How to use Ac power to replace the Nikon D40 battery

I still haven’t gotten the grip I mentioned a few posts ago. I don’t know if I will. I have figured out a clumsy hack to get the job done and I might just run it this way, or perhaps clean it up a tiny bit.

This is the battery with little aluminum strips taped to it. The battery compartment is too tight for regular wires, so foil was the only way to do it.

aluminum foil wiring for battery pack d40
aluminum foil wiring for battery pack d40

This pic shows the “wires” coming out of the battery grip. I have alligator clips on a 7.3V 200Ma cell phone charger. I connect it to the foil and off we go!

battery grip showing aluminum "wiring"

The reason why I have the battery in there is because without it, there isn’t enough juice to fully actuate the shutter. I think that some kind/type of capacitor would also do this, but I’m afraid I don’t what kind would work.

This might seem unnecessary and awkward – and it is most of the time. It is necessary when I do time lapse photography, because otherwise the battery dies after a few hours. I’m pondering rigging up some kind of large amp hour battery to deliver 7.4v the same way so I can do long time frame time lapses “off the grid” but I keep getting mired in voltage regulator discussions. Does anyone have any experience / suggestions?

In case you didn’t read my previous post, there are products out there that do this, but not many. Here is a battery grip from fotodiox that may or may not be able to power the camera while connected to the wall. I received mixed messages from the vendor.

And there is always the straight-from-nikon version, but it is too expensive for my tastes as well. First thing is, the wall adapter costs a mighty $70

The second thing is that you still have to buy a $30 battery “dummy” to plug the adapter into! AHHHHHHHHHHH!

So in conclusion: Spend a few minutes at the junk shop to find a charger with a close voltage, spend a little bit of arts and crafts time with the tinfoil and tape, and you will be able to run off of wall power for roughly $7 instead of $100!

7 replies on “How to use Ac power to replace the Nikon D40 battery”

  1. Hi, I think your idea is great but also that you don’t really need a grip, I’m going to try aluminium tape or very thin wires soldered to the connections of a dummy batt, this may work

  2. I am building a solar powered system for a D40 to handle time lapse. Power comes from a solar panel to a 12V battery, and I will reduce the voltage to 7.4v through a car cigarette lighter voltage reducer. I plan to wire a dummy battery off this. All going well will be a system that can be left for days, I have cased it all in a modified microwave!

  3. oh i agree completely! The dummy grip was a little bit easier because there was more flex in the battery door. That made it easier to bring the wires through. Other than that, there isn’t any reason provided you are using an external intervalometer.
    thanks for reading!

  4. Nice hack. But wouldn’t there be a way to use the AC socket in the side. D80 has it, but once again, NIkon decided to use a weird, non-generic plug. Any ideas?

  5. Hi Jasja!
    As far as I know there isn’t an ac outlet on the side. Even the adapter that nikon sells is a ‘dummy battery’ kind.
    I think that is just one of the down sides of buying Nikon’s cheapest slr.
    I agree though – if there was an outlet I would MUCH rather use it.

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