# Corolla 1993 EV Data



## evlowrider (Jul 23, 2009)

Hi David,

Nice write up, looks like a job well done there. This conversion confirms a couple of designs that I'm planning on using, such as the external charger and using the 3-phase 5-pin connectors and using the 2 spare pins.

Does having the all batteries in the front make a noticable effect driving performance?

What strapping did you use for the batteries?

Also, since you've been through the process a couple of times i think - does the vehicle certifier focus on anything in particular?

Pete.


----------



## enp13 (Mar 26, 2009)

I am very surprised that using a standard 3 phase 5 pin plug for a low voltage DC application was permitted by the certifier. I'm sure any electrician would confirm that it is never good practice to use standard AC connectors for anything other than standard AC because that is what people expect them to be used for. The implications of an "enthusiastic friend" or repair person mistakenly plugging a live 3 phase extension cable into this socket are horrendous. For anyone else still insistent on this approach, I would strongly suggest coming up with a way to prevent this. One suggestion is to modify the socket and plug so that standard ones won't insert. A simple way would be to "key" the outer plastic edge with protrusions or hollows. This is actually how that series of plugs prevents a plug with a higher current rating from being accidentally plugged into a socket with a lower rating.

One would also assume (as with any plugs, switches, fuses, relays etc used on DC EVs), that the DC ratings have been checked?? I did a quick web search but couldn't find anything conclusive for this series of connectors. David might be able to confirm for us on this one.


----------



## djmjnewton (Aug 14, 2008)

Hi,

You are of course correct. The plug has been stickered as is the socket on the car. I will take your advice and make the plug unique as you suggest. Can you suggest a commercially available alternative plug and socket that has five pins two of which could handle the 120VDC the other two handling low current BMS signalling, 1 redundant spare?

As to the handling question, the car goes really nicely around town. As to cornering on a flat road it seems to handle them nicely as well.

I used blue plastic Danban strapping doubled up with the wire joiners. I obtained a brochure from the manufacturer that specified it with a 150kg breaking strain. Two of them made 300kg, which was above the 2.5G required for battery support in the engine bay. The plastic strapping being an insulator made it easy to thread over the top of the cells with no chance of short circuit. It is also inexpensive. In retrospect however after having cut and restrapped 4 times so far I will try to come up with a conventional metal edge bolt tie down alternative next time.

As to the certification process, I have only done it twice. I notice that the Certifiers like writing down verified manufacturers data in all the boxes on their Draft Cert check list that is available as a PDF from Gavs EV website. I followed that document and also consulted with the Certifier as to what solutions were acceptable before going ahead with what could end up being an expensive error. I think a good professional rapport with the Certifier is the best asset you have in the process.

I hope this helps

David
GreenEV.co.nz


----------



## enp13 (Mar 26, 2009)

Provided it is uniquely modified (i.e keyed), I really like the approach of using a three phase connector. But I would need to see a published DC rating before I would consider it myself.

Another easy approach is to use the required number of Anderson/SMH connectors, bolted together (with a nut for spacing in between each one) on top of each other to form a single multipin connector. They are widely available, have the necessary DC voltage and current rating (including breaking current ratings), and the pins are not easy to touch accidentally on the small ones. Not super cheap or waterproof though.

Did you take any power or current measurements at 100kph or faster? I am interested to know how much power it takes to do these speeds, especially on inclines such as the rise up to the bridge over the Waimak River.


----------



## djmjnewton (Aug 14, 2008)

The Anderson connecter idea was one I failed to consider after hearing Mr Rickard of EVTV deriding them but certainly has merit although I was after a better moulded professional looking finish.

The 100kph current varied up to about 160A but could be as low as 90A this was under load so the pack voltage was running at 118V or so for the 38 cells. I have yet to test on a decent hill like Dyers Pass Rd. I will report data on that when I have it.

David


----------



## Grant_NZ (May 28, 2008)

Nice conversion David. In regards to the batteries, I remember Gavin mentioning that the certification requirements say that if the batteries are located inside the vehicle they must be in a sealed box with adequate ventilation, regardless of their chemistry. I see yours are in the engine bay, did you have any in the car?


Regards
Grant


----------



## djmjnewton (Aug 14, 2008)

Hi,
Thanks. No none in the car. The pack under the bonnet solved a lot of problems but I am at the weight limit for this vehicle so if I wanted more range I would have to do a rear battery box as well. (I made one for lead acids but then went Lithium when the Alto batteries died.) My little Suzuki Alto is certified using a rear one that is naturally ventilated so gets away from all the control fans etc and may be a solve you could consider. I did a series of Google videos that are linked from my greenev webpage under project cars. Having batteries in the rear evens up the mass distribution as well but you lose spare tyre or luggage room. The spare tyre needs to be bolt restrained and for the Corrolla I had considered standing a spacesaver up at the side of the boot space with the battery box cut in between the main stays for the suspension at the rear. Before you go cutting anything though I would strongly suggest consulting with the certifier as to what and where you intend to cut or weld as they have to take the safety risk for our cars once they certify them.

David


----------

