Solar Powered TI-82?

numlumps asks: "Recently, my batteries for my TI-82 ran out of juice. Since there is no environmentally friendly way to dispose of batteries in my area, I figured, why not do away with the things altogether? I figured if it were possible to power my calculator with solar power, I'd never have to buy batteries again, nor would I have to worry about toxic chemicals from old batteries leaking into groundwater and so on. Has anyone built a solar power kit for TI-82 and similar calculators? If so, how do I do it without ruining my calculator?"

Solar Panels

[FoxIVX]

With my limited experience with solar panels, they're basicaly a standard power cell, with a set voltage. Just get the right sized/power one, and solder (cleanly) the positive and negative terminal lead wires into the battery compartment. Using jumper wires across the individual battery spots where appropriate (if needed). Then just find a nice spot for the solar panel to live. The hard part with any of the TI Models is that they dont have a whole lot of real estate to play with, and you're gonna need a sizeable (think a few times larger than the usual 1/4 inch by 1 inch solar power cells) cell.

-Josh

Re:Solar Panels

[Wog]

You might not want to directly solder the wires into place... rather open the case and add wires going to some sort of small plastic connector. Use a hobby knife to cut a connector-sized opening in the side, and glue it in. This way, you can go back to batteries whenever you need to.

The 82 uses 4 AAA batteries. You might want to put the solar cells on a hat. :-)

memory?

[2MuchC0ffeeMan]

ti-82's and 83's need battery's for the memory right? remove the battery's and you have a dead memory ... kinda sucked when i wanted my cheat sheets in high school, after replacing the batteries, but wouldn't you get the same thing if someone turned off the lights?

Re:memory?

[nowindowz]

The TI-82 and TI-83, use a battery backup, it is a watch battery. If it is dead then there is no backup battery and every thing goes bye-bye.

rechargeables?

[xjesus]

Have you thought about rechargeables? With the latest developments in NiMH batteries, they actually last over twice as long as the old rechargeables. They also eliminate the 'memory' effect; so you can charge them whenever you want. Here's a link [4gdo.com] to a place that sells AAA NiMH batteries, a little under $2.50 a piece. You can get a charger from the same place starting at $8. They also have a Solar powered charger... you might be able to rig that to your Calc and never have to remove the batteries! (just leave it in the sun from time to time).
As for retaining the memory on the '82, I know that the 85 has a small watch like battery to help keep your RAM happy, so you don't loose those progs. If you ran soley on solar power this tiny battery would probably not last too long (unless you left the calc in light all the time).

Good luck!

Re:Upgrade

[mduell]

No, th TI86 was a graphinc calc and no TI graphing calc has ever had solar cells built in... You are thinking of the TI-30x or TI-104x...

Mark Duell

well

[ddent]

If you check out www.ticalc.org they have TONS of projects/mods for your calc (including overclocking.. hmm, now overclocking your calculator is new to me!!!) - and I think I saw a solar one in there somewhere.

Re:Upgrade

[Quietust]

He was thinking of the TI-36X, the solar version of the TI-35X.

-- Sig (120 chars) --
Your friendly neighborhood mIRC scripter.

no problem!

[Hadlock]

that's a really good idea, i don't know about the ti-82, but my 86 has a battery backup on top of the 4 AAA batteries, so when you take out the batteries, it doesnt get all the stuff deleted. Just hop on down to your local radioshack, pick up the right amount of solar cells that equals the voltage output of the batteries, somehow connect them all together, get in some GOOD sunlight, and you're set. Might not work in dark classrooms.

Re:overclocked calculators

[AFCArchvile]

I've heard of it; it can only be done on the TI-82 to TI-86 series; too bad, since I have the TI-89 with a 10-MHz 68000.

This is what I would do...

[cr0sh]

If I had one of these calcs (my standard sci calc TI something or another works fine for what I need it for - but I understand others have different needs)...

From what I have read, these calcs take 4 AAA batteries. This would probably be a 6 volt source. I would hook up a connector to the battery compartment, wired in parallel with the batteries, and use NiMH batteries as suggested, and charge them from a charger. This would be a very practical solution, and not too hard to implement.

Now, add the solar cells panel - go down to a Harbor Freight or Fry's Electronics (HF will be cheaper, but work with what you have), and pick up a 12 volt car battery solar charging system. These systems generally consist of a 12 volt panel of solar cells, sometimes two or three wired in parallel to up the current for charging a car battery. Get the smallest one you can.

Once you have the panel, you will need to open it up, and rewire the cells to be two (or however many) strings of cells, wired in parallel, each string of cells producing 6 volts. You essentially want enough current to charge the batteries, but not too much to fry them (by quick charging them for too long). If you want to find the current output, wire a 1 meg resistor as your load across the contacts, then check the voltage across the resistor, I=V/R (I may be wrong here - but this stuff is easy to look up, and I know I am close).

Most solar cells typically generate only .5 volts or less per cell, at typically 10-30 ma of current capacity. That would be 12-15 cells per string. If you want to make you own panel, look for solar cell grab bags - the cells migh be broken, but they are more than usable still...

I support the EFF [eff.org] - do you?