Not going to experiment anymore

[jrc]

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I've been running voltage tests on my M8 batteries; in the first test, I found that one hade discharged to an abnormally low level, apparently just before the Sudden Death syndrome. I got a new camera from Leica and was thinking about running the batteries through a discharge cycle again, but had such a good time shooting yesterday that I slapped myself upside the head and asked, "What the hell are you doing?"

 

So I'm quitting; I'm not going to try to replicate the failure.

 

What I am going to do is to recharge the batteries every time they get down to one bar, and I'm going to test the voltage level before I put a new one in, and when I take a used one out. I'l keep the multimeter right next to the charger.

 

I'm wondering -- asked this in the original thread, but didn't get an answer -- if one of you technical guys would know if there's either an electronic or software function in either a battery or the camera that keeps the camera from over-discharging? And if this failed (either the circuit or the software) and the camera kept discharging to a very low level (as it would if you were attempting to cycle it), would it at some point scramble the firmware?

 

JC

[papimuzo]

That is exactly what I though since the first post talking about "sudden death"of the M8:rolleyes:

Past experience with other type of device (handheld computers) shown that a supply voltage under some value brought a "death" or (better) "a special state". I said several times that some analysis on this be made by Leica. Guy has informed them, but no comments so far.

I'm pretty convinced that a protection should be put to avoid that the basic firmware loop enter into a state unforeseen, whatever the cause: bad charging, battery depleted, M8 keeping an "ON" state,...etc...

Of course this is only a theory: I have not an M8 till now, and have no made any voltage test. And I suggest that users should not play with a full battery discharge, even if for some there were no trouble:confused:

[wparsonsgisnet]

JC, it will be informative to have your battery level values. However, you will not be gathering data regarding the smarts in the battery that tells the camera what reserve is left.

 

I believe the M8's problem is that it does not get the information from the battery smarts correctly and is shutting *everything* off when it sees a "low voltage" value that it then uses to trigger shutdown.

 

The temporary fix that we have been pursuing is "calibrating" the battery's smarts; that is, making sure that the battery measures the high and low reserve points correctly -- as far as the battery is concerned.

 

The new v.1.10 of firmware is supposed to have a fix that will read the info from the battery more accurately than the current version does.

 

Batteries suck. I hope we get this right. Fortunately, for me at least, the shutdowns I have had have been fixed immediately with a fresh battery.

[scott kirkpatrick]

I'm not going to try to replicate the failure.

 

What I am going to do is to recharge the batteries every time they get down to one bar, and I'm going to test the voltage level before I put a new one in, and when I take a used one out. I'l keep the multimeter right next to the charger.

 

I'm wondering -- asked this in the original thread, but didn't get an answer -- if one of you technical guys would know if there's either an electronic or software function in either a battery or the camera that keeps the camera from over-discharging? And if this failed (either the circuit or the software) and the camera kept discharging to a very low level (as it would if you were attempting to cycle it), would it at some point scramble the firmware?

 

Yes, that's my guess. The battery should have a circuit built in to keep it from becoming a fire or explosion hazard, but that means a fuse which blows when too much current comes out or the charger voltage is too high. The camera should shut down when the battery voltage is too low for proper operation, for its own sake as well as for the battery's, and that is apparently what didn't happen. I don't know if Leica's batteries also have a circuit to protect from a slow excessive discharge, from which it would be difficult to recover. I've observed some 5 year old Nikon batteries which had self-discharged on the shelf. At first they wouldn't take a charge, but on the second or third try they reached full voltage and operated the camera properly. But they didn't have their full capacity any more. So that's consistent with no internal battery protection against running too far down. And running any digital circuitry with a voltage level slightly below spec can give funny results. Leica seems to be running their batteries between 4.2 and 3.5 volts, which is a pretty narrow range for Li-Ion, but a wide range for most electronic circuits. Presumably, inside the camera, this is reduced to a constant 3 volts. If the battery is providing less than 3 volts to work with, this could certainly cause problems.

 

scott