Jayco Precept 35s electricalissue

Hi Land-Yacht welcome to the forum. I'm assuming the low voltage alarm is for the coach batteries. Is the coach plugged in to shore power? has that problem come back, or are you now only having problems with the starter battery draining?

You stated everything electrical seems to be working fine. Are you referring to the charger and such, or are you referring to things like the interior lights and fans? If the charger or inverter, what component did you test and how was it tested and what were the readings if any?

The next time you shut down the coach, like you normally do, just use a multimeter in between the chassis/engine battery ground cable and the negative terminal on the battery. Set the meter to the 10 amp setting and it should show your current draw when you shut the engine down. Normal(?) should be around a 1/10 amp or less. Anything over that may be draining your battery. While someone is watching the meter, start pulling 12 volt fuses until you can isolate the circuit that is drawing too much current and draining your battery. It may be something as simple as a light that is not going off when the unit is parked.

Are you leaving your bay lights on when you leave the coach? Ppl often forget those because they are not apparent.....Dennis

E05 on your Dimensions by Magnum means that there is less than 11.0 volts while inverting which means the Inverter will not Invert to 120 for your Inverter controlled appliances.
You should have a FORD chassis. The Headlight switch may have the roller that increases and decreases the instrument cluster backlighting. IF the roller wheel is rolled to MAX brightness and then you feel a "click" when rolling up, you have engaged the interior dome light indent. Motorhomes do not connect the dome light wiring to the dash switch. They may connect to a light outside by the radiator, but rarely. On Ford Chassis, if the roller wheel is in that indent for a dome light, Ford's use a relay to power the non installed light. That relay uses 12 volt chassis power to engage. THAT will draw a Chassis battery down in a week or 2. Make sure that roller wheel is not in the clicked indent. Doug

Thanks guys , some good info , I will look into all these things when I go back in a week or so . Hopefully something simple .