Search found 773 matches

by Nevilleh
Thu, 10 Jan 2013, 11:04
Forum: Members Machines
Topic: Mr C's 2001 Prius revival
Replies: 19
Views: 3672

Mr C's 2001 Prius revival

I would've thought the error codes would be generated by low battery volts - how else can the ECU tell the battery state? - so having that "life extender" would prevent any errors being produced, at least by a low battery. But I know nothing about the Prius except it's ugly and expensive! http://for...
by Nevilleh
Wed, 09 Jan 2013, 12:38
Forum: Members Machines
Topic: Nevilleh's BMW
Replies: 337
Views: 57516

Nevilleh's BMW

I can think of a few roads in NZ that your Merc will do justice to Nev, the little built of guilt at the fuel burn will only sweeten the experience, like stolen fruit. Whenever I get depressed at my inability to get an EV build happening I go for a drive with my brother in his Dodge charger, it fee...
by Nevilleh
Wed, 09 Jan 2013, 12:25
Forum: Members Machines
Topic: Mr C's 2001 Prius revival
Replies: 19
Views: 3672

Mr C's 2001 Prius revival

There is an outfit in Auckland that "fixes" old Prius's by sticking a 12V lead-acid battery in the boot powering an inverter that supplies the Prius battery enough to make the thing think all is well. That is, it starts the petrol engine quite happily, but you can't go any distance on battery alone....
by Nevilleh
Wed, 09 Jan 2013, 12:21
Forum: Members Machines
Topic: jonescg's eCRX build thread
Replies: 42
Views: 10535

jonescg's eCRX build thread

You need a Protech BFS 180 charger. Rated at 5400 watts and can be powered by 3-phase for the max output, programmed to do whatever lesser output you want and powered by single-phase 230 V if that's your preference. Mine is set to 162 V and 2200 watts and it delivers a CC of 15 A up to the CV phase....
by Nevilleh
Tue, 08 Jan 2013, 20:44
Forum: Members Machines
Topic: Nevilleh's BMW
Replies: 337
Views: 57516

Nevilleh's BMW

No, not lost, just gone before..... I am still a firm believer in EVs and the electric BMW will find space in the garage for a while yet. I will still use it for my day-to-day running and short trips, but I've always needed another car for the times when I need to drive a couple of hundred k's or mo...
by Nevilleh
Tue, 08 Jan 2013, 19:31
Forum: Members Machines
Topic: Nevilleh's BMW
Replies: 337
Views: 57516

Nevilleh's BMW

Is this notification from the boss that pays you or the boss that you married?    http://forums.aeva.asn.au/smileys/smiley2.gif Actually from the dealer, but it came about because the boss that I married inherited a substantial amount of money last year and took pity on me having to drive around in...
by Nevilleh
Tue, 08 Jan 2013, 14:50
Forum: Members Machines
Topic: Nevilleh's BMW
Replies: 337
Views: 57516

Nevilleh's BMW

Well, I was going to get the twin turbo model, but its only 5.5 litres!
by Nevilleh
Tue, 08 Jan 2013, 11:36
Forum: Members Machines
Topic: Nevilleh's BMW
Replies: 337
Views: 57516

Nevilleh's BMW

One other thing to note is that if I drive it at a steady 100 kph the consumption rises to about 1.8 AH/km. Brick aerodynamics! I have a guilty secret to confess: I've received notification that my new car is on its way and its NOT an EV, its powered by a 6.3 litre, gas guzzling, V8. (Hides head in ...
by Nevilleh
Mon, 07 Jan 2013, 21:08
Forum: Members Machines
Topic: Nevilleh's BMW
Replies: 337
Views: 57516

Nevilleh's BMW

I think I would have to say that, unlike heads, motors are best kept single. Some figures from my car taken over the last 1000 kms: Average amp-hrs/km = 1.25 With 45 cells at say 3.2 V, that's about 176 watt-hrs per km. I find the AH/km most useful as I can quickly estimate range etc just from my od...
by Nevilleh
Mon, 07 Jan 2013, 11:28
Forum: Members Machines
Topic: Nevilleh's BMW
Replies: 337
Views: 57516

Nevilleh's BMW

Thanks for a lot of interesting comments guys. I THOUGHT I had a flexible coupling! I THINK the one I have now is much more flexible than the last one. Certainly it is possible to flex the rubber disk by hand, something not possible with the old one - which came from a wrecker, by the way. I think t...
by Nevilleh
Wed, 02 Jan 2013, 17:16
Forum: Members Machines
Topic: Nevilleh's BMW
Replies: 337
Views: 57516

Nevilleh's BMW

Hi Neville. Thanks for the cautionary tale. The misalignment and the too-rigid coupling would be enough to explain it, except in that case I'd expect the bearing nearest the break to be shot as well. Did you check it? If it was still good, the smaller shaft diameter may have been a significant cont...
by Nevilleh
Wed, 02 Jan 2013, 17:09
Forum: Batteries, charging, management and monitoring
Topic: Low cost BMS
Replies: 386
Views: 54018

Low cost BMS

I modified my bms to do top balancing and I've been running it a few times to see what happens. I've set the shunts to come on at 3.4 V and the charger to shut off at 3.6 V and I've cycled it four times now. Interesting that the charger reports that it has delivered about 1.6 AHrs each time and I'm ...
by Nevilleh
Sun, 30 Dec 2012, 15:37
Forum: Batteries, charging, management and monitoring
Topic: Low cost BMS
Replies: 386
Views: 54018

Low cost BMS

Yes, of course, but if the battery was nearly balanced to start off with, the balancing would be done as the charge is completed rather than as an extra thing to do after. Its a simple s/w mod, I think I'll try it out. Watch this space!
by Nevilleh
Sun, 30 Dec 2012, 13:50
Forum: Batteries, charging, management and monitoring
Topic: Low cost BMS
Replies: 386
Views: 54018

Low cost BMS

Another fellow (Arber) who has built my bms is dead set on having top balancing and suggests that turning on shunts for cells that get to, and above, say 3.5V while charging might go some way towards doing this. My original scheme was to turn on shunts for cells that reach 3.6 V (the max charge volt...
by Nevilleh
Fri, 28 Dec 2012, 12:39
Forum: Members Machines
Topic: Nevilleh's BMW
Replies: 337
Views: 57516

Nevilleh's BMW

My motor coupling failed recently. The one between the two motors, that is. Thought I'd describe what happened as a warning to other people who might couple two motors together. I used an old BMW rubber "doughnut" drive shaft coupling modified to do the job and I thought that would be quite satisfac...
by Nevilleh
Fri, 28 Dec 2012, 12:20
Forum: Members Machines
Topic: Weber and Coulomb's MX-5
Replies: 1698
Views: 342060

Weber and Coulomb's MX-5

Reading both yours and Renard's comments about access, I am moved to tell you that the inter-motor coupling in my BMW failed a little while ago confronting me with a daunting access problem. I originally installed the motor housing first, then the front battery boxes, motor controller, vac pump, PS ...
by Nevilleh
Wed, 26 Dec 2012, 21:22
Forum: Members Machines
Topic: Renard's BMW
Replies: 237
Views: 28772

Renard's BMW

Hey, you are to be congratulated for having a go at this!
I think that you will wonder why anyone bothers with thru-hole stuff once you've successfully made some smd boards.
Get an oven!
by Nevilleh
Tue, 18 Dec 2012, 19:00
Forum: Batteries, charging, management and monitoring
Topic: Low cost BMS
Replies: 386
Views: 54018

Low cost BMS

That sounds like a reasonable scheme - 12 cells per battery box, I mean. Of course, you would need to design the system with that in mind at the start, but that shouldn't be too hard. The price you quoted was 100-up and they are still $US22 each in less than 25 qty which is what the home builder wou...
by Nevilleh
Tue, 18 Dec 2012, 13:03
Forum: Batteries, charging, management and monitoring
Topic: Low cost BMS
Replies: 386
Views: 54018

Low cost BMS

Yes, the LTC6802 is an excellent choice - it does everything my modular bms does and handles 12 cells in a central system. BUT that's why I didn't use it! If you want to build a centralised bms and run sense wires to each cell then its the way to go. Even at $42 each = $3.60 per cell compared with t...
by Nevilleh
Mon, 10 Dec 2012, 17:06
Forum: Batteries, charging, management and monitoring
Topic: Low cost BMS
Replies: 386
Views: 54018

Low cost BMS

Been a while and I didn't see your last post until just now. You are right in that the output current of an optocoupler is proportional to the diode current, but when you see CTR figures like 100 - 300 % you realise that each one has to be calibrated. And then when you find that they drift all over ...
by Nevilleh
Sat, 17 Nov 2012, 13:15
Forum: Batteries, charging, management and monitoring
Topic: Low cost BMS
Replies: 386
Views: 54018

Low cost BMS

Woohoo! 192 linear optocouplers would cost you something like $US800 (HCNR200) plus a dual op-amp (another $1 each)for each one. You'd still have to make a pcb for each cell with at least those parts on it and then feed all the outputs to a vast combination of multiplexor chips. Could be done, cost ...
by Nevilleh
Fri, 16 Nov 2012, 18:29
Forum: Batteries, charging, management and monitoring
Topic: Low cost BMS
Replies: 386
Views: 54018

Low cost BMS

I'm a little surprised that throughout all this, no-one has mentioned our BMUs (till the post above). Perhaps it's perceived as being too fancy, or too specific to 40 Ah cells, or something. That may well be because its embedded in you MX-5 thread and people looking for info on BMS(s!) don't find i...
by Nevilleh
Fri, 16 Nov 2012, 16:14
Forum: Batteries, charging, management and monitoring
Topic: Low cost BMS
Replies: 386
Views: 54018

Low cost BMS

The first bms I designed was a "central" board with 8 inputs - for 8 cells - and used two quad op-amps. The ones I used were rated at 40-odd volts, so could be powered by the 8 cells in series OK. It used the differential inputs and the high CMR allowed it to work very well. The 8 op-amp sections di...
by Nevilleh
Fri, 16 Nov 2012, 11:45
Forum: Batteries, charging, management and monitoring
Topic: Low cost BMS
Replies: 386
Views: 54018

Low cost BMS

Well, it is what it is. There is no compunction for you to use it if you decide you don't like it. I have had personal experience of an electric motorcycle cutting power just because the bms detected a cell going too low and it very nearly killed me, so I won't countenance such a silly feature just ...
by Nevilleh
Thu, 15 Nov 2012, 14:05
Forum: Batteries, charging, management and monitoring
Topic: Low cost BMS
Replies: 386
Views: 54018

Low cost BMS

Sorry, don't understand what you mean by "took a sting of cells out, the master would now read the lowest as 0". It wouldn't! Try and understand how the daisy chain comms works and you will see why.
I've only been using it for a bit over a year - would you call that long term?