[haroon88]

Change the battery. Once I had a strange situation that K50 was not working with its original battery but worked with the battery that came with K70. Strangely the battery of K50 is still working with K70... don't know why but working well

[AstroDave]

If that far depleted, the charger won't charge it anymore.

It might recover if you leave it on the charger long enough. When I was doing battery testing, I (inadvertently!) let a battery completely discharge. I feared it might be kaput, but after 10-20 minutes on the charger, the green charging light came on and the battery seems to have fully recovered. Certainly worth a try to save a $50 battery!

[southlander]

Pam, Not exactly sure but had a similar problem a while ago. Left the card in the computer reader. Somehow, the computer formatted the card to Windows and when it was inserted into the camera, nothing, The camera wouldn't power up, nothing. Couldn't retrieve the card back to camera formatting but when a blank card was inserted and formatted to the camera, everything returned to normal. Windows formatted card was scrapped.

There is a small Windows program available that will format SD cards in the way that cameras like them. I think there is one on the SDcard.org site.

[35mmfilmfan]

There is a small Windows program available that will format SD cards in the way that cameras like them. I think there is one on the SDcard.org site.

Please see post #10, which advocates this very approach, with details.

[i_trax]

Please see post #10, which advocates this very approach, with details.

SD Memory Card Formatter | SD Association

To be able to format SD card you need to be logged in as Administrator , correct?

"Important Notice:
Administrator Rights is required for Windows and Mac OS/macOS to execute SD Memory Card Formatter."

You will need to know how to install Rosetta - necessity for some latest Mac computers.

[photogem]

It might recover if you leave it on the charger long enough. When I was doing battery testing, I (inadvertently!) let a battery completely discharge. I feared it might be kaput, but after 10-20 minutes on the charger, the green charging light came on and the battery seems to have fully recovered. Certainly worth a try to save a $50 battery!

We had this discussion recently.
When a Li-Ion is completly discharged, it NEVER EVER can be recovered!
That's a law nobody can change.
But .... if you leave your Pentax switched on and you don't use Auto-Power-Off, then it will still switch off before the Li-Ion is fully depleted. Thats why it went o.k. afterwards. Kind of a security buffer sensibly installed into most Pentax. Can't remember how it was for those with AA's, hardly used them except *ist-DS.

[AstroDave]

When a Li-Ion is completly discharged, it NEVER EVER can be recovered!

I guess we disagree - although it depends, I suppose, on what "completely discharged" is. This battery was reading ZERO volts on my voltmeter and had been that way for perhaps 10 minutes or so - I'd call that completely discharged. The battery was being run down with my test discharge circuit, NOT in the camera, so there was NO protection/detection of undervoltage and automatic shut-off. And, it did recover and was one of the ones that went through my several test discharge cycles with no apparent loss of capacity (after that, though, I did realize I ought to keep a better eye on the discharge cycle so nothing bottomed out again!)

[photogem]

No, we don't disagree at all. You just didn't give the correct necessary information.
Who on earth will do battery-testing as you now described it?
Less than 1% of all users I guess.

I did battery-testing with AUTO-POWER-OFF and LCD on having the Pentax standing next to where I work.
So I see how long it will stay on. Quite useful if one can keep an eye on it.
-------------------

If the voltage of one single cell within a D-Li109 or D-LI90 drops below 3V/DC it is damaged.
Each one of the two cells has 3,7V/DC.

For avoiding a critical voltage drop there is a protective circuit within the Pentax body switching off when the voltage drops below a certain point.

If one takes such the battery out and measures it, one usually can measure something around 3,5V/DC which is about 3,1V/DC under load.
Depends also on the material used for the cathode, because that defines/changes voltage as well. Different cathodes = slighly different voltages.

So if such a Li-Ion within a Pentax is at that limit when the Pentax will switch off and then is not charged very soon it depletes even further it will go below 3V and such it will die.

Exception is if the charge is done VERY SOON after the discharge, then damage CAN be avoided.
That's what you did but didn't make it clear it was just after 10minutes.
That is the exception.

It will be similar to that situation that a Pentax owner forgets to charge the battery after the body switched off but
remembers next day. Then it will be yet short enough because usually the discharge near 3V/DC

The Pentax charger with the Li-Ion plugged in charges with around 4,2V/DC
With 2 cells in series we have then 8,4V/DC, the 7,2 - 7,4 volts are just the nominal voltage (without load)


So one can say as a general rule:
- How often you charge a Li-Ion will not define aging! Because
a) any Li-Ion stored with around 50% of its charge and charged lets say 10x up to 60-70% will last much longer than
b) the same Li-Ion charged 1 x from 3.1V up to its max. voltage, so 0% to 100%!
Because Li-Ions age much quicker when either near empty or full!

So if your Pentax shows charging status 1 beam and you charge up to 2 beams, the battery will live much longer.
But it is inconvinient.

The other aging factors are temperature and temperature of the battery itself during charging.
Quickchargers will heat up the battery and shorten its life-expectance for at least 50%
This goes also for the new Pentax USB Charger! It is a quickcharger (because folks have demanded it)
But one should know and understand the difference to the older charger which charges slow.
Ideal would be even slower, but nobody is willing to accept such a long charge.