Are these in a stic pac or are the side by side. Need to see what the individual cell voltages are doing which will be tough if these are stick pacs. Read this and you'll see why need to know what cell voltage is doing - look at their maintenance paragraph - #3. You may have a few very low cells -

http://www.promatchracing.com/ibins.php


Is any one or two cells getting hotter than the others when you're charging??