I need to buy a Nikon D40 battery?

I have a Nikon D40 and will start shooting wedding photography soon. I will however need to buy some more batteries because I only have one. Are there any more powerful batteries I can use with the D40 or will I just have to purchase a few EN-EL9's?

Weddings with a D40… Well 10 points for ambition! Get a few EL9 batteries.

Get a battery grip for your camera too…

and you might want to see about investing in a second camera body and use the D40 as a stand-by…

get a D7 or D5 for the main work… Also, make sure you have enough lenses and some flashguns…

I'd be getting another camera and some fast glass along with a couple of flash guns. Not to mention public liability/ professional indemnity insurance along with those extra batteries…

You'll need more than extra batteries to do wedding photography. You'll need;

- a second DSLR body - preferably something with better low light performance than the D40 & use the D40 as backup
- fast prime or zoom lenses - my typical wedding lenses are 50mm f1.8, 85mm f1.8, 24-70mm f2.8 and a 70-200mm f2.8
- off camera flash (speedlights) - at least two, plus stands & modifiers & a means to trigger them.
- skill & experience in shooting manual (both camera & flash) and knowledge of lighting