1/5A to AA battery adaptors
Here are two photos of how I made adaptors to use 1/5A NiMH cells in place of a CR123. The cells are rated at 400 mAh and run my ARC LSL-P flashlight for about 45 to 50 minutes on a continuous run.
The spacer makes the 1/5A cell fit into a standard AA charger. The 1/5A fits into a plastic sleeve, with its negative end sticking out and a bolt making up the additional length fitted into the other end of the sleeve and contacting the positive end.
I found that white glue sticks from Office Depot have a plastic case that is almost exactly the right size with a little reaming out. I used bolts in the center, and cut off the heads. I cut the bolt to the right length, then screwed two nuts on each bolt to fit snugly into the plastic housing. I added a drop of solder to the top of the top cell of the pair. I did not put one on the bottom cell since heating the cell to make the solder bond may rupture the cell's vent membrane and make the cell dry out.
On the left, the two green-wrapped 1/5A cells. I have three sets of them. In the foreground, the white adaptors are what I am using. The black ones further back were an attempt to use shrink wrap instead of plastic sleeves, and did not work as well. Behind them are the Office Depot glue sticks that had plastic sleeves just the right diameter. To the right is the Maha charger, with batteries in place and charging. Wish I had a better macro camera.
I charge my batteries in pairs. My first charger for them was a Maha MH-C124-S. It works with a 12v input from a wall-wart transformer, so it can work on car voltage too. It charges 1, 2, 3 or 4 cells at a time. It is a slow charger for AA and AAA batteries, taking overnight or longer, depending on how many cells it is charging. It delivers 70ma to two 1/5A cells. I leave them in for 10 or more hours. They get warm but not hot. I can only hope I am not destroying them with an improper charge, but don't think so.
I now have a Maha C401FS, a much better charger that uses pulse width modulation and does not overheat cells. It works find for the 1/5A's on the five hour (slow) setting. I have not tried it on the fast setting.
The cells came from batteryworldcenter.com, but when I tried on October 13, 2004, I did not find them on their server. They are in Alhambra, California. There must be other sources of 1/5A cells.
The idea for using these batteries came from Whistler's Web page about them. He has good info and great photos, but not much on making the adaptors, so I put these photos up.
I have been using my NiMH rechargables every day since about January of 2004, with good results so far.
In October of 2004 I received some li-ion CR123 cells from JS Burley's. They look good but I have no experience with them yet.
This page was last revised on: October 13, 2004.
Contact me.
|