D800 or equiv... video battery question ?

[shadowlands]

I currently have eneloops in my battery grip. Camera says it’s fully charged.
I have the correct battery type plugged as well.
I’m taking photos, and all is well. Been shooting for days, like this.
Today I go to do a test video… as soon as I was done… battery level turned red was showed almost empty.
Video was only 20 seconds.
I thought, dang, guess my eneloops are needing a recharge.
Turned the camera off, removed the battery tray, then slapped it back in… now showing full charge again.
Huh?

 

[WayneF]

I don't know why it would change, but am GUESSING if you used it several seconds, to let it see the battery with a video load, it might change back? Video is much harder on the battery than photos.

Facts:

1. The big camera battery is lithium ion, and these have a chip in the battery housing that reads accurate charge level. This is the third pin on the battery contacts.

2. NiMH batteries (the Eneloops) for example for flash, have no such chip.

3. The simple equipment charge indicators are just voltmeters, reading the voltage. These are used for alkaline batteries, who's voltage starts at 1.5V, but drops steadily as used, and we discard them as dead at 1.1 or 1.0 volts. The simple voltmeter works fine for a charge indicator, to show that discharge process for alkalines.

4. But NiMH batteries hold a more constant voltage over their life. They start at maybe 1.3 V, and the simple charge indicators assume alkaline, and show only about 2/3 charge. But... that is fully charged. And then they stay there, they hold this voltage over their life (more or less), and then finally suddenly go dead at the end. This is a plus. Over most of the life, NiMH has higher voltage than alkalines have suffered. The only problem is the charge indicator, not the battery. We really don't have meaningful charge indicators for NiMH.

Bottom line. The equipment charge indicators work fine for lithium and alkaline, but are NOT meaningful for NiMH.
But, the NiMH batteries run circles around alkaline, regarding performance.

Just recharge your Eneloops. You don't have to wait so long before recharge next time.

 

[shadowlands]

I don't know why it would change, but am GUESSING if you used it several seconds, to let it see the battery with a video load, it might change back? Video is much harder on the battery than photos.

Facts:

1. The big camera battery is lithium ion, and these have a chip in the battery housing that reads accurate charge level. This is the third pin on the battery contacts.

2. NiMH batteries (the Eneloops) for example for flash, have no such chip.

3. The simple equipment charge indicators are just voltmeters, reading the voltage. These are used for alkaline batteries, who's voltage starts at 1.5V, but drops steadily as used, and we discard them as dead at 1.1 or 1.0 volts. The simple voltmeter works fine for a charge indicator, to show that discharge process for alkalines.

4. But NiMH batteries hold a more constant voltage over their life. They start at maybe 1.3 V, and the simple charge indicators assume alkaline, and show only about 2/3 charge. But... that is fully charged. And then they stay there, they hold this voltage over their life (more or less), and then finally suddenly go dead at the end. This is a plus. Over most of the life, NiMH has higher voltage than alkalines have suffered. The only problem is the charge indicator, not the battery. We really don't have meaningful charge indicators for NiMH.

Bottom line. The equipment charge indicators work fine for lithium and alkaline, but are NOT meaningful for NiMH.
But, the NiMH batteries run circles around alkaline, regarding performance.

Just recharge your Eneloops. You don't have to wait so long before recharge next time.

I appreciate you taking the time. I will charge them tonight, for sure....

 

[astroNikon]

I had to read that 3 times to make sense. Thanks WayneF

 

[dannylightning]

on my point and shoot cameras even if the battery's are about dead when i first turn the camera on it will usually show a full charge, 30 seconds to a minute later it will give the true reading on the charge of the battery. on my D5300 i noticed the other day it had 2 our of 3 bars on the charge indicator when i turned the camera on, i took took several shots and never looked at the charge meter again. shots, when i got home i plugged the camera in to the computer and i noticed it was telling me the battery was almost dead so i am guessing this camera also takes a few before it shows you the actual reading, i cant imagine i drained the battery that much in the 30 minutes or so i used the camera to take photos.

it seems its best to read the charge indicator after the camera has been on for a few.

 

[WayneF]

The DSLR has a Setup menu Battery Info, that will show the lithium charge status in 1% increments.
The little icon in top LCD is very much more crude.