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Finally I got my HP-67!
01-08-2020, 08:18 PM
Post: #12
RE: Finally I got my HP-67!
(01-08-2020 08:05 PM)Artur - Brasil Wrote:  I got the message!
Well, my aproach is completely different of what you say.
No more Ni-MH batteries neither NiCd. They are difficulto to control the charge process, as you have to monitor the temperature and voltage on cells.
HP charges are just one transformer inside - completely no control - circuits in calculators are so simple that some times you see just a resistor to limit current.
I had one cassette reader destroyed because one cell was defective and the whole set got so hot that case of drive was bended by heat.
Also, the leakage is a painfull and destroy everything in his way.

No, no! Li-Ion batteries have much, but 1000% better charging control, and in very thinny reay-to-use boards, that are sold for a banana cost. Your calculator got discharged, get one cell phone charger and plug it in. Couldn't be more easy!

Don't use any more NiCD or NiMH batteries. Adapt all your calculators to Li-Ion batteries. They are lighter, less expensive, easier to charge and last more.

My sincere advice!
Artur

Personally, I like sticking with the NiMHs. There are a ton of non-standard Li-Ion battery packs, but NiMH AAAs or AAs are easy to find. I never charge them inside the calculator; I use a modern charger that charges and monitors each cell individually. I'm getting great run time on my 65 with Eneloop AAAs, even with quite a bit of card reader use. Plus lithium batteries tend to be much more of a fire hazard.

The charger I bought can handle a variety of Li-Ion barrel-style cells (rather than the flat-packs used in most phones). I wonder if any of those would be small enough to fit inside the calculator with a holder similar to what's available for AAAs.
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Messages In This Thread
Finally I got my HP-67! - Artur - Brasil - 01-08-2020, 01:20 AM
RE: Finally I got my HP-67! - Craig Bladow - 01-08-2020, 04:06 AM
RE: Finally I got my HP-67! - Craig Bladow - 01-08-2020, 04:29 AM
RE: Finally I got my HP-67! - mfleming - 01-08-2020, 05:47 AM
RE: Finally I got my HP-67! - Craig Bladow - 01-08-2020, 05:28 PM
RE: Finally I got my HP-67! - Dave Britten - 01-08-2020, 06:09 PM
RE: Finally I got my HP-67! - Dave Britten - 01-08-2020 08:18 PM
RE: Finally I got my HP-67! - Dave Britten - 01-08-2020, 09:46 PM
RE: Finally I got my HP-67! - mfleming - 01-09-2020, 02:42 AM
RE: Finally I got my HP-67! - Craig Bladow - 01-08-2020, 07:22 PM
RE: Finally I got my HP-67! - teenix - 01-09-2020, 12:21 AM
RE: Finally I got my HP-67! - teenix - 01-09-2020, 01:40 PM



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