Replaced house batteries 2014 Sunstar 35F

[Chief141]

Hello all '14 Itasca Sunstar 35f. Replaced 3yr old house batteries. After 2 weeks they discharged done to 5VDC with the disconnect switch in the off position. So I figured it was time. New replacement batteries have been bench charged and load tested. Once installed disconnect swith will not turn on. Batteries at 12.7VDC or better. No power at the switch. Start the engine, 90 sec later switch is energized, house and inverter funtion normal. Engine shutdown, no house power, no inverter, disconnect switch no power.
Any insight welcome.

Happy Father's day were it applies.

[Morich]

Sounds like part of the "learning curve" as it is a somewhat frequent thing!
Step one is that you have been misled in thinking the disconnect on either the coach or the chassis will disconnect all the battery drains. WRONG!
sneaky things are left connected on each, to let things run down when stored! Chassis battery will often have igniton, radio presets and any automatic things like door lock, etc. The steps which fly out on almost all moves and turn on the light underneath, can be a big drain, especially th elight if we don't spot it in the daylight?
The coach side will leave safety equipment like CO and propane detectors still powered to prevent us going back to an RV full of gas to blow up!

suggest making sure both battery groups are charged first, then try the switch again?
The switch moves a relay which "latches" in the last postion thrown and has to have power to move from that latched position. So if there is not enough battery , pushing the switch will do nothing to move the relay. So easy first step to seeing if the switch is okay or failed, is to make sure it has good battery powers on both battery groups.

Try that and if still no good , we can look into the wiring further and sort what else may have failed.

Note that I think there will be two different battery disconnect switches so be sure both are on after getting both batteries ingood shape? Notice that the switches are not the type which we flip and they stay but are momentary that only act while we are pushing them. That can allow for some confusion if we think we have turned the switch on and THEN get the good battery to it. Good battery first, then push the switch to move the relay!!

[Chief141]

Thank you. As stated batteries are nee. I bench charged them and load tested both before installing today. 2nd time around. Dropped them in right after purchase last week. Rigged a shunt read a draw of 0.004 amps. What ever it is, it didn't go to sleep. Monitored that draw for 20 min. That aside, at the house, disconect switch all 5 contacts show ground. Once the engine is running within 2min there is power to the 2 pins on the switch connector as it should be. Shut the engine, no voltage to the anywhere on the switch.

[Morich]

Okay, sounds like a good time to do some checking and drawings may help.
For the overall wiring diagrams:
https://www.winnebago.com/Files/File...ram/Wiring.htm

There are two builds ( early and late) of that RV, so choose the correct after looking at the RV serial number. 7th digit of 1 is early build, 7th digit of 2 is late build!
Once on the right group, look for the "Chassis Electrical Box Assembly" group for the disconnect relays and where they set. Use the chart at top left of sheet one to get on the right sheet for your model!
That gets the drawing of the parts as we see them with lots of info for clues.
For the wire schematic style, go to "Body, 12 Volt Wiring Diagram" or for location info, go to the "installation" sheets.

Winnebago uses labels on the wires for ID.


Use this chart to "decode" the letters.
https://www.winnebago.com/Files/File...ical_guide.pdf

On drawings or wires, we can get the "from" and "to" info on wires from this chart.

I did not know if you were early or late but looking at early build here:
sheet 1

Click this snip to get a better view or go direct if I'm on wrong build?

Some info to show why not all power is cutoff when disconnect relay is open!



On both coach and chassis batteries there are wires going directly from the battery disconnect BEFORE the relay that go to the fuse buss bars!
Those will stay hot even when disconnect switch turns the relays off!

But a point to not is there are fuses that may give trouble on this section and they are not on the normal fuse/breaker panel!
Note the lbue marked items top left? Those may get blown when batteries are changed, so if still in trouble, they may need to be found and checked?

Keep in mind this is the drawing for the early build and check the correct drawing as the later build may have changes.

See if that does any good??

[Upinsmoke]

I apologize for this not necessarily being helpful, except to say that, several years ago, when I changed all 3 of my batteries, nothing went amiss, and it's been fine since then.

I'm not sure what may have gone wrong in your process (fuse shorted maybe) but obviously something changed. The drawings should help track it down.

I'm following to see what turns out to be the problem in case it does happen in the future.

[Chief141]

The rig is stored a distance from my home. I haven't been back to it. Will update