RMIT e-racing 2008

[EV2Go]

If you have any questions feel free to ask... That reminds me someone on here asked me for photos of the rear end of SAE cars a while back. Sorry i lost your email in the piles i have been dealing with. Sorry.

Cheers
Taffy
taffy.flynn (at) student (dot) rmit (dot) edu (dot) au

That might have been me... I was contemplating a while ago building a 3 wheeled (trike has less ADRs to comply with) road registered version of what you have done.

I wanted to scale up it a bit with 90Ah - 160Ah and run more voltage 144v - 170v and a Warp 9. What size warp motor would equal the one you used?

Did you do the 200A runs? I would be keen to see just how quick this thing can go. Nice to see the batteries on the side it gives me a much better idea of scale.

I was thinking of building something with a kerb weight of around 600kgs without driver.

[Taffy]

Hey EV2Go,
No 200A runs yet, trying to get a driver (me or another guy) and the battery guy in the same place at the same time over the next couple of days is a problem. Either Sunday night or Monday it will be run in anger, possibly not at 200A but 100+ and soft start turned off.
We keep triping the battery monitor at anything above 50.1A and the last cell in the line is heating up and discharging faster. This is causing some concern as we left it connected once and dropped a cell to 0.2V (BAD!!!). Does not happen to any other battery in the packs though. He was calling the supplier in perth to try and sort it out but i have not heard of the outcome yet.

[Clay]

That thing is awesome - well done mate. We've been talking for a while about trying to do a lightweight FSAE style hillclimber but you've just set the bar with that thing. Interesting colour - looks like the late 80's/early 90's Leyton House March F1 colour (Adrian Newey's first F1 team).

Cannot wait to see how your full power runs go. We'll have to build one over here and race you guys. But awesome job.

[Taffy]

Been too busy to put down any updates. Will get a full one once i get some more time.
Last weekwend (27-30) we ran the car at the SAE comp in werribee, had a good recieption with the car being on display for the launch night.
Had a few changes to be made to the wiring so was left doing some test running at 3:30am to ensure it all worked. Came back friday to pass tech inspection, mechanically passed with flying colours. Electrically there were some issues due to there being no rules mostly, i must congratulate hamish on his efforts to get past electrical inspection. After some work friday/sat mourning we passed.
Then took it out and passed a 70 degree tilt test and a braking test. Did not do noise testing as it was pointless.
I got to drive it out, though we were asked to 5/10's on track to ensure safety as we had no proof that our sidepods (battery box's) were structually safe in a high speed crash. First lap raised a few eyebrows with the speed and then half round the next i suddenly lost power then got it back again... rolling to a stop. We found a blown fuse in the low voltage circuit, which we changed and got it running again. It blew again at the start line and then a few more times when we took it away for testing that night. Sun mourning we thought we had it and Alex took it out on track for it to blow 1/3 of the way around. So we took back to the pits for a complete strip down and rebuild. Found the problem being a spring washer stuck under LV circuit board which explained why it blew when turning right and not left. Put it back togeather and out on track did 3 laps from cold starts of 1min 9, 1min 7 and 1 min 1sec. Then stopped to check the car over.
Got a call asking if we could run again ASAP, so we headed over and ended up sitting around for an hour waiting as the IC teams turned up late or early. Got back on track to do 9 more laps before stopping with the battery low voltage alarm going off. Ended up doing a few flying laps of 56.7sec which was in the pointy end of the field. Very impressed considering many of the teams averaged 1min 5sec laps.

We did a few interviews for Channel 31 (not sure when its going to air) and the SAE magazine. As well as meeting someone (who came to see this car) who is part of the group looking to set up a electric comp in Germany in 2010 based around these cars. Had alot of interest from other unis about this project so possibly will see a few Aussie cars entering that comp.

Special thanks goes to
AutoCRC
Holden
RMIT
RU Racing Team
Sprockets Australia
Bender
And to the rest of the team who put this car togeather.

Will post photos of what happens when u run thundersky batteries over 250A. We blew 15 cell monitors in those 9 laps and killed a few cells but it was well worth it.

Taffy

[Taffy]

Ok had some time to mess around with some of the pics.
Packed and ready to leave RMIT for werribee


The car in the pits


Inside view of the car


The car getting checked over by the officals


Danger!


That SAE logo means we were allowed to run


The team



Getting ready


On the tilt test - to make sure we dont leak fluids


Running on saturday with me driving


Me again


The washer that was blowing our LV stuff up


Thundersky nose badge


Alex getting ready


Alex driving sunday


Alex again


A blown cell monitor


Melted battery terminal

[Taffy]

R08E on the test track after removing the washer #1
http://www.youtube.com/watch?v=uQZpDmhnpoY

Take off and fuse blow...
http://www.youtube.com/watch?v=T00t0UOcbVk

[Electrocycle]

awesome stuff

We did a first test run of an electric go kart today.
It's running a perm132 motor and Alltrax 7245 controller. It accelerates surprisingly hard! The problem we have is that it's flexing things enough to make the chain jump teeth!

[acmotor]

Great work guys !

I gather the cell monitors were not actually the problem, it was the heated electrical contact at the battery terminals both cooking the monitor and potentially allowing the voltage across the monitor to go negative ?

Don't tell me the monitor copper straps were tinned ???
That is one of the EV wives tales. It can be good for surface contact but the solder 1)displaces and releases the bolting pressure and 2)has a higher thermal and electrical resistance than copper.

I would put the bus straps on first and the monitor above that. Use a larger spreading washer above the plate.
Do try and control the mechanical load on the bus bar in operation as movement will degrade the electrical contact.

Good thing about that loss of power is that when you have it sorted, the vehicle will go even harder !


You did bring a smile to my face when you pointed out the TS badge !!!
Thanks for that.

Maybe flick a report with pics off to TS ?

[Taffy]

awesome stuff

We did a first test run of an electric go kart today.
It's running a perm132 motor and Alltrax 7245 controller. It accelerates surprisingly hard! The problem we have is that it's flexing things enough to make the chain jump teeth!

Hey Electro,
Do you have any pics and videos of your set up? I am looking at building an electric kart for abit of fun. I saw mythbusters set up which turned out to be like what i did for our engine mounting.

[Taffy]

I gather the cell monitors were not actually the problem?

The cell monitors were not an issue. The problem appears to be over drawing the batteries, though no one has done any testing to prove what actually happened. Guess that will be a project for someone next year... killing thundersky batteries and cell monitors.

Don't tell me the monitor copper straps were tinned ???

Nope they were not, they had washers both sides including spring washers to ensure constant contact. They were not soldered, the battery monitoring system was soldered in the interconnecting wires (Red and black ones not the copper)

Do try and control the mechanical load on the bus bar in operation as movement will degrade the electrical contact.

Movement may have been a problem, though we did come up with an interest way of holding the packs from moving. Half pieces of PVC pipe act like shock absorbers but also reduce movement, not sure if that is a proven way of doing things but it worked during testing.

You did bring a smile to my face when you pointed out the TS badge !!!
Thanks for that.

We put them on the sides to cover a couple of un used holes on the nose as well.

Hopefully will have some kind of report, but everyone has gone away for the minute as well finished uni.

[acmotor]

Good to hear there was no tinning.

Looking at your arrangement, contact resistance would be of concern to me.
You mentioned washers both sides ? Do you mean between the battery terminal and bus bars ?
What were the washers made of ? zinc plated steel ? stainless ?

Copper or aluminium would be better as you know. Already on to it ?
When you are passing 250A you need everything going for you, both low electrical resistance and high thermal conductivity.

This may all be besides the point as the TS construction internally (and its ESR) may be holding you back. At 250A, more than half the power is lost before you leave the cell.

What plans do you have for other battery types ?

[Taffy]

I think the future will be to work with private industry if we can to get a custom battery - controller - motor. The aim is to have a fully fledged racer to send to germany in 2010 if that comp gets the go a head. Though my involvement is coming to an end, i graduated.

I believe 250A was the recommended cut off for TS batteries, we went into this knowning come race day we could kill $3K worth of batteries and all were happy if the performance made an impact. Before this was had a monitor that told the driver the amps and he could back off if he was pushing too hard, we had it mounted outside the cockpit but could not keep it come race day.

With the washers i believe they were stainless, it was not my area. At least the spring washers were with one of the washers being the copper the other just stainless from memory. I will be out there tomorrow rebuilding the packs i think so will look at it then.

[fffffred]

Resurrecting an old thread, but it brought back some good memories when I was back at Uni designing and racing these FSAE race cars. I'm actually in one of the photos posted above in the background wearing yellow UWA Motorsport colours. I remember seeing the green RMIT car.

10+ years down the track, this FSAE is now being dominated by electric cars, with the recent Australian competition being cleaned up by a tech school/uni from Munich.

https://tufast-racingteam.de/rennwagen/eb018/

[Bryce]

Was at the 2018 event with Melb Uni. (I work as there as the e-car safety trainer/electrical systems advisor). Was their first electric car-and they came 7th out of 14 EV entrants. (About 32 all up inc fossil cars). Bloody good result for first-ever EV! Event is fantastic showcase for EV developments. Munich car BTW was a work of art. 4 hub motors, full carbon monocoque chassis/aero package. Amazing! Their budget was rather more than the average though- and had some very high power auto industry sponsors to boot. Was actually surprised the Monash team was so close in the final result. Cheers Bryce