Hacking EN-EL14 into a power adapter

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Hacking EN-EL14 into a power adapter

Postby philips » Wed Feb 18, 2015 2:22 am

Hello there,

I have been trying to power my D5200 via a larger portable powerbank, but getting the original Nikon EP-5a connector ('dummy battery') was nearly impossible in my country. So i decided to modify one of my batteries for this purpose.

My first idea was to route external cable straight to the battery connectors on the inside, which would not be the best idea, as it would try to charge the original cells without any circuit. So I removed the cells, and tried hooking up the cables directly to the small circuit board, and id didnt work. The cells are connected with a middle tap (basically as the battery is 2 connected cells, one wire goes 'between' the cells and onto the board, for balancing purposes I guess) and it doesnt work work when the middle connector is left unconnected.

Here are some pictures of the battery internals for reference: http://goughlui.com/2013/11/27/teardown ... d-battery/

I have a 9V-out powerbank with huge capacity, and I was hoping I could wire it directly into battery's board (voltage should not be an issue here) to make it work. Do you have any ideas how to pull this off? Could a simple voltage divider work as the source for middle tap connection? I'm willing to experiment so feel free to suggest your ideas.

Thank you~!
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Re: Hacking EN-EL14 into a power adapter

Postby 4cc3ss » Mon Feb 23, 2015 4:35 pm

Myself did some work with the EN-EL14, and yes the batteries contain 2 cells and the circuit board which is the protection for short circuit etc...
and i was going to add a external power source via the internal battery, but i decided to use a cheap battery grip as this was possible using the
battery patch to allow 3rd party batteries, so i fitted a power socket to the grip and from this i was able to use a external power supply or a
external battery with greater mAh and also this kept the option of using 2 batteries with the grip and didn't have to destroy a battery :)

Here's a video of the mod which i did.
https://www.youtube.com/watch?v=U--cfB7IBuw

Good luck
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Re: Hacking EN-EL14 into a power adapter

Postby philips » Wed Feb 25, 2015 5:54 am

Thanks for the reply 4cc3ss!

I see that your grip has space for two EN-EL14 batteries, could you tell me where did you solder the wires from the external battery? That would help me a lot!

Great idea btw, but I'm trying hard to avoid bulkiness at all cost :D
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Re: Hacking EN-EL14 into a power adapter

Postby 4cc3ss » Wed Feb 25, 2015 4:40 pm

Hi,

Here you go.. p- is 0v and p+ is Vcc, please remember the center pin is the battery authentication, if this isn't connected the camera won't allow the battery,
unless you use the patch.
http://i307.photobucket.com/albums/nn316/Access41/Nikon%20EN-EL14%20Battery/nik-frnt-replicopy.jpg

And things are documented here, the search feature is very handy ;)
https://nikonhacker.com/viewtopic.php?t=616

Regards,
4cc3ss
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Re: Hacking EN-EL14 into a power adapter

Postby philips » Wed Feb 25, 2015 6:51 pm

Hey,

I did go thorough the topic, although I might have missed a few points, so please bear with me :)

So far I know that connecting just p- and p+ wont work, as I have tried it, and camera refused to work with it. I need to figure out what sort of input the middle tap needs. My best guess would be that as long as the values between p-/middle tap and p+/middle tap are equal (which means the cells are balanced) then it would allow the battery to operate.

I guess I just need to make a voltage divider between p- and p+, and connect the middle lead to the middle tap. I'll let you know how it goes when I get the time to do it.

Thanks!
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Re: Hacking EN-EL14 into a power adapter

Postby 4cc3ss » Thu Feb 26, 2015 4:54 pm

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Re: Hacking EN-EL14 into a power adapter

Postby philips » Fri Feb 27, 2015 2:17 am

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Re: Hacking EN-EL14 into a power adapter

Postby 4cc3ss » Fri Feb 27, 2015 4:43 pm

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Re: Hacking EN-EL14 into a power adapter

Postby Gadget93 » Thu Aug 13, 2015 3:49 am

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Re: Hacking EN-EL14 into a power adapter

Postby jeffpkamp » Sun Jun 12, 2016 6:05 pm

I recenty got myself a d5300 which as far as I know doesn't have a firmware hack that will allow it to ignore the nikon genuine battery check. I had done the grip hack a while ago before I found the firmware for my d5100, but it appears that my middle cable has lost its connection with the battery as placing a nikon battery in the grip fails the check. an ungodly amount of epoxy that I applied to keep cables in place has convinced me to try another approach.

I am going through the replacing the innards of a battery with a chip in it, but wanted to double check that I am doing this right before I go too much further. Right now I have what were the ground (neg of cell 1) and +8v (pos of cell 2) leads connected to a buck converter that drops a car battery down to 8.5 volts. From what I am reading the lead (4v lead) that connected to the middle of the two cells is what actually powered the chip, and it did so with the middle lead acting as the ground and the 8v lead acting as the positive to give the chip 3-4 volts power.

What I am wondering if any one has tested, is if this lead can take just being connected to the ground? Is that going to fry the chip?

My second approach would be to go straight from the car battery with a voltage divider. I have a few 10 ohm 1 watt resistors i could use to drop the 12v down to 8v and 4v.

Has anyone tried either of these approaches and had success?
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