Z9 vs Batteries

To be honest, the idea of trying to use a mirrorless camera for my skating photography, replacing the well-proven and power-frugal D5, seemed a gamble. How fast would that constantly-running imager, processing pipeline and electronic viewfinder run the battery down? Would I need a large set of spare batteries and multiple chargers to keep up with its power demand? I already knew what a power hog the D5 is in Live View mode; I wouldn't consider it usable that way. The new Z9 would need to be significantly more efficient.

Concerns and unanswered questions dissuaded me from investing in a Z9, until availability improved enough that I could demo one at a camera store and get feedback from experienced users. By late 2022, what I was hearing about the Z9 was giving me sufficient confidence to take the plunge. It also helped that Nikon provides a new higher-capacity battery for the Z9.

But still - those unanswered questions! How would I know for sure? Are there user options that can help conserve energy? Would I need to modify any of my shooting habits? Would a second charger be required to keep up?

For many years, I had an idea kicking around in my head, to add a current-monitoring loop to a camera body or battery so I could study the camera's current draw - and thus its power use. Up through the D5 generation, battery capacity was never a problem, but with the arrival of the Z9, I had a powerful incentive to finally get set up to do such a study.

The test equipment I have includes a scope with a current probe, which will register current from DC up to 125MHz. This only requires an accessible power wire that it can be clamped around, to make current measurements. The simplest arrangement would be to add a short loop of wire at one end of a battery pack, which would take the place of one internal inter-cell connection. But I couldn't bring myself to cut into one of the expensive Nikon EN-EL18d's, especially not knowing exactly how things are arranged internally.

Fortunately, Wasabi Power makes a much less expensive alternative, so I invested in one to serve as a test subject. If anything went awry, at least my loss would be limited to $80.

After a couple hours of careful work (No, I DO NOT recommend that anyone try this at home!), I was ready to begin my study with the successfully modified Wasabi battery:




D5 with modified Wasabi battery, in test



What I didn't realize at the start, was just how much information one can glean from monitoring battery current with a scope and meters. Suffice it to say that it turned into quite an epic project. Several weeks, 20 pages of notes and dozens of saved scope screen shots later, I've learned enough that it's going to take a number of posts here to describe just the essentials.

Battery current waveforms reveal the Z9 imaging pipeline frame rate, AF motor current and details of the image-taking sequence. Also, it's possible to investigate how the various battery chargers work. There have been some surprising discoveries - but more about that later.

So drop by from time to time, to see what the latest installment in the saga of "Z9 vs Batteries" will be!

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Source credit: Prov 2:6
- Marianne

Most of the energy that the Z9 uses, goes into steady operation in various modes. The corresponding power levels will give you a useful means of estimating how long your Z9 can run on a battery charge. I measure these power levels from battery current and voltage. Although battery capacity can be specified in mA-h, the W-h figure is more useful since the camera is a constant-power load in steady-state, not a constant-current load. That is, as battery voltage declines, current draw increases in inverse proportion.

The Nikon EN-EL18d has proven to yield a usable energy output of 35 W-h in my testing. To obtain run time in a camera mode listed below, divide 35 by the mode's power consumption in watts, to obtain the maximum run time in hours.

Test configuration: I test the Z9 with the 70-200/2.8 S and a TC 1.4x mounted, and VR off. Display brightness is at default level. Use of other lenses may slightly increase or decrease the Z9 power draw. Power impacts of the VR system and AF motors will be detailed in later posts.

"OFF" or Standby State

When you insert a battery, or the camera transitions to "OFF" or Standby, there is a steady 18mA draw from the battery which typically lasts 25-30 minutes. I presume this is topping-up of the camera's internal holdup battery which runs the clock and low-power system controller when a battery is not installed. If the camera is left sitting for a long time (weeks, months) with no battery, the topping-up may take longer than 30 minutes. The topping-up is re-initiated every time the camera goes into "OFF" or Standby, so for practical use in the field, this parasitic current is almost always present. I include it in my measurements.

When the 18mA draw times out, the "OFF" or Standby current is only 400 uA, which would take about 1 year to discharge the battery.

Playback Mode or Menu Access

The next step up in power consumption, is viewing images in Playback, or accessing camera Menus. Using the EVF, power consumption in Playback is 3.5W, or if using the LCD monitor, it is slightly higher at 3.6W. During Menu access, power consumption stays near 3.5W for either display.

Power draw does not depend on how bright the image is in Playback, that is, the backlight brightness does not vary between low-key and high-key images. The EVF backlight does use less power than the LCD monitor. Power variation for EVF minimum and maximum brightness levels is -0.01W and +0.06W; for the LCD monitor the variations are -0.18W and +0.18W.

Live View without AF

With the imaging system running to watch the scene, but with AF not active, power consumption is
Both displays off: 5.35W
LCD monitor, 30 Hz image refresh: 5.8W
EVF, 60 Hz image refresh: 6.3W
EVF, 120 Hz image refresh (CSM d20 set ON): 7.43W

Excluding the useless no-display condition, these power levels infer battery run time of 4.7 to 6.0 hours. Note the run time penalty for using the EVF (60 Hz) is less than 0.5 hours relative to the LCD monitor. This is the only mode where EVF use makes a noteworthy difference to power consumption, and then it's not due to the display itself, so it's rather beyond me why so many photographers keep mentioning that "the EVF uses more power." Ignore them.

Live View with AF active

With AF on, the imaging system may run at either 60 Hz or 120 Hz. It will not run at 30 Hz, even if the LCD monitor is used. Usually, the Z9 will select 120 Hz (even with CSM d20 set OFF), so for conservative estimation purposes, you should assume this will be the case. The 60 Hz rate occurs less frequently, as the AF system allows. So far, I have found no consistent correlation between camera settings and the Z9's choice of refresh rate for AF; it seems to vary randomly. It would be nice to have a menu option to give the user some control here, as there is a significant power savings. Note that the Energy Saving Mode option does not affect the AF refresh rate.

EVF, 120 Hz refresh: 7.35W
LCD monitor, 120 Hz refresh: 7.43W

EVF, 60 Hz refresh: 6.27W
LCD monitor, 60 Hz refresh: 6.31W

Assuming 120 Hz refresh, these power levels result in battery run time of 4.7 hours. That could be extended to 5.5 hours if the user had a means of keeping refresh rate at 60 Hz.

The next post will delve into the energy consumption for image taking, and some comparisons between the Z9 and D5.

Marianne,

I'll be looking forward to your findings to see how closely they align with what I've been doing here, though with a much simpler setup.

I have a couple RAVPower Power Banks (both have PD USB-C ports) that I will be using for extended Time Lapse and wanted to get a sense of how much power the camera uses in different modes, with different lens types (VR vs no VR, etc.).

I have a USB-C power monitor w/PD passthrough capability that I've confirmed is reasonably accurate and I just insert that inline at the camera power input and power via USB-C from an AC adapter or one of my power banks. It measures instantaneous voltage, current, Watts and accumulated mAh, mWh, as well.

I did learn something I hadn't noticed before, though it's not really relevant for most time lapse shooting unless you have a long interval and the camera set for a short timeout. The camera will go into battery charge mode between shots and comes out of charge mode a few seconds before the next shot. I don't know if this is documented anywhere. Likewise, this will also happen in normal shooting modes if the camera times out between shots even though the power switch is still in the "ON" position. Interesting!

Cheers!

Nice work Marianne. More info than I need for my shooting habits. But super interesting. Thank you.

Tom Stites said:

I did learn something I hadn't noticed before, though it's not really relevant for most time lapse shooting unless you have a long interval and the camera set for a short timeout. The camera will go into battery charge mode between shots and comes out of charge mode a few seconds before the next shot.

Click to expand...

And every time it does this, it tops up the battery again. Not really a good thing to do to your battery (unless it actually needs charging).

To prevent the battery charging in a time lapse setup, release the battery cover latch (and tape the battery in place if necessary). There is an interlock which prevents battery charging when the camera doesn't see the latch is locked.

Marianne Oelund said:

And every time it does this, it tops up the [internal] battery again. Not really a good thing to do to your battery (unless it actually needs charging).

Click to expand...

Is it certain that the internal "battery" is a battery, as opposed to a supercapacitor?
I haven't recently looked at supercapacitor tech so maybe it is a silly question.

pcgeekesq said:

Marianne Oelund said:

And every time it does this, it tops up the battery again. Not really a good thing to do to your battery (unless it actually needs charging).

Click to expand...

Is it certain that the internal "battery" is a battery, as opposed to a supercapacitor?
I haven't recently looked at supercapacitor tech so maybe it is a silly question.

Click to expand...

We were actually talking about the main battery (EN-EL18d), which the camera charges when "OFF" or in Standby if you have USB power connected.

As to the camera's built-in battery, it could very well be a supercapacitor. I haven't looked (and don't plan to).

Marianne Oelund said:

Tom Stites said:

I did learn something I hadn't noticed before, though it's not really relevant for most time lapse shooting unless you have a long interval and the camera set for a short timeout. The camera will go into battery charge mode between shots and comes out of charge mode a few seconds before the next shot.

Click to expand...

And every time it does this, it tops up the battery again. Not really a good thing to do to your battery (unless it actually needs charging).

To prevent the battery charging in a time lapse setup, release the battery cover latch (and tape the battery in place if necessary). There is an interlock which prevents battery charging when the camera doesn't see the latch is locked.

Click to expand...

Good point, wasn't aware of that interlock, will try that. Speaking of that, have you confirmed that power delivery still works in that case? The manual indicates that PD does not work unless a battery is installed. Perhaps that determination is made through the battery connector, not relying on the interlock switch. I'll have to try that later this evening.

I'm aware from my work with LiFePo4 batteries that they like to be stored at 80% charge if not actively cycling. A shame Nikon doesn't do as DJI does with their smart batteries that discharge to 80% if they're recharged and not used within 2-3 days. Though I can just imagine all the complaints about batteries not holding a charge!

Either way, I have Wasabi battery that is basically freebie...it arrived and wouldn't charge, so they sent me a new one and told me to just keep it and dispose of it as I wished. Of course I took it apart to see what cells they used and what sort of electronics package they used. I was able to charge the cells individually on my lab power supply and it's been fine ever since. Put the case back together and it's my day to day battery, none the worse for wear. Performance nominally equivalent to my OEM batteries.

Tom Stites said:

Good point, wasn't aware of that interlock, will try that. Speaking of that, have you confirmed that power delivery still works in that case?

Click to expand...

Yes, it does. The camera confirms battery presence by communicating with its internal monitor electronics. The latch interlock is only for charging safety, so the camera isn't exposed to the battery possibly falling out while it's being charged.

And I just checked that you only need to release the latch by about 20 degrees to prevent the battery charging (rotate it back slowly, just until the charging LED goes off). At that position, it will still hold the battery cover in place.

Tom Stites said:

The manual indicates that PD does not work unless a battery is installed.

Click to expand...

Correct. The battery is used to cover high-current transients if your USB supply isn't capable enough, so the camera requires a battery to be in place, to operate from USB power.

Tom Stites said:

Either way, I have Wasabi battery that is basically freebie...it arrived and wouldn't charge, so they sent me a new one and told me to just keep it and dispose of it as I wished.

Click to expand...

The battery can be charged from a lab supply, if it won't work on the Nikon charger.

I had one instance where my Wasabi battery wouldn't charge on the MH-33. It was at about 80% charge state, and the charger just flashed its "100%" LED once, and stopped trying to charge it. After several unsuccessful retries, I tapped the CAL button and was surprised to see it commence charging, instead of going into CAL mode. Strange.

There are a number of idiosyncrasies with the Wasabi battery, which I will be posting about later.

Major geek post, but suits me as I am an electrical engineer. Also interesting findings emerging already! Look forward to next installment.

Hi,

Heck, I do this sort of thing all the time at home.

Not limited to a camera. Actually, rarely with a camera.

I get paid to do such. No pay to go use a camera.

The Z battery drain immediately reminds me of the major battery headaches with the D1 series cameras and those batteries. The answer was to carry several and rotate thru them. The main issue was the camera would overrun the battery chemistry. So if you had a rotation, the chemistry would catch up and what had been a dead pack could be used for a second stint. And then one had to have a plan to keep it all straight. Or, just carry more than actually needed.

Stan

--
Amateur Photographer
Professional Electronics Development Engineer
Once you start down the DSLR path, forever will it dominate your destiny! Consume
your bank account, it will! Like mine, it did!

Have you seen any difference in performance between the Wasabi battery and the Nikon battery? After its initial charge, my Wasabi battery only lasted about half as long as the Nikon battery, if that, before it threw the “low battery” indicator up on the Z9.

But curiously enough, whereas the Nikon battery started recharging below the 50% level, the Wasabi battery started recharging above the 50% level. So the Wasabi battery threw the “low battery” indicator up when it had 50% of the charge remaining.

I used to regularly rotate my rechargeable batteries through past cameras, but if the Wasabi continues its early low charge indicator status, then it will truly be carried and used as a “just in case” spare.

Cool thread, by the way. Interested in the future posts.

archerscreek said:

Cool thread, by the way. Interested in the future posts.

Click to expand...

Definitely a lot of info about the Z9 and EN-EL18D, probably a bit more than what I need to know (although I have an electrical engineering degree as an undergrad).

Now, any speculation on what the EN-EL18E will be like and how much Nikon will charge for that? ;-)

[No message]

archerscreek said:

Have you seen any difference in performance between the Wasabi battery and the Nikon battery? After its initial charge, my Wasabi battery only lasted about half as long as the Nikon battery, if that, before it threw the “low battery” indicator up on the Z9.

But curiously enough, whereas the Nikon battery started recharging below the 50% level, the Wasabi battery started recharging above the 50% level. So the Wasabi battery threw the “low battery” indicator up when it had 50% of the charge remaining.

Click to expand...

Thank you for the additional details on Wasabi battery behavior. Your experience has a very familiar ring to it.

I will be adding a post about the Wasabi battery fairly soon. There are a few issues to discuss.

Marianne Oelund said:

archerscreek said:

Have you seen any difference in performance between the Wasabi battery and the Nikon battery? After its initial charge, my Wasabi battery only lasted about half as long as the Nikon battery, if that, before it threw the “low battery” indicator up on the Z9.

But curiously enough, whereas the Nikon battery started recharging below the 50% level, the Wasabi battery started recharging above the 50% level. So the Wasabi battery threw the “low battery” indicator up when it had 50% of the charge remaining.

Click to expand...

Thank you for the additional details on Wasabi battery behavior. Your experience has a very familiar ring to it.

I will be adding a post about the Wasabi battery fairly soon. There are a few issues to discuss.

Click to expand...

My assessments of Wasabi batteries and chargers sank due to my experience with the bundle that includes two batteries and a dual charger. The timelines during charging and calibrations are significantly different than the Nikon bats. That seemed odd since I had expected that the cells in both would nominally be the same part form factor: those ubiquitous 18650’s. However I haven’t ripped open any packs to check that.

Also, the Wasabi charger won’t calibrate at all. I’m on my second one since the first wouldn’t charge at all. I purchased and exchanged through Amazon.

--
Wag more; bark less.

just Tony said:

The timelines during charging and calibrations are significantly different than the Nikon bats. That seemed odd since I had expected that the cells in both would nominally be the same part form factor: those ubiquitous 18650’s.

Click to expand...

The cells are essentially the same. The difference is in the way the battery pack's monitoring circuitry meters the battery state. Nikon and Wasabi do it quite differently.

Love that Tek DSO...

This Q may be out of the 'scope' of this thread..

Is there anything proprietary or patented about the Nikon pack that would prevent someone like Wasabi from exactly duplicating/cloning it ?

Marianne Oelund said:

just Tony said:

The timelines during charging and calibrations are significantly different than the Nikon bats. That seemed odd since I had expected that the cells in both would nominally be the same part form factor: those ubiquitous 18650’s.

Click to expand...

The cells are essentially the same. The difference is in the way the battery pack's monitoring circuitry meters the battery state. Nikon and Wasabi do it quite differently.

Click to expand...

Good to know. My charging observations so far have necessarily been limited to the domain of Time; I have an inline USB-C monitor but it appears to not allow pass through of PD negotiations so I can’t operate the Nikon charger through it.

101Colors said:

Love that Tek DSO...

Click to expand...

Yes, it was a huge help for me, for many years as a working engineer. One of the best investments I ever made. In my retirement, it still comes in very handy.

101Colors said:

This Q may be out of the 'scope' of this thread..

Is there anything proprietary or patented about the Nikon pack that would prevent someone like Wasabi from exactly duplicating/cloning it ?

Click to expand...

I wouldn't be surprised if there are some patent restrictions which apply, but Wasabi could still design their own circuitry/firmware to perform true coulomb counting. For some reason, they chose not to.