Something's draining my house batteries?

[Bubba_Bill]

95 Damon Intruder, 37Kmiles. Replaced Magnatek converter/charger with the upgrade version. Was having a problem before that with the 2 house batteries pulling down to about 9v overnight, not plugged in to 110v. Took batteries and tested them, o.k. Voltage from charger: 13.30v. All 12v fuses removed to try and isolate where the drain is. Turned Shore power off last night, 9v this morning. When I disconnect the main battery positive cable, and reattach it clicks one of the 3 solenoids in the engine compartment. That solenoid seems to stay overly hot. Not sure of how these tie together. I'm guessing they switch back and forth depending on gen power, house batteries, or 110 shore power. No wiring diagram. Any ides? Thanks, Bill

[wa8yxm]

There are two types of solenoids used (Actually 3) in the motor home's 12 volt system. (The third one is the starter solenoid, it is kind of a 2B. it is like #2 but designed only for short term engagement)

1: Latching.. On this type some kind of latch, generally a magnet, holds the contacts either open or closed, A much larger magnet (The Coil, is an electro-magnet) is strong enough to "FLip" the status of the contacts. This one should not get all that hot as it should not have power on it for more than one second. To flip the other way, Flip the magnet (Reverse the power flow).

2: Continous (2b: momentary see above) this type is normally open, closes when power is applied, spring opens when power removed, they run hot.

NOW: if it's running hot as in overly warm, not Hot as in "Live wire" ALL THE TIME, then one of two conditions exists.

One there is a charger source AND it is bi-directional (Shore power or engine power)

2: The Control circuit for it is shorted and feeding power to it when it should not. (most likely).

[CA_Traveler]

It's just extremely easy and quick to read how much current wires are drawing and hence track down drains. No removing wires, pulling fuses etc.

[Bubba_Bill]

Batteries are 11 months old. Had them at home hooked together for a month and read 12.5v after sitting. The amp reader is probably helpful overall but not sure what it would tell me here. As I understand them, the solenoid always has power to one side. Ignition, or other 'signal' closes and allows current to pass thru. Seems maybe one of the three may be getting that signal or is stuck. Guess I'll try pulling the 'energizing' small wire off each one.

[CA_Traveler]

What does the solenoid power and what is it's purpose like battery disconnect, etc. I'm thinking it's always drawing power and perhaps should be a latching relay.

A DC clampon ammeter will go a long ways towards finding this and future electrical problems.

These tools are invaluable for the DYI RVer, especially for determing battery and AC loads. The clampon ammeter measures AC volts/amps, DC volts/amps, resistance, frequency (useful for checking a gen) and temperature. The accuracy is more than adequate for RV usage. The line splitter allows for easy measurement of AC amps for any plug in appliance. The female plug is on the bottom and the 2 loops allow for measuring 1x and 10x amps (useful for measuring small AC loads). About $75 for the pair. Check that any clampon meter you purchase can measure DC amps as they are less common than ones that measure only AC amps.

[2oldman]

How old are the batts?