Search found 494 matches

by Peter C in Canberra
Wed, 22 Jul 2009, 18:25
Forum: Technical and conversion discussion
Topic: DC-DC converters, how much power do we really need
Replies: 25
Views: 3453

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

Does the curtis make the contactor open every time you lift off the throttle? Weird... That is how their manual recommends configuring things and how I did it. They also recommend a resistor (several 100ohms from memory) to bypass the contactor to 'pre-charge' the input caps of the controller but n...
by Peter C in Canberra
Wed, 22 Jul 2009, 17:11
Forum: Technical and conversion discussion
Topic: DC-DC converters, how much power do we really need
Replies: 25
Views: 3453

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

Hmm. I have my DC/DC converter hooked up after the main traction circuit breaker but before the contactor. Consequently the DC converter has power available all the time to supply lights or anything else when the car is not running and the battery would not charge or discharge unless the DC converte...
by Peter C in Canberra
Wed, 22 Jul 2009, 14:50
Forum: Technical and conversion discussion
Topic: DC-DC converters, how much power do we really need
Replies: 25
Views: 3453

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

Doesn't a 30A circuit breaker "break" at about 60A? You may well be right. I really just wanted something that would sit ahead of the various circuits and fuses on the 12V system that would limit to somewhat less than the converter's 90A output. IE I had a big disparity between the 12V heater requi...
by Peter C in Canberra
Wed, 22 Jul 2009, 02:46
Forum: Technical and conversion discussion
Topic: DC-DC converters, how much power do we really need
Replies: 25
Views: 3453

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

Actually, I doubt that much current goes in or out of my back up battery. The battery just sits there and I think the DC/DC converter keeps up virtually all the time. Certainly I see the current meter on the high voltage system responding instantly to varying 12V loads.
by Peter C in Canberra
Tue, 21 Jul 2009, 22:58
Forum: Technical and conversion discussion
Topic: DC-DC converters, how much power do we really need
Replies: 25
Views: 3453

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

But there you go Hoops. Another feature for the EVworks DC-DC converter... aux battery current limiting ! In my car with the 90amp converter I have the 90amp fused output go to a solid state circuit breaker from Jaycar (~30amps from memory). It has two threaded terminals. On its input from the conv...
by Peter C in Canberra
Tue, 21 Jul 2009, 05:11
Forum: Electric motors and controllers
Topic: current limiting on Curtis and TS cells
Replies: 74
Views: 8999

current limiting on Curtis and TS cells

I went driving up various local hills while my daughter hung her head over the back seat to view the BMS LEDs in the hatch area (safely through a perspex cover!). She could see most of the green LEDs go out together as I floored it. There were a few she could not see. As I persisted I got more and m...
by Peter C in Canberra
Fri, 17 Jul 2009, 19:32
Forum: Technical and conversion discussion
Topic: DC-DC converters, how much power do we really need
Replies: 25
Views: 3453

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

In the case of the Iota DLS 90 (I assume the same for the 45 Amp version) my spec sheet says it is current limited. So, as suggested, it will deliver the rated current at a slightly reduced voltage if faced with everything turned on and a partially discharged battery. I have the 90 amps version to c...
by Peter C in Canberra
Fri, 17 Jul 2009, 18:57
Forum: Technical and conversion discussion
Topic: DC-DC converters, how much power do we really need
Replies: 25
Views: 3453

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

Something to factor in is that you should have a 12V backup battery in parallel with the DC/DC converter output. If for certain short periods you are exceeding the rated output of the converter I think you would just be drawing the excess from the battery. Once you stop reversing with hazard lights ...
by Peter C in Canberra
Sat, 11 Jul 2009, 20:42
Forum: Technical and conversion discussion
Topic: How to feed an original tachometer?
Replies: 35
Views: 6979

How to feed an original tachometer?

Hi,
I've been trying to upload a picture but it won't go for some reason, even when I cut it down to only 40kb. I'll try to email it to you instead.
Peter
by Peter C in Canberra
Sat, 11 Jul 2009, 20:14
Forum: Batteries, charging, management and monitoring
Topic: EV milage, first 1000km.
Replies: 26
Views: 3557

EV milage, first 1000km.

I just drove 38 km mostly at 80kmph with a few roundabouts, lights, hills, two passengers etc. and used 49Ahs. So, at a nominal 144V I get 144x49/38=186Wh/km. With 250Wh/km at the wall, 186/250=75% for the charger which is close enough to the 80% likely efficiency, considering this was a measurement...
by Peter C in Canberra
Sat, 11 Jul 2009, 01:19
Forum: EV Motoring
Topic: Tesla in Australia
Replies: 58
Views: 9308

Tesla in Australia

Richo wrote: So I guess if you live somewhere between Darwin and Adelaide you might get to see the Tesla!

Don't forget you can see in sooner in Canberra, 4th October!
by Peter C in Canberra
Fri, 10 Jul 2009, 20:42
Forum: Batteries, charging, management and monitoring
Topic: EV milage, first 1000km.
Replies: 26
Views: 3557

EV milage, first 1000km.

I have been thinking that I need to have someone lean over the back seat to watch the LEDs while I accelerate up a hill. Then I could know if it is always the same cell. It does seem likely that one cell is different from most of the others since the average voltage is about 2.8 when the 2.V alarm g...
by Peter C in Canberra
Fri, 10 Jul 2009, 20:01
Forum: Batteries, charging, management and monitoring
Topic: EV milage, first 1000km.
Replies: 26
Views: 3557

EV milage, first 1000km.

Re gears. I find that for most driving I can just stay in 3rd gear all the time. If I am stopped and anticipate wanting a quicker takeoff I will start in 2nd but change to 3rd as soon as I am across the intersection or whatever. Above 1000rpm I get plenty of acceleration in 3rd. If I am moving at al...
by Peter C in Canberra
Fri, 10 Jul 2009, 18:52
Forum: Batteries, charging, management and monitoring
Topic: EV milage, first 1000km.
Replies: 26
Views: 3557

EV milage, first 1000km.

For the last month, which is most of the time for which I have stats, the cells have been mostly in single digit (though positive) temperatures. I have a max/min thermometer in the back now. The average 2.8V/cell is at more like 2C and a bit above at which point one cell must be dipping to 2.5V beca...
by Peter C in Canberra
Fri, 10 Jul 2009, 00:53
Forum: Batteries, charging, management and monitoring
Topic: EV milage, first 1000km.
Replies: 26
Views: 3557

EV milage, first 1000km.

I'm using the TBS Expert Pro meter. It does count AH in a run. It has been plugged and unplugged a few times so I'm not sure if it has remembered all my consumption. I can check this next time a do a longer run to work out the AH/KM for several runs. My impression is that very roughly I use about 4A...
by Peter C in Canberra
Thu, 09 Jul 2009, 20:55
Forum: Batteries, charging, management and monitoring
Topic: EV milage, first 1000km.
Replies: 26
Views: 3557

EV milage, first 1000km.

The charger runs at constant 15 amp output till the voltage has climbed to (I think) 165V. Then it abruptly drops to 5 amp output and declines over some minutes (10 perhaps?). The BMS has the job of opening a relay on the AC input to the charger if any cells are going over voltage but I don't think ...
by Peter C in Canberra
Thu, 09 Jul 2009, 20:16
Forum: Batteries, charging, management and monitoring
Topic: EV milage, first 1000km.
Replies: 26
Views: 3557

EV milage, first 1000km.

Well, the charger output sits on 15 amps constant for most the charge cycle while the voltage gradually climbs (from ~150V to 165V from memory). Then there is a taper down from 5 amps at the end while the BMS has some of the cells bypassed and burning off a bit of power. A tiny bit of the power woul...
by Peter C in Canberra
Wed, 08 Jul 2009, 19:49
Forum: Batteries, charging, management and monitoring
Topic: EV milage, first 1000km.
Replies: 26
Views: 3557

EV milage, first 1000km.

No that doesn't quite stack up. On two occasions I have driven about 55km with no sign of running out of charge or about 65% discharge according to the gauge and assuming 90Ah total. So, I think my practical range is closer to 70km. The charger throws out a bit of heat so some is being wasted there ...
by Peter C in Canberra
Tue, 07 Jul 2009, 15:19
Forum: Batteries, charging, management and monitoring
Topic: EV milage, first 1000km.
Replies: 26
Views: 3557

EV milage, first 1000km.

I have now done just over 1000 EV Km in my ADC8" Charade/Thunderskys. Much of that is on Canberra's 80km/h roads and my commuting route involves a few hills. Since I have a dedicated power point for the car with a meter I can report that my 'milage' has been almost precisely 250 Watthours/km. This i...
by Peter C in Canberra
Thu, 25 Jun 2009, 18:07
Forum: Electric motors and controllers
Topic: current limiting on Curtis and TS cells
Replies: 74
Views: 8999

current limiting on Curtis and TS cells

thanks for that. I would expect a domestic freezer to be -20oC though. A domestic fridge should be +4oC. Anyway, your finding that they barely manage 2C for an acceptable voltage drop when close to zero degrees is consistent with my experience in the car in cold Canberra weather.
by Peter C in Canberra
Thu, 25 Jun 2009, 04:47
Forum: General EV Discussion
Topic: WHERE to get started
Replies: 5
Views: 847

WHERE to get started

Some excellent blog/websites detail peoples' conversions eg. google evcapri or kiwiev for a good start. If you find yourself in Canberra you are welcome to pay a visit for show and tell with my recently finished conversion. Also, come to the national EV festival on 4th October.
Peter.
by Peter C in Canberra
Fri, 19 Jun 2009, 19:25
Forum: Electric motors and controllers
Topic: current limiting on Curtis and TS cells
Replies: 74
Views: 8999

current limiting on Curtis and TS cells

I also would be interested in a plot of max current at 2.5V for various temperatures down to barely above zero degrees. In the last week or two I have been driving my car with cells at temperatures between 5 and 15 degrees. I now have a little max/min thermometer in there to keep track. I would sugg...
by Peter C in Canberra
Tue, 16 Jun 2009, 14:28
Forum: Members Machines
Topic: Peter Campbell's Charade
Replies: 22
Views: 8052

Peter Campbell's Charade

.... Hi Peter, just wondering what company supplied your motor and controller?.... I was originally planning to get the controller that Ian Hooper (ZEVA, now part of EV Works) was developing but it was not ready. I was also planning to get an Impulse 9" motor. The latter appealed because it was sim...
by Peter C in Canberra
Mon, 15 Jun 2009, 15:58
Forum: Electric motors and controllers
Topic: current limiting on Curtis and TS cells
Replies: 74
Views: 8999

current limiting on Curtis and TS cells

Is there some definitive source of info on the LiFePO4 charging chemistry and temperature? As far as I can tell my battery has been charging just fine at temperatures above zero, but not by very much. Zero is a suspiciously round number so it would be nice to know some further details. Does the lith...
by Peter C in Canberra
Fri, 12 Jun 2009, 04:23
Forum: Electric motors and controllers
Topic: current limiting on Curtis and TS cells
Replies: 74
Views: 8999

current limiting on Curtis and TS cells

Hmm. I just went out to check the temperature. At 10PM the battery compartment was 6 degrees when the air was 3 degrees and -4 is the predicted minimum. I had a timer set so the charger would not come on till 9PM so the charger has been running an hour. The battery gauge shows -6Ah so it should have...