I use a Nikon D750 and D7500 to shoot time lapses. Because I typically shoot over 2000 images, I use an external battery (Lanparte and TetherTools D-Tap) with a battery coupler to power the camera. I have been having problems lately, the cameras have been stopping before the batteries are exhausted or the SD card is full. The camera may show an "ERR" message on the top LCD but it is not explicit so as to identify the problem. The batteries have sufficient charge in them, but the camera stops for some reason. I have shooting in Aperture mode with ISO set to automatic between 100 to 1600. I have been using the internal intervalometer. I don't seem to have this problem if I use the internal batteries with or without the grip. Any ideas?

If the camera goes to "ERR" something is clearly wrong. I'd suspect the external converter not delivering enough power constantly. Nikon cameras can be operated with 9V, using 7.5V only as the internal batteries claim to provide is mostly not enough.

Thanks for the comment. I will add hand warmers and an insulating box to the external battery and try tonight.

Hi drew,

I have developed an adapter (QCCP / QCCP stick) that uses the special properties of a QC3.0 power bank to supply cameras with power over a long period of time. When using the QCCP in conjunction with the D750 and some power banks, problems arose because the D750 needs a very high current when triggered. The problem only occurred with some power banks. Most worked fine with the D750 and the QCCP. This can also be the problem for you if after a while the battery no longer has full capacity and the TetherTools D-Tap also has problems. You can find information about the QCCP here: https://tlpbf.de/components/ and a guest article by me with a lot of useful information can be found on Gunther's website:
https://gwegner.de/know-how/qc-powerbank...p-adapter/ and here: https://gwegner.de/ankuendigungen/qccp-s...ersorgung/

Regards,
Hans

Thank you for your comment on the QCCP and power banks. I will look into a more modern power bank and your adapter.