Electrical question

[Grey Wolf]

The two batteries in the outer compartment are dead. I attached the two inner cables together that go on the two batteries. With the engine running I still have no power in side the RV. Does it only work when the two cables are attached to a charged battery?

[John "T" Nordhoff]

  SORRY, I cant answer this question with the limited information you provided (plus NOT there to see whats what) but will offer some info which may or may not help you figure it out:

 1) "two inner cables" I don't know if that's the + and - 12 volts off the house batteries to your internal DC distribution panel or what????????? If one was to the + of a battery and the other to the - , you obviously need 12 volts there (ie a good battery)  to operate your 12 volt loads and connecting the two together IS NOT CORRECT.

2) Id think Id FIRST connect the cables as they were and check the electrolyte and then charge the batteries (as/if needed) and see if things work????????????

3) On most motorhomes when the engine is running an isolation device (relay or solid state) will eventually close which allows the engines alternator to connect with and charge BOTH the engine and house batteries while driving. If that's in place and working and if the house batteries aren't totally shot and run down and cables are correct, if the engine is running and the isolation device (relay or sold state) is closed then internal 12 volt loads should work. BUT IF THOSE TWO CABLES ARE INTENDED AS THE + AND - 12 VOLTS DO NOTTTTTTTTTTTT ATTACH THEM TOGETHER THAT SHORTS THINGS OUT 

 CHECK THE ELECTROLYTE LEVEL AND GIVE THE HOUSE BATTERIES A GOOD SLOW CHARGE AND CONNECT CABLES CORRECT AND SEE WHAT HAPPENS. Then you can investigate the circuits and isolation device (solid state or electromechanical relay) to see if the engines alternator is eventually (may be a time delay or other voltage sensing circuitry) getting connected to the house batteries also so they get charged via the alternator when engine is running.

 John T