Worx?

[tony sayer]

In article , EricP scribeth thus

Shows how much you don't know about electricity;(..

[Doctor Drivel]

You must eff off as you are an idiotic plantpot. Please put your finger in the socket.

[Doctor Drivel]

I've used French letters, not red ones.

[Dave Plowman (News)]

For once you're right. The very idea of you talking sense.

[Dave Plowman (News)]

If only your father had.

[Doctor Drivel]

A 12v drill can have "exactly" the same power a 24v drill. That is not a problem. To have them last the same amount of time in drilling, the 12v drill will need a bigger battery in A/hrs.

This adds cost as battery cells are expensive and are the main cost of a drill.

So, as batteries are expensive compared to knocking out motors en-mass, they go for larger voltage motors and then the batteries do not have to be as big (or as heavy, which is major point). They are balancing one against the other to keeps costs down. That is using the same type of battery of course, say Ni-Cads.

Current marketing means that generally the larger the voltage the greater the power - so the punter then can gauge the products on the market. All understood, all de-facto standard.

Now, a 12v drill can be the same power as a 24v drill, no arguments about that. Battery types are changing with Lith-Ion being introduced. That means that a 12v drill can be the same power as 24v drill, but put a Lith-Ion battery in it and matters change as these can be so much smaller in physical size and hold so much more energy. So a 12v Lith-Ion drill can match a 24v Ni-Cad drill in power and battery life and be at least the same weight, or even lighter. BUT!!! That is comparing apples with oranges (Lith-ion and Ni-Cads).

Using the same battery type we are back to stage one. Using 12v and 24v Lith-Ion with the same power still means the 12v drill will need a larger battery in A/hr to last the same amount of running time. Although all drills using Lith-Ion will be smaller & lighter than Ni-Cads.

[Doctor Drivel]

You must eff off as you are an idiotic plantpot. Please put your finger in the socket.

[Doctor Drivel]

You must eff off as you are an idiotic plantpot. Please put your finger in the socket.

[Dave Plowman (News)]

You don't know that identical sized cells come in different capacities? And don't vary in weight by very much? Higher voltage drills impress the unwary at the bottom end of the market. You should be well used to that.

[Doctor Drivel]

Eff off as you are a plantpot.

[John Rumm]

I was talking in terms of quality of cells, drill gearbox, speed control etc. Not suggesting the motor will draw the same current.

I don't follow that. If the 12V tool were delivering the same amount of mechanical work - same number of turns against the same rotational resistance, then the output power would indeed be the same, however that would also broadly suggest that the input power will be similar for both, which would result in the 12V drawing twice the current.

Are you suggesting there is little difference between say a 12V Makita combi and the 18V version?

The range of voltages seems much the same - lots of 18 and 24V LiIon stuff about. The 10.8V seems to be reserved for the smaller tools.

If you were building them to deliver the same power, then yes. In reality you are going to expect more power from the higher voltage tool.

down to a price and up in size usually.

[The Medway Handyman]

What a shame your dad didn't...

[Owain]

Maybe he did, but they leaked

Owain

[geoff]

Like father, like son, eh ?

[dennis]

Yes, that's why it needs twice the battery capacity to last as long. It also means it needs thicker wire as well as more turns. So the motor will be bigger and more expensive than a 24V motor.

Are they both aimed at the same jobs? If so there is little difference. However I expect the 18V ones to be bigger in size and price.

[The Natural Philosopher]

No.

The fact of the matter is that the only cell usable a few years ago was the NiCd Sub C of about an ampere hour capacity. They couldn't really do more than about 25A, so if you wanted more power you stuffed in more o them.

Hence teh more powerful drills had to use more of them.

However what determines the power with modern cells, is the motor - the cells will do 50-70A or good ones will, and capacities are pushing 4Ah.

[The Natural Philosopher]

Utter and complete bollox.

Its totally down to the way the motor is wound.

You can wind the same motor to do the same power RPM and torque on 12v or 24v. At twice the current.

[The Natural Philosopher]

Got it in one.

Who knows? the voltage is a useless guide to power and quality.

The power from a motor is roughly dictated by the mass of the thing, and its efficiency.

Gong up in voltage means more turns of thinner wre,for e same efficiency. It ends up identical.

[Doctor Drivel]

Wow! A Jocko and cowboy dumbo from Kent.

[John Rumm]

Ah, sorry, you meant turns as in the motor windings rather than revolutions of the motor....

The low end will do a subset of the jobs the high end will do. So I guess you can take that as yes or no.

It seems quite marked in handling...

Indeed.