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At one point I mused that it would be nice to be able to power the mice with the BL-5C Lithium Ion batteries that power my cell phone. They recharge quickly and hold a lot of current. Only problem is they are 3.7 volt batteries and the mice are designed to run on a couple of AA's in series... 3 volts. I wondered if the extra .7 volt would be a problem. One way to find out. A couple of jumpers later, I had my answer... the mouse seemed quite happy with 3.7 volts.
The hard part was finding a way to stuff the battery inside the mouse. You have to chop a lot of the battery compartment plastic out, remove the springs, and install a connector assembly that will match up with the BL-5C terminals (if you want it to be removable, more on that later).
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I also installed a small slide switch with which I can turn the mouse off to conserve battery power.
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The keyboard can take up to 4x AA batteries. I don't think its completely necessary to have 4 batteries to power it tho, provided the batteries in it have enough juice. But if you think just one 3.7v wouldn't be enough, how about 2? 7.4v seems like a much greater amount then 6v though,
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=110474252413
It is still active as of today.
Then again having no personal experience with those charging mats I don't know if this is a benifical idea.
I have the exact same mouse at home a pair of rechargeable batteries last up to six months on mine, so i find weird if your batteries only last a couple of days , maybe they are deffective , i don't know.
I use the control panels mouse battery meter as a guide and only once have found my self swearing at it because it ran out of power. lol I won't be trying it on this mouse but I was given an idea about remote maybe I will try to customize a remote to use a dead cell phone battery since the battery are excellent just the phone is dead.Great Idea anyhow later
take it a step further and try upping your current capabilities in your ups. i managed to double mine. led flashlights using laptop cells. glad someone is writing this stuff up
Having said that they are amazing cells and with a little care can really shine in a project like this.
Great project, but what stuck out was:
"Carefully Destroy" was priceless.
But careful destruction is what archaeologists do all the time. In fact, they sometimes stop short from excavate the whole ancient site, saying that they want to preserve something for future generations with better methods. When it comes to archaeological excavations, you only have one chance.
-.
I totally agree, being careful in destroying is the most fun-da-mental thing..
Nice work!
the good thing about this mod is that you can use it in other gadgets :).
thanks for sharing the info.
cheers
i did this cellphone battery swap with my 3 AAA battery powered LED desk lamp too...using the same china made universal battery charger..
Using a Fluke series 73 digital mutimeter, I measured a mere 5 ma standby and 30 ma in-use current draw. That was with the 3.7 volt battery in the white mouse. I threw a couple of AA's in the black mouse and measured 7 ma standby and 50 ma in-use! Well, that's counter intuitive. Hey, Mice! did you forget about Ohm's Law? To be sure, I hauled out my old Simpson model 240 analog meter, and it confirmed the readings.
So.... what? Do my batteries suck? Could be. They are fairly old. Maybe they have a lot of self-discharge? They are not the most expensive around. Matter of fact, several are chinese eBay cheapies. I use a Vanson "Speedy I Charger Ni-MH & Ni-Cd" and usually use the slower, lower current setting even for the Ni-MH's, in which they barely get warm to the touch.
As usual, I'm left with more questions than answers. *sigh*
Since the processor in a mouse is transistor based I'll try to explain it so you understand it. Transistors are not perfect linear devices. So an increase in voltage may not have the result you expect. Transistors have three basic states, well at least as far as digital devices are concerned. These states are full on, full off, and gain. (The name is different depending on the type of transistor, so I've used terms that are close to what you might see commonly used between all the types.) Digital devices don't really like this gain state. it's where the transistor is switching and not fully on or off, this period of time is usually very small, but it's during this period where the transistor draws the most power. Depending on the transistors design they will hit fully on or fully off at a specific voltage.
What this means in your case is that that extra .7 volts is causing your transistors in the mouse microprocessor to jump to the fully on and probably the fully off state faster. This means that the transistors will be in their gain state for a shorter period of time. Since they are drawing current high current for a shorter period of time they will consume less current.
Please note there are may be other reasons for this as well, such as limiting inductance, or capacitance. Just be careful when using mods like this, transistors (especially MOSFETS) don't always like too much voltage and you can easily let out the "Magic smoke" of your mouse IC. And not all battery power devices have a voltage regulator in them to prevent this. (voltage regulators consume power and in battery powered devices this isn't always a good thing) If you really wanted to see what was going on you would need an Oscilloscope. Which is not a small investment for a Hobbyist moder.
I have a B&K dual trace 'scope but what I don't have is a schematic of the mouse.
It used to be that circuits were easier to figure out before so many components were miniaturized and combined (integrated). I wouldn't be at all surprised to find mosfets in there and that's why it was a bit of a shot in the dark whether the mouse would work or "go poof!" with the higher voltage.
"Since they are drawing high current for a shorter period of time they will consume less current." -- I think you might have nailed it right there.
5ma * 3.7v = 18.5mW (idle)
30ma * 3.7v = 111mW (in use)
In a perfect world, with 2 1.5v AA batteries, you should see:
18.5mW / 3.0v = 6ma
111mW / 3.0v = 37ma
However, since you're using NiMH AA batteries, you're only getting 2.5V (NiMH have nominal voltage of 1.25V, rather than 1.5V)
7ma * 2.5v = 17.5mW
50ma * 2.5v = 125mW
Accounting for measurement errors and stuff, since I doubt it was actually reading exactly 30ma and exactly 50ma, and since the batteries aren't going to have exactly 2.5 volts, it seems to me like its drawing the same amount of power either way.
reg
ketan
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"May the good belong to all the people in the world.
May the rulers go by the path of justice.
May the best of men and their source always prove to be a blessing.
May all the world rejoice in happiness.
May rain come in time and plentifulness be on Earth.
May this world be free from suffering and the noble ones be free from fears"
---- Vedic blessing
reg
ketan
--------------------------------------------------------
"May the good belong to all the people in the world.
May the rulers go by the path of justice.
May the best of men and their source always prove to be a blessing.
May all the world rejoice in happiness.
May rain come in time and plentifulness be on Earth.
May this world be free from suffering and the noble ones be free from fears"
---- Vedic blessing
Logitech disappoint me a little by not putting this switch at design stage :/