Rechargable Batteries

[NextPerception]

I did a test a while back about that
I tried doing this 3 times

I measured the amount of time it took for four brand new batteries to be used up with 4 hours of use (no linking) a day. did this until bat. low screen apeared
The first try was 15 days
The second was 16 days
The third was 15 days

Next I tried using two batteries that whhere took out the second the battery low screen started apearing. I took these and put 2 in with 2 new batteries. since the old ones where aprox 1/4 used up then his new one should take about a week to run out.
for some reason this configuration only lasted 2 days each time until it started displaying this.

ever since then I always replace all batteries at once

[Darth Android]

thx jbirk. and i thought i knew alot about electroincs!

[Arcane Wizard]

[Flash]

[NextPerception]

so alkaline rechargables are the best for the calculator?
do you need a special type of charger or can you use a NiCd/NiMh charger to charge them?
charge rate?

[NETWizz]

They are called rechargable alkaline. You cannot recharge regular alkaline batteries.

Checkout http://rayovac.com

Although rechargable alkaline batteries do not charge many times, or have much power compared to others, they are the best for your calculaotr because they have all of the same properties of alkaline batteries.

You recharge them with the Ray O Vac Rechargable Alkaline Charger.
You cannot use a NiCD or NiMh charger on them!

Here is the good news: 2 Rechargable Alkaline AA's generally come with the charger, which costs $10 and you can buy a 4 pack of AAA's or AA's for about $6 making them $1.50 per battery. That is nothing considering that NiMh batteries are anywhere from $3 to $6 each!

About mixing battery types:

It is best not to mix used and new, new and old, and types.

In other words, do not mix an Alkaline with a Rechargable Alkaline, a NiCd or anything else.

What ends up happening is one battery goes dead faster than the others, and the good ones try to force electrons through the dead ones. This is potentially bad with rechargables because the current will be pushed through forward.

It is like recharging them to a negative voltage. Once you reverse charge them, they undergo a polarity change and will never charge correctly again because have damaged the internal chemicals.

Basically, if you are going to mix batteries, mix energizer with duracell and rayovac because they are all about the same in voltage, internal resistance, and composition. Besides, if they don't link and are disposable you have little to loose.

[anduril66]

Assuming it is possible to hook up a TI to a solar panel, about how large would the solar panel have to be?

[NextPerception]

well here i can help
solar panels are all you work with in beam robotics (i used to do that)
you would have two options with solar panels
you could have them trickle charging some rechargable batteries with a fairly small solar cell except when it is in your backpack with no light (unless you have one of those mesh back packs) it would get no light to charge with.
to completely power a graphing calculator with a solar panel you would need a huge chunk of silicon
if each battery is 1.5 volts and gives off 15ma of power then compensate for the lack of light inside most classrooms
(about 1/6 the light of outdoors on avrage if no windows)
it turns out to be about a solar panel about 6 inches by 6 inches give or take an inch or two in both directions

[anduril66]

Can you please teach me how to trickle charge batteries?

[Toksyuryel]

The TI manual says don't use NiCD batteries, not all rechargeables.

[NextPerception]

will alkaline rechargables get a memory if you recharge them before they are all the way dead?

[NETWizz]

No, but they will fail after about 10 to 25 charges anyway.

[NextPerception]

[Toksyuryel]

You're welcome.