Charging TV on shore power

[Willy Bee]

Some one told me that there is a set up that can be done that when your trailer and truck will be sitting for a long time that you can have the truck battery charging when your trailer is plugged into shore power and the truck in plugged into the trailer lights connection. Is this true and if it is how do you set it up? I know that when the trailer is plugged into the truck the truck will charge the battery in the trailer while your driving. How can you reverse that?

[Irlpguy]

Here is a diagram for the 7 pin connector on your RV and TV, the auxillary connection is the one that supplies voltage from the TV to the RV. If that is hot when the ignition is off on the TV (it should be) then by plugging in the TV to the RV you should have voltage from the RV batteries to the TV and it should maintain the same voltage as the RV batteries.

It is possible there is a diode in this circuit but I don't think so. There should be nothing you need to do but plug in your connector.

[sapest]

If you know better, plse correct me.
On a GM dual battery vehicle, the 'primary' and 'secondary' batteries are isolated from each other when the ignition key is off. In the scenario described, the secondary battery may be charged (given the wire gauge and run length from the 7 pin connector I dont know to what extent) but the primary battery will never see any charging voltage.
Do I have this correct?
Thx
-Steve

[Tom S.]

quote:Originally posted by sapest

If you know better, plse correct me.
On a GM dual battery vehicle, the 'primary' and 'secondary' batteries are isolated from each other when the ignition key is off. In the scenario described, the secondary battery may be charged (given the wire gauge and run length from the 7 pin connector I dont know to what extent) but the primary battery will never see any charging voltage.
Do I have this correct?
Thx
-Steve

No, they are not isolated. That's why if you have one bad battery, it will kill the other one too, whether the ignition is on or off.

[sapest]

TomS
True with diesels, but gassers with RPO 8B0 have the isolated second battery? Or am I still mis-informed? Thx
-Steve

[Tom S.]

quote:Originally posted by sapest

TomS
True with diesels, but gassers with RPO 8B0 have the isolated second battery? Or am I still mis-informed? Thx
-Steve

Ah, gassers, I'm not sure of. Could be?

[paulinbaja]

The power lead (red labeled auxillary in the above diagram) from the TV to the RV SHOULD be isolated by a relay. When the TV is not running there should be no connection from the TV power line to the RV. This prevents the RV from draining the TV battery if you stop and use the lights and etc. in the TV. You could use a switch and jumper the relay or put a shunt wire in place--but remember you run the risk of draining the TV battery if you remain hooked up.

[mhs4771]

That's the reason I disconnect that cord if boondocking for the night and remaining hooked up. If we have shore power I don't worry about it.