I have a 5yr old system and have been getting cell errors (T-15 no power). I have done all the testing on the board, fixed/replaced the relay problems, had to replace a switching transistor and fixed cold solder joints. Also had the cell tested and is good. After reinstalling the board, the system works and all is good for about 15min. Then I get a cell no power error. If I turn the system off and wait a few min, once i turn the system back on. All is good again for about 15min. Any idea as to what the next problem is? All the voltages check out, even after getting the error, voltage is still present at the cell itself. Thanks