Community Forums

ok-rver · 08-01-2021, 08:30 PM

New to us 2004 HR Scepter, lots of time with cruising boats. I have searched the forums and looked thru the 2004 wiring diagrams downloaded from another forum. I am trying to determine the function of the switch just inside the door that I believe is labeled battery cutoff. page 378 of the downloaded 2004 Scepter manual has the following:

BATTERY CUTOFF:
Controls the 12Volt DC power to the domestic fuse panels.

This switch is a low current switch with a funny sliding block. My assumption is that it is energizing something like a relay to allow large current flow. My sales guy who is kind of knowledgeable tells me it turns on "all" of the systems including 120.

I am familiar with the house and chassis battery disconnects, the combiner/relay that could be used to jump the chassis battery for starting, the diode block used to charge both battery banks from the alternator, and the forgot the name device that charges the chassis from the house when the inverter/charger is on. Did not see anything else in the battery compartment that would be heavy duty enough to flow the current required for the house.

I found a house disconnect labeled KIB LR9806 on the 12V front distribution wiring diagram. No wires connected to it. It maybe some kind of relay. text search for "disconnect" did not find anything else in the wiring diagrams.

First big question is what functions does this control and does it turn the function off therefore should be turned off using the lower rocking action of the switch when storing the MH?

As a hands on guy, I would like to know what it is connected to so when things don't work, I have a place to start.

Thanks for any help

Mike

Massparanoia · 08-01-2021, 08:38 PM

It should disconnect the 12v house batteries from the 12v electrical system of the RV. To prevent parasitic drainage of the batteries when in storage.

Old-Biscuit · 08-01-2021, 08:49 PM

It isolates the house battery when placing in storage

Rarely does it shutoff all DC
Parasitic draws from LP Detector, Stereo, Antenna booster etc as those can be wired directly to Battery POS post and can cause low battery voltage within 2 weeks of storage

120VAC and 12VDC are 2 separate systems.
*12VDC may be required for some 120VAC to function...circuit boards for Fridge/water heater/Air Cond Controls etc

Persistent · 08-02-2021, 08:15 AM

Old-Biscuit's answer is the correct one. Sometimes they are call "salesmen switches" because the first thing the salesmen shows a customer is this switch when he enters the RV and turns it "on".

The switch is usually not for long term storage. It is for dry camping. It minimizes 12 volt consumption while you are out for the day. Propane detector and other vital 12 volt devices may continue to work.

Most salesmen switches do not disconnect 120 volt systems, but there is no reason why the switch couldn't do that. There is also not much of a reason to shut things off when on shore power. You can test it by plugging in and switching "off".

Do 12 volts still light up?
Do 120 volt appliances still work?

As you suggested there is most likely a relay some where that does the main switching.

Have someone switch it "off" and "on" while you poke around listening for the clunk of a large relay. There are new solid state systems that may be silent.

I wish you good luck and happy trails ahead!

ok-rver · 08-02-2021, 06:13 PM

Today was taken up with moving MH from dealer to it's new storage bay. Spent several hours on the roof cleaning, thankfully it was only 89 in Tulsa today with a bit of clouds. Wife got the chance to drive around in parking lot, backing up and getting the feel of the wheel and shifting. Running gen when we extended slides to confirm no water had leaked into awnings and had front AC on. At some point, I pressed the battery cutoff switch and the front AC turned off. Hit the switch again and with a few second delay, the AC restarted. Tomorrow will have time to see what goes on and off with the switch.

Old-Biscuit · 08-02-2021, 07:11 PM

Quote:

Originally Posted by ok-rver

Today was taken up with moving MH from dealer to it's new storage bay. Spent several hours on the roof cleaning, thankfully it was only 89 in Tulsa today with a bit of clouds. Wife got the chance to drive around in parking lot, backing up and getting the feel of the wheel and shifting. Running gen when we extended slides to confirm no water had leaked into awnings and had front AC on. At some point, I pressed the battery cutoff switch and the front AC turned off. Hit the switch again and with a few second delay, the AC restarted. Tomorrow will have time to see what goes on and off with the switch.

A/C unit runs on 120VAC BUT control module/thermostat uses 12VDC
When you turned battery cutoff switch OFF you shutdown the DC System...lack of DC for A/C Controls
When you turned battery cutoff switch back ON you restored DC System.....thermostat was still calling for COOL so A/C Unit came back on

Circuit Boards use DC to function
No DC then no functions---Water Heater, Fridge, A/C Unit
*and of course any DC appliance/component ---Lights, water pump, furnace etc

ok-rver · 08-03-2021, 08:19 PM

My questions did not get answered by the posts above. I did spend a bit of time doing some research at the MH and have answered my own questions.
On to the next projects.

Mike

Old-Biscuit · 08-03-2021, 09:06 PM

Quote:

Originally Posted by ok-rver

My questions did not get answered by the posts above. I did spend a bit of time doing some research at the MH and have answered my own questions.
On to the next projects.

Mike

So what was the 'answer'?????

ok-rver · 08-07-2021, 09:40 PM

Found the relay. The forward driver side basement compartment has an approx 12' by 18" black cover over the forward section of the coach power distribution panel. It is divided into switched and un-switched fused circuits(labels on the board). The relay is a little bigger than an older starter relay. It has a circuit board protected with heat shrink connected to the coil circuit on the relay. It appears that it is a latching circuit that switches state each time the switch on the dash is rocked to the on position. Still don't know the function of the slider on the rocker switch.

My AC units are Dometic, same brand as was on my boat. The boat AC provided 12V to the thermostats from internal to the AC unit. I checked the house thermostat on the MH and it is powered up when the house system is energized. Now know were the thermostat gets its power and because the ACs came back on when the house circuit was re-energized, it appears the thermostat remembers last state when powered down and then re-energized.