Community Forums

elgarc · 02-24-2009, 04:46 PM

My user manual suggests that if you leave the rig for more than a few hours, you should turn off the 12V switch at the door panel during your absence.

I don't personally plan to do that when I am on shore power, however it seems a great battery saving idea when you are boon-docked. The problem: The refrigerator is on that circuit and I don't want to shut it off (I like frozen meats, ice cream and really cold drinks!). Is there a 'smart', 'easy' way to get around that problem? If there are no better ideas, I suppose I'll have to run a direct wire to the fridge from batteries.

paz · 02-24-2009, 06:37 PM

I don't know how other Tiffins are wired, but if I turn off the 12V switch on my Allegro Bay, the refrigerator stops working. This happens even on shore power because 12V is required to run the circuit board. I certainly wouldn't recommend going out for a day of sightseeing on a 90 degree day with the refrigerator turned off, even when boondocking.

I have to admit I'm too lazy to dig out my manual to check, but I thought it said if you're going to store your motorhome (not hooked up to shore power) for more than a few days, the 12V stitch should be turned off to avoid running the house batteries down.

elgarc · 02-24-2009, 08:31 PM

Well...here's what my Bus Owner's Manual says, quote:

"For routine, short-term use, there is a 12 VDC disconnect switch on the switch console located in the stairwell of the Allegro Bus. This switch - located in the upper, left hand corner of the switch console - can be used to disconnect the "house" battery from most of the 12 VDC circuits in the motor home so that there is no inadvertent drain on the battery while the owner is away from the motor home (e.g., shopping trips, day trips for sightseeing). It is a good idea to develop the habit of disconnecting the 12 VDC 'house' battery system whenever one leaves the motor home for the better part of a day so that the "house" battery is protected." Unquote.

Really, I can't understand why anyone should use that switch in that manner if they are on shore power anyway. But for boon-docking I can certainly see the advantage, and it's handy enough. But, as a fulltimer, I sure want my fridge working in any circumstance.

paz · 02-25-2009, 03:18 AM

The quote from your manual helped me overcome my laziness and dig out my manual. Mine says, "The battery disconnect panel is located near the interior step. There is a rocker switch on the lower left-hand side of the panel which can disconnect the battery when the motor home is to be stored for any appreciable time. Pressing this switch downwards disconnects the coach batteries only, not the chassis battery. This feature is designed to prevent the coach batteries from being drained during extended storage."

Does your Bus have a residential 'frige? That's the only reason I could see for recommending turning off the 12V switch. If you have a residential 'frige, it would be operating on the inverter from the batteries if you were boondocking (not just the circuit board as with an RV 'frige), but it wouldn't matter if you were hooked to shore power.

Pigman1 · 02-25-2009, 10:03 AM

In my opinion this is probably one of the least useful items Tiffin put on their rigs. They could have put a lot of other MUCH MORE useful things into their rigs before even considering this switch. They already have a rotary switch in the battery compartment to disconnect house batteries and another for engine batteries. I guess people are too lazy to walk to the rear of the rig to shut off power if necessary???

John

elgarc · 02-25-2009, 05:19 PM

No paz, my fridge is a 4 door Norcold. That's why in the OP I said my fridge shut off with that switch.

John, it is pretty easy to understand why that switch is useful to prolong the charge of the house batteries. Just being able to turn off the lights in the switch panel itself is a fair savings in power. There are times when you are boon-docked and inside the coach, perhaps at night, and want some temporary 12 V power for the lights or something else. Then simply flip the switch off when you go to bed. Going outside and opening the hatch then coming back in several times a day isn't real convenient, especially after dark and undressed. I agree with you that if you didn't boon-dock more than a day or so, and were always on shore power the switch is pretty useless.

I'm not good with schematics or maybe I could help myself. So, if nobody else has anything constructive to offer, maybe I'll try another forum for this.

paz · 02-26-2009, 02:37 AM

elgarc - if you find anything out on another forum, please come back here and let us know. Maybe someone at Tiffin could provide an answer.

Being full-timers, we haven't turned off the 12V switch in almost 3 years - even when we're on the road or boondocking. When boondocking, I monitor the battery voltage and run the generator when necessary. We only have two 6 volt batteries and they can easily go all night without dropping below about 12.2 volts, so I can't see the reason for Tiffin recommending turning off the 12V switch for shopping or sightseeing trips away from the motorhome.

Joe-K · 02-26-2009, 04:11 AM

This 12v disconnect switch discussion has got me thinking

On all of my previous motorhomes, the 12v disconnect disconnected all of the 12volt power being distributed from the house battery system. On those motorhomes I only used the disconnect during long periods of storage.

On our Allegro Bus, I had noticed that when switching off the 12v disconnect, there were certain items that stayed powered inside the coach. Prior to reading the quotes from the user manual that elgarc posted (thanks for doing that) I actually assumed that the 12 volt system in our Bus was not correct in that the disconnect did not shut down everything.

Now though, as I rethink things, I'm going to go and investigate exactly what items stay powered up when the disconnect is pressed. I'm beginning to think that there is a real advantage to having the electric switch disconnect as well as the master battery switch in the battery compartment.

As an example, if Tiffin intended the disconnect switch by the door to be a convenient way to way to kill all of the discretionary loads (lighting, water pump, display panels, etc.) but leave power to required items ( HVAC controls, automatic awning, refrigerator, etc) the system makes sense. The separate master power switch in the battery compartment is the one that serves a different function which is to completely remove battery loads during storage.

If that was the intent, I like it but I'll have to validate exactly what items still have power when the disconnect is pressed. I know on my rig, for example, the automatic awning still has power which makes sense should a storm come up and the wind sensor need to retract the awning while the owner is not around. If the disconnect switch killed that circuit, it would to be good.

Elgarc, the fact that your fridge and paz's loses power when you press the disconnect is the only things that puzzles me. Perhaps, it was done that way thinking it removes the liability of having fridge issue (cooling unit failure or fire) while the owners were not present.

We have the optional residential fridge in ours, but I know I have a 12v unused wire in the rigs basement that was labeled for the fridge. I actually used that wire as the power source for my macerator pump. I'll have to check to see if there is power on it when the disconnect is pressed.

elgarc · 02-26-2009, 09:02 AM

Good points Joe K. It will be interesting to hear what you find that remains powered. My King Dome remains powered. Didn't think to check the awning.

Really, our buses aren't built very 'green', what with the Aqua Hot motor and the heat exchanger motors, and also the multi light strips that are on at the same time as the florescents in bathroom and vanity (fixing that with a switch this weekend). Slide outs that require engine off (for a very good reason) but puts a load totally on the batteries. We love our coach. A few tweaks here and there will make it even more livable/lovable.