Thor Forums

[javelin]

Originally Posted by Muggs

The first week we brought our e450 based unit home the chassis battery drained.. Emergency start would not work due to being so low. I was not plugged in used the use/store button in store position. I since learned on our unit we always keep it plugged in and never use store position. If we did not have option to plug in I would add battery disconnects. There are parasitic draws on both battery banks. Our unit is always stored at either of our houses and plugged in. It also never sits more than 2 weeks at a time, usually less.

On a warning note, a few months back on a trip the chassis battery died while fueling. Running lights left on while fueling drew it down. I was able to start internal generator and use racecar charger to boost and continued. I now check battery capacity every quarter by unplugging and running inverter to power tv. When I first installed inverter it took 6 hours of tv to drop panel to 3 lights. Last week it only took 2. Time for new house batteries. I check chassis battery with cigarelle lighter display. When plugged in it goes from 12.4 to 13.2.

Just a comment regarding a wet cell battery state of charge. Your 12.4vdc measurement represents about 75% of full charge only. The voltage measurement to estimate state of charge should be taken at least several hours after battery charging has been stopped; and while battery is kept unloaded. When charging, your cigar lighter voltage monitor is confirming that you are at least "float" charging the battery, but it is showing you the converter output voltage across the battery. To get the last 25% charge and remove plate sulphation, your converter should probably be running over 14vdc (Absorption mode) holding that voltage while letting the charge current fall as the battery voltage rises. Some after market converters (like Progressive Industries) allow you to manually force this stage and also have an automatic mode as well if you leave it on shore power. There is lots of info on line about the "care and feeding" of wet cell batteries.