Cordless tools.

[Phil Pascoe]

I'm looking at the picture which appears to be three separate batteries, the first of which is labelled 6ah x 18v and it does specify that they are back compatible with existing 18v tools, so I assumed the batteries to be separate. It doesn't matter a jot to me - I'm never going to buy either. Surely if you are using three 18v x 2ah batteries to get 54v, you've still got a 2ah battery? You're not trebling the ah just because you treble the voltage?

 

[novocaine]

depends how they are wired but in short P=V.I is the equation.

you are assuming they are in series (to get 54v) not in parallel, the voltage is staying at 18v, so the amps are tripled and thus the Amp hours.

 

[lua]

Lord. That advertising really is awful.

"Reinventing how a current flows"

..ffs. That first video was next to useless, complete waste of time/effort/money. It just makes the brand look stupid. I don't know how these marketing people get employed. I wonder when they're getting to start knocking the competition like you see with supermarket brands or computer brands.

"This new tool allows me to do x,y and z. I could never do that with my Makita"

Also :

3 x 18v 2ah in series = 54v 2ah
3 x 18v 2ah in parallel = 18v 6ah

 

[Phil Pascoe]

depends how they are wired but in short P=V.I is the equation.

you are assuming they are in series (to get 54v) not in parallel, the voltage is staying at 18v, so the amps are tripled and thus the Amp hours.

How would they be wired to allow each 18v to be used separately? (showing my ignorance of batteries)

 

[novocaine]

they aren't using each 18v seperately, basically they are putting all the positives together and all the negatives together unlike normal where you'd put positive to negative in a chain. one keeps the voltage at 18v one would up the voltage to 54v as you suggest. by being in parralel each batteries ah is multiplied, in series each batteries voltage is mulitplied. hope that makes sense. if not have a google for batteries in parallel, they are people out there who can explain it way better than I can on here.

 

[lua]

they aren't using each 18v seperately, basically they are putting all the positives together and all the negatives together unlike normal where you'd put positive to negative in a chain

I believe they are chaining them up (series) as they specifically mention 54v.

 

[novocaine]

looks that way, but that 54v will be at 2ah, a clever switch to move it from series to parallel. guess it means you can get better torque curves for higher voltage tools and work time for less hungry tools (table saw vs drill)

 

[philipjdall]

Neither makes a difference. The nominal voltage of a li cell is 3v (or 3.2 depending chemistry), so each 18v cell is in fact 6 individual 3v cells wired in series. If you wire that 18v cell in series (or parallel) it makes little difference to the efficiency, but the general rule of thumb is that the higher the voltage the more efficient the system. So on paper the 54v system would be a better choice.

I only know all of this after years of flying large rc helicopters, where we typically run 12s 44.4 hv setups with massive current draw. Flight time is less than five minutes but these things can put out more power than a wall socket! Let's just say that battery tech in tools has a long way to go!

 

[Phil Pascoe]

I think I've opened a can of worms ... I'll read through and attempt to learn something at the end ... :lol:

 

[DiscoStu]

Phil I think the thread has gone off topic but I'm sure 18v is probably all you need.


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[graduate_owner]

I just watched that first DeWalt video and I have to agree if is a waste of effort. They claiim "power of the mains in your hands" (yeah, right) and that is the only actual advertising - the rest is just flash. Reminds me of car adverts.

Regarding the 54v by putting cells in series, that means 15 cells. As someone said, it only needs one cell to fail.

K

 

[novocaine]

from our Canadian cousin.
https://www.youtube.com/watch?v=pO1RqgAFP5Q

 

[DiscoStu]

Can't work out if he is an idiot or just pretending to be!


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[novocaine]

watch some of his other stuff and you'll figure it out. bit of both I fear. but jolly entertaining at times.

 

[Alexfn]

Its just an act hes clearly a very intelligent guy.


Not to mention last time i checked he was being sponsored to the tune of 4 grand a month to make those videos..nice work if you can get it

 

[novocaine]

I think he has his moments, he knows what he knows though and that makes it entertaining, didn't realise he was up to that amount of cash for it.

 

[transatlantic]

He seems like a nice guy and you can tell he's very interested in what he's doing. I think he'd be doing it without being sponsored. I think the 'comedy angle' does wear a bit, but I still watch it if I don't have more interesting woodworking things to watch

I like his tear down videos the most, very interesting. Was great to see the insides of a festool. Wish he'd do a lot more!

.. although I do take what he says with a pinch of salt. Seems like a lot of what he knows is through word of mouth

 

[woodenstx]

lots also depends on the C of the cell/pack... It might be 2Ah, but it might be able to discharge at 5C, meaning you get 10Ah for 1/5th of an hour instead...
Or its 1C and you only get 2Ah but for the full hour. Less torque for your motor but longer running time.
in many cases, the C of the battery is more important than the Ah's it can do. But not many compnaies let that one slip.

I like the idea of the convinience cordless gives but as my Hilti 18V nimh packs are dying, I'm using a mains drill more and more for screwdriver operations and have to say there hasnt been many situations where the cordless would have been prefereable. Might look at the Makita 1/4" mains impact driver

 

[Jelly]

I'm another in the camp that doesn't really understand why anyone would want battery tools if they don't Need to be away from mains...

I do use (but not own) a Bosch blue 18v drill which is adequate for most tasks, and have access to its Ryobi equivalent which is adequate for wood (for which I rarely use a drill anyway), but not metal... But I'll usually reach for a brace or breast drill when the going gets tough.

 

[transatlantic]

I'm another in the camp that doesn't really understand why anyone would want battery tools if they don't Need to be away from mains...

I personally CAN'T STAND power leads. I seem to always get things caught up or I'm always tripping over them! And when you have lots of tools out, it's just far less clutter.


Oh and when using dust extraction, it's one less thing to get in the way.