6 volt motor power source

I think it's to allow your grandchild to prep 'timber' for your 'matchstick' Eiffel Tower / Cutty Sark project. ;-)

What did I win?

Cheers, T i m

Drill or electric car. ;-)

One of the improvements they did the Enfield 8000's (PIEV) is raise the battery voltage from 48 to 72 and adjust the gearing to match (more revs, less current).

Pulling away fast in my (48V Moke version) would see around 400A and cruising at 30 mph around 200. ;-(

I believe modern EV's have the battery voltages up much much higher so you don't need cables as thick as my thumb everywhere. ;-)

Cheers, T i m

ROTFL; I wonder how many greens actually believe that sort of thing? Quite a lot, I suspect.

I don't think that sort of thing is anything specific to 'greens', in fact, real 'greens' would probably know what works and what doesn't, I'm talking about yer average Joe in the street who couldn't see an issue with a perpetual motion machine. ;-(

Cheers, T i m

Looking at green party beliefs & policies should answer that question. No, the answer isn't good.

NT

There is a staggering ignorance of science, even amongst scientists.

I was talking to a Russian undergrad last time I went to a college meeting of the engineering society. He wanted to know why jet packs for personal flight weren't being developed. I explained to how the issue with thrust is related to momentum change, and how a little air being accelerated (mv) a lot (Jet pack) uses way more power (1/2mV^2) than a lot of air being accelerated a little (helicopter).

(for those who like to understand, plot thrust - mV - against energy -

He didn't seem to get it.

The point is you may understand the science but until you actually run the numbers, you can be way out of line., Like the other engineers convinced that 'renewable' energy lowers carbon emissions - "Run the numbers" I said "You have the qualifications, now do the calculations".

It's awfully easy to get qualifications in 'science' without really understanding anything...

You mean you can't find a lower voltage tool from anyone that matches it? Who would have guessed? :-)

So basically we are in agreement, for stuff you can actually buy, more volts = more better.

For theoretical stuff that no one makes, you could in theory have a theoretical drill with a lower voltage that works as well as an actual drill with higher voltage. Yes I agree, as a thought experiment its worth 10 seconds consideration. Now lets move on.

What that tool designers know what they are doing?

I have not yet looked at the XGT range at all. Personally I was quite content with the tools that simply used 2 x 18V batteries for higher performance when required - it seemed like a sensible way forward.

However I can see that from a competition point of view they probably felt the need to offer a higher voltage platform to match what the other makers are doing.

Now, having done a higher voltage platform, they also need to do a comparable range of tools that use it (and they do not far short of 300 that use the 18V platform). So you will get some tools that genuinely

Yup, 400V or thereabouts seems quite common.

When I was referring to 'greens' there it was more from the POV of those who have chosen to not eat meat, for heath, animal cruelty / exploitation, environment pollution and a sustainability POV, not those advocating windmills and solar panels etc (although I'm sure there is some crossover between those who support 'The Green Party' and all those issues, as there is with those who don't support The Green Party but are Vegans and do care about the environment).

Cheers, T i m

Yes, pandering to marketing hype.

MOSFETs are affordable for controlling voltages up to 600V. For higher voltages you would migrate to IGBTs which have much greater losses.

I can't see EVs going much higher in voltage.

Lets try this from a different angle; what would be the point in making say a 12V tool, that has the same power output as an 18V one? Where is the actual advantage?

You will need more expensive cells that can cope with higher average and peak current delivery. More copper in the wiring, and the motor windings. More expensive semiconductors in the speed controllers. If you are going to go for parallel arrangements of cells to get the energy density, you then have new problems matching the cell characteristics, and charging them without overcharging some cells. Then in use you have more heat dissipation to worry about - so less endurance and more waste energy.

So you end up with a more expensive tool that is heavier, where additional battery packs are more expensive, and probably won't last as many cycles. Basically you are on a hiding to nothing.

So does marketing come into it, yes of course you get bragging rights, and in reality Makita's 40V tools will only offer marginal performance gains over their equivalent 2x18V products. However I will concede that it means they can bring 2x18V levels of performance to tools where the form factor would not suit two battery setups. (e.g. take the combi drill, they don't do a 2x18V combi drill (it would ruin the handling), so the 40V tool does actually make sense if the jump in torque to 140 Nm is necessary for your application).

Its seems perverse to dismiss higher voltages as *just* hype, however if you may have to accept that being enlightened you are going to be stuck with less effective tools for some jobs.

Well we all have wind turbines attached to our chimney stacks as once advised by the green lobby.!

Just go on Youtube and see how many schemes there are for creating free energy and then wonder why none of them have been adopted by the energy industry. Perhaps it's true there is a conspiracy by the gas and oil industries to stop innovation into alternatives :)

For entertainment, I watched one of these video where first a microwave oven has to be stripped apart to get a coil. Attach a small magnet to a bit of rubber and in turn attach this to the end of a long tube which is positioned above the coil (the magnet being close to the coil). Connect the coil to a digital multimeter and 'bang' the tube. Hey presto the multimeter shows by vibrating the tube/magnet it generates some free power. The idea is that by mounting the tube outside the wind will vibrate it. I assume that with tens of thousands of these tubes a house could become self sufficient in electric power.

Remember Dick Strawbridge who made the TV series about his new green lifestyle and driving around in cars fuelled by the local chip shop oil, harnessing the power of the stream that ran through his 100 acre property that barely powered a 25W light bulb etc.? He seems to have given up that utopian existence - perhaps reality struck!