or you can get one of these.  I bought one for each battery:

http://www.odysseybattery.com/chargers.html

On Oct 24, 2013, at 12:47 PM, Jon Hadlich wrote:

For the $200 it costs to replace them, there no question in my mind with the electrical systems everyone is currently putting in their airplanes. Be sure to buy a "battery minder" brand charger to maintain the odyssey battery. They require a slightly higher charge rate than the concord. Double check with the manufacturer or the battery minder guys.

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Jon Hadlich
AI Systems
(541) 815-7381