Inverter/Charger Use

[Gary Winzenburger]

This is a general question about using, or not using the inverter/charger. I really don't know exactly when it should be turned on. I know that the engine's alternator shouldn't be used solely to re-charge the batteries, so can I turn the inverter/charger off, as well as the generator while traveling knowing the batteries are fully charged and in good condition? Assuming I don't use the AC unit(s), the refrigerator either turned off or on propane, and there'll be 30 or 50 AMP service waiting for me at the campground.
Thanks,
Gary

[Edward Buker]

Gary,

Anytime that you have an AC source generator or otherwise the charge function should be on. These are smart chargers and will go to charge level maintenance mode when your batteries are fully charged. As far as the inverter function being enabled that is your choice. I usually leave that function off unless I need it but some folks leave it enabled for music etc. requiring 120V while traveling or TV while boondocking etc.

Later Ed

[Dennis Crawford]

Gary,

Your charger should come on anytime there is AC power present (Shore or Gen-Set).  Depending on your coach, you may or may not have a system that will take care of both battery banks.  Remember the charger only charges the house batteries.  You either need a BIRD module with a Big Boy switch, Xantrex echo charger or some other monitoring device to do the maintenance charge on the chassis batteries.

The engine alternator will charge both banks while driving.

As far as the inverter is concerned, that is your choice.  I leave mine on in case I need AC power while traveling.  You also may have an Automatic Generator Start module.  This device can be set to automatically start the gen-set if the house battery voltage drops below a set point or if the inside temp reaches a certain set level.

Hope this helps.

Dennis



Dennis

[Keith Oliver]

Gary:

You likely have the Xantrex "Freedom" inverter/charger, with a panel above the driver to tell you what it is doing, as I have in my 1998 Contessa.  Note the red lights on the display.  Whether the inverter switch is on or not, when you are plugged into shore power, or the generator is on, you will see the "charge" light on.  You will also see the amps measure lighted, so will know how much charging is being done.  When you are not plugged in or generating and these lights are off, you may want to switch on the "inverter" and will again see the amps measure lighted, which will show you how much power is being sucked from your house batteries.  Know that without any load whatsoever, the inverter itself will suck your batteries down quite quickly, so be careful to use it only when you need to.  If you are mobile, your alternator will easily supply all your inverter will consume, so you don't need to worry about having the inverter on while you drive.  Just be careful when you are dry camping, to keep the inverter off at all times that it isn't needed.

[Gary Winzenburger]

Thanks so much for the information. Battery management is one of the biggest concerns I have - very complex, but needed in these big coaches.

[Joel Weiss]

 Know that without any load whatsoever, the inverter itself will suck your batteries down quite quickly, so be careful to use it only when you need to.  If you are mobile, your alternator will easily supply all your inverter will consume, so you don't need to worry about having the inverter on while you drive.  Just be careful when you are dry camping, to keep the inverter off at all times that it isn't needed.

I don't know if there's something wrong with your inverter, but ours sure doesn't suck the batteries down unless there is a load.  Since we have a residential fridge we need 120V power all the time, so we never turn the inverter off--ever.  We never had any problems doing this when we had the Xantrex and our new Magnum is significantly more efficient than the Xantrex was.

[Keith Oliver]

Joel:

I have a much newer Xantrex inverter on my boat, on which I have measured consumtion of power just to run the inverter.  On that MS2000, before turning on any load whatsoever, the inverter uses between 6 and 8 amps.  When using an AC appliance, the readings are consistent with adding the rated amperage of the appliance to the power needed to keep the inverter turned on.
I haven't actually measured the "Freedom" on my 1998 Contessa, but with its technology being 7 or 8 years older, I doubt it is as efficient as the inverter on my boat, so I am just as vigilant of the "inverter - off" switch.  I wouldn't want the unwary to suffer a depleted battery without knowing about the inverter's own load.

I don't doubt your stated lack of problems, but you no doubt closely monitor your battery state while dry camping, due to having an AC load that must be supplied all of the time.

[Joel Weiss]

Keith:

I just checked the specs for my new Magnum MS2812 and its power consumption without load is rated at 30 watts (2.5 A).  That's a lot less than what you are measuring on the Xantrex.  Furthermore, if you are willing to let it "turn off" unless it sees a large load (which means it probably won't power the TV and other devices which draw small currents when off) then it will draw <8 watts while "searching" for a load.  Sounds like technology has improved a lot over the past decade.

In comparison the Xantrex 458 manual that I still have online does cite 12A as the no-load current drain for that unit.  You're not seeing that much and neither did I but that's all the manufacturer claims it will do.   I guess I simply never realized it could consume that much power; that's why its cooling fan seemed to be always running.

Joel

[Keith Oliver]

Joel:  Thanks for looking those numbers up.  I don't think the old "Freedom" has a mode that would allow you to leave it off and come on by itself when it sees a load, so I wouldn't ever just leave it on.  My MS2000 does have such a setting, and it wouldn't come on for small loads, so getting it to power the microwave eg, was a hassle, as it wouldn't recognize the microwave in that mode, although it is a large load once you press start.  
I guess, based on the year of his coach, that the OP, Gary, has an old "Freedom".