Battery powered hand tools

[popsy]

Is there a way to know how powerful battery powered tools will be? The only information given is the voltage of the battery. We have 3.6 v powered grass shears and are considering ones that have a 12v battery. Should we expect the 12v ones to cut more powerfully, all other things being equal?

[Jeff Corey]

Originally posted by popsy
Is there a way to know how powerful battery powered tools will be? The only information given is the voltage of the battery. We have 3.6 v powered grass shears and are considering ones that have a 12v battery. Should we expect the 12v ones to cut more powerfully, all other things being equal? Even though you apparently hit the wrong board, Mr. Wizzard can tell you that you have not provided enough information for freakin Einstein to answer you.

[popsy]

Originally posted by Jeff Corey
Even though you apparently hit the wrong board, Mr. Wizzard can tell you that you have not provided enough information for freakin Einstein to answer you.

OH. See, I thought that this being a technology board, and all, might mean there were people available who might know about stuff like this. As for information, I provided what was available to me. If you have no answer, there are probably many other ways of saying so, even ignoring the post seems like a good possibility.

Which board do you suggest would be more appropriate for a question involving technology? Or is battery power not considered technology? I found one definition of technology as this: The application of science, especially to industrial or commercial objectives. But I shall wait in anticipation for your response to clarify it for me.

[TeaBag420]

Originally posted by popsy
Is there a way to know how powerful battery powered tools will be? The only information given is the voltage of the battery. We have 3.6 v powered grass shears and are considering ones that have a 12v battery. Should we expect the 12v ones to cut more powerfully, all other things being equal?

Sorry Jeff Corey "New York Skeptic" (is that like "New York lawyer"?) gave you a less than gay welcome, but it's probably less a matter of voltage than engine design and size of the battery.

To answer your question, yes there is a way to know how powerful battery powered tools will be. Try them. When in doubt, more is better, so go with the 12V model.

(There's some distinction between upper and lower case abbreviations in the context of electricity but I forget what it is, so "v" may be correct).

[popsy]

Originally posted by TeaBag420
Sorry Jeff Corey "New York Skeptic" (is that like "New York lawyer"?) gave you a less than gay welcome, but it's probably less a matter of voltage than engine design and size of the battery.

To answer your question, yes there is a way to know how powerful battery powered tools will be. Try them. When in doubt, more is better, so go with the 12V model.

(There's some distinction between upper and lower case abbreviations in the context of electricity but I forget what it is, so "v" may be correct).

Thank you for your advice. Much appreciated. You confirmed what I had suspected. And trying them can be difficult over the Internet. :p One takes one's chances, I guess.

I used 'v' as it was used in the blurb for the tool. I hadn't even given a thought as to the possibility of an error of usage. Oops.

[WildCat]

I don't know much about the science of it all, but I can tell you that voltage isn't everything. I have extensive experience in using cordless drills, and some brands are much more powerful (torque) than others. My 14.4 v DeWalt does most things effortlessly, a 14.4v Ryobi we once used couldn't drill its way out of a paper bag. Probably the same for grass shears.

But why mess w/ the shears? Yesterday I bought a cordless (24v) trimmer/edger for $80. It trims far better than shears do, you don't have to bend over or kneel down, and it edges taboot!

[NoZed Avenger]

Originally posted by WildCat
But why mess w/ the shears? Yesterday I bought a cordless (24v) trimmer/edger for $80. It trims far better than shears do, you don't have to bend over or kneel down, and it edges taboot!

If you like your tabooties edged, that is. Some prefer them natural.

[popsy]

Originally posted by NoZed Avenger
If you like your tabooties edged, that is. Some prefer them natural.

I do like my tabooties with an edge. :D

Wildcat, we do have a battery string trimmer but I have a water garden around which I have to trim the grass and I can't seem to find a way to not have the grass clippings thrown into the water. What kind of trimmer/edger do you have?

What you've said about voltage not being everything is certainly what I was concerned about. My original question included "all other things being equal" but the big problem is that they are not, are they. At least the shears aren't prohibitively expensive.

My husband and I had a discussion about whether higher voltage automatically meant higher power, thus my question to this board. Thanks all for your answers.

[SezMe]

Originally posted by popsy
Wildcat, we do have a battery string trimmer but I have a water garden around which I have to trim the grass and I can't seem to find a way to not have the grass clippings thrown into the water.
A water garden...in Phoenix???? I think you've been out in the noonday sun a tad too much. :)

Seriously, I've read stories that Phoenix has major water problems. I would think a water garden (depending on what that is, exactly) would be verboten by the distinguished city fathers.

[popsy]

Originally posted by SezMe
A water garden...in Phoenix???? I think you've been out in the noonday sun a tad too much. :)

Seriously, I've read stories that Phoenix has major water problems. I would think a water garden (depending on what that is, exactly) would be verboten by the distinguished city fathers.

Phoenix with a water problem?! Ask the golf course owners with all the grass and big artificial lakes, all the people who grow non-native plants in their yards. You wouldn't even know we are in a desert, let alone in the middle of a drought.
Phoenix gets to pretend it doesn't have a water problem because we get water from the Colorado River via the CAP (huge canal that brings the water over hundreds of miles). My little water garden, a pond in which I mainly grow water lilies and some goldfish is not a heavy water user. I do get water lost to evaporation but not as badly as the swimming pools which have no leaf cover. There are many, many swimming pools here. Our ground water is being pumped out for too many people, and I'm one of them:( who want the advantages of the desert with none of the disadvantages.

[Dilb]

Originally posted by popsy
Is there a way to know how powerful battery powered tools will be? The only information given is the voltage of the battery. We have 3.6 v powered grass shears and are considering ones that have a 12v battery. Should we expect the 12v ones to cut more powerfully, all other things being equal?

Everything else being equal, the 12V would be more powerful.

Electrical power is Voltage * Current, or V*I. In an ideal system V is related to I, so power is related to V*V. However, there is a limit to how much current can be supplied. If the 3.6V battery can supply 1 Amp, but the 12V can only supply 0.1 Amp, then the 3.6 V battery is 3x more powerful (at 3.6 Watts) than the 12V battery (at 1.2 Watts). The current limitation depends on the construction of the battery, so it would have to be tested to determine what it is.

Then there are factors like how well constructed they are, which means that actual testing is necessary to determine which are better. In generally higher voltages should be more powerful, unless it's a marketing trick.

[davefoc]

I think what Dilb said is right.

However, I think that the way battery powered drills use voltage as a key specification is curious and I don't understand why it is done.

The voltage, without more information, tells one absolutely nothing about the potential performance of a power tool. It is completely conceivable that a high voltage power tool would have less power power than a lower voltage power tool.

Even if one knew the voltage and current characteristics of the battery pack one still couldn't know the power or maximum torque specification of the tool itself since that would also depend on the characteristics of the motor.

All that aside, I have considerable experience with two cordless drills: a 12 volt Dewalt and an 18 volt black and decker. The 12 volt Dewalt was an excellent, reliable drill that performed welll for most tasks. It was inadequate for driving longer larger screws (three inch or longer) into wood, for drilling holes with hole saws and for driving screws through hardibacker board that is used for backing ceramic tile. The 18 volt black and decker performs those tasks very well and except for the fact that it is somewhat heavier and larger performs all the other tasks that the 12 volt Dewalt drill performed well also.

For certain tasks such as drilling holes in concrete I still use a corded drill although I suspect some of the battery powered hammer drills would do very well at drilling holes in concrete.

[Soapy Sam]

There is also the matter of gearing. Though in my experience of such tools, given the same gearbox, the higher voltage tool will go flat faster than the low voltage one. However, due to quantum uncertainty, both will go flat before you finish the job.*



* (And probably before you start.)

[CBL4]

For most people, the 18V Ryobi is a good choice. They are cheap and do most jobs well. I renovate houses on the side and they do OK. I have not had them break but I have had one battery die. They are great addition to electric powered saws and the drill will do almost you need.

If you are using them a lot and/or have lots of money, get a 18V DeWalt. They are great but cost at least twice as much as the Ryobi.

Edited: I just noticed you said "grass shears." I know nothing about them.

CBL

[Bearguin]

Heck. You guys are lightweights when it comes to cordless tools ;)

I have:
cordless screwdriver (not a drill) ~3V
cordless ratchet (looks like the above) ~3V
9.6V drill - Craftsman
12V drill - Matercraft (Canadian Tire)
18V drill - Black & Decker (same manufacturer as Dewalt)

and in the 14.4 V Black & Decker series
drill
cut-off saw
circular saw
weed-eater
hedged trimmer (X2) I owned 1 then bought the second as I wanted the weed-eater and the combo kit was cheaper.

To address the question, of the two B&D drills, the 18v really outperforms the 14.4v. I'd assume that this is the closet you can get to "all things being equal" as the two drills are pretty much the same vintage and only the voltage is different.

[Drooper]

She said "battery powered hand tool" uhu hu uhu

[davefoc]

Bearguin wrote:To address the question, of the two B&D drills, the 18v really outperforms the 14.4v. I'd assume that this is the closet you can get to "all things being equal" as the two drills are pretty much the same vintage and only the voltage is different.

It is true that the market, for whatever reason, has loosely followed the rule that the listed voltage is more or less representative of the power and battery capacity of the tool. However, there is no reason that I know of other than custom that an 18 volt tool should be more powerful or have more battery capacity than a 12 volt tool. The battery in most cars is nominally 12 volts. The starter motor is one heck of a lot more powerful than an 18 volt drill motor. It is certainly possible to construct a 12 volt battery pack with 50% larger cells that would have roughly the same capability to supply power, the same energy capacity and the same size as an 18 volt battery pack.

I see Bearguin has an 18 volt Black and Decker drill. I have the one with the detachable head. I have mixed feelings about this feature, but overall I like it. It is really amazing to me what good quality tools one can buy these days for so little money. Especially if one buys tools in the big kits.

[Ririon]

A rechargeable battery cell is usually 1.2 V (with a space before the uppercase V for the nitpickers). Thus, a 14.4 V battery has 12 cells and a 18 V battery has 15 cells.

A battery cell has a limited capacity for storing electric energy and delivering electric power.

If you use the same cells, more cells equal more power.

So yes, in this case, more volts usually equals more power.

Ririon

[chance]

In the great tradition of “The Red Green show� -- 12V is the best option because when the internal batteries eventually die, you can open it up attach some leads with alligator clips and use your car battery. ;)

However it’s surprising just how good a 9.6 volt motor runs on 12V, (use short controlled bursts) :)

[TjW]

Originally posted by popsy
Is there a way to know how powerful battery powered tools will be? The only information given is the voltage of the battery. We have 3.6 v powered grass shears and are considering ones that have a 12v battery. Should we expect the 12v ones to cut more powerfully, all other things being equal?

In general, the higher voltage battery systems will provide more power.
Someone else pointed out that power is current (amperes) times voltage.

Cell construction and chemistry is what determines the maximum current a battery can discharge at. Most of the tools I'm aware of use similar cells -- either NiCd or NiMH, usually C or sub C sized.

A single cell has a nominal voltage of about 1.2 volts. So a 3.6 V system has 3 cells in series. A 12V system will have 10 cells in series, and so on. Since the cells are similar, and can supply similar currents, the higher voltage pack can supply more peak power.

If you're looking for maximum runtime at lower peak power, look for a NiMH battery pack. For maximum peak power go with NiCd -- it will source more current at a given battery size than NiMH.

Also, for a given cell size, unless you are running at maximum power all the time, the larger battery packs will provide longer run times. Since they're higher voltage, to supply the same power as their lower-powered brethren, they need less current. This discharges the cell more slowly, and so it lasts longer.

Of course, all that just addresses the battery pack. A low-efficiency motor or a crummy gearbox could negate the higher-voltage battery pack advantages.

[Ririon]

...and recycle batteries containing cadmium (NiCd).

Please.

Ririon

[Art Vandelay]

Originally posted by popsy
Should we expect the 12v ones to cut more powerfully, all other things being equal? Well, all things can't be equal, can they? If the voltage is different, something else must be different, right?

ChanceHowever it’s surprising just how good a 9.6 volt motor runs on 12V, (use short controlled bursts)Actually, it's really easy to lower the voltage on a DC source. Just get a homogenous resistor. If the resistor is 12 inches long, and the source voltage is 12 V, then each inch is 1 V. So 9.6 inches would be 9.6 V.

[popsy]

Originally posted by Art Vandelay
Well, all things can't be equal, can they? If the voltage is different, something else must be different, right?



I said "all *other* things being equal". It's my hypothetical question, therefore if I want to have all other things being equal, I can do so. The question was meant to elicit commentary on battery voltage. It did so, and I thank those who answered. I learned some stuff and saved some money by not buying something about which I knew nothing and had no way to try.

[Art Vandelay]

Originally posted by popsy
I said "all *other* things being equal". It's my hypothetical question, therefore if I want to have all other things being equal, I can do so. Not without violating the rules of physics.

[IXP]

As others have said, the power provided by a battery is the product of the current it can provide and the voltage. Using larger cells will produce more current capability at the same voltage. So what should you look for when evaluating the power of a battery operated tool? The weight! When using similar battery technology, the more they weigh, the more power they will produce, regardless of what volatage they are using. Of course you should weigh only the batteries, not the whole tool.

I have found that this method works well for a large varieity of items. For instance, you can also use this rule with speaker systems. Weight correlates better with quality than any other factor you can easily quantify, such as price. (tongue firmly in cheek)

Caution: This method is not recommended for evaluating bicycles, hot air-balloons, down comforters, or sexual partners.

IXP

[Elind]

Originally posted by popsy
Is there a way to know how powerful battery powered tools will be? The only information given is the voltage of the battery. We have 3.6 v powered grass shears and are considering ones that have a 12v battery. Should we expect the 12v ones to cut more powerfully, all other things being equal?

All other things =?

Generally higher voltage will translate to more power, but not always. It's just that the higher the voltage the smaller the motor can be for the same torque.

Look at battery size. Bigger is better. Look at price. Mostly higher is better. Look at brand. If you've never heard of it don't buy.

[Dragonrock]

It's been years since I've played with electronics, especially motors, but as I recall a rough idea is that a higher voltage means more speed and higher available amps mean higher torque. As the motor bogs down it draws more current in an attempt to maintain speed. If the batteries can't provide enough current then the motor will slow.

But, motors that are the same size and same voltage can have different speeds if the number of windings within the motor is different, so higher volts doesn't always mean higher speed. The thing to look at is voltage times available amps. Since packs are becoming more standardized than they were when rechargables first appeared the available amps on most battery packs are the same so after all that rambling, my point is, yes, higher voltage will generally mean more powerful tools.