Originally Posted by 01DHS
The previous owner of my 1995 Land Yacht 30’ motor home had installed an auxiliary battery disconnect solenoid. I am now running into a problem with drained aux batteries. I leave the disconnect switch in the on position. The 2 auxiliary batteries are new installed this past May. My mechanic said the charging system is working. The converter, generator and alternator are all doing as they are supposed to do. We are wondering if the correct solenoid was installed? The solenoid is a White-Rodgers # 124-906 (same model as the aux start solenoid). The solenoid is installed between the positive battery post and the power distribution terminal block. Is it the wrong solenoid or perhaps wired wrong? Any help would be greatly appreciated.
Solenoids come in two varieties, power-on, and power-off. If power-on, when the solenoid is energized, it holds the switch in the "On" position. If power-off, when the solenoid is energized it holds the switch in the "Off" posiiton.
So, the solenoid switch itself is a parasitic draw if it's power-on and you left it on. Turn it off when you're not using it, and the battery shouldn't drain anymore.
I'm actually confused as to why there would be a solenoid switch in the first place. A simple mechanical switch would do the same thing in most cases, and most battery disconnects I've seen are mechanical, not solenoid.