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Re: [OM] OMD batteries update please

Subject: Re: [OM] OMD batteries update please
From: Chuck Norcutt <chucknorcutt@xxxxxxxxxxxxxxxx>
Date: Thu, 04 Jul 2013 20:13:50 -0400
According to the Wiki article on Li-ion batteries there are two common 
Li-ion chemistries with each having slightly different open circuit and 
charging voltages: "Batteries with a lithium iron phosphate cathode and 
graphite anode have a nominal open-circuit voltage of 3.2 V and a 
typical charging voltage of 3.6 V. Lithium nickel manganese cobalt (NMC) 
oxide cathodes with graphite anodes have a 3.7 V nominal voltage with a 
4.2 V max charge."

Since these voltages are per cell you'd have to double them for dual 
cell batteries as are typically used in larger cameras.  That would give 
6.4/7.2 volts and 7.4/8.4 volts.

All of my older Canon and Minolta batteries are labeled 7.4 volts. 
Where 7.6 comes from I don't know.  But I do note that the Oly charger 
is labeled 8.7 volts and not 8.4 volts.  That would seem to go along 
with its 7.6 volt battery label.  The "compatible" Progo battery says 
7.6 volts as well but the charger is labeled 8.4 volts and not 8.7.

Perhaps there is some new and improved Li-ion chemistry at work here 
(there are many such chemistries).  On the other hand, maybe it's just 
hand waving and puffery.  To further confuse the issue I note that all 
of the latest Canon DSLR cameras use the LP-E6 battery which is labeled 
(you guessed it)... 7.2 volts.

If it works use it.

Chuck Norcutt


On 7/3/2013 4:48 PM, JOHN DUGGAN wrote:
> Moose,
>               I just carefully looked at the small print on the back of the 3 
> types of battery in my collection.
> Genuine Olympus   7.6v 1220mAh  chipped uses Olympus charger.
> hahnel                      7.6v 1170mAh  chipped uses Olympus charger.
> No name                  7.2v 1220mAh Dedicated charger.
> You will note that the no name battery is nominally 7.2v even though it is 
> sold as BLN1 compatible.
> At present the Olympus and hahnel batteries seem to have the same discharge 
> charecteristics, last for about the same number of exposures, and keep their 
> charge.
> The no name batteries however do not last for anywhere near as long and if 
> not used seem to lose a lot of their charge. Could this be down to 7.2v 
> versus 7.6v?
> The hahnel batteries cost just under 1/2 the cost of the Olympus, with the no 
> name costing about 1/4 of the Olympus.
> I will buy the hahnel in the future.
>
> Regards
> John Duggan,
> Wales, UK
>
>
> ________________________________
>   From: Moose <olymoose@xxxxxxxxx>
> To: Olympus Camera Discussion <olympus@xxxxxxxxxxxxxxxxx>
> Sent: Wednesday, 3 July 2013, 21:16
> Subject: Re: [OM] OMD batteries update please
>
>
> On 7/2/2013 2:50 PM, Chuck Norcutt wrote:
>> I think I'd stick with the Progo but only because the Progo and its
>> charger are 100% Oly compatible.  I alread knew the Progo battery talks
>> politely about its status to the camera.
>
> Something popped into my mind about this. What if ... Progo has not entirely 
> correctly decoded the Oly battery-camera
> communications?
>
> They claim greater capacity, yet deliver fewer shots. As I/we have assumed, 
> that could be because their capacity rating
> is wrong - or Oly is using larger mAhs. :-)
>
> It could also be because the battery communication with the camera isn't 
> quite right, and the camera is shutting down
> for insufficient battery power when there is, in fact, adequate power for 
> many more shots.
>
> As the camera does work with batteries that make no attempt to communicate 
> with it, it must have two means of
> determining when a battery has run down. One would be based on intelligent 
> battery/camera communications, the other
> presumably on simple battery voltage. Oly would have at least two incentives 
> to set that voltage high. They don't want
> it to die 'dumbly' in the middle of shutter operation, image writing, etc. 
> and they would like to sell many of their own
> batteries. (Why they price their own so high is a mystery to me. It they were 
> $30, I'd have two or three of them,
> instead of the one Oly that came with the camera and three third party 
> batteries.)
>
> As the Progos get about the same number of shots as un-decoded batteries, 
> it's possible the camera is shutting down
> based on voltage alone, not camera comms. My Wasabi batteries do show full 
> when recharged and lower amounts left on the
> camera battery indicator as they are used. That must be based on voltage 
> alone, and is impossible to distinguish without
> a lot of testing from a smarter communication.
>
> Is it possible that Progo has only decoded the battery/charger communications?
>
> It's at least a theory that accounts for the apparent anomalies between rated 
> mAh capacity and no. of shots capacity.
> Could also explain why more third party makers don't as yet sell 'decoded' 
> batteries, because they know they've not
> cracked the comms completely.
>
> I'm not saying one should not (or should) buy the Progos. They do, in fact 
> charge on the Oly charger, and deliver a lot
> more shots for the $ than the Olys. Also, I only bought one, sans charger, so 
> I know nothing about the charger.
>
> Theoretical Considerations Moose
>
-- 
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