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Wolfpack Fan · 07-26-2011, 10:07 PM

We're relative newbie's to motor homing. We just got our 05 National Dolphin 5320 in December. Nice upgrade from tent camping for sure! I'm hoping someone will take the time to explain the electrical in's and out's to me.

I know I could pull out the encylopedia set of manuals and probably learn a lot from them, and have looked through them several times and learned much. To be quite honest though, people on this forum are just cool folks, and it's a lot more fun interacting with the experienced folks here on the forum, than reading through a bunch of boring manuals. I'll read them when I need to.

My understanding of the electrical system is this.

If I'm running the big genny (7kw), the invertor should be off and we can pretty much run anything we need. Hot water heater, if needed, should be in the 110v mode.

If I'm running our baby genny (1kw), plugged into the shore power cable, via the 30 amp adapter and the 110v adapter, the invertor should be off and power consumption shouldn't exceed the genny's steady output capability. Hot water heater should NOT be in 110v mode, but can be in 12v mode, because little genny charges batteries while running. Or does the invertor need to be on to charge the house batteries?

If I'm connected to our house via the shore cable, 30 amp adapter and 110v adapter, the invertor should be off and power consumption shouldn't exceed the capability of the circuit it's plugged in to. Hot water heater isn't needed because we're at home, but if needed it should be run off of 110v so long as the breaker on the house doesn't trip. Or should the invertor be on in this situation?

If we're dry camping, I should turn ON the invertor if I need 110v off of the house batteries. (2-6V golf cart bats) Heavy electrical loads should be avoided, unless for short duration. Hot water heater should be avoided because of high current draw. I figure using house batteries should be limited to charging phones, listening to a non battery small stereo or small tv or running some lights and maybe a fan.

Don't remember the brand of my invertor, but I researched replacing it once and it's around $1200. It's a smart invertor and is rated 2000 watts. I'm not sure whether it's supposed to be on or not when on house or shore power. Right now motor home is sitting in front of house, hooked to an extension cord plugged into house. No appliances are on in motor home. With invertor off, house batteries read 12.9 volts. With invertor on reading went to 13.6. My assumption is that the smart invertor allows the batteries to get a charge from the house power so long as the invertor is on.

So.........................................:whistl ing: How close am I to accurate friends. Am I on the mark pretty much, or sorely in need of some learning. Looking forward to a lot of replies. If someone wants the brand of the invertor I'll dig it up from the manuals.

Rainbirds · 07-27-2011, 12:42 AM

First, find and report the make and model of your inverter. It will help us reply in more detail. Many inverters have a default mode that if left in the invert mode while connected to shore power will lie dormant until shore power is cut and will seamlessly cut in so you don't miss the latest nuance on the soap that you are watching. The disadvantage of this is that if your fridge or hot water is on 110, or your AC is running, you will suddenly be pulling waaaaay to many amps from the batteries.

We use this mode when in Mexico, doubtful shore power and watching TV and don't want the set to suddenly switch off. In this case the AC is OFF and the fridge and hot water are on propane. (A fridge or water heater can draw 40 amps from the batteries through the inverter when in AC mode!)

A little more detail given and we will be able to answer in more detail.

Please don't hesitate to ASK. The only dumb question is the one you should have asked but didn't before it was too late!

Wolfpack Fan · 07-27-2011, 06:06 AM

Quote:

Originally Posted by Rainbirds

First, find and report the make and model of your inverter. It will help us reply in more detail.

Thanks Rainbirds, Invertor is a Xantrex Freedom 20.

bbeane · 07-27-2011, 08:23 AM

Long post. First off is your coach 50A or 30A shore power? One or 2 roof ac's. Next your HW heater is really designed to run on electric only when plugged into the proper shore power, and unless you have a 50A shore power system the water heater will use a lot of power on a 30A system. As long as you only turn it on when you need hot water they don't use a lot of gas. With only 2 6V house batterys your inverter will not run very long, 10A 110v draw=100A DC draw. As to your small jenny about all it will do is run your battery charger. The only time I turn my inverter on is when we are not running the generator or on shore power, and then we try to avoid heavy loads for long periods (coffee pot,microwave, hair dryers and such). For those times I simply start the onboard generator, I just don't see much need of baby generators. Bottom line is you are pretty much correct.

bachler · 07-27-2011, 09:02 AM

I could not get a clear understanding if you were talking about an Inverter ( 12V.DC. to 120 AC) or an converter ,( 120ac to 12VDC.) Primary funtion. Most Inverters , 1500/2000 Do have a High dc charging Rate; Most Converters have a Very low 12 volt charger built in; As to the question weather They should be on You only need One coffee pot to fill your cup. 2 pots can make it messy, trying to fill one cup.. Use only one input the;; inverter; shore power;; Genset;;. Most of the later coaches have an automatic switch and will sellect the best one, automaticly;;

wa8yxm · 07-27-2011, 09:49 AM

About the only things I'd change in that is this: 30 amps is 110-120 volt, so you do not adapt to 110 volts you adapt to the 15 amp plug. That said, I knew what you meant so no harm done.

IF, And I stress IF your converter is plugged into an outlet (LIke mine is) On either the 1KW baby gen or house power I'd consider unpluging the converter from the RV's 120 volt, plugging it in DIRECTLY to the generator or house via the proper extension cord (NOTE: my converter has a 20 amp plug.

Of course if your inverter is also a converter this won't work.

And leave the inverter on.

Though on house power if you want to power the whole rig, just remember what you cn and can not turn on (appears you do)

Recommendation 2: Have an electrician install a proper 50 amp RV outlet either on the house or next to where you park the RV, and use a proper dogbone adapter for the 30 amp rig.

Why 50? Two reasons..

1: (Lesser) Upgrade, if you upgrade the RV
2: (Major) I read all the time from folks here on the forums who have had a 30 amp outlet installed and the electrician did not fully understand that a TT-30 outlet is a 120 volt device, even though it is printed on the box, and printed on the outlet, he still wired it WRONG and blew over a kilobuck of electronics in the RV. This simply does not happen with the 50 amp outlets. (Well, a lot less likely to happen in either case, like 99% less or more)