M7 Lithium 2 x CR1/3N Lithium or 4 x SR44 Silver Oxide

[wlaidlaw]

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I have twice now gone to my M7 and found the batteries flat over the last 9 months. I bought 3 sets of CR1/3N (supposedly Varta) from Amazon last year but like much stuff in France, from an Amazon seller not Amazon themselves. Not that it makes much difference now, as Amazon co-mingles directly bought and seller supplied items on their stock shelves. I have checked with a meter and there is no measurable battery drain, with the camera switched off. It has been sitting on a shelf, so not the usual problem of the power switch being knocked on in a bag and the shutter button sufficiently depressed to keep the camera active. I have seen other complaints about the CR 1/3N batteries, since they changed from silver to lithium, being under-voltage when new, at only 2.7V and therefore quickly dropping below the 2.5V the M7 needs. The other problem could be, were my batteries genuine or fakes? I have had very poor fake lithium Duracell batteries before from Amazon France (a ten pack of CR123A). I wondered therefore, given that the current draw on an M7 is very low and there is little real benefit to using lithium batteries, I might be better reverting to using 4 x SR44 Silver Oxide batteries rather than two lithium CR1/3N batteries? 

 

Wilson

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[TomB_tx]

I've had some CR1/3N go flat quite fast myself. I think the SR44 would be a good option. However, I also have a number of cameras with meters, and after having the batteries leak in my M6 a few years ago and ruin the meter board (and shutter brake), now I always take out the batteries and put them in a small plastic bag attached to the strap.

[wattsy]

A set of CR1/3N batteries in an M7 should last for a good 70 rolls of film or, in my experience, much more than a year if only sporadically used. Either something is unwontedly drawing a current in your M7 or that batch of batteries is dodgy. Why not just buy a couple of Duracell (or other branded) CR1/3N from a source other than Amazon? Other retailers still exist, even in France.

[wlaidlaw]

A set of CR1/3N batteries in an M7 should last for a good 70 rolls of film or, in my experience, much more than a year if only sporadically used. Either something is unwontedly drawing a current in your M7 or that batch of batteries is dodgy. Why not just buy a couple of Duracell (or other branded) CR1/3N from a source other than Amazon? Other retailers still exist, even in France.

 

Ian, 

 

I have had a set of Duracell CR1/3N and put them in a couple of days ago and will see how they get on. I checked the camera was powering down automatically properly and then checked the resistance across the battery terminals, which was in the 200 kiloΩ range, showing battery drain when switched off, must be minimal. 

 

Wilson

Edited October 3, 2018 by wlaidlaw

[pico]

Either something is unwontedly drawing a current in your M7 or that batch of batteries is dodgy.

 

I am concerned about counterfeit batteries and wish all counterfeiters were as clueless as this (picture).

[edstock]

If you are in the US get on your computer and type in, Batteries an Bulbs. Or try Adorama in NYC they have a very comprehensive listing.

[wlaidlaw]

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I now know there was a problem with my M7, which may have been the the cause of the battery drain. Not long after I posted this thread, it jammed up completely and on disassembly, the wind on/shutter cocking gears were found to be out of sync, with the lock disc at the bottom of the mechanism in the wrong position. Alan Starkie feels that this may be due to the anti wind back latch under the wind on lever, jumping out of its lock position, when used with a Motor Drive but the whole drive train was in any case, very dry/lacking in lubricant. This was in spite of the camera having been to Solms not many years ago for the VF and DX update, when I would have hoped they would have done a full CLA. This was with the previous owner, so I don't have the bill to see what work was listed. I also used RCR123A rechargeable batteries with the Motor-M for a while. These are higher voltage than the regular Lithium-Manganese CR123A batteries and have considerably lower internal resistance, making the motor run noticeably faster. This may have been shaking the non-wind-back latch out of lock. The lack of lubricant may have also have meant that the on/off contact was not sliding fully into the off position, leading to increased battery drain. Notwithstanding this, I still have some suspicions about the "Varta" batteries from an Amazon France marketplace seller.

When I got an earlier motor drive, the M4-2 with the M4-P I bought last year, I found it would not work at all with 4x lithium (non-rechargeable) 1.7V AA batteries, jamming every second wind-on, each operation. When I put in regular 1.25V NiMH rechargeables, it worked perfectly. The lithium batteries obviously provided too much voltage and current for the mechanism, which is all reliant on torque measuring switches to turn on and off. After I found that out, I then reverted to regular CR123A batteries in the later Motor-M but it may have been too late by that point and the latch could have been damaged. I am sending Alan Starkie my Motor-M and M4-2 Winder today, so that he can watch them running on my M7, with the top cover off, to see what exactly is happening. The M4-2 Winder is far more violent than the later Motor-M and has a very large and torquey motor in comparison, so if any winder is going to show up the problem, it would be the M4-2.

Wilson

[wlaidlaw]

Update on my M7 problem. The root cause of the jamming was eventually traced. It was not the anti-wind back catch jumping out of lock, as we thought but a cracked motor drive shaft. This shaft holds the intermediate gear in correct sync. When the gear was correctly synchronised, the camera worked for a couple of manual winds but on mounting the Motor-M, immediately jammed again totally. This time the cause was immediately evident as the shaft had now fractured completely. Apparently this is not unknown for M7's that have mainly been used with Motor-M or Leicavit winders. It looks as if the shaft had its thread cut too deeply and maybe incorrect heat treatment or lack of it to reduced machining stress. A new shaft has been ordered from Leica. Alan Starkie has actually ordered a few of them as he expects other M7's may suffer the same malfunction and we don't know how much longer M7 spares will be available, now it is out of production. Given that Leica sold off the R8 and 9 spares, a few years after they went out of production, to someone who appears to have no interest in providing a spares service to the R8 and 9 owners, I am not too optimistic about the M7's future spares availability. 

Wilson

 

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