Inverter Question

[sweeney153]

I am trying to learn all I can about RV wiring before I actually buy any thing. When reading about inverter wiring I saw references to the Ignition lockout which shuts of the inverter when the engine is running. My question is why would you want it to shut down when the engine is running and does it have to wired to shut down when the engine is running,

My be a stupid question but I hope some one can help me understand it.


Thanks

Kevin

[JohnEd]

Kevin,

I may be wrong but I believe that "cut out" switch is a misprint.  There are people here that run down the road with 2 or three ac powered AC units running.  They have no over the road coach AC.  They run off of big inverters and the generator provides the juice.  Now there is a problem with the inverter trying to charge the bats while the engine alternator is in the circuit but you can disable the inverter charge function in the better units.

You want to look at Gumpy's site and I would strongly urge you to contact Sean off line in email about EVERYTHING you do.  Maybe he wants you to post it....I don't know.

Having one or two inverters in your design will dramatically alter what and how you install.  Good move on your part with this.

HTH,

John

[Jerry Liebler]

JohnEd,
    Please tell, what is the problem with having both the inverter (powered by the genset I assume) and the bus alternator charging the house batteries simultaneously.  I have this capability though I rarely need to run the genset.  I see no problems as both the inverter and the bus electrical system have good voltage regulating properties and both will stop charging when the batteries are fully charged.
Regards
Jerry 4107 1120

[Jerry32]

Jerrys correct , you can hook up as many charging sources as you want and the batteries will still charge.I have solar engin and inverter goinat the same time . Jerry

[sweeney153]

I should have kept reading. I found the answer.

Ignition Lockout for Enhanced Safety
Recreational Vehicle Industries Association (RVIA) and some states require a TV, in a recreational vehicle, to be 'OFF' if in view of the
driver when the vehicle is in motion. Connecting the ignition lockout turns the inverter off when 12 volts is applied to the lockout
wire by the ignition.

[JohnEd]

Jerry,

I answered this from my email connection to the board.  Must be lost or stuck somewhere. Here is what I answered:

Jerry,

I have no pat or authoritative answer for you.  Both of the dc sources you suggest have separate regulators in them.  Both of the sources have ripple of some amplitude and each generates noise of some amplitude.  My intuition from 30 years in, around and near tricity says "don't do that without getting the all clear from the mfr."

On the surface of it it looks like two 12 volt sources charging a battery and what could be simpler that that.  Contact Xantrex and Magnum.  Contact Dick Wright.  My vote is caution and I always opt for the adventure.  $1500 inverter....multi thousand genny...hummmmm!

John, Pleased to have told

I hadn't seen Jerry's answer about having successfully wired and operated the bus system with two charging sources operating simultaneously.  He says he has had no problems.  Great!  Nothing speaks of success better than success.  Still, you have time, run it past Dick Wright and the mfr of your inverter.    The problem is that there may be some set of circumstances where the system self destructs and I am clueless as to what that might be.  If this were a hundred dollar lash up I would go for running with the success story.  With this money at stake I opt for some expert to hold my hand.  It boils down to expense and that is relative to each of our circumstance.  Multi grand is a tall order for me.  But note, I didn't say anyone was wrong or anything couldn't be done.  Just my best guess.  I have seen simpler things burn down, literally, and all anyone could say was "I would never have imagined!!".

Good luck now and thanks for the questions.

[buswarrior]

What I've seen in coaches with another charging system besides the alternator is the no-gen light lit on the dash, if the other charging system is running.

A problem if the stock HVAC is cut out by the same circuit, protecting the batteries it thinks aren't being charged....

Otherwise, just a reminder to shut one of them off.

happy coaching!
buswarrior

[Jerry32]

John, apparently you are not familir with the fact the battery is the filter so it makes no difference as to  ripple oflutter in the DC You are confusing the use of the DC supplies for operation som piece of equipment. Did you forget the battery?? Jerry

[JohnEd]

Jerry,

I did not forget the battery.  In a perfect world there is no resistance in the leads to and from the battery and  generator.  Hence, there can be no different voltage anywhere in that circuit cause the bat has the circuit clamped to the voltage.  Any spike is shunted by the bat....mostly.  It not only isn't a perfect world but it is a deteriorating world...as far as bats and low voltage circuits are concerned.  As the terminal's QUALITY of connection deteriorates with age, you get resistance and that resistance develops voltage drop.  I think the max ripple is the max voltage that can be generated by the current through the resistance.  The B+ line going to my gen has 4 bolted connections including the bat.  Currently it drops 4 volts when it starts to crank and that goes to 4.8 after a few turns.  I think it has always been resistive cause the problem I was working on is that it turns over slow but always fires after 8 or ten spins.  In that 00 or 000 cable and connections I have 1/3 the resistance of the starter.  This is what I was talking about when I caveatted my observation that some have had this system, two charge sources operating  simultaneously, perform well for years.  There are a host of variables and such that may impact the Inverter or gen dc supply regulator.  I really and truly do not know but "so far so good" is something overheard said by a man falling from a twenty story building as he passed the tenth floor.  99% of my life is based on what has worked in the past and it amazes me how many reinvent the wheel and do it wrong.  

The more you have at stake the more you verify, check and prove.  !00 bucks, who cares.  $100K and we have a committee approving the plan.  Billions and we develop an agency to make certain that every conceivable.....you get the pic.  In this case there may be a few grand on the line.  There should be no risk of fire because there are fuseable links between all the chargers and the bats....no wait....is that true?  A little levity there.

Maybe it is just me, Guy.  It is good.

John