And still it keeps on going

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grsbanks
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Joined: Tue Apr 25, 2017 9:23 am
Location: Preston, Lancs, UK

And still it keeps on going

Post by grsbanks » Tue Apr 10, 2018 12:12 pm

Maybe I should think about replacing the battery in my beta unit some time soon :)

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Not SwissMicros staff, just an enthusiast.

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Walter
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Location: Close to FRA, Germany

Re: And still it keeps on going

Post by Walter » Tue Apr 10, 2018 12:53 pm

I assumed there would be a voltage limit with the calculator refusing to work below. Where is it?
DM42 SN: 00041 --- Follower of Platon.

HP-35, HP-45, ..., HP-50, WP 34S, WP 31S, DM16L

keithdalby
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Re: And still it keeps on going

Post by keithdalby » Tue Apr 10, 2018 1:01 pm

Interesting font ;)

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H2X
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Location: Norway

Re: And still it keeps on going

Post by H2X » Tue Apr 10, 2018 1:31 pm

Walter wrote:
Tue Apr 10, 2018 12:53 pm
I assumed there would be a voltage limit with the calculator refusing to work below. Where is it?
Maybe it's in lemming mode?

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DM42 SN:00040
Be enter not or (Hamlet Yoda not)

toml_12953
Posts: 436
Joined: Wed May 03, 2017 5:46 pm
Location: Malone, NY USA

Re: And still it keeps on going

Post by toml_12953 » Tue Apr 10, 2018 3:42 pm

H2X wrote:
Tue Apr 10, 2018 1:31 pm
Walter wrote:
Tue Apr 10, 2018 12:53 pm
I assumed there would be a voltage limit with the calculator refusing to work below. Where is it?
Maybe it's in lemming mode?
Yeah, but the alternate route isn't as fast! :o
Tom L

आपका दिन शुभ हो
DM42 SN: 00025 (Beta)
SN: 00221 (Shipping)

Zaphod
Posts: 24
Joined: Sat Mar 31, 2018 9:34 pm

Re: And still it keeps on going

Post by Zaphod » Tue Apr 10, 2018 3:44 pm

Walter wrote:
Tue Apr 10, 2018 12:53 pm
I assumed there would be a voltage limit with the calculator refusing to work below. Where is it?
Processor data sheet says lower supply limit is 1.71v , although the Vbat monitoring is done internally via a divide by 3 network , so I wouldn’t like to rely on it being too accurate ....

Anyone actually physically measured battery voltage and then checked what the system reports ?

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stefanoaz
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Re: And still it keeps on going

Post by stefanoaz » Sat May 05, 2018 7:10 pm

As the battery voltage goes down in stand-by mode, the battery internal resistance increases. That means that, under load, such as running a program, the battery voltage will sag more. Since the calculator battery meter has a filtered response time, it will not report the total depth of the sag during current surges.

Bottom line - by the time the battery reaches something like 2V at standby, you have consumed more than 90% of the battery's energy. I wouldn't take it to any kind of - for instance - college entrance exam, before replacing the cell.

Looking at the datasheet, the battery resistance increases 6x by the time the open cell voltage drops to 2V (bottom right graph on the datasheet):

http://data.energizer.com/pdfs/cr2032.pdf
HP-41C, 48SX, DM-42 s/n 830

grsbanks
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Re: And still it keeps on going

Post by grsbanks » Sun May 06, 2018 7:17 am

You're preaching to the choir :)

I was deliberately running the battery down to see how the machine behaved with such a low power supply.
Not SwissMicros staff, just an enthusiast.

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Russel
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Location: USA

Re: And still it keeps on going

Post by Russel » Sun May 06, 2018 6:49 pm

grsbanks wrote:
Sun May 06, 2018 7:17 am
[...]I was deliberately running the battery down to see how the machine behaved with such a low power supply.
Is 1.90 volts the lowest you have seen? Have you replaced the battery yet? You know what they say about the curiosity and the cat...

rprosperi
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Location: New York

Re: And still it keeps on going

Post by rprosperi » Sun May 06, 2018 7:37 pm

Russel wrote:
Sun May 06, 2018 6:49 pm
Is 1.90 volts the lowest you have seen? Have you replaced the battery yet? You know what they say about the curiosity and the cat...
So, you're looking to be killed? :?
--bob p

DM42: β00071 & 00282

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