Angmo

Tell yah a story. A few years back, the electronics mfg company I worked for had an issue. My company also built batteries for its products and a Chinese firm built fake batteries complete with our company logo. Sr management of course met about it. Engineers studied the fake battery and determined it was equal to or higher in quality than what we built.

The meeting went on discussing lawyers, legal actions etc... I suggested why don’t we just buy the company instead. Win win.

Bipod

Nikon doesn't make batteries. Somebody is making the EN-EL9 (7.5 V 1100 mAh Lithium-ion) for Nikon.
Duracell does make batteries: the Duracell DR9900-US replaces the EN-EL9.
https://www.duracelldirect.com/digital-camera/nikon/oem-pno/en-el9--fa4yf7.html
But buy any brand you like anywhere you like--it's a consumable.

Nikon also doesn't make battery chargers--somebody makes them for it. Buy any brand you like
anywhere you like. But it's worth spending a little more to get a good one: all chargers are not
created equal.

topcat Loc: Alameda, CA

I have used other than Nikon batteries for several of the Nikons that I own, also for my compact cameras that I used to use. There have never been a problem.
I am not sure what brand this battery is, so I can't even guess on the quality. I suggestWasabi, they are a good brand with many good reviews.
Those people that will only use the original manufactures, I think they are wrong. There is no way that this will ever void your warranty, and I have never heard of it damaging a camera.
But if you have a lot of money, go for the expensive stuff, if it will make you feel better.

Bipod

The primary consideration in today's camera batteries us
energy density. That may or may not be your primary
consideration. So before buying a camera, it's worth considering
whether the battery type(s) it uses will meet your needs.

Other considerations include:
* cost
* availability
* weight
* time to recharge
* lifespan (number of charge-discharge cycles)
* charge shelf-life
* fire risk

Many rechargable battery technologies are available in portable
devices: lead-acid gel cells, rechargable alkaline, nickle-cadmium,
nickle-metal-hydride, and lithium ion.

Each technology has a different open circuit voltage and a different
recharge parameters. Some can be recharged quickly with a very
simple charger, while others will take a long time unless a "smart"
charger is used.

In addition, some cameras either require or can use non-rechargable
batteries; zinc-carbon, alkaline, or lithium metal.

One cannot simple replace one battery type with another. I used to
have Kodak camera that was spec'ed for alkaline batteries only:
it would not run on Ni-Metal-Hydride rechargables or on cheap
zinc-carbon disposables. It required the higher voltage (1.59
volts open circuit, fully charged) that alkaline batteries provide.

So the camera manufacture determines which type(s) of battery
will (1) operate and (2) fit inside the camera. Cost is not a
big consideration--especially if it also sells batteries! Neiher is
recharge cycles. Or fire risk.

We all use batteries in our homes, but it's not always a happy
relationship. Think of batteries as a sort of pet: one has to
learn about its care and feeding. While not cute or cuddley,
batteries can be faithful servants.

Bipod

The recent history of cameras has been the story of increasing power requirements:

-- Before 1962 --
* no battery in camera (light meters were Selenium)
* However, flash bulb attachments did contain batteries.
--1960s--
* battery powers: light meter
* battery types: mercury button cell or silver oxide button cell
* External battery-powered winders aso became available in the mid-1960s.
1962: Minolta SR-7 SLR: battery powers CdS light meter and hot shoe -- mercury button battery
1966: Yashica Electro 35: first electronically controlled (electro-mechanical shutter) camera
battery powers meter and shutter (no hot shoe) -- 6V alkaline A32PX
-- 1970s --
* battery powers: light-meter and shot shoe
* battery types: 2 button cells, silver oxide or mercury (dep. on camear)
* external winders (containing batteries) common
* external xenon flash units (containing batteris) common
1975: Eastman Kodak invents the digital still camera, but fails to bring it to market
1975: Cromemco Cyclops -- first commercial digital video camera (no image storage)
-- required an external AC adapter to operate
-- 1980s --
* battery powers light meter, hot shoe and film advance: alkaline or linthium, usually proprietary
* winders and flash units (containing batteries) still common
1983: Canon demos digital camera at Los Angeles Olympic Games -- fails to bring it to market.
Future digital cameras sold by Canon would be made by Eastman Kodak until the PowerShot in 1996.
1986: Nikon SVC -- first commercial DSLR
battery powers sensor and electronics -- Nikon BP-60 battery
1988: Nikon QV1000C -- Nikons first widely available DSLR.
--1990s--
* battery powers sensor, LCD screen and electronics (including microprocessor)
* battery types: alkaline and ni-cad, format AA or proprietary
1991: European Commission bans mercury batteries
--2000s--
* battery powers: sensor, LCD screen, electronics (much more memory, much faster
microprocessor)
* battery type: lithium-ion, large battery pack or AAs

Low-power chips have kept battery sizes reaonable, fed by reduction in fab scale.
But Moore's Law is reaching diminishing returns. And battery energy density has
hit a brick wall (Lithium-ion rechargeables in some devices have been self-igniting).

If processing and memory requirements continue to skyrocket, then either batteries
will get much larger and heavier, or operating hours between recharges will decline
sharply. Technology is not a magic lamp, and discoveries in basic science do not
happen on a schedule or to meet consumer needs.

A new microprocessor fab facility currently requies a $5 bn investment and 5 years
to build. A vast amount of money has been channeled into battery research, but no
new recharable battery chemistry has been brought to the consumer market in the
last 27 years. The most recent were Nickle-metal-hydride in 1989 and Lithium-ion.
in 1991.

Camera designers would do well to being to reduce the amount of processing done in the
camera, in order to support power requirements of more memory and larger sensors.