684-1251-012 12V Power Seal DC Contactor, 1 Pack

I ordered the Trombetta 684-1251-012 continuous duty battery solenoid as a spare part for my Winnebago Solis Pocket 36A (chassis battery boost / house charging solenoid). This is a direct replacement for the OEM relay. I verified both the coil resistance with a multimeter and it matched the spec sheet coil resistance of 13.8 ohms. I put 12VDC voltage across the coil on the bench and the contacts closed as designed. This solenoid closes whenever the van engine is running to allow the engine alternator to charge the house batteries.

Bolted right in, same as original. Works as it should, solved ongoing issue where house batteries were not being charged by alternator.

Original equipment replacement in my RV

Identical replacement.

While driving, the house batteries in my Class C RV are used to power my unit's residential refrigerator via a DC-to-AC inverter. During this time the drain on them is substantial. Before the end of a day's driving they would run down low enough for the voltage monitoring system to generate an alert and for the refrigerator to stop running. I traced the problem to a failed underhood Trombetta relay which, in conjunction with a solid state device called an Isolator Relay Delay (IRD), uses the output from the engine's alternator to charge the house batteries while the vehicle's engine is running. The Trombetta is a known failure point in this setup and a more robust—albeit more expensive—alternative is available, but for my particular use case replacing the Trombetta was my preferred way forward. I'm happy with the end result, and even though I know it won't continue to work forever at least next time I'll know exactly what needs to be done. Depending on how long the new Trombetta lasts, when it fails I'll either replace it with another identical unit or go with the higher priced but longer-lived alternative.

Works as supposed to

Used in an RV for battery isolator

This unit is a direct replacement for the battery isolation solenoid in a Thor Chateau Motorhome. The original died after 10 years of use. This made the repair quick and easy.