I found this on Thom Hogan's site regarding the D500 Battery:
Updated (see bottom)
So here’s some not so good news: a lot of third party EN-EL15 batteries that work fine in my D7200 simply don’t work at all in the D500. I’ve verified that Watson and other third party batteries I’ve got laying around show 100% in the D7200, but show the blinking battery indicator and no charge in the D500. Readers report troubles with other third party batteries, such as the Promaster version.
Nikon has obviously changed their pin detection algorithms again, though whether intentionally to trip up third party batteries or not is unclear. However, all the third party EN-EL15s I have to examine are not 7v, 1900mAh like Nikon’s version. The Watsons are 7v, 2000mAh. Another brand that’s generically marked is 7v, 2550mAh.
But that’s not all. Not a single Nikon EN-EL15 I have shows the same power level remaining in my D500 as it does in my D7200. This struck me as odd, so I tried all my EN-EL15 and clone batteries in my D750 and D810, too. That proved interesting. The D7200 and D750 report the same value for all batteries, the D500 reports a lower value, the D810 reports a still lower value. All for the same battery just moving from camera to camera.
That probably means that Nikon is looking at how hard the camera might draw on the battery (e.g. worst case load) and adjusted their internal tables or algorithm accordingly. It may even have to do with buffer depth and how long the camera might have to write to the card.
Still, Nikon has gotten themselves into trouble with their very conservative power management before. The F6 was notorious for reporting dead batteries when they were just fine, a problem that was later fixed in firmware by resetting the trigger point ;~). I seem to recall a couple of early DSLRs having battery reporting issues, too.
Bottom line: you’re going to need Nikon EN-EL15 batteries for your D500, at least until the third parties figure out what Nikon did and work around it.
Update: after posting this, I got a number of messages from D500 owners who were having battery issues. It’s clear that the Watson batteries don’t work. Any battery that isn’t 7v 1900mAh doesn’t work as far as I can tell from data I’ve received to date.
But more worrisome is this: a lot of people are reporting one or both of two things: (1) Nikon’s own EN-EL15 batteries don’t work in the camera; (2) Nikon’s EN-EL15 batteries report vastly lower battery remaining values in a D500 than in a D810 or other Nikon DSLR that uses the same battery.
In terms of #1, I can’t replicate it with my half dozen EN-EL15s, but I’ve now received so many responses where people have that problem, I have to believe there’s a real problem here. I’ve asked for markings on all the reported “Nikon battery doesn’t work” cases I’ve received to see if there’s some clear indicator there. Nikon has been making EN-EL15 batteries for many years now, so this problem is entirely unexpected.
#2 is more explicable. As I noted, it could just be that the tables were changed because the D500 draws more current in maxed out situations (e.g. shooting 10 fps in bursts). But…the problem I have here is that my EN-EL15 batteries report only slightly different values in the various Nikon DSLRs I test them in, which is what I would expect from a small table value change. But I’ve gotten many multiple reports of high variance, such as a battery showing 74% in a D810 and 36% in a D500. That is more indicative of programming problem in firmware, I’d say.
I’ll repeat what I’ve written before: the D500 feels rushed to market. Someone in Tokyo thought that the D5/D500 launch would mimic the extremely successful D3/D300 launch in 2007, but I’ll bet that the D500 wasn’t originally on the same schedule as the D5, that it was pushed up. There are too many loose ends—e.g. the unfinished iOS Snapbridge app—that suggest this.
Overall, the battery issue just becomes another in the series of QC problems that Nikon has become known for in new model introductions. This continued friction is why so many previously loyal Nikon users are rethinking their commitment to the brand.
Apr 26, 2016, 2:08 PM
