Constant Duty Solenoid in Battery Compartment 1988 MCI-9

[bronson]

Hello. Had a question about wiring in the battery compartment. When I got my bus last summer the constant duty solenoid in the battery compartment was not hooked up. I tested it and it was bad. I bought another and now want to make sure it is hooked up correctly. The solenoid is activated when the battery disconnect switch is turned on. No wires were hooked to the solenoid except ground and wire from disconnect to s terminal which activates it.  When I bought the bus the wire that feeds 12 volt to equalizer was hooked up to the positive post of the 2nd battery, putting 24 volts to the 12 volt terminal of the equalizer. I found in the manual that it should go to battery 12 volt and have corrected this. There is another wire coming off the 12 volt terminal of the equalizer and it goes to a 40 amp breaker then disappears under the bus. There is a smaller gauge wire on the neg post of the second battery (12 volt), it disappears under the bus. Where doe this wire go to? Is it on the correct post? Or is this the 12 volt wire that the solenoid would feed?  I either overlooked it or cant find it in the manual. I am not finding the constant duty solenoid in the wiring diagram. Hope this makes sense. Had a photo to attach but it is too large to attach. Its dark now and snowing, will have to take another one tomorrow.    Thanks. Gary

[pvcces]

Gary, I don't think that you are going to be able to answer your questions until you learn what that solenoid is supposed to do. I think that it is not in your manual because it is not original equipment.

Usually that type of solenoid is used by busnuts to tie two battery banks together so that a single charging source will charge both banks of batteries if one is charging.

The single most frequent failure of these setups comes from failure to consider the maximum current that might flow between banks. Inverters and starting loads are sufficient to fry these components under some conditions.

We use a Pathmaker to detect, connect and disconnect the banks. We use that output to run a constant duty 500 amp or higher solenoid. All of the circuit uses big wire. 12 volts should have 4/0 wire. 24 volts should have 1/0 or 2/0 wire.

Food for thought.

Tom Caffrey

[bronson]

The manual talks about an optional 12 volt power source with a cut off relay and I am thinking this is it. It says there is a wiring diagram later in the manual but I dont see it.

[pvcces]

It doesn't seem likely, Gary. The wire sizes are a dead giveaway.

Tom Caffrey