'09 Chateau not charging

[wogden]

A good friend bought a one owner '09 used Chateau last year and now tells me that his batteries do not charge as he is driving the rig. They will charge if he plugs into shore power. Anyone have a circuit analysis that they could share with me so I can go up to his place and see what is going on with this charging circuit. Or any tips on what to look for as well.

[Finelinevan]

This is easy as I just went through trouble shoothing exact same issue on my BT cruiser. There is a part that when you turn the key allows the rv alternator to charge the coach battery the runs all the acessories. When the key is off it also stops that accessorie battery from drawing from the starting battery. They make a battery isolator as its called. OR a dual battery relay with an isolator built into it as most likley you will find on your rv as I did with mine its more heavy duty.
Here is company link I am buying mine from
Inexpensive 12V 150+ amp smart DC battery isolator and smart split charge relay for RV, car, and truck applications.
It also is setup to except the emergency battery start which most RVs have on them that if you coach battery is charged up and your enginge starting battery is dead this emergancy start switch allows the coach battery to open power when switch is held to enging battery and start engine. Like a jump start. Replace this and your charging issue will be corrected. Its very simple to replace.

[Finelinevan]

If ya want to double check on the one side of relay is the line that comes from alternator and the other side when rv is switched on will allow that current to flow through relay to coach battery. Take that side off and measure with ohm meter voltage should be 13 volts or so. If you measure nothing then relay is stuck inside and wont allow current to flow. You can also check small wire that is line from key start that tells relay to open and allow currrent from alternator to flow through relay. That should have a fuse on it check to see if it good 1st that may also be issue. When you turn key you should here a clunk sound thats the relay opening. Mine made that sound so I knew it was telling it to open but inside relay It had to be stuck not allowing it to make connection to allow current to flow.