Battery Disconnect... What does it disconnect??

[kfp673]

Have had my trailer for 2 years and have a habit of always turning off the Batt disconnect if it's going to be parked for more than a week or two. Recently I started working on a few lighting upgrades to LED, adding LED strips etc and noticed all the lights still worked with the disconnect off. Checked a few other things... Slides worked, TV worked.... So what exactly does the disconnect actually disconnect? It is in my front compartment and it is definitely wired into something but no idea what. Fully understand there's no way for any of you to give a factual answer without testing, but just curious if there was an RV standard. Now I am plugged in to 110 at home right now so does the AC/DC converter skip the battery even for 12V items? If I was unplugged would most items (12v items) not longer work? Thanks!

[doxiemom11]

We have 2 disconnect switches. One for the engine battery and another for the house portion.

[DrewE]

There are variations in how things are wired.

On my motorhome, on one side of the disconnect are the house loads, and on the other side are the battery, converter, battery combiner relay (which allows the alternator to charge the house battery when the engine is running), and a couple of always powered loads--the entrance step and the dash radio clock/memory line, I think.

Often the converter is separated from the battery by the cutoff switch and so always connected to the house loads, rather than being connected to the battery and isolated from the house. Sometimes there are other always-on circuits, such as the propane and CO detector, slide motors, etc. On travel trailers, the emergency breakaway brake system should always be unswitched.

[RambleOnNW]

What the battery disconnect does disconnect depends on how the 12 volt system is wired. On our rig the battery disconnect cuts off the entire house 12 volt system but the house batteries will still charge from the converter if external AC plugged in.

[ksg5000]

Also - your battery disconnect may not be functioning correctly. As I recall mine is based on latching relay which has a couple of fuses. Probably worth a few minute to check whether your battery disconnect is working.

[Super_Dave]

" If I was unplugged would most items (12v items) not longer work?"


Not most, nothing in the trailer would work.

[way2roll]

I had a previous Class A that when plugged into shore power it would "bypass" my disconnect. In other words, with the disconnect on and not plugged in, nothing would work - as expected. But when I plugged in, everything worked, including all 12V. Not sure if that is the same as what you are explaining but it may help in some way.

[dodge_guy]

valhalla360 wrote:

rdhetrick wrote:

dodge guy wrote:
Yes, the converter powers up the system even with battery disconnected.

I'll add that this is normally true, but not always. I had a 5th wheel that HAD to have a battery installed and connected for the converter to work. Without the battery (or with the battery disconnected), and while plugged in to shore power, no 12v anywhere but 120v was fine.

Didn't make any sense to me, but it was true. I'm not certain it was like that from the factory or if a previous owner did some re-wiring.

Actually that makes more sense as you are less likely to stress/overload the converter as the battery will smooth out up any heavy loads.

actually you guys are correct. the converter doesn't put out enough amps on its own to run a slide or power tongue jack. only the inside lights. the system nneds a battery to function properly.

[wopachop]

midnightsadie wrote:
put a disconnect right at the battery then things are dead and your battery will hold a charge much longer.east to install.

Added bonus you get to drive down the road with your emergency brakes disconected.

Hopefully people understand thats a joke. Be very careful about where you put the disconnect and how your system is setup while driving.

[midnightsadie]

put a disconnect right at the battery then things are dead and your battery will hold a charge much longer.east to install.

[valhalla360]

rdhetrick wrote:

dodge guy wrote:
Yes, the converter powers up the system even with battery disconnected.

I'll add that this is normally true, but not always. I had a 5th wheel that HAD to have a battery installed and connected for the converter to work. Without the battery (or with the battery disconnected), and while plugged in to shore power, no 12v anywhere but 120v was fine.

Didn't make any sense to me, but it was true. I'm not certain it was like that from the factory or if a previous owner did some re-wiring.

Actually that makes more sense as you are less likely to stress/overload the converter as the battery will smooth out up any heavy loads.

[rdhetrick]

dodge guy wrote:
Yes, the converter powers up the system even with battery disconnected.

I'll add that this is normally true, but not always. I had a 5th wheel that HAD to have a battery installed and connected for the converter to work. Without the battery (or with the battery disconnected), and while plugged in to shore power, no 12v anywhere but 120v was fine.

Didn't make any sense to me, but it was true. I'm not certain it was like that from the factory or if a previous owner did some re-wiring.

[dodge_guy]

Yes, the converter powers up the system even with battery disconnected.