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Old 05-19-2015, 08:08 AM   #1
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Where does the power draw from (cig lighter vs. outlet)?

I am curious if anyone knows where the power is drawn from for the cigarette lighter socket and the outlets in different scenarios?

For instance:
1. When the engine is running, but the generator is not on.
2. When the engine is running and the generator is on.
3. When we are parked and connected to a power source.

I don't want to drain the battery if the cig lighter sockets only draw from the battery when the engine is turned off.

The reason I ask is because we have phone chargers and satellite radio connectors that can use either/or. I'm wondering if we need to have both while traveling.

~ Darlene ~

2014 Coachmen Mirada 35BH

previous owner of
2014 Rockwood Mini-Lite 2306
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Old 05-19-2015, 07:55 PM   #2
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The lighter is getting 12v from the battery. I doubt you'd ever drain the battery charging a phone but guess it could be possible. The outlets should not have power unless 1) you have an inverter that converts 12v from the battery to 110v at the outlet, or 2) the generator is running or 3) you are on shore power. Hope that answers your question.
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Old 05-19-2015, 08:59 PM   #3
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Without knowing your type of coach the best answer I can give you is this:

12v Aux port built into factory cab dash = draws power from chassis battery (engine battery)

12v Aux port in coach area (everywhere but the cab) = draws power from coach battery

Now to maybe answer your second question... Most newer and older higher end coaches have a system called BIRD that connects both the chassis and coach batteries together if a voltage of 13.x+ is detected at either battery source.

What does that mean? If your engine is running your chassis battery is being charged/maintained as you'd expect plus a charge current is also being sent to the coach battery. If your coach has 120 volts AC (generator or power pole) then your coach batteries are being charged as you'd expect plus current is also being sent to your chassis battery.
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Old 05-20-2015, 06:53 PM   #4
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This I can answer due to having two of mine recently worked on.... The outlet by the leveler keypad and one on the dash draw power from house batteries and here's a 20 amp fuse in lower fuse bank that control them.... The other 12V outlet on dash draws power from engine WHEN KEY IS ON...... Makes it perfect for plugging in my sat radio.... I plug in a 12V splitter into the outlet by the leveler keypad and plug in my GPS and TPMS..... FYI: I kept blowing that 20amp fuse and we finally discovered that the wires plugged into the plug itself were loose and it wouldn't ground....

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Old 05-20-2015, 06:54 PM   #5
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Also FYI - I have a Berkshire

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Old 05-23-2015, 12:05 PM   #6
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My 2011 Georgetown 327DS has only the cigarette outlet on the dash readily accessible. That draws from the chassis battery and is powered all of the time, even with no key in the ignition. There's another similar outlet in the overhead cabinet above the passenger seat, behind the antenna switchbox where it's almost impossible to reach and use.

I needed additional 12V circuits so I installed a (fused) direct line from the battery to the drop leaf table cabinet behind the passenger seat. It has two PowerPole outlets and is capable of supplying 30A if necessary. After I replaced all of the interior lights with LEDs, I added another 12V outlet under the front facing bench seat at the dining table. That 12V circuit is powered by a tap off of the lighting circuit for the street side slide which runs through that bench seat. The bench seat circuit also powers a 50W inverter that provides enough power for a litterbox, sewing machine, or soldering iron.

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Old 06-08-2015, 10:14 AM   #7
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12 volt Cigarette plugs

The dash cigarette lighter plug is probably wired to the chassis battery and may only be active if the engine is in ACC or running.

The cigarette plug on the antenna amplifier (if you have one) runs off the coach battery.

When the engine is running, both batteries should be tied together so the engine is charging both batteries.

120 volt outlets

Unless you have an inverter, your outlets will only be live (have power on them) when your plugged into shore power or your generator is running.

Here is a simple electrical diagram that may apply to your Mirada.

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light, power, electrical

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