plugged in but no power to coach or house batteries

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tnsharon07

Active member
Joined
Feb 23, 2008
Posts
42
Hi all,

Another first for me, and it's electrical, so I start out confused!  1997 Dutch Star DP lives in a detached garage, but as it was going to be quite cold, I plugged it in to power up my electricals and turned on my little space heater inside, as I've done for years to protect it when we have extraordinary weather.  When it warmed up (and I remembered), a week or so later, I stepped into the MH and turned off the heater, which was purring nicely.  Some days after that, the better half asked me if the MH still needed to be plugged to shore, so I went out to unplug it.  Surprise!  I had virtually no power inside:  I had left the breaker open, so the outlets had some power and the little heater was still receiving electricity, but only enough to barely light the power light.  My overhead lights only barely came on - you had to squint to see that they were getting any juice.  House meter showed 4.4 volts on the house batteries.  I unplugged the heater, shut off the breaker, and left the coach hooked to shore to see what happened.

Checked on it last night, after another few days, and still no luck:  4.4 volts on the house batts, so obviously no interior power (i.e. overhead lights).  Interesting and maybe significant symptoms:  when I plug in, I can hear the power transfer switch clunk into action and start humming.  My Iota inverter has a tiny green light on top; that green light does NOT illuminate.  My house disconnect switch inside the coach does not disconnect anything; the tiny red light on that switch comes back on (tho very dimly) even after I hold the switch down until it goes dark - as soon as I release that button, the light starts glowing faintly again.  I interpret this house disconnect switch situation to mean that the coach is still using power from the house batteries, even though I'd prefer the coach to just sit tight for now!

I'm not sure that the inverter is doing its thing.  Are there fuses or breakers or something in the inverter?  I do see that a couple of finger-thick cables run from the inverter into the bowels of the coach (or vice versa), and each of these cables has as "bus fuse," I think it's called... I don't know how to test those fuses, though.  What about the plug that the inverter plugs into - wonder where that breaker or fuse is?  I suppose I could run an extension cord out there and plug the inverter into that cord to see if the green light comes on?

Can someone give me a quick overview of the power routing here?  It seems visually obvious that the shore power comes first into the power transfer switch.  From there, a similarly thick cable runs into the bowels of the coach basement.  Something must come back out of there into the inverter, but I can't see where the connection comes from, nor do I actually understand where it would go FROM the inverter.

Any thoughts on what my likely culprit might be?

Should I put my trickle charger on my house batteries, separately from my troubleshooting my other problems?

Dang electricals...  any thoughts are appreciated!

Sharon
 
Hi Sharon,
I would check the house batteries to make sure they are not frozen. If they are not I would disconnect from the coach cables and get them on a charger as soon as you can. I would then second run a different power supply to the coach. It sounds like your shore power connection may be having problems. Perhaps low voltage at the post? The dim light on the heater concerns me as once the transfer switch clicks your outlets should go live with whatever power is feeding the coach. If the transfer switch is not fully engaging it is possible that the batteries were backfeeding into the system thus killing them.. Most important though is to try to salvage the batteries. If they are laying at 4.4 volts and have been for very long it may be over for them.

Another thing I would consider is disconnecting the batteries from the coach and see how the inverter responds. If the lights come on you may have a collapsed cell or cells in your house batteries. I have seen that happen before. The inverter is working OT to get the batteries up which are basically dead shorting the system thus kicking the automatic overload...

 
Thanks; I don't think the house batts are currently frozen, as it has been above 45 degrees here for days and days.  But I'll definately get them on a charger.  I was savvy enough to realize that they may already be permanently dead, but only time will tell.

Your other suggestions are a bit above me (sorry!):  if I disconnect the house batteries, don't I break the circuit so that plugging the coach in is irrelevant, or even ill-advised?  But you're suggesting to disconnect them, leave those cables just hanging there not touching each other, then plug the coach back in to shore to see what happens then?

What second power supply to the coach might there be?  Running my generator?  Or plugging from a different outlet in the garage (which I did first, with no impact)?

I know I have lots of steps to take on this one, so i definately appreciate all the suggestions, and will take the required steps.
 
and, oh yeah, why can't I just put the charger on the batteries without disconnecting from the coach?  Seems to me that's how I've touched up my batteries in the past....
 
I'm pretty sure you have an "Inverter/Converter" such as Magnatrek or Xantrex.  The Xantrex especially has a circuit breaker on the body of the Inv/Conv box.  Find that box in one of the bays and look for a circuit breaker or a "push in" re-set fuse button.  It sound like you are not getting electricity through to charge the batteries.  That is the most simple thing to check for first.

Marsha~
 
By all means if the batteries are not frozen put the trickle charger on 'em and bring 'em back up,, IF you have six volt pairs they may survive, alas Marine/Deep cycle, are not so robust but there is a much slimmer chance they will survive if restored promptly.

Watch them carefully.. Here is why.  There are several conditions that can cause what you see, One is shorted cells in the battery, if this is the case, the trickle charger can cause a problem if you are not careful.  So check and if the batteries seem to be coming up to voltage properly. GOOD.

Now the rest of the cuases.

Bad switch (Transfer, or disconnect) bad connections, blown fuse or tripped breaker in/to converter, bad converter (may be part of inverter) and running the heater off the inverter instead of off a "Mains" outlet.

IF all breakers and everything else looks good, it may help to open the breaker box and check for loose wires,, UNPLUG first please. (Dangerous voltages if plugged in)  Many RVers have a few screws loose and this is where many of them are located.
 
Have you verified that you now have shore power into the coach?  You could have lost all 120v power, so fnd something that is not powered through the inverter and try it.  Water heater in electric mode is one example. Air conditioners is another.

Your inverter/charger can't do any charging without a source of power to run from, so verify that next. If the inverter has a standard power plug that plugs to an outlet, unplug it and plug a lamp in place of it and see if it lights. If it does, you are getting power that far.

Yes, the inverter probably has its own internal circuit breaker. Usually a button on the front or side.  That is for 120v output and affects the power to any outlet powered through the inverter.

The big fuses in the fat wires are for 12v power to the inverter when no shore power is available. Should not be involved if you have already verified that shore power is reaching the coach.
 
Hi all,

Thanks for the responses and ideas.  I augmented your suggestions by calls to Iota and Newmar.  My results are as follows: 

I unplugged the converter from the receptacle in the bay of the coach, plugged the coach into shore, and could not power the little flashlight I had plugged into the converter's spot.  Therefore, I interpret that to mean that, when plugged in to shore, no power is actually coming into the coach probably.

Next I unplugged from shore and attempted to start the coach to back it out so I could try the generator.  The coach fired right up, even after sitting for 2 months.  Conclusion:  chassis batteries are fine.

Got it out into fresh air and started the generator just fine.  Immediately the voltmeter inside the coach showed 13.7 volts on the house batts, all systems inside (that I tested; come to think of it, I did not check every plug) were working, like the furnace and the one plug I checked via my space heater.  The converter was talking to the batteries (I know this because the little green light on top was illuminated.  Interesting that the light was on even before I plugged the converter back into its receptacle.)  I ran the generator for a few hours.  When I shut it off, the house batts were sitting at 12. 4 or something close to that.

As I understand the assistance and advice I've been given, this analysis would point to the power transfer switch or breaker box (or points in between) as the culprit.  I don't believe it's my shore cord, because when I do plug in to shore I hear a clunk and hummmm from my power transfer switch.  At first, I assumed this means the switch is working, but I'm told that clunking and humming don't mean that it is working properly.

Any suggestions on checking the power transfer switch?  It's by Todd on this '97 Dutch Star.  I have no idea if it is original.  Is it possible to pull the cover and see breakers or fuses inside?  Will peering under the cover possibly provide any info?  I know i don't want to do that if there is any juice going into that box, though. 

Another suggestion was to pull the breaker box cover and check for loose wires, which I am capable of doing.  Though this seems a long shot to me, as the coach was parked and working just fine one day, and then not getting power the next even though nothing had changed except I turned off the space heater.  But then, electricals are over my head a bit.

So anyway, these are my only two current ideas.  Plus I'm curious to see how much power the house batts lost overnight here, as it was in the 30's.  Thanks for any further ideas, if anyone has one.  Sharon
 
tnsharon07 said:
Any suggestions on checking the power transfer switch?  It's by Todd on this '97 Dutch Star.  I have no idea if it is original.  Is it possible to pull the cover and see breakers or fuses inside?  Will peering under the cover possibly provide any info?  I know i don't want to do that if there is any juice going into that box, though. 

Another suggestion was to pull the breaker box cover and check for loose wires, which I am capable of doing.  Though this seems a long shot to me, as the coach was parked and working just fine one day, and then not getting power the next even though nothing had changed except I turned off the space heater.  But then, electricals are over my head a bit.

Sharon,

The Todd switches are junk and I am quite surprised there is one still working or even installed.  If you are comfortable with checking the wires inside the switch let us know and we can help.  If not find someone who can trouble shoot it as I suspect that is the problem.

The switch is configured to the generator and must switch to the shore power when shore power is present.  It sounds like that is not happening.  If true, the switch is bad.  A new switch is about <$200 probably plus installation.  It is not hard but must be done correctly or bad things can happen, fire, etc.

BTW, there is a lot of help specific to Newmar on the Newmar owners forum on Yahoo,  http://groups.yahoo.com/group/newmarowners/
 
Jim Godward said:
The switch is configured to the generator and must switch to the shore power when shore power is present.  It sounds like that is not happening. 

It does sound like the switch is configured this way from reading the OPs prior post.  Is this normal configuration for Newmar?  I always thought it was normal (if not standard) for the inactive condition of the switch to allow shore power through on the NC contacts, and for the generator to be wired to the "override" input connections.
 
Have you plugged in again after having run the generator??  I am not sure which way the power transfer switch (relay) sits when Idle, ie relay operated or non operated, but it does have two sets of contacts, make, break (and common). It could be that the pair used when connected to shore power is burned and now making an inadequate contact while the set used when on generator is fine, as evidenced by your test. Can you open it for a look-see? That will depend on the make and model of the switch but, if you can it may be informative. Can it be fixed? Maybe a swift hit with your hand or a small rubber mallet will do something but that will only be temporary.  I doubt that the breaker panel or points in between is the problem because all that is common to both generator power and shore power . What you likely have is burned and sticking contacts in the transfer switch itself proving inadequate contact when on shore power..
 
Thanks, everyone!  My husband is brilliant with these things (though does not take the lead on the RV, since he married into it only 2 years ago and is afraid to break anything!).  He can easily follow troubleshooting instructions, and I'm pretty ok with doing so.

Meantime, Newmar told me on the phone that the switch is defaulted to the gen setting; in other words, it lives in gen mode and has to switch for shore power.

I have not plugged in after running the generator, tho given the default to generator, it has probably not tripped.  I will go check.  I will then pull the cover and have a look around.  I will report back soon.  Thanks!

And oh, yes; I did live in TN when I named myself.  But I'm now in the NW corner of Washington, but thanks for the Lebanon idea - that would not have been far from my old home at all.
 
Meantime, Newmar told me on the phone that the switch is defaulted to the gen setting; in other words, it lives in gen mode and has to switch for shore power.

All the more reason to suspect burned contacts that have been caused over the years by not removing the power at the post before plugging in!!! (While plugging in or unplugging, the relay operates/releases causing an arc at the contacts, eventually burning them, when power  drawn by the house circuits was  consumed or cut off ).
 
ok, after sitting the coach without any incoming power overnight, i still have 12 plus volts on the house batts, per my inside meter.

I just plugged it in, and now everything seems to be quite normal!  Fridge switched over to AC power, space heater worked out of an outlet... then I shut off my breakers and the fridge switched over to propane.  So now everything inside is turned off, and coach is plugged in, and inside meter shows 12.8 on the house batteries.  For me, this is normal.  And oh, the little green light on the converter is not illuminated, but Iota told me the light does not mean power/no power, so I'm not going to focus on this.

So all is well except that I remain just as puzzled by electrical stuff as I did before!  I cannot understand how the house batteries went down to 4.4 volts while the coach was plugged in (tho it was only plugged to a 15 A outlet, there was virtually nothing on inside).  Maybe today's performance is related more to the charge on the batteries than the behavior of my switch or converter?  Beats me.

Since I don't know what happened, I imagine I'll duplicate this failure some day.  And when I do, I'll know where to start and what to do.  And I may still pull the cover off the transfer switch and have a look-see today, just to satisfy my curiosity.

Thanks for all the great help - as always!  s

 
It's good practice to turn the pedestal circuit breaker off before either plugging or unplugging the shore power cord to prevent arcing at the outlet.  However, in your case, you also need to remove any large loads in the coach itself before switching shore power on or off.  Turn off things like the electric water heater, refrigerator, converter/charger, and any electrical heaters before switching to or from shore power to minimize arcing on the transfer switch relay points.  The easiest way to do this is to turn off the main circuit breaker in your load center before changing power sources.  After power is connected, either generator or shore, turn the breaker back on.
 
Oh, Cool!  Thanks, Ned.  Turns out I do that every time, so I'm not screwing that part up!

Final report:  the inside of the transfer power switch is a thing of beauty:  clean, bright, shiny, no corrosion or black marks, no funny smells. 

So I guess I'm done for now, and thanks again for all the great help!
 
I doubt that you are done for now if the batteries are reading only 12.8V when plugged to shore power.  You need to make the following DC voltage comparisons:
  • Plugged in to shore power
  • Unplugged with Gen running
  • Unplugged with Gen OFF
The reading should be approximately 13.6 to 13.8 in the first two tests, since the same converter is supplying the voltage in each case.  The third test will have the lowest reading (approx 12.6-8 volts).
 
the inside of the transfer power switch is a thing of beauty:  clean, bright, shiny, no corrosion or black marks, no funny smells. 

You did not mention the relay contacts, were you able to see and evaluate their condition?? I doubt they would be pristine, adequate maybe but not pristine on a 15 year old unit.... Operating the relay may have dislodged something though...

In doing the tests suggested by Just Lou, I would suggest using a voltmeter across the battery terminals. I would also expect to see something around 13.2 volts or better in the first 2 of his suggested tests.
 
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