Grips and batteries (cells) hypothetical question

I tried a search but came up empty.

"hopefully" aimple hypothetical question..

In continuous use - heavy use for as long as the cells would last be it measured in hours, or a few hours a day for two or three days on vacation..maybe a week, etc.......as long as I can actively use a camera (one week vacation? Two week vacation? etc.). just overall use - using my 40D that takes Canon's proprietary 7.4 (nominal) volt Lithium Ion cells, and a vertical grip that holds two cells, and shooting under virtually identical conditions (all things being equal....use of LCD if any, use of pop up flash if any, etc..) - which would last longer? Two fully charged 511 cells in the grip or six primary lithium AA cells like the Energizer L91 cells?

I know that the obvious answers are "carry spares" etc.

But as I said in the thread title, this is a hypothetical question - even though I have a practical reason for asking...just more complex to explain than the effort is worth and would probably just needlessly confuse the issue.


Thanks,
D.

I found this on a review someone wrote, "Canon rates the use of six "AA" batteries as having a life of 400 warm shots, and 200 cold shots with no flash. Using a flash reduces each by 100 shots.

40D -- 2200 shots warm/1900 shots cold without flash
1600 shots warm/1400 shots cold with flash"

http://www.epinions.co​m …_A_1/content_42​3738576516

Edit: also read some comments here: http://photo.net …gital-camera-forum/00PoGu

Delija wrote in post #10888503
I tried a search but came up empty.

"hopefully" aimple hypothetical question..

In continuous use - heavy use for as long as the cells would last be it measured in hours, or a few hours a day for two or three days on vacation..maybe a week, etc.......as long as I can actively use a camera (one week vacation? Two week vacation? etc.). just overall use - using my 40D that takes Canon's proprietary 7.4 (nominal) volt Lithium Ion cells, and a vertical grip that holds two cells, and shooting under virtually identical conditions (all things being equal....use of LCD if any, use of pop up flash if any, etc..) - which would last longer? Two fully charged 511 cells in the grip or six primary lithium AA cells like the Energizer L91 cells?

I know that the obvious answers are "carry spares" etc.

But as I said in the thread title, this is a hypothetical question - even though I have a practical reason for asking...just more complex to explain than the effort is worth and would probably just needlessly confuse the issue.


Thanks,
D.

Are you sure you're not confusing 'cell' and 'battery?'
Nominal voltage of a lithium cell is usually ~3.7v... Each of your camera batts is probably a two cell battery.
Of course, I could be talking out of my ass

As for endurance, if all things are equal between the two setups (both similar lithium chemistry, constant current drain, temps, etc) then the setup with the highest capacity battery (ah/mah) should win...

spleenrippa wrote in post #10888591
Are you sure you're not confusing 'cell' and 'battery?'
Nominal voltage of a lithium cell is usually ~3.7v... Each of your camera batts is probably a two cell battery.
Of course, I could be talking out of my ass

LOL..no, ...you are exactly right, I meant to call the 511 LiIon rechargeable's "batteries" and the AA primaries "cells".

spleenrippa wrote in post #10888591
As for endurance, if all things are equal between the two setups (both similar lithium chemistry, constant current drain, temps, etc) then the setup with the highest capacity battery (ah/mah) should win...

Yes, well, that would seem to make sense, (more than that, it SHOULD make sense - would make life easy!) - but the Canon brand 511A is labelled as having an mAh rating of 1390, yet they seem to last a very long time (even just one without a grip to hold two).

I've also read that some third market 511 batteries claim to have significantly higher mAh power, but reading reviews people that buy them and test them, they find them to be far lower than the claims - I've tried the cheap Ebay 511 batteries (2 for $10 with a charger) and I don't think they are labelled as per amperage hours, so it's easy for sellers to say anything - I didn't care, I just wanted a charger for $10 that could plug into a car's power source. It was easy to dispose of the batteries - which I did since they were so uneven I didn't want to mix them - never a good idea with LiIon.

The Eneloops are 2000 mAh and I use them exclusively in my Speedlites - I'm not that concerned with self discharge for the flash units since I rarely use them without knowing I'll need them in advance - easy to keep backups charged. (I do use the Energizer primary lithium cells in my SX10 Powershot just because of the shelf life - I want the camera to work when I pick it up which sometimes can be very infrequently).

I have read a lot of posts where owners of sx10 and sx20 (and I'd guess SX1 and whatever other cameras use AA cells) - got very little "staying power" with the high (2750) mAh cells and got many more shots with the 2000 mAh Eneloops and "Duraloops". Maybe can blame some of that on self discharge, but I also have read where people try and take 1000 shots in a day, so self discharge would seem to be a non-factor.

The Primary lithium cells seem to last forever in my SX10, but I don't use it frequently enough to ever have gotten a shot-count on a set. But they don't indicate mAh ratings on the cells or package (I guess a call to the Bunny might get the info). I just took a look at sealed packages of alkaline C and D cells (from my hurricane box) and no mAh ratings there either. Seems like only rechargeable cells (or batteries) have mAh published.


Seems like the more "thinking" that I give it, the more confused I get - especially reading so many posts about how the high mAh AA NiMH cells seem to go dead so fast in the SX cameras.

BTW. while you are right in LiIon cells being 3.7 nominal volts I've noticed that the 123 size LiIon seem to be available in 3.6 and 3.0 volts. I guess for the sole purpose of making things even more confusing! LOL

The CFP forum guys that talk about this stuff all seem to be electrical engineers, so it's easy to get answers over there, just not any that "lay people" can easily understand. (at least speaking for my own dumb self)

Peace,
D.

The two Canon batteries outlast AA batteries in my 30D by miles. But I always carry AA batteries and the cassette as an emergency stop gap, which has saved my bacon a number of times. Certainly its easier now I can recharge back at base and not have to track down replacements, but AA batteries are far more readily available than any other battery.

Consider AA as emergency backup. Battery grip or not isn't too important. You can have the spare in the pocket just as well.

My 7D has been used quite a lot for playing now, but still has about 20% left in the batteries, after 2400 shots. The LP-E6 batteries are long-lasting.