Search found 773 matches

by Nevilleh
Thu, 05 Feb 2009, 14:28
Forum: Batteries, charging, management and monitoring
Topic: More Li batteries
Replies: 84
Views: 10610

More Li batteries

Thanks for the note about "edit post". Makes one look a little less stupid if one uses it! The email contact I have been dealing with is: "alex" <hihon03@chinabatteries.net> and he is very keen to sell me something. I noticed their max rating was 3C (cell esr <4 milliohms) and they are offering me a...
by Nevilleh
Wed, 04 Feb 2009, 22:54
Forum: Batteries, charging, management and monitoring
Topic: More Li batteries
Replies: 84
Views: 10610

More Li batteries

Might be good if I include the link:
http://hipower.en.ecplaza.net/1.asp
by Nevilleh
Wed, 04 Feb 2009, 22:52
Forum: Batteries, charging, management and monitoring
Topic: More Li batteries
Replies: 84
Views: 10610

More Li batteries

Has anyone ever heard of this supplier? They are offering 50 Ahr cells at around $US70. I have bought TS 40 AHr ones at $US60 each direct from TS (plus shipping costs).
by Nevilleh
Wed, 28 Jan 2009, 18:05
Forum: General EV Discussion
Topic: Electric Beemer
Replies: 144
Views: 15031

Electric Beemer

I found the 5072 at the local agent. It's an obsolete model, so bought it at a very good price, the last one in captivity apparently. Yes, a 12v battery is so obvious! Makes me wonder if I really have enough intelligence to be tackling something like this..... A bunch of 60v chargers is one answer, ...
by Nevilleh
Wed, 28 Jan 2009, 14:22
Forum: General EV Discussion
Topic: Electric Beemer
Replies: 144
Views: 15031

Electric Beemer

OK, tear me to bits on this one: I have a 1988 BMW 318 (E30), an 18 kw 3-phase motor (415v delta, 4-pole) and a Danfoss VLT 5072. My plan is, of course, to electrify the thing. I hope to use a couple of hundred LFP40 cells to power it, if the budget will stand it. I think it should achieve 110 kph a...
by Nevilleh
Tue, 27 Jan 2009, 20:35
Forum: Batteries, charging, management and monitoring
Topic: Home grown BMS ideas !
Replies: 781
Views: 114581

Home grown BMS ideas !

I did read on the Tesla Motors web site that they had dropped the charge voltage by .1v in the interests of battery longevity. Seems like you can do more harm by over-volting the things than anything. Mind you, they are/were using 18650 cells. I'm really starting to wonder if just monitoring the cel...
by Nevilleh
Tue, 27 Jan 2009, 03:18
Forum: Batteries, charging, management and monitoring
Topic: Home grown BMS ideas !
Replies: 781
Views: 114581

Home grown BMS ideas !

Sorry, need to reply to my own post! Duh..
Shift the decimal point one place left in those thirty-something voltages! Also, 7 to 8 degrees.
Must be the couple of glasses of Aussie red.....
by Nevilleh
Tue, 27 Jan 2009, 03:09
Forum: Batteries, charging, management and monitoring
Topic: Home grown BMS ideas !
Replies: 781
Views: 114581

Home grown BMS ideas !

I have to admit that my equaliser is a digital multimeter. I have been checking the cell voltages whilst charging and just recording them to get a handle on what they do. So far I have found less than .08 volts variation between the 16 cells I am testing. I stick my trusty Dick Smith variable power ...
by Nevilleh
Mon, 26 Jan 2009, 21:38
Forum: Batteries, charging, management and monitoring
Topic: Home grown BMS ideas !
Replies: 781
Views: 114581

Home grown BMS ideas !

I have used a couple of SMPS in series - 2 x 27V @ 5.4A - quite successfully as a "48V" charger. They are adjustable from a nominal 27V +- 10% and they are current limited at a bit over 5 A. I am charging a 16 x LFP40 pack so I set the two supplies to their max which equates to 4V per cell. They pro...
by Nevilleh
Mon, 19 Jan 2009, 21:22
Forum: Electric motors and controllers
Topic: AC motors, multipoles, torque
Replies: 549
Views: 68930

AC motors, multipoles, torque

Looking at the curves on TS web site, you can calculate the internal res from the difference between the 40A discharge curve and the 20A one. I get just on 4 milliohms.
by Nevilleh
Mon, 19 Jan 2009, 20:56
Forum: Electric motors and controllers
Topic: AC motors, multipoles, torque
Replies: 549
Views: 68930

AC motors, multipoles, torque

Well, I am truly glad that you commute by train! Thanks for running those numbers for me and I am thinking that the best compromise for performance/price/range/longevity is still the 318 driven by my 18 kw motor with the 5072 controller and 220 LFP40AHA batteries. A couple of hundred kms range with ...
by Nevilleh
Mon, 19 Jan 2009, 15:17
Forum: Electric motors and controllers
Topic: AC motors, multipoles, torque
Replies: 549
Views: 68930

AC motors, multipoles, torque

Woody, I am interested in all those torque curves you published several pages back and I'd really like to know how to do it for myself. Do you have a quick and easy solution?
by Nevilleh
Mon, 19 Jan 2009, 15:13
Forum: Electric motors and controllers
Topic: AC motors, multipoles, torque
Replies: 549
Views: 68930

AC motors, multipoles, torque

Well, I guess the 5072 would be even better! How do you reckon an 18 kw 4 pole motor and a 5072 would perform? With say a couple of hundred TS cells to propel it?
by Nevilleh
Sun, 18 Jan 2009, 21:34
Forum: Batteries, charging, management and monitoring
Topic: Home grown BMS ideas !
Replies: 781
Views: 114581

Home grown BMS ideas !

I found an article in EE Times-India that describes an active charge balancing system for Li-ion cells that looks very good. I can't put in a link as you have to log on to read it, but I have it as a .pdf file if anyone wants the full text. It describes "bottom balancing" where a cell lower than the...
by Nevilleh
Sun, 18 Jan 2009, 17:02
Forum: Electric motors and controllers
Topic: AC motors, multipoles, torque
Replies: 549
Views: 68930

AC motors, multipoles, torque

Thanks Woody. Useful link.
What do you reckon to the 6062?
by Nevilleh
Sun, 18 Jan 2009, 13:56
Forum: Electric motors and controllers
Topic: AC motors, multipoles, torque
Replies: 549
Views: 68930

AC motors, multipoles, torque

I had thought to remove the gearbox. Changing gears is one of those things an electric car should do away with! I have yet to find a detailed spec on the 5042. And I don't have much on the motors - only what is on the nameplate, which is power and rpm. The fellow that imported them doesn't know much...
by Nevilleh
Sat, 17 Jan 2009, 20:01
Forum: Electric motors and controllers
Topic: AC motors, multipoles, torque
Replies: 549
Views: 68930

AC motors, multipoles, torque

Yes, I think so. Can be delta connected I mean. I haven't got one here but I seem to recall that all the winding ends are brought out to the terminal box. I see what you are getting at (I think!) in that such a connection would allow the motor to be well over driven by 600v. I better go read the spe...
by Nevilleh
Sat, 17 Jan 2009, 18:48
Forum: Technical and conversion discussion
Topic: EV Power Consumption
Replies: 38
Views: 4706

EV Power Consumption

Hi Antiscab No, they are standard 12v (6 cell) batteries, Yuasa "Portalac" made specially for electric scooters. We import into NZ the Taiwanese "EVT" scooters and have found them to be by far the best performers of the vast numbers of such machines being produced now. We keep well clear of Chinese ...
by Nevilleh
Sat, 17 Jan 2009, 16:47
Forum: Electric motors and controllers
Topic: AC motors, multipoles, torque
Replies: 549
Views: 68930

AC motors, multipoles, torque

Whoops! Didn't realise you had started a new topic, sorry. I'll go read the BMS stuff soon! acmotor and Richo seem to be the ones right up there with IMs and VFD controllers, so I need to ask: If you were starting a new project, what would be your preferred choice of controller and motor? I see that...
by Nevilleh
Sat, 17 Jan 2009, 14:28
Forum: Electric motors and controllers
Topic: AC motors, multipoles, torque
Replies: 549
Views: 68930

AC motors, multipoles, torque

I quite like your circuit and one of my first thoughts when looking into BMS's was something along those lines. It's not too hard to prevent overcharging with a shunt circuit like this, but discharging the cells to a too low voltage is just as damaging. Your circuit gives an undervoltage indication,...
by Nevilleh
Thu, 15 Jan 2009, 22:53
Forum: Technical and conversion discussion
Topic: EV Power Consumption
Replies: 38
Views: 4706

EV Power Consumption

Magneto, are your batteries "deep cycle" ? (I'm not familiar with the brand you quote). We use 12v x 50 AHr PbA deep cycle batteries in electric scooters and the specs for battery life are: 360 cycles at 80% DOD. 1000 cycles at 50% DOD. So you can see you shorten their life considerably if you take ...
by Nevilleh
Thu, 15 Jan 2009, 21:52
Forum: Electric motors and controllers
Topic: AC motors, multipoles, torque
Replies: 549
Views: 68930

AC motors, multipoles, torque

Thanks for the replies. I am getting a better understanding of it all as I read more. I checked with Danfoss here and they have a single 5042 in stock (obsolete now, apparently) which they have offered to me at the "keen" price of $NZ3900! That's about 3200 Australian and I seem to recall reading th...
by Nevilleh
Thu, 15 Jan 2009, 19:37
Forum: Electric motors and controllers
Topic: AC motors, multipoles, torque
Replies: 549
Views: 68930

AC motors, multipoles, torque

I've been reading through all this stuff with great interest as I am completely new to many of these ideas, particularly the VFD. I am puzzled as to how an 11 kw motor can be persuaded to produce so much more power! What am I missing here? There's obviously a lot of expertise amongst the people on t...