I recently read an article entitled "20 Tricks of the Trade" (for RVers) and one of the items said "Never start your vehicle or run the generator while you are plugged into shore power." While starting the generator, if nothing else, would be wasteful and noisy, I want to know why starting the engine while still on shore power is a no-no. It seems to me that pulling in the slides and raising the jacks are very power intensive and when I start my engine to do these, I have always stayed on shore power to draw from it until completing these 2 tasks so that I didn't drain the batteries unnecessarily at the start of my journey. It has been my understanding and expectation that the Trombetta solenoid and BIRD would properly manage and isolate the power sources.I've probably done this 100-150 times without incident. Am I lucky, or is the advise in this article flawed? If it is sound advise, please explain why.

I think the potential risk is that with many RV wirings, when you start the engine, it pulls from both the engine and the house battery. If you are plugged into shore power, there could be a risk of pulling too much power. I don't know how likely that really is or not.With my clipper, my boss is actually wiring it so the engine only pulls from the engine battery by using a delay switch. After about 20-30 seconds, once the engine has started, the house switch will connect and the house battery will charge from the alternator. There will be a toggle switch in the dash so that if the engine battery is dead, I can jumpstart the engine from the house battery - otherwise, I'm only pulling power from the engine battery.

Winnebago actually recommends the engine running when extending and retracting the slides on my 2013 40U Journey. Because of the power requirements.

I never worried about starting the RV plugged in or not, generator running or not.I think that some people have a 'theory' that it is dangerous, while reality is that the design protects us from anything going wrong.The generator can be run safely while plugged into a 120 volt outlet. There is a safety device to prevent any danger from this.You can start the engine or generator while plugged in or not. You really do not save all that much power by leaving the RV plugged in while putting in or out the slides. While the motor might draw as many as 65 amps, this is less than 1 minute, so only 1 amp hour. .. . .That is the same amount of power consumed by a light bulb over 1 hour. Same with the water pump, it will consume 7.5 amps per hour. However in that hour, it will also pump 2 GPM or 120 gallons. So you can empty the water tank with only about 5 amp hours of power, really in-significant. Have fun camping!Fred.

Been RVing from 60,s never had a prob,. Starting engine while plugged in. See no prob. either.Gen will over ride shore power conn. Just hope your auto transfer switch is working as it should.

rvluckyorwhat wrote:I want to know why starting the engine while still on shore power is a no-no. As others have indicated, for short periods it isn't a problem.You will simply have two charging sources connected to the batteries at the same time.....which is not a problem, short term.

starting engine while plugged in to short power

23 Replies

Golden_HVAC
Explorer
Jul 19, 2015
I never worried about starting the RV plugged in or not, generator running or not.

I think that some people have a 'theory' that it is dangerous, while reality is that the design protects us from anything going wrong.

The generator can be run safely while plugged into a 120 volt outlet. There is a safety device to prevent any danger from this.

You can start the engine or generator while plugged in or not.

You really do not save all that much power by leaving the RV plugged in while putting in or out the slides. While the motor might draw as many as 65 amps, this is less than 1 minute, so only 1 amp hour. .. . .

That is the same amount of power consumed by a light bulb over 1 hour.

Same with the water pump, it will consume 7.5 amps per hour. However in that hour, it will also pump 2 GPM or 120 gallons. So you can empty the water tank with only about 5 amp hours of power, really in-significant.

Have fun camping!

Fred.
Pop-Pop_C
Explorer
Jul 19, 2015
Winnebago actually recommends the engine running when extending and retracting the slides on my 2013 40U Journey. Because of the power requirements.
toedtoes
Explorer III
Jul 19, 2015
I think the potential risk is that with many RV wirings, when you start the engine, it pulls from both the engine and the house battery. If you are plugged into shore power, there could be a risk of pulling too much power. I don't know how likely that really is or not.

With my clipper, my boss is actually wiring it so the engine only pulls from the engine battery by using a delay switch. After about 20-30 seconds, once the engine has started, the house switch will connect and the house battery will charge from the alternator. There will be a toggle switch in the dash so that if the engine battery is dead, I can jumpstart the engine from the house battery - otherwise, I'm only pulling power from the engine battery.

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starting engine while plugged in to short power

23 Replies

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