Search found 421 matches

by zeva
Thu, 12 Nov 2009, 02:52
Forum: AEVA WA Branch
Topic: EV WORKS ELECTRAKHANA
Replies: 5
Views: 1841

EV WORKS ELECTRAKHANA

Just a couple of updates to clarify things.. 1) Anyone's welcome to bring their EV down to display, but please contact us if you are interested to take your vehicle out on the track. (The purpose of the event is to demonstrate road-going EVs to the public so they'll be getting priority. Vehicles don...
by zeva
Mon, 09 Nov 2009, 23:33
Forum: AEVA WA Branch
Topic: EV WORKS ELECTRAKHANA
Replies: 5
Views: 1841

EV WORKS ELECTRAKHANA

PS: http://www.evworks.com.au/Electrokhana.pdf

As well as AEVA members, we hope the event can raise awareness of EVs among the general public too, so if you'd like a few flyers to give out to your friends or post at local notice boards, PM me your mailing address and I'll pop some in the post.
by zeva
Fri, 07 Aug 2009, 07:19
Forum: Technical and conversion discussion
Topic: NCOP power output question
Replies: 9
Views: 1225

NCOP power output question

In NCOP13 Code LV1, it says that the electric motor cannot have more than 20% more power output than the original ICE I've never heard of this rule actually being enforced, unless you build something ridiculously out-of-spec. Basically if your EV drives similarly to a normal ICE vehicle during the ...
by zeva
Tue, 21 Jul 2009, 03:38
Forum: Technical and conversion discussion
Topic: Soapbox on regenerative braking
Replies: 278
Views: 30646

Soapbox on regenerative braking

I agree about overcharging being unlikely under normal circumstances, but can think of two instances where a big power shunt would be valuable: 1) People living at the top of hills, so spend significant time going downhill first thing. (Not common but I know someone this does apply to.) 2) Braking h...
by zeva
Tue, 21 Jul 2009, 02:53
Forum: Technical and conversion discussion
Topic: Soapbox on regenerative braking
Replies: 278
Views: 30646

Soapbox on regenerative braking

Note... a feature for custom made EV units. They are quite capable of 'wasting' some power and getting warm under software control.    http://forums.aeva.asn.au/smileys/smiley1.gif My thought on this subject would be to have an independent current shunt device in parallel with the battery pack whic...
by zeva
Tue, 21 Jul 2009, 02:02
Forum: Technical and conversion discussion
Topic: Soapbox on regenerative braking
Replies: 278
Views: 30646

Soapbox on regenerative braking

It seems that way until you actually try to buy or design such a resistor. Dissipating 20 to 50 kW as heat, without starting any fires is difficult, and so is simply finding the space to fit this very large incandescent object. Think how much space a 500 W floodlight occupies. You'd need 40 of them...
by zeva
Mon, 20 Jul 2009, 23:40
Forum: Technical and conversion discussion
Topic: Soapbox on regenerative braking
Replies: 278
Views: 30646

Soapbox on regenerative braking

PS: Coulomb, I reckon a big shunt for dissipating regen energy is useful even when the batteries are happily accepting a charge. ThunderSkys etc can only take about 1C charge current which doesn't represent a huge amount of regen braking force. But it's still better to slow a vehicle down with a mot...
by zeva
Mon, 20 Jul 2009, 23:31
Forum: Technical and conversion discussion
Topic: Soapbox on regenerative braking
Replies: 278
Views: 30646

Soapbox on regenerative braking

coulomb's on the money. To clarify the need for rotor excitation, basically the VFD drives the motor as normal but targetting a speed X rpm slower than its current RPM (X being negative slip). Due to the voltage/frequency ratio with induction motors, this means the driving voltage is lower than the ...
by zeva
Fri, 17 Jul 2009, 05:40
Forum: Technical and conversion discussion
Topic: DC-DC converters, how much power do we really need
Replies: 25
Views: 3401

DC-DC converters, how much power do we really need

OK you've inspired me to be a little more rigorous with my testing too: Quiescent current, key off: 0.4A                                   key on: 3.0A Headlights low: 10.2A                     high: 11.4A Park Lights: 2.5A Brake lights: 3.6A Rev. light: 1.2A Hazard lights: 8.6A (50% duty so 4.3A av...
by zeva
Fri, 17 Jul 2009, 04:41
Forum: Technical and conversion discussion
Topic: DC-DC converters, how much power do we really need
Replies: 25
Views: 3401

DC-DC converters, how much power do we really need

Hi all, A few times lately I've been reminded of the need for EV builders to migrate towards all weatherproof components in EV engine bays, and DC/DC converters are one of the main culprits. Historically most people have used AC/DC battery chargers "off label" as DC/DC converters - IOTA being a comm...
by zeva
Mon, 13 Jul 2009, 06:59
Forum: Batteries, charging, management and monitoring
Topic: More Li batteries
Replies: 84
Views: 10609

More Li batteries

I have a Camira station wagon with 45 thundersky 90AH LI-ions and am considering buying another 45 40AH set to run in paralel under the bonnet, let them charge from the main pack's charger and then rig the BMS to cut them off when a cell reaches 4.2, any comments. So long as you keep the same numbe...
by zeva
Sat, 11 Jul 2009, 04:54
Forum: The Lounge
Topic: Nikola Tesla would be 153 today!
Replies: 10
Views: 1688

Nikola Tesla would be 153 today!

Tesla sure was one smart cookie. The history between Tesla and Edison is interesting too, fighting over AC vs DC for mains power. (Hmm AC vs DC, sounds familiar http://forums.aeva.asn.au/smileys/smiley4.gif ) Edison was a pretty ruthless opponent from what I've heard and pretty much ruined Tesla in ...
by zeva
Sat, 11 Jul 2009, 04:45
Forum: Batteries, charging, management and monitoring
Topic: More Li batteries
Replies: 84
Views: 10609

More Li batteries

Zeva, according to the above, the SE's sag is slightly worse in every case. Oh, these are per cell voltages under load, not total sag for N cells. Presumably, after both have been charged to about 100% SOC? It would be really great to record the per cell voltage just before the load is applied, as ...
by zeva
Fri, 10 Jul 2009, 23:41
Forum: Batteries, charging, management and monitoring
Topic: More Li batteries
Replies: 84
Views: 10609

More Li batteries

Hi folks, We have some preliminary data of the Sky Energy 180Ah cell which was installed in Rob Mason's BMW and tested along side the 160Ah ThunderSkys. So far just some comparative data on voltage sag:                    T/S            SE AMPS 200               3.15        3.19 400               3....
by zeva
Tue, 07 Jul 2009, 05:46
Forum: Batteries, charging, management and monitoring
Topic: More Li batteries
Replies: 84
Views: 10609

More Li batteries

coulomb: That's some great data there, thanks for sharing. Lower internal resistance is almost always a good sign in my book! I'll have to work out an easy way to get similar data for the Sky Energy cells. What's your test setup if I may ask? I built a little battery tester a while back, but it was ...
by zeva
Tue, 07 Jul 2009, 00:27
Forum: Batteries, charging, management and monitoring
Topic: More Li batteries
Replies: 84
Views: 10609

More Li batteries

Coulomb: Out of curiosity, do you have any means of testing/calculating internal resistance? I'd be very interested to hear how they compare with ThunderSky.. We'll be doing the same with a couple of Sky Energy sample cells we brought over. I hope they end up being comparable to TS at least. A bit o...
by zeva
Sun, 28 Jun 2009, 18:30
Forum: General EV Discussion
Topic: Reverse Trike Rego
Replies: 24
Views: 25098

Reverse Trike Rego

I don't think the P50 would be registerable in australia. The crumple zones are your knees, after all. I think in canada they make something called the t-rex, which is a reverse trike with quite high performance. AFAIK trikes are under similar regs to motorbikes so don't need crumple zones? Regardl...
by zeva
Sat, 27 Jun 2009, 01:38
Forum: Batteries, charging, management and monitoring
Topic: Ultracap's in eV's
Replies: 36
Views: 4243

Ultracap's in eV's

still not sold on the supercap idea. supercaps (even when behind a boost/buck converter) have poor power density (and horrific energy density). To be meaningful, the boost/buck converter have to be rated close to that of the motor controller. The resulting power silicon, (ripple) caps and inductor ...
by zeva
Thu, 25 Jun 2009, 22:02
Forum: EV Motoring
Topic: iMiev passed all 83 safety tests
Replies: 57
Views: 7952

iMiev passed all 83 safety tests

Personally i see this as just another attempt to keep EV's out of the serious car market & keep dinosaur cars alive for a few more years. I agree, unfortunately there's so much commercial inertia behind the status quo - the auto industry doesn't really want to change. The fact that we private conve...
by zeva
Thu, 25 Jun 2009, 20:33
Forum: EV Motoring
Topic: iMiev passed all 83 safety tests
Replies: 57
Views: 7952

iMiev passed all 83 safety tests

Enormously disappointed, yes. Surprised, not really. *sigh*

Whatever happened to their old "thirty something thousand" estimate!?

And yes, on the bright side I guess it means I won't have to look for a new line of work in a hurry.. conversions may be the best bang for your buck for a while yet.
by zeva
Tue, 23 Jun 2009, 06:02
Forum: General EV Discussion
Topic: 2 Speed Gearbox
Replies: 309
Views: 50504

2 Speed Gearbox

We've chatted about them a bit at EV Works meetings and might bring some over. They are a more elegant solution for EVs than reusing the old mechanical compressors but yes, a pretty expensive way to go once you include the necessary inverter. I'm very interested to pursue reverse cycle A/C in EVs be...
by zeva
Sat, 20 Jun 2009, 09:16
Forum: Technical and conversion discussion
Topic: Soapbox on regenerative braking
Replies: 278
Views: 30646

Soapbox on regenerative braking

Well I think everyone agrees that commutated motors have a limited lifespan and will only be around while they offer a significant cost and/or simplicity advantage. Despite my original rant, I would quite like to have regen on my next EV. Mostly to save wear on my brakes, in truth! So I guess those ...
by zeva
Sat, 13 Jun 2009, 20:23
Forum: Batteries, charging, management and monitoring
Topic: Silly Charging Idea No3
Replies: 20
Views: 3550

Silly Charging Idea No3

I see it's more than double yours. I used a GVM of 1365 kg. Holy moly what are you and Coulomb doing to that poor little MX5!? http://forums.aeva.asn.au/smileys/smiley2.gif ( Curb weight of the 1st Gen was 940kg) Also Crr of 0.025 sounds unusually high to me, I was under the impression that modern ...
by zeva
Thu, 11 Jun 2009, 18:49
Forum: General EV Discussion
Topic: MiEV to cost $60,000
Replies: 7
Views: 613

MiEV to cost $60,000

Disappointing to hear this may be the case. I can't imagine it really costs 4x as much as the equivalent petrol burner to manufacture! I was at a talk yesterday by Andrew Simpson of CUSP (and ex-Tesla) who mentioned that in Australia the Prius are more expensive than they should be, since the factor...
by zeva
Thu, 04 Jun 2009, 23:11
Forum: Batteries, charging, management and monitoring
Topic: Exchange rates and Thundersky batteries
Replies: 23
Views: 3236

Exchange rates and Thundersky batteries

OH NO! The cat's out of the bag a little early... But yes, it's true. Rob Mason, Rod Dilkes and I recently decided to start a joint venture "EV Works". We've all been in the EV game for some years now but came to the conclusion that we needed to be part of a larger venture to really get things done....