A123 batteries for ign.

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A123 batteries for ign.

Postby Jim Kraft » Sat Oct 25, 2008 5:44 pm

Hi all; Just wondering if anyone has tried the new A123 batteries for ign. yet. They just could be the ideal battery for our needs as they are 3.3 volts with a very flat discharge curve. You would only need one cell which would cut down on space, and only one connection. The only thing I have not been able to nail down is how to charge them. I have been using 3 NIMH batteries, and these seem to work fine, but it would be nice to only use one cell. The A123 batteries from all I have read so far are much tougher and don't have the problems that the Li-Poly's do. For the HIMH batteries, I use a 15 minute charger that charges indivdual cells, so have to remove them from the plane to charge them. I know I could get a special charger that would charge them in series, but have just been using what I have. I use a 4 AA battery box from Radio Shack, and cut one cell holder off to make it a 3 battery holder. The A123 batteries are really new tech., and that is why I am asking here for info. Thanks
Jim Kraft
 
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Postby jccrall » Sat Aug 29, 2009 4:20 pm

Jim, I assume you have found the answer to your question about using an A123 battery by now. It has been almost a year since your post but maybe others scanning this forum would like to know about this.

A123 batteries (or single cell in this case) are safer than regular Li-poly cells in that you can discharge them at a high rate and rather deeply into their capacity plus they can be charged at a high rate as well. They are encased in a metal "can" and weigh more that the Li-poly cells that are encased in a plastic cover. A123 cells require a somewhat different charge values and thus must be charged with a charger designed to handle A123 cells. Many new Li-poly type chargers now include an A123 charge mode. The main down side, as I see it, is that unless you have access to an appropriate charger you will incur a fairly hefty cost to get setup to use an A123 cell for your ignition circuit source. Many R/C modelers have now gone electric and you may be able to get use of an A123 capable charger from a friend or fellow modeler. If you want to buy your own setup you are looking at $100 plus for a charger and power supply.

Having said all of the above, an A123 cell should make a good, safe source that can be setup to charge without removing it from your plane (something NOT to be recommended for regular Li-poly cells).

John
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Postby Jim Kraft » Mon Sep 21, 2009 5:07 pm

Hi John; Thanks for the reply and info. I check here every so often so am glad you replied. I guess I will stick with my NIMH batteries for a while. Maybe the prices will come down on the chargers when they have been out for a while. I have a new ign. circuit that I am using on my control line planes, that shuts off 2 seconds after the engine quits. This really saves the batteries since I do not have to run to the plane to shut it off manually. Seems like they always quit with the points closed. Thanks again for your info.
Jim Kraft
 
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Postby G WILLIE » Thu Feb 11, 2010 5:58 pm

There is a gizmo out called a LiPo Dapter. This is a small circuit board that is connected between a NICAD charger and a LiPo. They also make a version that does the same thing, but for A123 cells. The Dapter uses the power from the NiCad charger and take care of all the other things necessary to safely charge the A123 cells. The A123 cells are great. First off they are safe, they don't catch fire or explode. They can be recharged safely in 15 minutes. They will supply high currents. Best of all, they don't self discharge like NiCads; they are always ready when you need them. Throw away your NiCads!! The following site has the Dapter info.

http://www.slkelectronics.com/lipodapter/index.htm
G WILLIE
 
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Postby G WILLIE » Thu Feb 11, 2010 6:01 pm

Also, there is a guy on RC Groups named Everydayflier who has tons of posts regarding the care and feeding of A123 cells. I got my 2300MaH cells from Dewalt packs and my 1200 MaH cells from Black and Decker VPX packs.
G WILLIE
 
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