Newbie needs advice on electrical issue

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Windebrook

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Joined
Oct 9, 2014
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13
Hi all,  Brand new here: having found i need some help I thought it was time to join.  We are owners of a 2005 Itasca Horizon (40 ft., diesel) and even after 5 years we are still learning as we go (when we can actually "go").  We make lots of mistakes and I think this may be another.  We hadn't used our "home" in about 6 months but had left it hooked up to shoreline the entire time, with a trickle start from house to chassis batteries. We would start it (and generator) up every few weeks, and generally check everything over, run a few components, check things , etc.  Tuesday my husband checked everything over and had no problems.  That same  night we had torrential rains and a sudden power outage lasting about 4 hours. The next day we had these problems: 1) no lights - or anything 12v related; 2)110 appliances  still worked; 3) all 3 house batteries were dead; 4) Fan on inverter/charger not kicking in (which i thought always did); 5) We ARE able to get 12v power from generator and from engine running but not from shoreline (or dead batteries of course). It appears that something is interfering with the flow of 110 to the 12v system and battery charger. We have a  Dimension inverter/charger which i am beginning to suspect but wanted to see what everyone else thought.  After much researching online I am wondering also about inline fuses and transfer cases/switches, and if batteries are dead because we left them on a constant charge by being plugged in to shoreline for so long and once no shore charging, they just drained down to nothing.  I have checked the breakers under bed and even reset the inverter one (clicking was heard from inverter like normal) but do not know where or what to look for with inline fuses.  Any ideas or suggestions will be much appreciated.  Even if this involves pro tech repair, I would like to be knowledgeable about what they come up with for repairs.    We are attempting to charge batteries externally but not looking good so far. Thank you again.  Harry & Bev in MA
 
Leaving the coach on shore power should not be an issue with a decent charging system.  The Dimensions product isn't great, but as long as it is working at all, it should handle the chores ok. Have you checked to see if the 120v power source for the Dimensions is working? It probably has a reset button on it somewhere too.

If you get 12v power when the generator is running, at least part of the charger must be working ok. The generator doesn't produce 12v - it merely provides 120v power to the charging system. And the transfer switch must be working because you get 120v from shore power, plus it switches to generator when you run that.

A question:  How old are the batteries and what type & size are they?  It appears that your ran the batteries dead during the power outage (inverter was on, maybe), and now the batteries won't charge. And if they are bad or really, really dead, the charger won't send power to them because they appear to be shorted. It may even be the charger tripped its internal circuit breaker (requiring a reset, as I mentioned above)..
 
Hi Bev - we have essentially the same coach (except I replaced the Dimensions charger/inverter when our coach was brand new with a Xantrex RS2000), how old are your house batteries?
 
Hi Gary and John...nice to meet you and thank you.  Gary by "120v power source for the Dimensions" do you mean the shore line?  If so then yes the incoming power is fine.  There is a white push button type of circuit breaker (what's it called?) on the dimension that is not "popped" out...is this the reset and if so how do you reset it?  I don't see any other reset buttons on the unit.  The batteries I think are about 2-3 years old.  Would them being dead interfere with the shoreline supplying power to lights, etc? 
 
Check the battery disconnect switch. It controls a latching relay that needs battery power to switch states from on to off and vice versa. it doesn't draw power after latching. It may be in off position and you may not be able change it without the engine running if the batteries are totally dead, which could be the case. They may have boiled dry if you haven't been checking them.
 
Check the battery disconnect switch.

Yes this was in operating position as i checked this when gen or engine running.

They may have boiled dry if you haven't been checking them

These are maintenance free batteries - i don't believe that fluid levels can be checked or refilled.

On your Dimensions control panel, does it show any 12V charge current?

The control panel only works when engine or gen running and is showing it as charging at 13.5.  Otherwise after these are turned off, the readings drop quickly and panel gets no power so becomes inoperable.

The problem seems to be only shoreline power not getting to 12v system.  Gen and engine power the 12v fine.

Thank you
Bev
 
Windebrook said:
The problem seems to be only shoreline power not getting to 12v system.  Gen and engine power the 12v fine...
There is a large current "strip" fuse in series (I forgot what amperage it is, maybe 150 amp?) with the Dimensions output, this is a flat fuse on one of the large red cables from the Dimension near the house batteries.  Check that and make sure it's not blown.
 
Thanks everyone for input.  Will see if can find that strip fuse.  Also going to replace batteries as they are not taking a charge.  Spoke with Dimensions rep a bit ago and he said that if batteries are below a certain level (9?), the inverter/charger won't even kick in to charge.  So we are thinking when power went out, inverter/charger went off, and weak batteries to begin with must have dropped below that level and having no charger after power came back on, continued to drain completely overnight.  Batteries may have been just barely holding on before power went out.  Solar panel has never worked well for us either but am betting if batteries were bad, solar would not have been able to keep up anyway.  He also said that if batteries are dead, the shoreline will not power 12v.  As we still get 12v from gen and engine, this still confuses me...any opinions on that?  So there we are, will start with batteries.  I am going to start a new post about that and will keep this one updated as we move forward.  Thanks again for all help.

Bev

 
Gary by "120v power source for the Dimensions" do you mean the shore line?

That's only the beginning of it. There will be a circuit breaker, probably 30A, that feeds 120v power to the Dimensions so that it can provide charging, 12v conversion, and pass-through power to the outlets whenever shore or generator is active. You may have shore power to the coach, but you need to make sure it is reaching the  inverter/charger.

There is a white push button type of circuit breaker (what's it called?) on the dimension that is not "popped" out...is this the reset and if so how do you reset it?

Yes, that is the reset for the internal circuitry. Just press it in. If not "popped out", it is probably ok.

John also mentioned a large fuse or fusible link in the big wire that goes to the battery. If this has blown, you get no charge to the batteries when shore power is on, and no 12v to operate the inverter when no shore power is available.
 
I am probably wrong but here goes - it seems to me that gen and shore (120) would both come into same circuit breaker and from there go to the converter (or in my case the inverter/charger) and larger appliances.  So if I am getting perfect power from gen this would mean the interrupt is somewhere between shore and the circuit breaker, yes?
 
thanks John, this is exactly where my confusion lies.  As both Gen and shore come into the transfer switch box and come out as one to the load center, why do I have power for larger appliances and 12v on gen, but only larger appliances, no 12v on shore? Any ideas?
 
No ideas.  On on the surface of it, what you describe is impossible.  Therefore we need to get more technically detailed in the analysis of what works and what does not, and under what conditions.

The only independent source for 12v you have is from the diesel engine + its alternator. You can get 12v power when the engine is running without other components working, but you shore and generator are the same as far as 12v is concerned.
 
I think Gary is on-track here - apparently the gen set has an alternator (which I have never confirmed one way or the other) which is being the source of the 12V charge current.  Going to guess your problem is Dimensions related and/or a house battery bank problem.  I would pull all three house batteries and have them load tested - one bad cell in one battery can screw up the entire bank.
 
What about a faulty or stuck transfer switch?  I had similar issue with my current coach when it was new. Turned out that the transfer switch was stuck, and thus killed the whole battery bank (six 6 volt batteries). 
 
The Onan 7500/8000 is an inverter generator, so it does indeed have an alternator that produces DC to feed the twin inverters. Might also power its own fuel pump, but I don't believe it produces any externally usable DC. The RV model assumes that an external battery provides starting power, while the similar (but not identical) industrial model has its own battery system for starting.
 
Gary RV Roamer said:
The Onan 7500/8000 is an inverter generator, so it does indeed have an alternator that produces DC to feed the twin inverters. ..
Yes, I'm aware of the large alternator driving the inverter.  If it doesn't have an alternator designed to keep a start battery charged then I'm out of ideas vis-a-vis the OP's problem.
 
I think the key factor is the electrical diagram shows a 50 amp shore power cord with two hot legs.  One leg feeds the major appliances through the load shedder, the other feeds the 30 amp breaker going to the inverter.

The inverter then feeds all of your 120 volt outlets and charges the batteries when 120 volts is available from the 30 amp breaker in the main load center, or from the inverter if it is on and 12 volts is available.

Take a voltmeter and look at the voltage to neutral on the two main 50 amp circuit breakers in the load center.  I'll bet you'll find the breaker that feeds your major appliances has 120 volts at all times, and the other one that feeds the inverter only has 120 volts when you're on the generator and shows 0 volts from shore power.

If this is the case, start at your shore power socket.  Verify you have 120 volts to neutral on each of the two hot legs in the socket.  If not, try turning it's circuit breaker off and then on.

If there's power on both legs of the shore power socket, the problem is in the transfer switch, or possibly in the shore power plug or cord.  Most likely you have a bad connection or contact on one side of the transfer switch so one leg is working correctly to feed your major appliances while the other is not letting shore power to the inverter but is passing generator power.

If you're not comfortable using a voltmeter to check live circuits, find someone who is to give you a hand.

After you get shore power voltage to both 50 amp breakers and to the inverter, you can then see whether or not the charger will revive the batteries.
 

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