RE: E-Flight battery not charging.
If you have a digital multimeter, you can do some basic troubleshooting.
I don't know anything about your charger or battery, but the first thing I would do is check the voltage of the battery. If any cell is too low, your charger may be refusing to charge the battery as a safety precaution. Lipos that have been discharged to too low a voltage may be damaged, and so the charger might be "smart" enough not to charge such a battery.
Checking the battery voltage at each pin of the charging connector will also reveal if the pack is out of balance or if one or more of the cells has become disconnected from the charging connector. If a cell shows "zero" volts, it is probably a bad or broken connection. Fixing such a connection can be tricky, since you might need special solder.
You should also check the voltage at the Deans connector. Perhaps one of your solder (not "sodder") joints has gone bad.
Have you tried the charger with other packs to be sure it is working?
- Jeff