Hi, when you say your batteries measured 13.8 vdc you were probably charging them via the converter (battery charger) either powered by shore or generator......so that is not their true unloaded terminal voltage. You should turn off the charging source and disconnect your coach loads (use/store to off) and then measure the battery voltage. They should probably be off for a while before testing voltage, but I suspect they probably are not even close to fully charged (12.6+ vdc for wet cell batteries). Fully discharged is about 11.9 vdc. If these are wet cell batteries, I would suggest checking water levels in each battery cell and only use distilled water for top ups (careful adding water as this is acid in the batteries). Then try to charge them for 24 hours (use/store "on" while charging) and retest again unloaded to see if they have been charged fully. You may need to replace the coach batteries if they are damaged and won't take or hold a charge.