Search found 3917 matches

by Punx0r
Feb 19, 2018 10:46 am
Forum: General Discussion
Topic: Perth bike path speed bump trial set to force speeding cyclists to slow down
Replies: 5
Views: 38

Re: Perth bike path speed bump trial set to force speeding cyclists to slow down

That's ridiculous.

For one thing walkers will be tripping up on those unless they're painted a highly contrasting colour
by Punx0r
Feb 17, 2018 6:40 pm
Forum: Battery Technology
Topic: 18650 questions - How does internal resistance relate to voltage?
Replies: 11
Views: 127

Re: 18650 questions - How does internal resistance relate to voltage?

You can't measure the resistance of a live circuit with a multimeter. At best the measurement is meaningless, at worst it will damage the meter.
by Punx0r
Feb 16, 2018 8:13 am
Forum: E-Vehicles General Discussion
Topic: Wind and Solar vs Coal, Gasoline, Nuclear
Replies: 1621
Views: 34561

Re: Wind and Solar vs Coal, Gasoline, Nuclear

The big issue in the whole discussion of SA is that they are shutting down carbon generation without first having replaced it. I think that's a fair assessment. Like I say, it's a local political issue but Hillhater uses it to assume RE cannot work anywhere on the planet. What's the probable cause ...
by Punx0r
Feb 16, 2018 7:57 am
Forum: Motor Technology
Topic: PM Motor theory - formulae etc.
Replies: 71
Views: 24705

Re: PM Motor theory - formulae etc.

They do :)
by Punx0r
Feb 16, 2018 7:55 am
Forum: Battery Technology
Topic: Common pack design mistakes, how to avoid?
Replies: 235
Views: 18486

Re: Common pack design mistakes, how to avoid?

The cell IR does make a difference - the lower it is, the greater the effect of the interconnect resistance on current sharing.
by Punx0r
Feb 16, 2018 4:08 am
Forum: Battery Technology
Topic: Need help on 18650 battery series/parallel plan
Replies: 10
Views: 175

Re: Need help on 18650 battery series/parallel plan

This is potentially a complicated pack. The end of this thread shows the sort of thing that can be done to ensure the electrical connections are good to evenly balance the load on each cell: https://endless-sphere.com/forums/viewtopic.php?f=14&t=84412&start=200 However with a pack this large you may...
by Punx0r
Feb 16, 2018 3:54 am
Forum: Motor Technology
Topic: PM Motor theory - formulae etc.
Replies: 71
Views: 24705

Re: PM Motor theory - formulae etc.

My limited experience of sensorless operation on ebike controllers is they are not good. From a start under load they can initially hunt backwards and forwards a fraction of a turn until finding forwards. Generally it's good to get the bike rolling with an initial push before applying throttle. This...
by Punx0r
Feb 15, 2018 5:45 pm
Forum: Motor Technology
Topic: PM Motor theory - formulae etc.
Replies: 71
Views: 24705

Re: PM Motor theory - formulae etc.

Part 1: Output power is torque * rpm. At pull away, rpm is 0, so power is 0, until ...? True. The power output of a stalled motor (which is what it is at start-up) is zero and efficiency is 0%. What the motor is producing though is torque, it is applying a static force even though it is doing no wo...
by Punx0r
Feb 15, 2018 5:46 am
Forum: E-Vehicles General Discussion
Topic: Wind and Solar vs Coal, Gasoline, Nuclear
Replies: 1621
Views: 34561

Re: Wind and Solar vs Coal, Gasoline, Nuclear

If this thing is intended to often run for 2 days straight then that makes it baseload? Just not a regular one? It's definitely not a peaker and not a load follower as they ramp down at night (less than 24hr usage pattern). Regardless, I struggle to understand why someone would select reciprocating ...
by Punx0r
Feb 14, 2018 5:39 pm
Forum: E-Vehicles General Discussion
Topic: Wind and Solar vs Coal, Gasoline, Nuclear
Replies: 1621
Views: 34561

Re: Wind and Solar vs Coal, Gasoline, Nuclear

Thanks Bill, let's see what appears in a decade or so!
by Punx0r
Feb 14, 2018 3:28 pm
Forum: E-Vehicles General Discussion
Topic: Wind and Solar vs Coal, Gasoline, Nuclear
Replies: 1621
Views: 34561

Re: Wind and Solar vs Coal, Gasoline, Nuclear

\Serious question: How many of these next-gen thorium/molten salt reactors have been built as at least a working prototype yet?
by Punx0r
Feb 14, 2018 7:33 am
Forum: E-Vehicles General Discussion
Topic: Wind and Solar vs Coal, Gasoline, Nuclear
Replies: 1621
Views: 34561

Re: Wind and Solar vs Coal, Gasoline, Nuclear

3). The entire 211MW capacity of this $295m plant is only equal to ONE of the 8 thermal 200MW generators in the old plant ! 4). Since Wind generation is given priority in the wholesale market, its a fair assumption this new plant will be on standby much of the time, lowering its CF dramatically, ef...
by Punx0r
Feb 14, 2018 7:30 am
Forum: E-Vehicles General Discussion
Topic: Wind and Solar vs Coal, Gasoline, Nuclear
Replies: 1621
Views: 34561

Re: Wind and Solar vs Coal, Gasoline, Nuclear

Like I said before, if you bought a car and it could only drive on average %23 of the claimed speed you wouldn't buy it. You are aware that the average speed driven of almost every vehicle on the planet is a lot less than it's top speed? Or do you only drive your car flat out on an empty oval circu...
by Punx0r
Feb 12, 2018 6:05 pm
Forum: Battery Technology
Topic: C Rating of 18650 cells in my project? Advice please.
Replies: 14
Views: 183

Re: C Rating of 18650 cells in my project? Advice please.

Ah, yes , apologies, please disregard my last post.

That fuse rating is sailing surprisingly close to the wind!
by Punx0r
Feb 12, 2018 5:34 pm
Forum: Battery Technology
Topic: C Rating of 18650 cells in my project? Advice please.
Replies: 14
Views: 183

Re: C Rating of 18650 cells in my project? Advice please.

Just looked at Wikipedia and the Gen 1 RAVEV is stated as being 50kW, so that's ~130A.

However, it also says the battery is 288V 90Ah NiMH.

You need to take some caution there as NiMH can get a bit explodey if not charged or if connected in parallel with another battery properly.
by Punx0r
Feb 12, 2018 5:29 pm
Forum: Battery Technology
Topic: C Rating of 18650 cells in my project? Advice please.
Replies: 14
Views: 183

Re: C Rating of 18650 cells in my project? Advice please.

Yes, with parallel cells the total current draw is shared evenly between them. The exception to this is where the connections to some cells have different resistance than others. E,g. if the cells at the end of a long string of parallel cells connected by wire or nickel strip that is too thin will h...
by Punx0r
Feb 12, 2018 3:59 am
Forum: Motor Technology
Topic: 2 controllers in paralell for one hub motor, is it possible?
Replies: 31
Views: 541

Re: 2 controllers in paralell for one hub motor, is it possible?

In every controller circuit I look at, from the simplest bare-bones example with its "Main capacitor" , to (what I assume to be) the most well-designed and sophisticated (from here ), where there are paired (polorised and non-polarised) capacitors per phase, labelled C15/C18, C16/C19 and C17/C20 re...
by Punx0r
Feb 12, 2018 3:31 am
Forum: Battery Technology
Topic: Cells sold with pre-soldered tabs
Replies: 2
Views: 112

Re: Cells sold with pre-soldered tabs

Yes, 18650 li-ion from NKON with tags. It works OK but is more work and not as neat as a spot-welded pack and I'm not sure I'd do it again as there is now more choice of spot welder's available.
by Punx0r
Feb 10, 2018 10:15 am
Forum: Battery Technology
Topic: Samsung 30Q hard voltage drop under load?
Replies: 9
Views: 325

Re: Samsung 30Q hard voltage drop under load?

You can see what the voltage should be for the 30Q at different discharge currents over the discharge cycle in the chart on page 6 here:

https://eu.nkon.nl/sk/k/30q.pdf

See if it matches up with your observations
by Punx0r
Feb 10, 2018 10:03 am
Forum: E-Vehicles General Discussion
Topic: Wind and Solar vs Coal, Gasoline, Nuclear
Replies: 1621
Views: 34561

Re: Wind and Solar vs Coal, Gasoline, Nuclear

If you bought a car and at times could only drive it at 5% the legal speed, you wouldn't buy it Intermittent walking-speed driving due to traffic is reality for a many drivers. It's not ideal, but is workable. Also, your own chart you posted shows Wind power fluctuating between 20-40% capacity fact...
by Punx0r
Feb 10, 2018 9:57 am
Forum: E-Vehicles General Discussion
Topic: Wind and Solar vs Coal, Gasoline, Nuclear
Replies: 1621
Views: 34561

Re: Wind and Solar vs Coal, Gasoline, Nuclear

Coastal areas at least tend to be windy and those winds fairly regular/predictable. If you have a decent tidal range then there's the potential there for tidal hydro. I have zero problem with continued fossil fuel usage where it is required on technical or practical grounds. Reduced and/or intermitt...
by Punx0r
Feb 07, 2018 3:49 am
Forum: Motor Technology
Topic: Removable method of securing motor's axle nuts
Replies: 9
Views: 211

Re: Removable method of securing motor's axle nuts

Clamping torque arms
Disable regen unless you really need it
by Punx0r
Feb 07, 2018 3:19 am
Forum: General Discussion
Topic: Tesla, first car in space
Replies: 18
Views: 381

Re: Tesla, first car in space

The rocket required a dummy payload. Normally a large steel block would have been used but the car was sent instead for the lulz.
by Punx0r
Feb 06, 2018 6:43 pm
Forum: Motor Technology
Topic: Multitooth motor winding idea
Replies: 27
Views: 571

Re: Multitooth motor winding idea

They exist in industry though (just one article that jumped out at the top of a google search): http://www.ciif-expo.com/article/show.php?itemid=279 1m diameter, <1000rpm, up to 100 poles, 20,000Nm torque direct-drive PM brushless motors . They mention that they are "high conductivity", but then lis...