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NEC never made an adapter to use regular batteries in your 800 or 880 in the event that you were unable to recharge it. So one day, when I had too much time on my hands, I took an old 880 battery pack that no longer worked and built my own. It operates using 9 AAA batteries.
The first step is to separate the case halves. This is really the hardest part as it takes time and effort to score the case. But once complete, you can then separate the components as you see I have done in this picture.
 Visible is the casing itself, the pcboard and the lithium ion cells.
 Now I took the case and ground out all the plastic ridges that were in the case so that I have lots of working room.
 I also ground down the pc board, making sure I didn't disturb that actual connector, but I don't need any of the pc board components at all. But I will keep the board so that I can use it to resecure the connector back into the case later.
 Now you need to solder a couple wires to the outer contacts on the battery connector. The connector is offset, not in the center of the pc board. The connector side with the long part of the pc board is the positive and the short side is the negative terminals.  Here I have now hot-glued the connector in place, though epoxy would have worked just as well.  I knew I was going to need some plastic to use as spacers and insulators...so I just took an old CD case and cut it up for the plastic.
 Here is that same piece just pictured. I am using it to protect the pc board
 To get the width correct, I placed 3 batteries in side by side, and then cut another piece of CD case plastic and then glued it into place. I then backfilled behind the plastic with hot glue so that it would move with batteries pressing against it. Again ugly, but functional.  I imagine I could have purchased the springs I needed, but since I had an old TV remote control unit that didn't work, I broke it up to use the battery springs. Here you can see I soldered on spring to the wire that goes to the connector, and just hot glued in the other spring to a piece of plastic that I cut up from a green colored CD case. I will do the same thing to the other end.
 Here is the other end. Not pretty, but electrically functional. I filled up the areas beyond the plastic with hot glue and let it harden to act as a filler. That way there isn't any give when I insert the batteries. You need to think about the spring location so that the polarity of the batteries matches the springs and contacts.  Here you can see the batteries in the case and the modified top half of the case back in place. By cutting the opening the way I did, I can now slide the batteries in place with both halves glued back together. The reason for the smaller cut slots is to aid in removing the old batteries by making them accessible/visible.
 When all is done, I have inserted my home-built battery pack. You can barely see the marks or scoring along the case halves with the battery reinserted. You don't get a tremendous amount of time on AAA batteries, just a little over an hour and a half with a new set of nine. It wasn't difficult, but cutting the pieces with a pocket knife wasn't easy either. I think if I did it again, I could have make it much more pretty. But more importantly, it works. |