Prelude conversion project - some questions

Technical discussion on converting internal combustion to electric
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jonescg
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Re: Prelude conversion project - some questions

Post by jonescg » Tue, 12 Jun 2018, 09:39

HV distribution rev 1.png
HV distribution rev 1.png (31.62 KiB) Viewed 316 times
R indicates a resistor across the main terminals of the contactor.
(edited to use the words closed and open, instead of off and on)
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Richo
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Re: Prelude conversion project - some questions

Post by Richo » Tue, 12 Jun 2018, 12:44

Why not put the charger in the battery box before the main contactor?
Then you only have mains going in and HV coming out of the box.
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Re: Prelude conversion project - some questions

Post by jonescg » Tue, 12 Jun 2018, 13:55

I have some lower current HV connectors and 4 m of cable which can come directly from the battery pack. I just figured if I'm going to be putting a contactor in series with the charging leads, I might as well use the same one as the discharging leads. Anyway, the charger is the size of a small briefcase, so It probably wouldn't fit.
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Re: Prelude conversion project - some questions

Post by Richo » Wed, 13 Jun 2018, 12:35

With mains coming out of the box small 240V Relays can be used to isolate the mains and the car is HV safe while charging.
Unless the charger can go in the battery box its best to have the contactor(s) on the HV lines as you have drawn.
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Re: Prelude conversion project - some questions

Post by jonescg » Sat, 30 Jun 2018, 21:38

So the shopping list is nearly complete:

Motor - Greatland 60 kW peak liquid cooled PMAC
Inverter - Greatland liquid cooled drive; works well with said motor. Hopefully the adapter plate will be quick, and the protective shelf separating the motor from the inverter and other parts will be a smooth process too. We might skip the clutch as the motor seems to be powerful enough to spin tyres in third (based on Jamie Pardoe's Jumbuck).

Charger - TC Charger, 6.6 kW CAN capable, liquid cooled. I might use the same cooling loop as the inverter and motor.

EV-West AVC2 Modular EV Power control boards for the J1772 protocol on the charge inlet. Oh yeah I better find a charge inlet...

DC/DC converter - From TC also. 1.5 kW air cooled unit with 12 V digital enable signal as well

Hot water unit - 350 V DC 2 kW kettle type. Will set up with a pump and contactor, activated from a switch on the dash.

Air Conditioning compressor - 350 V DC powered, uses 12 V signal and PWM to vary speed. Might be just as easy to set it to full speed and switch it on or off from the dash. Wiring it is easy. Plumbing it and gassing it well that's another story.

Brake vacuum pump - OzDIY parts (thanks Graeme).

Power steering pump - From a Holden Astra. This is a 12 V high powered fluid recirculating type. Will need to set up to run whenever the drive contactor is engaged. I found a 150 A relay at Altronics which should be able to handle the load.

Battery - 25 kWh worth of high energy density lithium cobalt cells have arrived. PCBs and busbars are made and ready to assemble. Liquid cooling plates to be fabricated in the meantime. The battery will be a single unit which goes in place of the Prelude's fuel tank. Except there is a bloody 4-wheel-sterring rod in the way... It's not a show stopper, but it does complicate the battery construction. Construction hasn't started in earnest, but I think that will take quite some time. The battery will be thermally managed with coolant circulating through the plates and out to a large aluminium radiator (matches the original radiator). The coolant will go via a heat exchanger which allows refrigerant to pass through it, so on really hot days the AC compressor can help keep the battery cool.

BMS - ZEVA units and main control unit. The MCU can change the charger output currents and voltages as well.

Miscellaneous - this is the stuff that catches you out. Things that take 5 minutes to discover and 5 weeks to recover. Trying to make use of the car's original 12 V wiring and getting utterly lost... Contactors, fuses, relays, indicator lights, microswitches, weatherproof enclosures, conduits, lugs... the list goes on. I fully expect the car to take a solid 80 hours to convert, assuming all the parts are ready to go and there are zero surprises (and there have already been some).
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Re: Prelude conversion project - some questions

Post by brendon_m » Sun, 15 Jul 2018, 14:02

jonescg wrote:
Sat, 30 Jun 2018, 21:38

Air Conditioning compressor - 350 V DC powered, uses 12 V signal and PWM to vary speed. Might be just as easy to set it to full speed and switch it on or off from the dash. Wiring it is easy. Plumbing it and gassing it well that's another story.
I don't know where abouts in Perth you are but at my work we can make up custom a/c hoses and systems. Getting the fittings / ends can be tricky sometimes but we regularly cut old special fittings off pipes and weld them onto new ferrules and crimp on new rubber hose. Splices and Tees etc for split systems with lock off valves are all possible. One
other trauma you would have to be careful of is that I know production Ev's use a special a/con oil in their systems to help with high voltage isolation(I'd assume your pump would also have it). So you would want to make sure the original system parts get flushed right out to avoid contamination

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Re: Prelude conversion project - some questions

Post by jonescg » Sun, 15 Jul 2018, 14:11

Very good to know! Yes there will be a need for adapting the additional AC parts to the existing system, particularly crimping onto the heat exchanger after the evaporator/blower unit.
I'm in Willetton, but will be moving to Kalamunda soon.
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Re: Prelude conversion project - some questions

Post by brendon_m » Sun, 15 Jul 2018, 14:16

jonescg wrote:
Sat, 30 Jun 2018, 21:38
Power steering pump - From a Holden Astra
My experience with these is that they can suck a lot of power because the pump runs all the time You'll probably want to try to have it wired so it only runs when trying to steer (although they take a while to get up to speed) or something.
Alternatively has anybody used/adapted an electric assisted steering column out of another car(I know the hyundai i30 has them). Leave the factory rack in the prelude without the hydraulic lines connected and modify an i30 column (or part of it) into the car?

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