Faster Recycle Time

[D L]

I believe... all else being equal, an increase in capacity from 2000mAh to 2700mAh (or any increase in capacity) won't decrease your recycle time, when the batteries are fully charged. It should be exactly the same.

However, since the voltage gradually drops as these AA batteries deplete, the voltage drop will cause an increase in recycle time. The batteries of the higher capacity will drop voltage slower than the lower capacity batteries. So after 100 flashes, for example, the recycle time of the higher capacity battery should be faster.

[dem]

I just received a reply from B&H
"You could use the Eneloop charger for the Powerex NiMH batteries, but the 2700mAh batteries are not going to speed up your recycling time. It would just give you greater life."

That's an easy way of making your life greater, just buy some batteries.

FWIW, I am using both standard white 1900 mAh and black Pro 2500 mAh Eneloops alongside a bunch of rechargeable Energizers. Pro Eneloops make the flash work noticeably quicker than the rest. The downside is that they are rated for "only" 500 cycles not 2000 or so.

EDIT: a video which compares 8 types of batteries: https://youtu.be/qANbVb9BoMo
Eneloop Pro has the shortest recycling time, standard white Eneloops came #5.

[george013]

That's an easy way of making your life greater, just buy some batteries.

FWIW, I am using both standard white 1900 mAh and black Pro 2500 mAh Eneloops alongside a bunch of rechargeable Energizers. Pro Eneloops make the flash work noticeably quicker than the rest. The downside is that they are rated for "only" 500 cycles not 2000 or so.

It all depends where you compare it with and what the required load is.
What I've found is that the recycling time now of the eneloop and normal NiMh batteries are equal. Based on the specs of different flashes. I assume they compare it with the pro-line looking at the capacity. See by example the SB-700 and SB-900 specs. But the max number of flashes that can be used is with normal NiMh batteries over 10% higher. It makes sense when you take in account the bigger inner resistance.
http://www.nikonusa.com/en/nikon-pro...Tabs-TechSpecs
http://www.nikonusa.com/en/nikon-pro...Tabs-TechSpecs

I still think eneloop is a hype in photography.

George

[dem]

What I've found is that the recycling time now of the eneloop and normal NiMh batteries are equal.

This is what I found as well for standard white Eneloop batteries. As I said, I found the black Pro Eneloop batteries faster than others I've got.

I assume they compare it with the pro-line looking at the capacity. See by example the SB-700 and SB-900 specs.

They do not specify the nominal capacity nor type of the Eneloop batteries they tested.

But the max number of flashes that can be used is with normal NiMh batteries over 10% higher. It makes sense when you take in account the bigger inner resistance.

The inner resistance affects only the recycle time - the higher the resistance, the longer it takes to recycle. The inner resistance does not affect the number of flashes, that is mainly defined by the capacity, e.g. a 2700 mAh battery should give about 50% more flashes than a 1800 mAh one.

[george013]

This is what I found as well for standard white Eneloop batteries. As I said, I found the black Pro Eneloop batteries faster than others I've got.

They do not specify the nominal capacity nor type of the Eneloop batteries they tested.

The inner resistance affects only the recycle time - the higher the resistance, the longer it takes to recycle. The inner resistance does not affect the number of flashes, that is mainly defined by the capacity, e.g. a 2700 mAh battery should give about 50% more flashes than a 1800 mAh one.

The battery is declared empty when the recycling time exceeds 30s.
It's not a simple calculation the number of flashes. As you and everybody experienced, the recycling time gets longer.
I even don't know what a normal charge would be for a flash. How much ampere does it need to function. The load an unload curves are given for continues 500mA.

George

[rpcrowe]

I should be receiving my Powerex charger and 2700 mAh batteries shortly from B&H. Then I will do a pseudo scientific test between these batteries and the 1900 and 2000 mAh Eneloop batteries I presently have. I will even throw in a set of Energizer and a set of "no name" batteries. I received 24 Chinese AA "supposedly" alkaline batteries, free of charge, when I bought some tools at a tool discount store (Harbor Freight)...

[george013]

Years ago I bought my first digital camera, a HP photosmart xxx. At a certain moment the batteries where empty within no time. I was puzzling what to blame, the camera or the batteries. I measured the shortcut currency of the batteries and one was very different. I replaced that one and could shoot further.

I did the same trick now with some different batteries, just out off the loader. A Duracell 2450, Duracell 2650 and a Eneloop Pro. All of them had a shortcut currency of 6.7A. A Duracell 1800 gave a shortcut currency of 4.6A. But that was the oldest one as you can guess.

I don't think there's a difference in prestation between a Eneloop and a non Eneloop NiMh battery.
And I still think the argument of the low self discharge is a non argument for a photographer.

George

[rpcrowe]

I received the 8 Powerex 2700 mAh batteries from B&H, loaded four of them (right out of the box) into my flash and shot some experiments using my very patient model. This is a ceramic dog that my wife made before she spent all her waking hours in dog rescue...



Using my 600EX RT flash bounced off the ceiling (modified with a Joe Demb Flash Diffuser Pro) at the normal distance from which I usually photograph my rescue dogs, I was able to shoot as fast as I could press the shutter button at ISO 160. There was really no difference when I boosted the ISO to 320 I used ETTL exposure with the camera in manual at 1/60 second @ f/4

Since I am quite happy with the performance of these batteries, there is really no reason for me to make tests with other batteries...

The charger seems great... It applies a charge to the batteries individually and has 3-modes of charging. Slow, fast and deep charge. The deep charge is used to rehabilitate batteries.

http://votogs.com/review/powerex-270...ble-batteries/

[george013]

I received the 8 Powerex 2700 mAh batteries from B&H, loaded four of them (right out of the box) into my flash and shot some experiments using my very patient model. This is a ceramic dog that my wife made before she spent all her waking hours in dog rescue...



Using my 600EX RT flash bounced off the ceiling (modified with a Joe Demb Flash Diffuser Pro) at the normal distance from which I usually photograph my rescue dogs, I was able to shoot as fast as I could press the shutter button at ISO 160. There was really no difference when I boosted the ISO to 320 I used ETTL exposure with the camera in manual at 1/60 second @ f/4

Since I am quite happy with the performance of these batteries, there is really no reason for me to make tests with other batteries...

The charger seems great... It applies a charge to the batteries individually and has 3-modes of charging. Slow, fast and deep charge. The deep charge is used to rehabilitate batteries.

http://votogs.com/review/powerex-270...ble-batteries/

I don't think you'll find any difference.
But by raising the iso to 320, the output of the flash will be less, so recycling quicker when the capacity of the battery is going down. Assuming you've a "smart" flash.

George

[Manfred M]

Richard - I've been using the PowerEx batteries for years and they do well for me.

From what I have read, the main tradeoff between the Eneloop batteries is that the recharge time is slower on the Eneloop than with standard NiMH batteries like the PowerEx, and the last time I looked the Eneloop batteries had a lower power density (less flashes vs normal NiMH). This is a function of the low self-discharge design.

I have two PowerEx charges (one 8 cell and one 4 cell) and I just rack up the batteries the night before I head out for a shoot and get them all recharged. This is the same thing I do for my camera batteries, so it's just part of the workflow. I don't shoot so occasionally that I need the low self-discharge feature of the Eneloops.

I do use an external battery back on the SB-900 and it roughly halves the recycle time on the flash. It was a cheap Chinese unit I bought on eBay and I have no complaints about build or performance. The cost was about 20% of the OEM version.

[dem]

I measured the shortcut currency of the batteries and one was very different... A Duracell 2450, Duracell 2650 and a Eneloop Pro. All of them had a shortcut currency of 6.7A. A Duracell 1800 gave a shortcut currency of 4.6A. But that was the oldest one as you can guess.

To keep George company I checked shortcut current for a bunch of batteries I've got in the drawer.

Rechargeables: 2500 mAh Eneloop Pro - 4.9 A, 2300 mAh Energizer - 4.6 A, 2000 mAh Energizer - 4.6 A, old 1900 mAh Eneloop - 4.0 A.

Alkaline batteries: Duracell - 4.2 A, Kodak Extra - 4.1 A, Panasonic Essential - 3.8 A

The main conclusion is that George has better leads on his multimeter than me

Ohm's Law R = U/I tells us that the combined resistance of the multimeter and the internal resistance of the battery is between 0.24 Ohm and 0.32 Ohm in my case. About 0.22 Ohm comes from the leads and the rest 0.02 - 0.10 Ohm is the internal resistance of the battery. The results are consistent with other sources:

http://www.learningaboutelectronics....nal-resistance

In other words, if it was not for the leads, the shortcut current could have been about 50 A. There are videos on youtube of people short-circuiting batteries with a paper clip to start a fire.

[george013]

To keep George company I checked shortcut current for a bunch of batteries I've got in the drawer.

Rechargeables: 2500 mAh Eneloop Pro - 4.9 A, 2300 mAh Energizer - 4.6 A, 2000 mAh Energizer - 4.6 A, old 1900 mAh Eneloop - 4.0 A.

Alkaline batteries: Duracell - 4.2 A, Kodak Extra - 4.1 A, Panasonic Essential - 3.8 A

The main conclusion is that George has better leads on his multimeter than me

Ohm's Law R = U/I tells us that the combined resistance of the multimeter and the internal resistance of the battery is between 0.24 Ohm and 0.32 Ohm in my case. About 0.22 Ohm comes from the leads and the rest 0.02 - 0.10 Ohm is the internal resistance of the battery. The results are consistent with other sources:

http://www.learningaboutelectronics....nal-resistance

In other words, if it was not for the leads, the shortcut current could of been about 50 A. There are videos on youtube of people short-circuiting batteries with a paper clip to start a fire.

The trick I used was just to pick out a different battery. If the amperes are about equal, then the batteries are equal. If one battery is in bad state, then I would say the amperes are different. The values them self are worthless. And don't do that with battery packs or stronger batteries.

Further you can assume that the maximum amperes that can be transported is physical limited.

When you want to use the Ohm's law, you must use the drop of the voltage and one of the other 2 items.
When you want to know the internal resistance, let a currency flow through a known resistance, measure both the drop of the voltage and the currency. Then you can calculate the total resistance. And subtracting the known external resistance gives you the internal resistance. Like the drawing in your link.
I think I remembered well.


George