Prelude conversion project - some questions

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

Post by antiscab » Thu, 14 Nov 2019, 21:50

seems legit :D
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Re: Prelude conversion project - some questions

Post by Rusdy » Fri, 15 Nov 2019, 06:23

Google as usual listens my browsing, so, this pops out in my news feed :D :

https://www.gizmodo.com.au/2019/11/the- ... ert-lever/

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Re: Prelude conversion project - some questions

Post by jonescg » Fri, 15 Nov 2019, 06:38

Ahhh Japan. Always interesting and never disappointing 😅
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Re: Prelude conversion project - some questions

Post by brendon_m » Fri, 15 Nov 2019, 06:55

As I said the other day, I would add a tx valve to the heat exchanger and run it in parallel with the original evaporator. All you need then is 2 Tee pieces and possibly a lock off solenoid or 2 to isolate either half of the system when it's not needed so you aren't absorbing heat you don't need to.
You could also add an extra condenser at the front to help disperse the extra heat.
However without having a red hot radiator next to it the condenser won't be having to work as hard.
Is the coolant loop of the batteries always going through the radiator? If so maybe some tricky valves on the water might be the way to go because any heat you get rid of in the heat exchanger will be picked up by the radiator.
Maybe you could remove all other coolant loops and only have the batteries, heat exchanger and a pump

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Re: Prelude conversion project - some questions

Post by francisco.shi » Fri, 15 Nov 2019, 08:57

I am going to face the same problem. I was thinking of using the evaporator to chill water that I can then run thru whatever I need to cool down. So all you need is a pump to pump the water to either the batteries or the evaporator in the cabin. Not sure if it will be better. Having an evaporator to cool down water that then runs thru the battery means all I have to do is just have a bigger evaporator that cools the water and I can get rid of all the gas pipes and only deal with chilled water.

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Re: Prelude conversion project - some questions

Post by jonescg » Fri, 15 Nov 2019, 09:36

brendon_m wrote:
Fri, 15 Nov 2019, 06:55
As I said the other day, I would add a tx valve to the heat exchanger and run it in parallel with the original evaporator. All you need then is 2 Tee pieces and possibly a lock off solenoid or 2 to isolate either half of the system when it's not needed so you aren't absorbing heat you don't need to.
You could also add an extra condenser at the front to help disperse the extra heat.
However without having a red hot radiator next to it the condenser won't be having to work as hard.
Is the coolant loop of the batteries always going through the radiator? If so maybe some tricky valves on the water might be the way to go because any heat you get rid of in the heat exchanger will be picked up by the radiator.
Maybe you could remove all other coolant loops and only have the batteries, heat exchanger and a pump
The battery heat is absorbed by the coolant and pumped through the heat exchanger. It's a closed loop, and shares an overflow/surge reservoir with the heater loop. So nothing battery related is at the front of the car. The radiator only cools the motor-controller-charger loop, and even without a fan seems to shed enough heat. Should the fans fire up it never gets above 40'C. I bought a 50'C thermostat switch from Jaycar, but no part of the system gets hot enough to activate it :) However if the air conditioning system is operational, the fans will be running exactly as intended, except they will also be shedding heat from the condensor as well.

Is there anything wrong with putting them in series as I'd originally intended, and just letting it do it's thing? I mean, worst case scenario it just doesn't get very cool. But even that is better than nothing.
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Re: Prelude conversion project - some questions

Post by francisco.shi » Fri, 15 Nov 2019, 10:28

I think if you put a TX valve then a small evaporator that cools the battery coolant then the cabin evaporator it will work as long as you dont freeze the battery coolant and you do not have so much load from the battery coolant that the gas comes out warm from the first evaporator.
How cold the cabin evaporator gets will depend on how much heat the gas has to remove from the first evaporator.

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Re: Prelude conversion project - some questions

Post by brendon_m » Fri, 15 Nov 2019, 10:53

jonescg wrote:
Fri, 15 Nov 2019, 09:36
Is there anything wrong with putting them in series as I'd originally intended, and just letting it do it's thing? I mean, worst case scenario it just doesn't get very cool. But even that is better than nothing.
I just think there's more control with what heat you are absorbing when you can lock out parts of the system.
Also when in series the TX may not flow enough to flood the heat exchanger with refrigerant. Long story short is it might not cool as well as it could.

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Re: Prelude conversion project - some questions

Post by jonescg » Fri, 15 Nov 2019, 11:14

https://electricrevs.com/2018/12/20/exc ... nt-design/
Looks like the Kona has a very similar system to my proposed one, with a few key points - the battery heat exchanger and the cabin evaporator are in parallel, and both have expansion valves ahead of them. No idea if they can be adjusted on the fly though.
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Re: Prelude conversion project - some questions

Post by T1 Terry » Sat, 16 Nov 2019, 14:40

Possibly a water heat exchanger, https://freezetec.com.au/products/marin ... ondensers/ water can carry 3 times the thermal energy of air, so the same area water radiator as the air conditioner condenser radiator would effectively equal an air conditioner air heat exchanger 3 times the size.

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Re: Prelude conversion project - some questions

Post by brendon_m » Sat, 16 Nov 2019, 14:59

But at some point you will need to dump the heat into the air and you'll just need a radiator for the water/refrigerant condenser.

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Re: Prelude conversion project - some questions

Post by jonescg » Sat, 16 Nov 2019, 18:27

An atomizer spray for the condensor? 😞
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Re: Prelude conversion project - some questions

Post by brendon_m » Sat, 16 Nov 2019, 19:21

Well, when a condenser absorbs too much heat we run a garden hose over it, so yeah you can build the first EV with water injection 8-)

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Re: Prelude conversion project - some questions

Post by brendon_m » Sat, 16 Nov 2019, 19:36

The aircon will be working it's guts out to cool the water in the heat exchanger circuit but once that heat is gone hopefully there won't be too much heat being added from the cells. Remember that aircon condenser was designed to shed all the heat that the cabin gets on a summers day, along with originally having a 100°C heater next to it.
This is where a 2nd TX would be helpful because you can make the aircon cool the coolant down to say 25°C and if it gets there then lock off that refrigerant circuit but the rest of the aircon can still work in the cabin.
Also if there's a lock on the original evaporator you can dedicate the full cooling abilities to the cells rather than cooling a cabin you don't need too.
Unfortunately I think it's going to be a case of plumb it up a see if it works.

One thing going in your favour is I don't think the kona's condenser is overly big (relative to other cars) so if it can cope then the prelude stands a chance.

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Re: Prelude conversion project - some questions

Post by jonescg » Sat, 16 Nov 2019, 21:02

Cool. Now to find a responsible location for the compressor... It's very tight below the shelf. If it goes above, it means more flexible hose is required to make it work, but that's good as you can twist it ad pull it out of the way if you ever need to work on the rest of the system.
***
Well today was the hottest spring day ever recorded in Perth - 40.8'C in the shade, after a few days of >35'C. Global warming is here.
So I decided, before handing the car over to Francess I'd give it a good long drive to see what sort of range is possible, knowing that warm weather makes for low impedance cells.
Kalamunda to Welshpool, then to Armadale to try the Schnieder charger at McDonalds (it didn't work - same as at Melville Renault - turns off after a minute). Then back through Maddington, on to Harrisdale to try the Chargepoint chargers there (with a Type-1 to Type-2 adaptor, works a treat!).
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Then along South Street (70 km/h zones) to Freo to try the EO chargers (no dice - literally nothing).
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The Doctor was in by this stage, so we hugged the coast trying to stay cool. Onwards to the RAC charger in West Perth. Again, the Type-1 to Type-2 adaptor worked a treat and it charged merrily from the 7 kW AC supply. I think we managed to put about 1.5 kWh in while testing.

From here we headed north up the freeway (80-100 km/h zones) and east at Hepburn Ave (80 km/h zones) and onto the Northlink expanse of tarmac which was all 100 km/h zones. Peeled off at Great Eastern Hwy and took it east to Kalamunda Road and back up the hill. At the top of the hill the 20% alarm sounded. Pulled in at home with 19 % on the gauge, but given we put extra power in along the way, call it ~15%. 175 km travelled, half city half freeway. The cells hit 44'C at the top of the hill, but spent most of the day under 35'C.
Very impressed with the range on this car. I'd hazard a guess of 150 km range at freeway speeds, and 200 km at city speeds, weather depending.
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Re: Prelude conversion project - some questions

Post by brendon_m » Sat, 16 Nov 2019, 22:52

Very impressive that's quite a bit of a drive.
Im getting the feeling that you are never going to give the car up but. There will always be another test... :lol:

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Re: Prelude conversion project - some questions

Post by jonescg » Sun, 17 Nov 2019, 18:23

Well I've left the car with Francess more or less permanently now. Next Saturday I'll get the aircon guys to look at it, and while I have the car, install the rear battery cover and make sure it's secure. Then it's a trip to the weighbridge followed by a date with the engineer.

I've ordered a Type-1 to Type-2 adaptor, and an Open EVSE with single phase and Mennekes plug. It will be portable enough with a 32 A plug on the end. I don't think Francess is inclined to take it on long trips needing a charge somewhere along the way, but there's options at least.
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Re: Prelude conversion project - some questions

Post by francisco.shi » Mon, 18 Nov 2019, 12:08

You mentioned a date with the engineer. Can you drive the car before you get the final inspection?

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Re: Prelude conversion project - some questions

Post by jonescg » Mon, 18 Nov 2019, 12:42

francisco.shi wrote:
Mon, 18 Nov 2019, 12:08
You mentioned a date with the engineer. Can you drive the car before you get the final inspection?
Sort of :)

Technically you need a temporary movement permit when transiting between workshops, but the car is still licensed and insured (although, any claims would fail if crashed in this state). If you ever got pulled over you would be issued with a yellow sticker notice, which means you need to take it to an inspection centre, which we're going to be doing anyway.

In short, no, you probably shouldn't be driving it, but it's not exactly a big deal either.
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Re: Prelude conversion project - some questions

Post by jonescg » Tue, 19 Nov 2019, 15:24

http://www.ariazone.com.mk/pdf/Automoti ... Manual.pdf

A very useful manual for how an A/C system works.
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Re: Prelude conversion project - some questions

Post by jonescg » Sat, 23 Nov 2019, 12:46

Well the A/C guys reckoned it will be best to put it in series - it won't be as epic at cooling, but won't result in big pressurisation either. Apparently things get a bit expandy when parked in the sun, and having two evaporators in parallel would increase the likelihood of it over-pressurising. The vapour leaving the evaporator is at about 1'C which is nice, but probably won't have enough cool in it to bring the temperature of the coolant down much. The alternative is to put the expansion sensor bulb on the output of the heat exchanger, but means modifying the blower unit a lot. I guess we just have to plumb it and see.
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Re: Prelude conversion project - some questions

Post by brendon_m » Sat, 23 Nov 2019, 14:27

You should move the thermistor to the heat exchanger if you can as well, that way the compressor won't cut out because the evap is too cold. Or at least make it less sensitive with a resistor or something.
Also, perhaps you could put something between the expansion sensor and the evaporator outlet pipe(layers of tape maybe?) that way it won't be as cold as it should be and flood more refrigerant into the evap and thus more for the heat exchanger. Not as good/effective as moving it but it might work and it should be much easier.
Be careful but, you don't want liquid refrigerant back to the compressor, apparently liquids don't compress very well :?

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Re: Prelude conversion project - some questions

Post by jonescg » Sun, 24 Nov 2019, 22:00

I had the car for the weekend to get the air conditioning looked at, and to finish the rear two modules.

Main issue with the rear two modules was securing them so they can't move vertically or side to side, as well as tidying up the plumbing, HV cables and the fuse. The fuse was just mounted right on the terminal, but I have moved it to a spot in front of the modules where it's got a bit of clearance all around. I have not yet installed a manual isolator, and my rationale is thus: splitting the battery here is easy enough with an insulated 13 mm socket and spanner, but critically, I can still measure ~150 volts between chassis and the other side of the fuse. When grounded it passes a current of about 2.5 mA, but enough to give you a tingle when you'd rather not feel it. So isolating it back here is no different to isolating it under the bonnet.
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Anyway, the aluminium SHS works pretty well as a support for the clear polycarbonate false floor, and it also helps keep the battery secure. Just another couple more lengths of 19 mm SHS to pick up and it's as good as done.

Then my focus will shift to the aircon, and trying to manage the precharging of the A/C compressor....
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Re: Prelude conversion project - some questions

Post by jonescg » Sat, 30 Nov 2019, 16:04

The car is 99.99% done. All we need to do now is drive it down to the air conditioning guys and get them to install the new plumbing and re-gas the system. I'll be brazing the new fittings onto the heat exchanger on Monday so they just need to make up some new short hoses and fittings.
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I also finished the boot space - it's got full aluminium support across the top of the rear modules so you can load it up with as many bags of potting mix as you dare. Clear polycarb is there for easy inspection.

Once the A/C is in, we can get it over to the weighbridge and have it certified. I am not expecting any grief, but you never know. It will need 4 new tyres, I know that's for certain.
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Re: Prelude conversion project - some questions

Post by francisco.shi » Sat, 30 Nov 2019, 16:18

If it is overweight what can you do to make it pass?

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