Search found 12 matches

by drgrieve
Fri, 28 Sep 2012, 03:35
Forum: General EV Discussion
Topic: Curb weight and gross weight of utes.
Replies: 9
Views: 2560

Curb weight and gross weight of utes.

Hi all, Was wondering how others have managed this weight issue? It would seem that most donor cars when converted with a reasonable pack size to drive 100 to 150 kms will go over the GVW by 100 KG or so. Is is just a matter of reducing the number of passengers seats by 1, or will the engineer allow...
by drgrieve
Sun, 19 Aug 2012, 06:06
Forum: Members Machines
Topic: barnard's Toyota MR2 - now Mr240
Replies: 213
Views: 26636

barnard's Toyota MR2 - now Mr240

I would be interested to hear the justification behind float charging being bad. Once a cell is full and you try to push more charge into it, you start to plate. This causes loss of capacity. 3.4v static voltage is full. Charging at a higher voltage than 3.4V will cause overcharging - BUT - when cha...
by drgrieve
Sat, 18 Aug 2012, 05:24
Forum: Members Machines
Topic: barnard's Toyota MR2 - now Mr240
Replies: 213
Views: 26636

barnard's Toyota MR2 - now Mr240

Hi Barney, What is your peak charge voltage? That is, what is the highest voltage your charger gets to before switching off? Hi Rod. I can answer this one... I have noticed 2 different figures: 165ishV (in feb12) and 161V (last week, aug12). Back in Feb I was noticed the floating charge process see...
by drgrieve
Fri, 17 Aug 2012, 03:56
Forum: Members Machines
Topic: Ian Hooper's RX7 Conversion
Replies: 102
Views: 23663

Ian Hooper's RX7 Conversion

Now no dyno charts unfortunately but if you haven't already you should read John Metrics dual stock warp 9 (but with new Helwig brushes as now sold with) matched with dual Zilla 2K HV controllers. He's running 199v and 2000 amps to each motor and the thread is packed with charts from the Zilla logs....
by drgrieve
Fri, 17 Aug 2012, 03:36
Forum: Members Machines
Topic: barnard's Toyota MR2 - now Mr240
Replies: 213
Views: 26636

barnard's Toyota MR2 - now Mr240

An assortment of comments… Self discharge with lithiums is in the order of 1% per month. Differences in self discharge is a fraction of this, amounting to say a few % capacity per year. I gather that self discharge is closer to nothing per year. I've seen a few reports on cells sitting on the self ...
by drgrieve
Thu, 01 Dec 2011, 22:46
Forum: Batteries, charging, management and monitoring
Topic: tabless A123 ?
Replies: 30
Views: 4285

tabless A123 ?

Yeah that is where Jack Rickard got some recent test cells from. He regards the cells as most likely genuine.

Much better deal than the tab less ones I spotted on ebay.

Now for someone to come up with cheap, easy and effective way to modualize them.

Some assembly required!
by drgrieve
Fri, 11 Nov 2011, 21:44
Forum: Members Machines
Topic: Lead Wing's BMW E30
Replies: 26
Views: 7929

Lead Wing's BMW E30

Bah after posting I understand your question. Not rpm to kph but rpm as power and why is it limited. That is a much more complex question. This thread explains a bit. Essentially for a series DC motor amps gives you torque, and volts gives you a wider RPM band before torque drops off due to back EMF...
by drgrieve
Fri, 11 Nov 2011, 21:21
Forum: Members Machines
Topic: Lead Wing's BMW E30
Replies: 26
Views: 7929

Lead Wing's BMW E30

Do you have your motor RPM hooked up to tacho? Hopefully I can explain. The normal e30 five speed gearbox runs the following gear ratios (1st to fifth). 3.72, 2.02, 1.32, 1.00, 0.81. What this does is trade torque for RPM. In first gear the motor in comparison to wheel rotation is completing 3.72 ro...
by drgrieve
Thu, 10 Nov 2011, 15:58
Forum: Members Machines
Topic: Lead Wing's BMW E30
Replies: 26
Views: 7929

Lead Wing's BMW E30

Thanks - that gives me quite a bit to think over. Was is the diff ratio for your donor? No idea, but standard 318i diff. I think your diff ratio is 4.1 to 1. By using a rpm/gear calculator and assuming your type diameter is standard 14" 195 65 or 14" 175 70 (around 600mm), you would see 2200 rpm at ...
by drgrieve
Wed, 09 Nov 2011, 20:32
Forum: Members Machines
Topic: Lead Wing's BMW E30
Replies: 26
Views: 7929

Lead Wing's BMW E30

Can you tell us a bit more about the direct drive. I'm looking at a E30 conversion but I didn't think about the idea of direct drive until I saw this thread. I have a lot of questions! Was is the diff ratio for your donor? Top speed? How long before the low end acceleration kicks in? Any 0-40,60,80,...
by drgrieve
Wed, 13 Jul 2011, 03:09
Forum: Technical and conversion discussion
Topic: Toyota RAV4 - EV ? Any Thoughts ?
Replies: 7
Views: 1969

Toyota RAV4 - EV ? Any Thoughts ?

See this post for a spreadsheet with different cars drag coefficients.

viewtopic.php?t=2682&start=1
by drgrieve
Wed, 13 Jul 2011, 03:05
Forum: Technical and conversion discussion
Topic: Minimise finished EV weight
Replies: 15
Views: 3348

Minimise finished EV weight

http://forums.aeva.asn.au/uploads/2039/VehicleEfficiencies_.png Hi I've uploaded a spreadsheet that I've used from diyelectriccar. It's useful to look at different cars aerodynamics. The kw to maintain speed I think is on the high side - but I don't have any real world figures to compare to. Enjoy....