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subtroll
Explorer
Jun 19, 2018

Replacing Battery Interconnect Solinoid

My 2004 National Tropi-cal electric systems appear to be working property except both Chassis and Coach batteries remain isolated from each other. AC sources(shore and generator) charge coach batteries fine but do not charge chassis batteries. Engine alternator charges my new chassis batteries fine.

Have located the Battery Interconnect Solenoid (out of the way behind a circuit board) and measure chassis battery voltage on one side and coach battery voltage on opposite side (~1 VDC difference). Measured 12 VDC on one control terminal indicating solenoid is energized but not connecting batteries. (I assume solenoid is normally open and closed when energized.) Believe that also confirms that whatever relay actuates the relay is OK.

Looks like replacement will require both sets of batteries and AC power to be disconnected and I don't know what solenoid to order. Looks to be similar to Battery disconnect relay in another compartment. Think I'll wait until my road trips are complete this year before replacing it.

Any suggestions?
  • While tbat brand has fouur studs, that isn't always the case. Neither of my rigs have had an isolated stud. Both were grounded through the solenoid case.

    Percussion persuasion is not recomended, you appear to have found your problem, trust you meter and your gut.
  • My Dolphin solenoid gave it up in the middle of the Alaska Highway. A local garage put in the new one. I think I remember the mechanic mentioning there was a delay timer so that solenoid did not engage until the motor had been running for 30 seconds. The circuit board may be the delay timer. Wish could help with a model for replacement but I recall the mechanic said it was easily available, even in the middle of the Yukon.

    Dave