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Anatomy M9/M8 Battery

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There are two negative pins and one positive on the Leica M8 & M9 charger. I put a meter on them and got readings I cannot understand - yet. They vacillate wildly within different voltage ranges.  I've yet to apply the meter to a charged battery because the contacts are buried in plastic, but I will soon.

 

Before I make an utter fool of myself, does anyone have an idea regarding the roles of the negative pins? Does one read the internal chip? Why do voltages change every second?

 

One objective is to eventually read the internal chip to detect fake or defective batteries.

.

Edited by pico

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Have you put an O-Scope on it?

 

http://batteryuniversity.com/learn/article/inner_workings_of_a_smart_battery

 

Smart batteries have a communications bus between themselves and the charger. If I were to guess, the charger 

 

Thanks for the informative link! It appears from your linked article that the Leica M8/9 battery is not particularly smart. It has only three pins.

 

I have no O-Scope and will pass.  At one time I kept one of those crappy cheap batteries with the intention of breaking it down to look at the circuits but since I retired I have no access to the chemistry and apparatus. All is good.

 

Do you know if the yellow 80% light ever goes off? Mine remains on regardless of time in the charger.

Edited by pico

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The yellow 80% LED only comes on when the battery reaches the 80% mark. When a battery is first inserted- the 80% is off, the green LED flashes. Even a battery at close to full mark will start off in the charger with the 80% indicator in the off state. After a ~1 minute, the 80% LED turns on. I just tried this with a charged battery. The charge light went solid about a minute later.

 

3 wires is all that is needed to charge and provide communications function. Only two contacts are required to charge a battery. 

Edited by Lenshacker

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The famous headline evokes associations and expectations ... 


...
 
 
Anatomy of the Leica M8's Battery 14464
 
 

 
 
 
Anatomy of the Leica M8's battery circuit board
 
 

           (bottom: millimeter paper,  E. Leitz 16464/OTZFO and APO Rodagon D on T echnologically optimized sensor (Sony successor sensor NEX-7)) Edited by Dao De Leitz

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The function of the controller board results from the data sheet of the used IC DS2438.

Block diagram and naming of parts are based on the application note AN123, Page 2, Figure 2.

(CC Carger- Control - 'own name', RT :11,75kΩ)

 

 

 

 

 

 

Maxim Integrated, DS2438 Smart Battery Monitor – Data Sheet: http://datasheets.maximintegrated.com/en/ds/DS2438.pdf

Maxim Integrated, AN123: http://pdfserv.maximintegrated.com/en/an/AN123.pdf

 

 

 

Zeiss has obviously adopted the proposed circuits of the semiconductor manufacturer.

The connection order of the terminals are consistent in my illustrations.

 

 

A deeper understanding of the battery management gives the application note AN131.

Maxim Integrated, AN131: http://pdfserv.maximintegrated.com/en/an/AN131.pdf

 

.

Edited by Dao De Leitz

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... does anyone have an idea regarding the roles of the negative pins?

 

 

I suppose the connection 'CC' - Carger- Control - ( RT /Rcc:11,75kΩ) is used for simple battery detection - inserted / empty.

 

________________________________________________

 

Where can I look up short SMD markings?

What is the original part name of the following two components of the protective device?

 

 

________________________________________________

 

 

There will be another report on a winter resistant battery grip for use in a cold environment at low temperature. Maybe next year, or later ... (;-)

 

Planning - modification 'Winder-R' for digital - Winter Battery Grip M8.

 

 

To this end, I am still looking for broken or old original batteries to make a contact / plug-in unit in the same way as in the video ' Assembling The Leica M9' 14:04 Link:  https://vimeo.com/6551861

 

 

 

 

Thorsten

Edited by Dao De Leitz

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Thank you for the excellent information, Dao De Leitz.

Can you simply make a cast of the battery connections?

Jaapv - algenate? (Is it still used?)

 

If not, then PM me. I will send you a battery.

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Late to this conversation and my memory is a bit hazy but in the early days of the M8, I repackaged the first version of the charger to run off a laptop brick and into a case about the size of the later charger. Maybe the thread is still around, look for "Travel Charger".

 

At least in the first version of the charger, the data line was not used and the Charger Control line is simply to monitor temperature. If the battery pack is getting hot and bothered, you don't want to continue charging which could make matters worse.

So I think that CC line tells the charger there's a battery connected and to start the charge cycle but also to stop the charge if it gets too hot. The charger itself uses a charge pump to vary the output current according to the battery voltage and to deem the battery fully charged when the current falls below a certain threshold.

 

You cannot reliably determine the state of charge of a battery from its output voltage so the 25m Ohm resistor is used to monitor current in and out in a Coulomb-counter. What goes in (mostly) comes out and you can determine the state of charge that way. There are other effects such as battery ageing, internal discharge and so on which affect the accuracy.

 

The data line is used by the M8 to run the simple battery meter but also the camera will shut down if it thinks the battery is flat whether or not it is. In 2009, I did a series of tests showing how the power consumption varies when you take a shot which involved running the camera off a lab power supply. I connected the supply in place of the lithium battery with the chip still in place but the camera still shut down, presumably because the chip said the "battery" was exhausted.

 

A word of caution. Early M8s has a problem which became known as the T2 problem; a mis-specified transistor which was prone to failure and it's likely this was what finally killed the camera I dismantled. That camera is now a drawer of parts with not much usable except for a spare LCD display which is no longer available. The reason for the caution was that the camera failed at the end of those power consumption tests and it may be the mismatch between what the battery chip said and what power was available hastened its demise.

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Mark and Dao , just an information for me , do you think , for those buying generic batteries
the "protection circuit" does also exists or not ?
  as battery costs a third of the price

Personally I buy original batteries Leica.

 

Thanks Dao and Mark for your interesting posts and schemes

Best regards

Henry

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Late to this conversation and my memory is a bit hazy but in the early days of the M8, I repackaged the first version of the charger to run off a laptop brick and into a case about the size of the later charger. Maybe the thread is still around, look for "Travel Charger".

 

At least in the first version of the charger, the data line was not used and the Charger Control line is simply to monitor temperature. If the battery pack is getting hot and bothered, you don't want to continue charging which could make matters worse.

So I think that CC line tells the charger there's a battery connected and to start the charge cycle but also to stop the charge if it gets too hot. The charger itself uses a charge pump to vary the output current according to the battery voltage and to deem the battery fully charged when the current falls below a certain threshold.

 

You cannot reliably determine the state of charge of a battery from its output voltage so the 25m Ohm resistor is used to monitor current in and out in a Coulomb-counter. What goes in (mostly) comes out and you can determine the state of charge that way. There are other effects such as battery ageing, internal discharge and so on which affect the accuracy.

 

The data line is used by the M8 to run the simple battery meter but also the camera will shut down if it thinks the battery is flat whether or not it is. In 2009, I did a series of tests showing how the power consumption varies when you take a shot which involved running the camera off a lab power supply. I connected the supply in place of the lithium battery with the chip still in place but the camera still shut down, presumably because the chip said the "battery" was exhausted.

 

A word of caution. Early M8s has a problem which became known as the T2 problem; a mis-specified transistor which was prone to failure and it's likely this was what finally killed the camera I dismantled. That camera is now a drawer of parts with not much usable except for a spare LCD display which is no longer available. The reason for the caution was that the camera failed at the end of those power consumption tests and it may be the mismatch between what the battery chip said and what power was available hastened its demise.

But Mark, Leica did replace the T2 transistor on all the cameras of that small series they could lay their hands on and AFAIK can still do the T2 upgrade if needed.

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...do you think , for those buying generic batteries

the "protection circuit" does also exists or not ?  as battery costs a third of the price

 

Best regards

Henry

 

Hello Henry,

 

The reports here (LUF)  say that the replicas have no energy management, that is recognized and used by the camera.

 

They even save on glue 

  , so let's have a look  into  my  'OTB':

 I expected one Resistor, maybe a simple protection circuit.

 

 

...

 

 

I am completely surprised. This I did not expect:

It looks like a full replica, including a DS2438 SOIC-8.

There is a similar protective circuit,  but they used other semiconductors.

Obviously I can recognize everything that correlates to the block diagram.

 

I will not analyse more, so far this battery still works.

But, without functioning level  indicator, as it is described here in the LUF (Anomaly with …)

 

 Maybe one should only reprogram the internal '40-byte nonvolatile user-memory'.(appropriately copy, clone, ..; DS AN)

 

Back to your question.

My copy looks 'all right', but from outside, you can't see what you get.  In the worst case you get what you pay for ...

 

Thorsten

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Thank you for the excellent information, Dao De Leitz.

Can you simply make a cast of the battery connections?

Jaapv - algenate? (Is it still used?)

 

If not, then PM me. I will send you a battery.

 

 

 

It still is, however for electronics I would recommend a silicone material.

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So in summary , not the same protection circuit

but what is annoying is the camera does not recognize the generic battery.

Thank you for this important clarification Thorsten.

Best regards

Henry
 

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