Battery drain

[Al F]

5 hours ago, arboldt said:

I may have inadvertently identified the problem while creating a new one.

We'd had the MH on shore power for a couple days, then had to disconnect it. The next day, the battery level was 12.7 (per the control monitor). Another day, and it was 12.5. Sounded good. However, the backup camera was no longer working. This leads me to believe the backup camera was the culprit. Don't necessarily understand it, but... The camera was coming on automatically when I put it in reverse; the power switch had no effect.

Now I need to find the fuse for the backup camera. It's not on the 12 V fuse panel. Assuming that's what the problem is, then I should put an in-line switch to turn if off when we're dry camping in one place for more than a day. I'm also assuming the several times I disconnected the battery cables is what created the issue.

Yesterday we drove a couple hours, then parked at my brother's, not connected. A couple hours after we stopped (approx 4 pm), I checked the monitor and the battery was at 13.1!. This morning (11-ish) it was 12.7. So I don't know if the 13.1 was accurate and it actually dropped 0.4 V or if it just returned to 'normal'. Since then I did get shore power out to the MH, so should be good.

Normally the backup camera only gets power when the ignition switch is on, but usually you need to press the power button to get it to come on when in drive or neutral, but is set up to automatically come on when the transmission is put into reverse.  Bottom line the camera should not be the problem.  Since you have a motorhome and the camera come installed from the factory it is unlikely they would wire the camera to always have power. 

About your 13.1 volt reading.  That is a normal reading right after being charged. When being charged from shore power you will likely see it at about 13.4V right after disconnecting from shore (or generator) power.   It is known as a "surface" charge.  After a number of hours the battery should drop to the 12.6-12.7V range. 

Now about your first reading of 12.7V one day after being on shore power, then seeing 12.5V the second day, we really need to know what it is the 3rd day and the 4th day. 

If it continues to drop 0.2V each day, you still have a problem and should start your trouble shooting over.   I suggest pulling the negative cable from the batteries and using your amp meter see how many amps are being discharged.  If those readings are still the same negligible discharge of 0.18amp you reported earlier, you have a bad battery. 

[Kirk W]

13 hours ago, Al F said:

Normally the backup camera only gets power when the ignition switch is on,

Not only is this true, but those camera systems usually are connected to the engine 12V  and not to the coach system. There are two different systems that can both get power from the alternator when the engine is running but they should be separated with the engine off. Most RV camera systems are designed and wired to turn on automatically when you go to reverse and the on/off switch function is there to allow you to turn the camera & monitor on while driving if you wish to use it while traveling forward. The on/off switch does nothing with the ignition switch off. It is very unlikely that it has anything to do with your coach batteries draining while parked but it is possible that it could drain the chassis battery if the ignition has been bypassed. It would have to be rewired to make it drain the house batteries.