getting stuck and was failing to update the outputs. I did a bit of investigation and it appeared as if the ADCs were failing to update. The control loop did jot stop but because the readings were not being updated it would look like it was getting stuck.
Processor getting stuck.
Processor getting stuck.
20210413_195304.jpg (1.41 MiB) Viewed 214 times
Today I did more work on it and it turned out to be the interrupt priority. The ADC interrupt had a lower priority than the control loop. That caused the ADC interrupts to pile up.
I gave higher priority to the ADC interrupts and reduced the sampling frequency of slow signals (like temperature and bus voltage measurements) and that fixed the problem. Just before coming baco home I did a quick test and the tripping has stopped. I managed to get a bit of speed without tripping. I will post a video tomorrow.
francisco.shi
Senior Member
Posts: 550
Joined: Mon, 17 Sep 2018, 16:30
Real Name: Francisco
Location: Brisbane, Strathpine

Re: Francisco's Electric Pajero

Post by francisco.shi »

As promised here are some short videos.

First is getting out of the shed and driving off.


Then we test maximum regen braking.


The we test the maneuverability of the E pedal.
Not there is no master cylinder. All braking is from regen.
My version of the E pedal is a little different to the standard setup. It allows very accurate control of the braking and it also allows for easy coasting.


Wanted to test a bit of off-road but have nothing worthwhile.
User avatar
brendon_m
Senior Member
Posts: 823
Joined: Sat, 28 Oct 2017, 11:00
Real Name: Brendon McCarrol

Re: Francisco's Electric Pajero

Post by brendon_m »

Big ol 4wd hooning about and the loudest sound is the birds chirping
francisco.shi
Senior Member
Posts: 550
Joined: Mon, 17 Sep 2018, 16:30
Real Name: Francisco
Location: Brisbane, Strathpine

Re: Francisco's Electric Pajero

Post by francisco.shi »

It would make a pretty good ad for an electric 4WD :lol:
Rusdy
Groupie
Posts: 277
Joined: Mon, 09 Jun 2014, 16:45
Real Name: Rusdy
Location: Australia
Contact:

Re: Francisco's Electric Pajero

Post by Rusdy »

francisco.shi wrote: Thu, 15 Apr 2021, 21:56 It would make a pretty good ad for an electric 4WD :lol:
Oh, what a FRUNK!!!
francisco.shi
Senior Member
Posts: 550
Joined: Mon, 17 Sep 2018, 16:30
Real Name: Francisco
Location: Brisbane, Strathpine

Re: Francisco's Electric Pajero

Post by francisco.shi »

I am going to put a fridge in there so when I get back after a bike ride I can get cold drinks out of the engine bay and show off to my friends. :lol:
francisco.shi
Senior Member
Posts: 550
Joined: Mon, 17 Sep 2018, 16:30
Real Name: Francisco
Location: Brisbane, Strathpine

Re: Francisco's Electric Pajero

Post by francisco.shi »

The only thing missing in the engine bay is the Air conditioning compressor and the AC charger/DC-DC converter so should have plenty of space left.
User avatar
brunohill
Groupie
Posts: 208
Joined: Thu, 08 Feb 2018, 22:32
Real Name: Phil
Location: Wangaratta

Re: Francisco's Electric Pajero

Post by brunohill »

Plenty of room for a 3 phase AC charger. I guess the next thing would be a modified solar inverter to provide 230 volt AC outlets.
Last edited by brunohill on Fri, 16 Apr 2021, 20:55, edited 1 time in total.
francisco.shi
Senior Member
Posts: 550
Joined: Mon, 17 Sep 2018, 16:30
Real Name: Francisco
Location: Brisbane, Strathpine

Re: Francisco's Electric Pajero

Post by francisco.shi »

I was going to put a 3ph charger but not sure if it is worth the extra cost.
The 3ph charger is about 3 times the price of a single phase. I am planning on have DC fast charging so 3ph charger may not be necessary.
francisco.shi
Senior Member
Posts: 550
Joined: Mon, 17 Sep 2018, 16:30
Real Name: Francisco
Location: Brisbane, Strathpine

Re: Francisco's Electric Pajero

Post by francisco.shi »

I have been thinking making it V2H capable.
The plan is to connect an inverter via the DC charge port.
I am going to make an isolated bidirectional DC link and feed the output to a solar inverter via the solar panel inputs and the solar panels will go to my converter. So that way I can feed the house from the solar or from the car.
I think the best option is to have an external inverter instead of internal so I don't have to carry it around all the time. It would only be necessary if I go camping.
User avatar
coulomb
Site Admin
Posts: 4642
Joined: Thu, 22 Jan 2009, 20:32
Real Name: Mike Van Emmerik
Location: Brisbane
Contact:

Re: Francisco's Electric Pajero

Post by coulomb »

francisco.shi wrote: Fri, 16 Apr 2021, 21:01 The plan is to connect an inverter via the DC charge port.
I am going to make an isolated bidirectional DC link and feed the output to a solar inverter via the solar panel inputs and the solar panels will go to my converter.
Neat! Presumably, you'll have some sort of adjustable sag that the inverter sees, so it knows when to stop drawing power (when it sees what it thinks is the maximum power point).

That way, if the house only needs a little power, and you want to keep some energy for the car (and not stress the car battery with needlessly fast discharge), you can turn it down. Or turn it up to charge the house battery quickly, if you don't plan on using the car for a while. Or export a bunch of power to the grid if the grid power price is really high, and you can get access to that sort of payment.
Nissan Leaf 2012 with new battery May 2019.
5650 W solar, 2xPIP-4048MS inverters, 16 kWh battery.
1.4 kW solar with 1.2 kW Latronics inverter and FIT.
Patching PIP-4048/5048 inverter-chargers.
Post Reply