Lithium ion 50g



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    I am trying to transfer some lib files I used to use to my new HP49G+ The connectivity kit says the file is not compatible with my calculator. I thought I was still able to use these older programs. I tried to transfer it anyway, but when I bring it up on the stack (so I can transfer to port 2) it is a bunch of characters. Not a Lib file I can transfer. Any suggestions?
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Lithium ion 50g

Postby Eric Rechlin » Sun, 08 Mar 2009 12:29:35 GMT

About a year ago, somebody made a post to this group about modifying their 
calculator to use a lithium ion battery.

I see that someone else has done the same with the 50g, but this time posted 
a bunch of nice photos and detailed instructions.  This was not written by 
me; I don't know if the author reads this group, but it wasn't yet posted 
here so I felt I should post it:



Eric Rechlin 

Re: Lithium ion 50g

Postby jdoliva » Mon, 09 Mar 2009 05:45:10 GMT

My opinion:

-2X battery life (theoretically, not thoroughly tested).
-Rechargeable through USB.
-Don need a battery charger anymore.
-An achievement feeling if you DIY.

-You can kill your expensive calculator in the process.
-Takes time. Time is money.
-LiPo batteries are dangerous to tamper with.
-Not available everywhere as NiMH AAA.
-When batteries die (be it aging or too many cycles) you have to hack
your HP again (time consuming, risky).
-If, for some reason, your batteries die in a situation when you
really need your HP, you're fried, you can't just take out a fresh
pack of NiMH AAA and replace batteries. USB ports or AC outlets are
not available everywhere.

You can go easily through many 4 hour long exams with a fresh low self-
discharge AAA NiMH package. Notice "low self-discharge", normal NiMH
probably won make it due to high self-discharge rates.
Plus, who wouldn check battery status prior to an exam?

Contrary to the author, I consider devices with standard batteries are
more convenient, since standard batteries are always available

Re: Lithium ion 50g

Postby Bill Markwick » Tue, 10 Mar 2009 03:37:02 GMT

I guess the hobbyist felt warm and fuzzy when he got that hack to
work, but would you really trust a battery company that advertises
12,000mAh when it's really (or maybe doubtfully) 1,400?  You could
cause some serious damage to the calc (if only cosmetic) trying to
open it for the sake of a 40% improvement over 1,000mAh AAA cells.

I use NiMH batteries in the calc, my photoflashes, flashlights, etc,
and they're all normal types, not low-self-discharge.  I've never
noticed any problems.  Besides, slipping in another set of batteries
sure beats hacking the calc open again when the internal lithium cell


Re: Lithium ion 50g

Postby sc_usenet » Tue, 10 Mar 2009 06:48:35 GMT

I totally agree. Standard batteries will be available in the future
(or at least be much more accessible than custom Lithium cells). They
are also widely available no matter where you are, so you can buy a
replacement set of batteries nearly anywhere if need be.

For important exams, either
(a) check battery status of the NiMH cells
(b) charge NiMH cells the night before
(c) invest in 4 alkaline cells that you know are fully charged

Or, do all three and use the alkalines as a backup.


Re: Lithium ion 50g

Postby Olaf Kaluza » Tue, 10 Mar 2009 07:09:39 GMT

 >About a year ago, somebody made a post to this group about modifying their 
 >calculator to use a lithium ion battery.

Yes, that was me. And I had to charge it last month.

 >I see that someone else has done the same with the 50g, but this time posted 
 >a bunch of nice photos and detailed instructions.  

Pah! I dont cut an ugly hole in my SX....


Re: Lithium ion 50g

Postby bokubob » Tue, 10 Mar 2009 12:44:16 GMT

Aye.  When I added a lithium polymer to my 49g+, I kept the battery
bay intact and added a switch to allow the use of standard AAAs on the
fly.  You can see what I did on my page:


Similar Threads:

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I have a "NI2040" lithium ion battery (spare part for a VA7100 controller) on
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3.50G 1.5v AAA Lithium Batteries OK?

Looking at Energizer's data sheet on the 1.5V Lithium AAA cells it
apears that they are much closer to depleted than alkaline cells when
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Have any members compared AAA Lithiums in the 50G with standard
alkaline AAA batteries and noticed additional life from the Lithiums?
If so how much.

I saw that this had been discussed before but no clear statement was
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Lithium cells were discharged at replacement.  I have seen it noted
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when they trigger the low battery warning on the 50G.

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