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#34391 - 05/21/15 07:19 AM Magic Mouse Battery Life
Douglas Offline


Registered: 08/04/09
Loc: Seattle, WA
I just bought an Apple Magic Mouse a couple of months ago. Works great but the battery life is only 2 weeks on rechargeable batteries.

Had a Logitech Bluetooth Mouse and battery life was almost 5 weeks. I leave the mouse on all the time, but 2 weeks seems ridiculous to me.

Any suggestions?

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#34392 - 05/21/15 07:53 AM Re: Magic Mouse Battery Life [Re: Douglas]
Ira L Online


Registered: 08/13/09
Loc: California
Don't use rechargeable batteries. See if you get more longevity from alkaline batteries. I can go for months with a trackpad, cordless mouse or Bluetooth keyboard and alkaline batteries.
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#34394 - 05/21/15 10:31 AM Re: Magic Mouse Battery Life [Re: Ira L]
Douglas Offline


Registered: 08/04/09
Loc: Seattle, WA
I'll go get some alkaline batteries and test them out. BTW, the batteries that came with the mouse lasted only 9 days.

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#34396 - 05/21/15 11:21 AM Re: Magic Mouse Battery Life [Re: Douglas]
joemikeb Online
Moderator

Registered: 08/04/09
Loc: Fort Worth, Texas
Going along with Ira's suggestion, I have experimented with a variety of rechargeable batteries over the years and while I have not kept the detailed records necessary for a truly scientific study, I have generally found the longevity of rechargeable NiMH batteries to be about ⅔ that of alkaline batteries when they are new. Unfortunately that lifespan gets shorter as the batteries are recharged again and again. But a recharged NiMH is noticeably longer lived than even a brand new NiCad. I have also experimented with the so called "long life" or "extra life" alkaline but I could not tell any significant difference between their lifespan and that of the less expensive alkalines such as gold top Duracells or Ray-O-Vac Ultra Pros.
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#34397 - 05/21/15 12:04 PM Re: Magic Mouse Battery Life [Re: joemikeb]
grelber Offline


Registered: 08/05/09
Loc: North of 49th ||
When I got my 21.5" mid-2011 iMac with extended (wired) keyboard and Magic Mouse, I found that the NiCad AAs that came with the MM lasted ca 3 weeks — not an auspicious sign.

I decided to get Apple's Battery Charger (MC500LL/A, Model A1360) which came with 6 rechargeable AAs (NiMH) — and at the time Best Buy had an even better deal than the Apple Store. I've been more than satisfied with their performance.

Since January 2012 I've recharged the batteries (in rotation) 57 times and my average use is 3 weeks (mean 21.3 days, range 16-32 days). The batteries still function as they did when new.

Take that for what it's worth.

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#34399 - 05/21/15 12:46 PM Re: Magic Mouse Battery Life [Re: grelber]
artie505 Online


Registered: 08/04/09
I needed rechargeable batteries for the heated innersoles I bought this past winter, so I bought eneloops and their proprietary charger, which have garnered unanimous excellent reviews. (Edit: I also use them in my pocket electric shaver.)

My experience is that they don't compare to basic copper-top Duracells in either strength of initial charge/recharge or longevity.

They are a hell of a lot less costly to run, though. smile


Edited by artie505 (05/21/15 12:48 PM)
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#34401 - 05/21/15 02:04 PM Re: Magic Mouse Battery Life [Re: artie505]
joemikeb Online
Moderator

Registered: 08/04/09
Loc: Fort Worth, Texas
Originally Posted By: artie505
My experience is that they don't compare to basic copper-top Duracells in either strength of initial charge/recharge or longevity.

Not surprising since the nominal output voltage of an Alkaline battery is 1.5V while that of NiCd and NiMH batteries is 1.2v (or 1.25v if they are Mil Spec). Note that the output voltage of NiMH is relatively flat until the battery is very nearly empty while the output of alkaline and NiCd lowers at a relatively constant rate throughout the discharge cycle.

Originally Posted By: artie505
They are a hell of a lot less costly to run, though. smile

Less costly yes, but not as much less than one might think after factoring in the cost of the charger and the electricity to run the charger. In my case I also factor in the aggravation of having to replace the batteries so often. Murphy's law applies to battery failure too. tongue
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#34407 - 05/21/15 05:44 PM Re: Magic Mouse Battery Life [Re: artie505]
Douglas Offline


Registered: 08/04/09
Loc: Seattle, WA
I have been using the eneloop rechargeable batteries, for about 4 years, as well. As I said, those lasted 4 to 5 weeks in my Logitech wireless mouse.

Difficult trade off of filling landfills with dead Duracell batteries or getting lousy life out of rechargeable batteries.

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#34408 - 05/21/15 06:36 PM Re: Magic Mouse Battery Life [Re: Douglas]
artie505 Online


Registered: 08/04/09
I've only got short experience with eneloops, but both things I use them in, particularly my innersoles, draw a lot of power, and at $20 for 4 batteries and a Panasonic charger I'm very satisfied with the trade-off from Duracells...as long as Murphy keeps his nose out of my business, that is.

Are Rechargeable Batteries Really Cost Effective? seems like a pretty good analysis, although the poster used Canon e6s, not Duracells.

(Apple's charger, which, for $29 [including 6 batteries, supposedly eneloops], only charges two batteries at a time, is not particularly well reviewed.)

Edit: Rather than allowing dead batteries to take up their own space in landfills, there ought to be a law mandating that dead tires be filled with dead batteries before being sent to the giant tire pile in the sky.


Edited by artie505 (05/21/15 06:40 PM)
_________________________
The new Great Equalizer is the SEND button.

In Memory Of Harv: Those who can make you believe absurdities can make you commit atrocities. ~Voltaire

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#34409 - 05/21/15 06:57 PM Re: Magic Mouse Battery Life [Re: joemikeb]
artie505 Online


Registered: 08/04/09
Originally Posted By: joemikeb
Note that the output voltage of NiMH is relatively flat until the battery is very nearly empty while the output of alkaline and NiCd lowers at a relatively constant rate throughout the discharge cycle.

That actually sounds like a preferable, albeit more costly, way for a battery to discharge. Is it, is it case dependent, or am I misunderstanding?

Originally Posted By: joemikeb
Less costly yes, but not as much less than one might think after factoring in the cost of the charger and the electricity to run the charger. In my case I also factor in the aggravation of having to replace the batteries so often.

The article to which I linked in my reply to Douglas seems to me to be a pretty good cost effectiveness analysis.

In my case, with my innersoles burning 4 batteries in about 2 hours...once every day (and even forgetting about my shaver), the eneloops are a serious & very economical MUST!


Edited by artie505 (05/21/15 07:01 PM)
_________________________
The new Great Equalizer is the SEND button.

In Memory Of Harv: Those who can make you believe absurdities can make you commit atrocities. ~Voltaire

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#34414 - 05/22/15 05:56 AM Re: Magic Mouse Battery Life [Re: artie505]
Virtual1 Offline


Registered: 08/04/09
Loc: Iowa
tossing my 2c into the ring, I've been using rechargeable batteries for 30-35 years. (yes, they really had them that long ago) GE was the pioneer (as was my GE cellphone in the early 90s!) later followed by Panasonic. For awhile those were the only two names in NiCD. I had those little arcade "tabletop" games, frogger and the like, and they devoured C batteries. So I really liked the rechargeables.

Nowadays I am still using them, in their embedded format (iPhone) as well as discrete. (mostly AAs) $9 (shipped) gets you four 2300mAh AA batteries, that even ship charged. Not counting the charger (I use one from radio shack actually, does 8AA at a time) you've broken even by your 3rd or 4th use, and will get many more uses out of them in the future.

They're usually able to provide higher spontaneous output current than alkaline batteries. I can get more transmit power out of my radios using rechargeables than alkaline, despite their being slightly lower voltage.

I think the MM's problem is the continuous slow discharge. I don't think they perform as well under slow continuous discharge. Apple needs to implement wireless charging with the magic mouse. Place your mouse on the "new mouse pad" when you are done with the computer. Mouse is always fully charged when you come back to the computer. (I was just daydreaming about a new "I'm a mac - I'm a PC" commercial where the PC keeps running down his batteries, while the mac is standing on a glowing platform and is acting very energetic)
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#34416 - 05/22/15 10:34 AM Re: Magic Mouse Battery Life [Re: artie505]
joemikeb Online
Moderator

Registered: 08/04/09
Loc: Fort Worth, Texas
Originally Posted By: artie505
Originally Posted By: joemikeb
Note that the output voltage of NiMH is relatively flat until the battery is very nearly empty while the output of alkaline and NiCd lowers at a relatively constant rate throughout the discharge cycle.

That actually sounds like a preferable, albeit more costly, way for a battery to discharge. Is it, is it case dependent, or am I misunderstanding?

It is chemistry dependent.
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#34422 - 05/22/15 11:41 PM Re: Magic Mouse Battery Life [Re: joemikeb]
artie505 Online


Registered: 08/04/09
Sorry, but you misread my question.

I asked whether a "flat" battery discharge is generally, if at all, preferable to a discharge that "lowers at a relatively constant rate throughout the discharge cycle", or is it case dependent?

By way of example, having the batteries in my innersoles maintain an even discharge level and suddenly crap out would be desirable (to me, anyhow), but I can imagine other devices in which that behavior might not be preferable.

Or did I totally misunderstand your post?

Also, I assume that "Mil Spec" in "...the nominal output voltage of...NiCd and NiMH batteries is 1.2v (or 1.25v if they are Mil Spec)" means "military specification", and I'm wondering whether the extra 0.05v is critical or just another military boondoggle designed to make a $1.00 battery cost $7.00?

Thanks.
_________________________
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#34425 - 05/23/15 09:01 AM Re: Magic Mouse Battery Life [Re: artie505]
joemikeb Online
Moderator

Registered: 08/04/09
Loc: Fort Worth, Texas
I tried to conceive of a situation where the flat discharge rate would not be preferable and came up empty. That does not mean the flat discharge rate is not without its downside. For example in a flashlight with normal alkaline batteries the light will begin to dim as the battery's end of life approaches making the light less useful but at least providing warning of impending failure. With a flat discharge cycle you switch the light on and nothing happens (this is especially true with LED bulbs that depend on a minimum power level to light at all). Even in that scenario there are plusses and minuses on both sides and only the user can decide which they prefer. I personally prefer a flat discharge — providing the battery will hold a charge over long periods of inactivity and the battery capacity is comparable (ie will have a reasonable service life.

While I have served in the military and later when I worked on projects for military use, I have never been associated with military procurement so anything I say about MilSpec should be considered in that light. The military is fanatical about minimizing the failure rate of everything because failure in combat invariably endangers lives. Yes the military does pay through the nose for many things that are apparently available at civilian sources for a fraction of the price. Take for example a simple stainless steel bolt. The military may pay $3 for a bolt while the apparent same bolt at Home Depot may cost 35 cents. But the similarity is only apparent. The Home Depot bolt was probably made in China of inferior metals, has crystalize internal areas and although rated at a sheer strength of say 300 pounds may in fact fail at less than 100 pounds sheer load. The MilSpec version is admittedly over-engineered for safety and not only rated at a sheer strength of 400 pounds and has been tested up to maybe 450 pounds and each and every bolt subjected to rigorous and expensive testing post production. At the same time the Home Depot bolt may be expected to remain in service for months up to a few years, but there are combat aircraft flying today that were built with those expensive MilSpec bolts fifty and sixty years ago. Not even commercial airlines expect that kind of service life.

The same philosophy is true of the MilSpec battery. It is not built with a goal of meeting market price, rather with the goal of having that slight extra edge in power and capacity that might, just might, make the difference in keeping one or more of our troops alive in extreme conditions.

As longs I am on this soapbox that added cost is not always necessary… When I was developing software for the military, we spent 80 to 85% of our effort in developing and testing software designs before we ever wrote a line of code because we were fanatical about providing software that was as error free as possible. Our goal was 3.5 defects for every million lines of code where a defect was defined as anything the customer did not like — even if it was something the customer had specified in their requirements. We never reached the 3.5 defects per million goal, but we did get very very close. Our compatriots on the commercial side continually criticized our efforts as far too expensive and only possible when the government was unquestioning of the cost. But in fact as our error rate dropped the cost of development went down until we were routinely producing our software at a significantly lower cost, in a much shorter development life cycle, and a tiny fraction of the error rate than our commercial software colleagues. To plagiarize a hackneyed phrase in quality circles we actually did everything cheaper, faster, and better. Why that ended is another story in corporate greed and short sightedness.
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#34441 - 05/26/15 04:56 AM Re: Magic Mouse Battery Life [Re: joemikeb]
Virtual1 Offline


Registered: 08/04/09
Loc: Iowa
Originally Posted By: joemikeb
I tried to conceive of a situation where the flat discharge rate would not be preferable and came up empty.


Here's a quickie: handheld radios generally have two power settings, "low" and "high". Low cuts down the transmit power to a specific amount, maybe 1 watt. High generally just belts out as much power as possible, shunting the batteries straight to the power amplifier in the radio.

Current is supplied "on demand" by the load (transmitter), drawn from the supply (battery), as long as the supply can support the demand being made by the load. This is true of any electronic device. The supply dictates the voltage, the load (by its resistance) determines the current. (voltage = current x resistance, power = current x voltage = voltage^2 / resistance)

So I can increase transmit power by lowering resistance in the load (switching transmit power to hi, which lowers load resistance, which raises current so long as voltage remains constant), or by raising the voltage

What all this means is that if voltage drops, my transmit power is also going to drop, and there's nothing I can do to compensate. (since my load is already at maximum draw, by presenting its lowest possible resistance) So while my battery is discharging with use, if my voltage drops significantly during discharge, my radio will rapidly lose transmit range. Once I am out of range of the other radio, that's it, the radio is useless for communications. And with (power = voltage^2 / resistance), power drops with the SQUARE of the voltage drop, so losing voltage is a big problem when power is important. And it gets worse. With radio, you need to quadruple your power to double your range... so range is more closely related to voltage^3 !

I would much rather the batteries maintain their higher voltage as long as possible, and "die suddenly", with the voltage jumping off a cliff at the end. Any power remaining in the battery after the voltage falls below a certain point may be totally useless. The only problem there is you have to pay more attention to the remaining capacity, because you can't just look at the voltage to determine how much charge remains.
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#34562 - 06/03/15 08:23 AM Re: Magic Mouse Battery Life [Re: Virtual1]
alternaut Offline

Moderator

Registered: 08/04/09
Originally Posted By: Virtual1
I would much rather the batteries maintain their higher voltage as long as possible, and "die suddenly" [...]
If it works as intended, Batteriser may be just the thing for you. cool
And as a bonus, the article also provides some info on the character of the voltage drop when a constant current is drawn from the battery. tongue
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#34568 - 06/03/15 09:58 AM Re: Magic Mouse Battery Life [Re: alternaut]
Virtual1 Offline


Registered: 08/04/09
Loc: Iowa
interesting article. though my shenanigans detector is starting to beep when I get to the "they broke into my office" part.

Either way though, the concept is somewhat sound. From an electrical engineering standpoint there are questions that need to be answered first though. Right off the block I have to ask how it can do anything at all without drawing power from the battery in the first place. Even if the battery is "full charge" and it's not having to boost anything, it has to operate the FET that is strapping the battery to the device. That and the monitoring electronics, while in "passive mode" have to draw something. I could see this as a slow-discharge problem.

Second, you can't step up (or down) DC power for free. DC step-up is somewhat notorious for being inefficient. Here again I see energy loss due to heat in the electronics.

Third, stepping up or down requires an LC circuit. Both the L (inductor) and the C (capacitor) tend to be the largest two parts in the arrangement. (the stepping IC being the third) I'm really amazed they found space to fit those into the sides of that widget. Unfortunately, to cut corners on size with L and C, you lower L and C, and that lowers efficiency. Again losing power.

Fourth, even under the best of conditions, steppers waste power and generate heat. I used a 12->5 step-down in my truck to run my USB devices, and it overheated and smoked on me, it had gotten quite hot before it failed. And this was a larger, manufactured unit, not some supermini hack. That heat directly reflects energy lost from the source. And when your source is a battery, there is just that fixed amount of stored energy to work with, draining that directly affects runtime.

All of the above bite into total available energy. The question then becomes "is it a winning proposition? Can you get more time out of your gear with the gadget than without?" In other words, yes, it probably can drain a battery more completely, but are you really getting to use any of that in a net gain in total usable power? I wouldn't mind having one to play with, but I would start my testing with some skepticism.

A fourth, less related issue is the size. It looks like they did a good job of keeping the top and bottom contacts very thin, but I've seen several gadgets that require the cells to be round to use them, like my digital camera whose batteries slide in vertically into cylindrical holes. This wouldn't be physically compatible.
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#34578 - 06/03/15 09:40 PM Re: Magic Mouse Battery Life [Re: alternaut]
Douglas Offline


Registered: 08/04/09
Loc: Seattle, WA
I saw that article too and for $10 I'll definitely give it a try and see if it works.

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#34580 - 06/04/15 05:45 AM Re: Magic Mouse Battery Life [Re: Douglas]
Virtual1 Offline


Registered: 08/04/09
Loc: Iowa
while it might work with the magic mouse if you turn the flat part up, I don't think those will fit into a keyboard?
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#34588 - 06/04/15 11:40 AM Re: Magic Mouse Battery Life [Re: Virtual1]
slolerner Offline


Registered: 08/25/09
Loc: New York City
Fwiw, I'm really happy with the Mobee Charging pad that comes with it's own rechargeable battery pack that goes where the AAs used to go. Had it for years and just recently had to replace the battery pack. Just keep in mind, if you plug it into the usb port on the computer and turn off the computer, you turn off the charger, duh.

(It's a proximity charger)


Edited by slolerner (06/04/15 11:42 AM)
Edit Reason: More

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#34592 - 06/05/15 06:14 AM Re: Magic Mouse Battery Life [Re: slolerner]
Douglas Offline


Registered: 08/04/09
Loc: Seattle, WA
I had not thought of a charging pad. Will any charging pad work or does it have to be the Mobee? The Mobee seems kind of expensive but there are other charging pads that are less expensive.

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#34593 - 06/05/15 07:11 AM Re: Magic Mouse Battery Life [Re: Douglas]
slolerner Offline


Registered: 08/25/09
Loc: New York City
Hi Doug,

I don't know of any others, but I do know that the Mobee works well for certain and the replacement battery pack I had to buy after a few years was easy.to get. This one is $36:

http://www.amazon.com/s/ref=nb_sb_noss_2?url=search-alias%3Daps&field-keywords=Mobee&rh=i%3Aaps%2Ck%3AMobee

It'a little tricky to get the battery pack in all the way so the mouse bottom cover closes all the way but don't force it, just noodle around a little. Play with the black latch on the mouse. Also, if you get an iPhone or iPad usb wall charger with two ports, you can charge your phone and the magic mouse while the computer is off. And free-up your computer USB ports.


Edited by slolerner (06/05/15 07:15 AM)
Edit Reason: Clarity

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#34599 - 06/06/15 09:43 PM Re: Magic Mouse Battery Life [Re: Douglas]
Douglas Offline


Registered: 08/04/09
Loc: Seattle, WA
I went to the store to get some alkaline batteries and at the last minute just decided to continue using my rechargeables. Just don't want to add to problems. Probably will try the battery extender device when it come out, that may change my equation.

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#34612 - 06/08/15 03:05 PM Re: Magic Mouse Battery Life [Re: Douglas]
Virtual1 Offline


Registered: 08/04/09
Loc: Iowa
Slashdot just covered this... debunking the batterisers claims

best comment:
Quote:
Even 50% is totally unrealistic.

In real devices it's more likely to shorten battery life then to extend it:
a) There's losses in the booster (the inductor must be TINY - no way it can even be 90% efficient)
b) Ohm's Law tells us that if we increase the voltage across a device it will use more current (Boost from 1.3V to 1.5V? 20% more current will be drawn!)
c) Remote controls, etc., use single-digit microamps when you're not pressing buttons. Quiescent current in even the best boosters is also microamps, the life in a low power device like a remote control could easily be halved.

Summing up: You'll have to look long and hard to find a device where this will actually be a net benefit (and many of those devices will have a battery life indicator which will be a) Important, and b) Stop working when this is in use...)
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#34613 - 06/08/15 03:27 PM Re: Magic Mouse Battery Life [Re: Virtual1]
slolerner Offline


Registered: 08/25/09
Loc: New York City
Originally Posted By: Virtual1
interesting article. though my shenanigans detector is starting to beep when I get to the "they broke into my office" part.

Yeah, that pic of the hole in the drywall that the door handle supposedly made during the "break-in" looked a little like when Daffy Duck runs through a wall and leaves outlines of his webbed feet.

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