New Owner, School Me On Electrical System!

[ZagRacing]

Hi All,

Looking for some advice on the electrical system on my new to me, 1998 Damon Ultrasport Diesel.

I am new to RV's but I consider myself very decently fit to work on anything mechanical or electrical once I have my head wrapped around the topic.

There is a long list of repairs that I need to do to this RV to get it back to fighting trim.
Yesterday I had to replace the filler hose for the propane tank to power the Onan generator. It had a split from rubbing against the body and after a 50.00
visit to a local hose shop, I have a new one on there and I am heading to see if it holds propane today.

First I need to understand the layout of all the electrical circuits and what does what.

So here is the list:
1) Coach batteries
2) House batteries
3) Shore power
4) Inverter

I received the RV with toasted house batteries but excellent coach batteries.
The rig fires right up and runs like a champ. So no worries about the actual coach electrical.

Upon inspection of the inverter / house battery setup I found some stuff that was failed and also made me scratch my head.
The batteries themselves are all shot. No doubt I will put 4 new deep cycle batteries in there very soon.
The inverter (Heart Interface 25) is mounted in the storage bay on the passenger side closest to the rear wheel.
After reading the manual for the unit, it states that the leads should be no longer than 10' to the house batteries. Well that's interesting as the house
batteries are in the front of the rig which is much longer than 10'.
The original leads come out of the storage bay under the chassis and they are about 10' long or less.
Then there is another set of leads attached to those that run all the way to the front of the rig and attach to the house batteries.
The extensions are attached lug to lug with a couple of bolts and then covered in electrical tape. This cannot be stock????
The inverter is throwing a couple of warnings on the remote panel inside so I believe that the unit needs service but the electrical layout
here simply doesn't make sense to me. The inverter should be mounted in the front close to the batteries but I cannot see where it could mount
to keep it away from dirt and moisture. At a bit of a loss here so anyone that owns the same MY Ultrasport could really help me out by helping me identify how your
inverter is mounted and connected to the house batteries.

General questions.
Do the house batteries need to be there right now?
I am going to fire the generator for the first time today. The batteries are all out as they are shot.
Was going to cover up all the positive leads from the house batteries with electrical tape today just to get the generator running.

How does the system function?
I need someone to point me to a place where I can learn what does what?
The shore power is self explanatory but according to the manual, only one AC unit works when on shore power. I find that odd?

What do the house batteries power and are they bypassed anyway when there is shore power?

As far as the inverter is concerned, I assume it takes over for the 120vac when the generator is off but when the generator is on, is it still necessary?

You can see that I am struggling to wrap my head around what runs what and when?
I will certainly figure this all out eventually but for right now, my first goal is to get the generator running and then sort the inverter and the house batteries.

Thanks in advance for helping on this.
You guys have probably had to do this a number of times for others.
In the meantime, I am going to do some searching for information on this great site!

Cheers
Bernie

 

[John Hilley]

I don't think the inverter was installed by Damon. The persons installing had to work with the layout. The inverter should be as close as possible to the batteries, longer runs require heavier cables. I believe that model inverter has a built in battery charger for the house batteries. The generator may also start on the house batteries rather than the chassis batteries. The inverter probably has a built in transfer switch to allow AC to pass through from Generator or shore power to the circuits fed by the inverter.

 

[ZagRacing]

I don't think the inverter was installed by Damon. The persons installing had to work with the layout. The inverter should be as close as possible to the batteries, longer runs require heavier cables. I believe that model inverter has a built in battery charger for the house batteries. The generator may also start on the house batteries rather than the chassis batteries. The inverter probably has a built in transfer switch to allow AC to pass through from Generator or shore power to the circuits fed by the inverter.

I think the gennie starts from the chassis batteries. The house batteries were pretty far gone when I inspected the vehicle but he was able to spin the starter on the gennie even though the rig had no propane. It would make sense to have it that way as a depleted group of house batteries means you can't start the gennie to get power back up. I will test that theory today.

I believe the best that I can do in this instance is at least move the inverter to the forward most bay. That would knock 10 + feet off the length of cable needed to reach the house batteries that are directly at the front of the chassis. I would need to extend the cables that go to the inverter for the rig power though and also the remote display but I think that is better than having 30' of battery cable running from the very front to almost the very back of the rig right?

I can also confirm that there is no fuse between the inverter and batteries and also no switch. The cables came out of the inverter and directly to the batteries.
Something else for me to upgrade I suspect.

Thanks for this information. Will bring back more details later today.

Bernie

 

[ZagRacing]

Theory incorrect.

The house batteries DO provide power to the starter for the gennie. Lesson learned.

So I went and put some LPG in the tank (5 gallons)
While working on the battery thing at the front of the rig, I could smell propane.
I am in pretty close proximity to the generator at this point so I am wondering if it is normal to smell LPG from the generator when it is not running?
I would assume not but since it is a air pump with paths in and out of the unit, I was wondering if LPG can escape through there somehow?

I used bubble fluid to spray around all the fittings in the area around the gennie but they are all bubble free.
Its possible I guess that there is a leak on the flexible line running from the metal piping to the gennie or else I could have a leak somewhere around
the fuel system of the gennie itself. Just thought I would ask if others have smelled it around their generators.

Went ahead and hit the starter and the gennie fired right up and runs smoothly.
I know with gas engines that have been sitting, the seals don't seal very well anymore until they get some fuel on them and swell. Wonder if this could be similar?
Turned off the tank at the end just in case.

Bernie

 

[Charlie 5320]

The generator should have a solenoid valve to cut the propane off make sure it works. Unplug the 12v wire from it and see if the generator will run. If the solenoid doesn't shut off you will have a leak at the carb as it doesn't have a needle and seat like gasoline.

 

[boatbuilder]

You are correct in your assumption it is better to use longer 120VAC wires off the inverter than longer battery cables.  There should be a large fuse at the batteries on the positive battery cable. An ANL or Class T fuse are the most common. You can find fuse holders and fuses online from many marine sources. 
The odor in propane is added. It separates from the propane when the pressure is released. If you only had a small amount in the tank the odor may be stronger also. The odor chemical is even heavier than the propane and settles out.  92GA is right on about the solenoid valve.

 

[peteduffy]

Zag-

Do yourself a favor and buy this book:  http://www.ebay.com/itm/like/181428801815?lpid=82

The RV Repair and Maintenance Manual by Bob Livingston. It's my RV bible.

Hopefully you are not confusing INverter with CONverter.  It's a common mistake I have seen a lot. 

Shore power provides 120V, just like your stick & brick house.  So does the genset.  And so does the inverter.

I installed my inverter in the storage bay next to the batteries, and ran the remote to the interior of the coach.  That keeps the cables short between the batteries and the inverter, while keeping the inverter clean and away from any outgassing of the batteries.  Use the proper fuses as mentioned.  Check with the inverter manufacturer for specs, installations instructions, etc.

My RV came with a genset and shore power, both hooked up to a transfer switch.  So I could be plugged in to shore power, and start up the generator at the same time, and the transfer switch would automatically select the power source.  Both are 120V (household power)  Depending on how it's wired, either the genset or shore power would be primary, and the other secondary.

When I added my inverter, I added another transfer switch in series with the first one.  Now, no matter what 120V power source is on, the transfer switches ensure that ONLY ONE is being used.

So for 120V appliances in your RV, like the microwave and air conditioners, and all your household plugs, are powered from either shore power, the genset, or the inverter.  That's easy enough.

The 12V stuff in the house, like the fridge electronics, most lights, furnace, WH electronics, water pump, ceiling fans, and stuff like that, all run off the house batteries (12V).  BUT-if you have 120V household power supplied (if you are plugged into shore power, have the genset running, or have the inverter on (if wired in like mine)) then the CONverter takes that household 120V power and turns it into 12V power to supply all the 12V house stuff, AND it charges the house batteries (and possibly the chassis battery-I'm not sure.)

The chassis battery does just what you think-it powers all the "car stuff" like the starter, headlights, etc.

I hope that helps.

Now for the solar panel and that system....

 

[ZagRacing]

This is all very good information gents and I appreciate it very much.

I can wield a wrench and a multimeter as good as anyone but this is a whole new paradigm for me so please remain patient with me as I muddle my way through this.

I will indeed pick up that book as suggested. I do need a reference source to wrap my head around all of the new buttons, features and equipment on the rig.
Have never owned anything like it

Thought about the smell coming from the generator. I was cranking the starter for a little bit to move the LPG from the tank in the back to the generator that's mounted in the front.
Maybe the smell was the gen pushing through vapor since the LPG had not arrived yet?  Tomorrow I will fire it up again and see if it repeats itself. I will also pull the 12v wire off the solenoid to
make sure the gen doesn't start with it removed. What initiates the solenoid? Is it on the starter motor circuit? (ie it activates when the starter motor is activated?)

My rig comes the same as mentioned Pete.
It has shore power, a genset and the inverter.
You mention a transfer switch and I am certain I must have one. Is this a separate item or do they come incorporated in the inverter?
I assume its separate since you say it also switches between shore and gen?

Right now I am on hold until I get the inverter moved to a location closer to the batteries. The Damon Ultrasport has the batteries right at the front of the unit. The inverter (Heart Interface 25) was mounted in the very last bay. I can get with about 15 feet of the batteries I assume but that's about it. Better than 30 feet though which is where it was. So once that is done, with the 120vac and control panel extensions in place, new batteries, I will be able to have the entire electrical system operating at once so I can figure out what works and what doesn't.

I don't have the house battery setup in place but while I was running the gennie today I thought I would see if the roof AC units were working. I couldn't get them to run but I am not sure I even know how?
There are two thermostats in the rig, one in the bedroom and one in the main area. This coincides with the two AC units. I tried putting both thermostats to cool and I heard a click from one and nothing from the other. Should I have been getting roof AC with the gen running but no inverter hooked up or do these two work in conjunction meaning that the inverter completes electrical circuits? The owners manual shows a pair of switches to turn the roof AC on but I will be damned if I could find these switches. There are three unmarked rocker switches right down by the main door but flicking these back and forth did nothing.

I will figure it all out but I guess it will be one step at a time.

 

[Charlie 5320]

What initiates the solenoid? Is it on the starter motor circuit? (ie it activates when the starter motor is activated?)


Yes, and it has power as long as the gen is cranked or is running. Another thing you could do is remove the air cleaner turn the tank back on and see if you can smell propane again without cranking the gen. If you smelled it right after you shut the gen down, that is normal, because the line will bleed the pressure off after the solenoid closes.

 

[John From Detroit]

Another thing you said you had some propane put in and THEN smelled it.

This is actually not at all unusual since they vent a bit during filling.. Folks talk about opening a valve so it "Lets the air" out of the tank because "Air can not be compressed" Now if you are scratching you head and wondering "Then what does an air compressor do" you are smarter than they are.

The valve has a very long name something like the "Visual overfill indicator valve" or something like that, "Spitter valve" for short, When it spits liquid (A very dense white cloud of condensed water vapor is what you see) tank's full.

There is no air in the tank, just propane and the stinky stuff they smell it up with... And thus that is the "Air" that comes out of the valve, propane and odorant.. So it's natural to smell a bit right after filling.

 

[peteduffy]

Zag-

The geneset and the inverter are 2 different things.  Separate sources of 120V ac (alternating current, not air conditioning, which I write as A/C).  One does not go "through" the other. The genset changes rotational energy (through the internal combustion engine or other source, like a giant hamster on a wheel) into 120V ac.  The INverter takes 12V dc from your batteries and changes it to 120V ac.

The transfer switch is just an automatic switch that shuts off one power source when the the other is turned on.  And vice versa.  So basically one side of the transfer switch has 2 inputs, the genset and the shore power.  The output goes to your 120V breaker panel.  See attachement for rough diagram. 

When I added my inverter, I took the output of the first transfer switch, and made it one of the inputs of the 2nd t.s., with the other input being the inverter, and the new output being the breaker panel.

Now wrap your head around this:  when driving down the road, my son wants to turn on the inverter so he can plug in something like his computer (120V ac).  Genset is off.  The problem with this is that since the inverter is supplying 120V ac, the appliances like the fridge and CONverter don't know or care where it's coming from.  So the fridge automatically changes from propane to 120V ac heating element.  And the converter, doing its job, takes the 120V ac from the inverter and turns it into 12V dc, and charges the batteries.  But the INverter is taking the 12V battery power and turning it into 120v ac, which the powers the CONverter which turns it into 12V dc, lather rinse repeat.  If everything were 100% efficient this would be no problem.  But the converter, inverter, batteries, and wiring all have resistance, so with both the inverter and converter on at the same time,  all you are doing is producing heat and wearing down the batteries.  Solution?  We just turn off the breaker that controls the CONverter whenever we turn on the INverter.  I'm sure I could rig a switch or something, but this works for now.

My transfer switches are separate and not integral to the inverter, but some inverters do have them built in. 

Also, I got my inverter-to-battery wiring under 5'.  I would have mounted the inverter inside the cabin if there were a good place for it near the battery bank, but I couldn't find or make one without lengthening the cables.

 

[peteduffy]

Now the air conditioning (a/c) issue.  That is powered by 120VAC, (household power), meaning either shore power, the genset, or the inverter.  However, unless you have a REALLY BIG inverter, and one heck of a battery bank, forget about running the a/c from the inverter.  I have a 2000 watt pure sine wave inverter, with four, 6V golf cart batteries (2 wired in series to make 12V, then both pairs of 12v wired in parallel.) and it won't even turn on an air conditioner.  The startup current draw overloads the inverter.  So if you want cool air, plan on plugging in or running the genset.

My rig is set up so that only one rooftop a/c can run while plugged into shore power. I have 30 amp shore power.  But, I think the bedroom rooftop a/c was added sometime after the rig was built.  But, the way they set it up is that BOTH rooftop a/c units can run at the same time from the genset.  But not the shore power.  I haven't really investigated this too much.

Also, on my genset, (Onan 7000) there are 2 switches (breakers), just out of view, on the right hand side.  So if I'm running the genset, have both air conditioners going, and the wife plugs in her blow dryer while the coffee maker is on, then some power will go out inside the coach (whatever circuit was overloaded.)  The breaker panel in the coach shows no tripped breakers.  The genset is still running. Lots of head scratching until I found those breaker switches on the genset.  Reduce the load inside and flip the switch and all was well again.  I think one breaker on the genset goes to the main breaker panel in the coach, while the other genset breaker goes directly to the bedroom a/c.

I also have a switch that selects either shore power with a/c OR laundry, or genset with a/c AND laundry.  The switch looks factory, and the coach is wired & plumbed for laundry, but we don't have one.  We like the extra storage.  So I don't think the switch really does anything.

The thermostat should work pretty much like the old type house thermostats.  There might be a delay between when it clicks and the furnace or a/c turns on.  Also, there might be a switch to change from a/c to heat.  And one for the fan to be on or auto.  If you can get the furnace to turn on, then the thermostat should be good.  If all the settings are correct on the t-stat, and the a/c still won't fire up, check the breaker in the breaker panel.  But you'll have to be on shore power OR have the genset running to power the air conditioning.

Good luck.  Once you figure out the 12V and the 120V systems, it's really pretty straight forward to someone technically inclined.  Hang in there and keep at it.

 

[ZagRacing]

Zag-

The geneset and the inverter are 2 different things.  Separate sources of 120V ac (alternating current, not air conditioning, which I write as A/C).  One does not go "through" the other. The genset changes rotational energy (through the internal combustion engine or other source, like a giant hamster on a wheel) into 120V ac.  The INverter takes 12V dc from your batteries and changes it to 120V ac.

The transfer switch is just an automatic switch that shuts off one power source when the the other is turned on.  And vice versa.  So basically one side of the transfer switch has 2 inputs, the genset and the shore power.  The output goes to your 120V breaker panel.  See attachement for rough diagram. 

When I added my inverter, I took the output of the first transfer switch, and made it one of the inputs of the 2nd t.s., with the other input being the inverter, and the new output being the breaker panel.

Now wrap your head around this:  when driving down the road, my son wants to turn on the inverter so he can plug in something like his computer (120V ac).  Genset is off.  The problem with this is that since the inverter is supplying 120V ac, the appliances like the fridge and CONverter don't know or care where it's coming from.  So the fridge automatically changes from propane to 120V ac heating element.  And the converter, doing its job, takes the 120V ac from the inverter and turns it into 12V dc, and charges the batteries.  But the INverter is taking the 12V battery power and turning it into 120v ac, which the powers the CONverter which turns it into 12V dc, lather rinse repeat.  If everything were 100% efficient this would be no problem.  But the converter, inverter, batteries, and wiring all have resistance, so with both the inverter and converter on at the same time,  all you are doing is producing heat and wearing down the batteries.  Solution?  We just turn off the breaker that controls the CONverter whenever we turn on the INverter.  I'm sure I could rig a switch or something, but this works for now.

My transfer switches are separate and not integral to the inverter, but some inverters do have them built in. 

Also, I got my inverter-to-battery wiring under 5'.  I would have mounted the inverter inside the cabin if there were a good place for it near the battery bank, but I couldn't find or make one without lengthening the cables.

My heads gonna pop....................lol

I need to digest this for a while but thank you very much for the thorough explanation!!

 

[peteduffy]

On a rig this old (mine's 2 years older) you're gonna have to be handy or rich.  I surfed the internet and found manuals for almost every appliance-fridge, furnace, range, converter, distribution panel, a/c, etc.  I downloaded them and made a binder I keep in the RV.  I plan on burning the pdf files to a CD sometime.

Here's one source I found:

http://bryantrv.com/docs.html

It also has troubleshooting.

Just hope you never have a supply plumbing leak.  I just had one, and it was inaccessible, so I had to pull the furnace out to get it.

You'll learn which tools to always have handy.  The multimeter is at the top of the list.  Also, you'll figure out which repair parts to have on hand, sealants, caulks, extra fuses, hose splicers, duck tape, etc. I keep a toolbag behind the driver's seat.

So the information is out there.  This forum is one good source, but keep googling until you get what you need.  There are more systems in an RV than in your house, so just imagine taking your house, with all the appliances and systems, and shaking the crap out of it, and see how well everything survives.

BTW, I bought my batteries a Sam's Club.

 

[ZagRacing]

Now the air conditioning (a/c) issue.  That is powered by 120VAC, (household power), meaning either shore power, the genset, or the inverter.  However, unless you have a REALLY BIG inverter, and one heck of a battery bank, forget about running the a/c from the inverter.  I have a 2000 watt pure sine wave inverter, with four, 6V golf cart batteries (2 wired in series to make 12V, then both pairs of 12v wired in parallel.) and it won't even turn on an air conditioner.  The startup current draw overloads the inverter.  So if you want cool air, plan on plugging in or running the genset.

My rig is set up so that only one rooftop a/c can run while plugged into shore power. I have 30 amp shore power.  But, I think the bedroom rooftop a/c was added sometime after the rig was built.  But, the way they set it up is that BOTH rooftop a/c units can run at the same time from the genset.  But not the shore power.  I haven't really investigated this too much.

Also, on my genset, (Onan 7000) there are 2 switches (breakers), just out of view, on the right hand side.  So if I'm running the genset, have both air conditioners going, and the wife plugs in her blow dryer while the coffee maker is on, then some power will go out inside the coach (whatever circuit was overloaded.)  The breaker panel in the coach shows no tripped breakers.  The genset is still running. Lots of head scratching until I found those breaker switches on the genset.  Reduce the load inside and flip the switch and all was well again.  I think one breaker on the genset goes to the main breaker panel in the coach, while the other genset breaker goes directly to the bedroom a/c.

I also have a switch that selects either shore power with a/c OR laundry, or genset with a/c AND laundry.  The switch looks factory, and the coach is wired & plumbed for laundry, but we don't have one.  We like the extra storage.  So I don't think the switch really does anything.

The thermostat should work pretty much like the old type house thermostats.  There might be a delay between when it clicks and the furnace or a/c turns on.  Also, there might be a switch to change from a/c to heat.  And one for the fan to be on or auto.  If you can get the furnace to turn on, then the thermostat should be good.  If all the settings are correct on the t-stat, and the a/c still won't fire up, check the breaker in the breaker panel.  But you'll have to be on shore power OR have the genset running to power the air conditioning.

Good luck.  Once you figure out the 12V and the 120V systems, it's really pretty straight forward to someone technically inclined.  Hang in there and keep at it.

Pete,

Just for my own piece of mind,

The inverter is completely disconnected right now from the rig until I get the cabling reworked
I have one car battery in the house battery location with all the positives connected to it. I did this just to have 12v to start the generator and test one thing at a time.
The generator does fire up and runs smoothly
I have no current access to shore power where the rig is parked.

Is it safe to say that with the generator running, I should have access to all 120v locations? (ie AC units, wall sockets, etc)

I am going over to fire up the generator and see if I can track down the rigs breaker panel.
There is one panel at the very front but it is 12v as the bus bar connects to the batteries.
Somewhere else in there must be the 120v panel

I will also look for the breakers off the generator itself

B

 

[Alfa38User]

It should be mentioned that in some Inverter installations, not all the a/c plugs are wired. Some may have only a dedicated plug or three wired to an inverter output. In your case, this was likely a previous owner's add-on so all bets are off as to how it is wired. Most motor homes and trailers come only with a CONverter which is powered by 120V when plugged in or running the generator. It charges the house batteries and supplies 12V to the house.

On peteduffy 's description and diagram, the power source is wired to the power distribution box (through a transfer switch) and thus everything can be powered from that source (but... if that source is a battery powered inverter the usual caveat applies... LARGE battery bank etc. crazy interaction possible by charging the battery but pulling from it at the same time etc.... not the usual case BTW.)

As Heart Interface etc were acquired by Xantrex et al this may help located some information on your inverter system:

http://www.xantrex.com/power-products-support/document-downloads/discontinued-products/discontinued-products-inverter-chargers.aspx

 

[Alfa38User]

Is it safe to say that with the generator running, I should have access to all 120v locations? (ie AC units, wall sockets, etc)

In theory YES... There is an ATS (Auto Transfer Switch) that normally connects the generator output to the breaker panel and disconnects the power cord. The "ATS" in some cases is a manual operation, that is to say, you unplug the power cord on the coach end and then plug in  a cord from the generator.

The 120V Breaker panel can be skillfully hidden behind a decorative wood door but are normally in a metal box. It is very likely located not too far from where the 120V pedestal cord plugs into the motor home. (12V panels, have fuses, more often than not.)

You did not mention what 120V type of connection you have, a 30 amp or 50 amp. It may make a difference in how A/C (air) are powered up from the generator. (Your main c/b will either be 1 30 amp or 2 50 amp units)

 

[peteduffy]

Zag-

yes, I think it is safe to say that with the generator running, all 120V things should be hot.  Also, don't forget that there might be GFCI outlets in the bathroom and kitchen.

This simple video explains it all clearly.

https://www.youtube.com/watch?v=rLDgQg6bq7o

 

[ZagRacing]

Zag-

yes, I think it is safe to say that with the generator running, all 120V things should be hot.  Also, don't forget that there might be GFCI outlets in the bathroom and kitchen.

This simple video explains it all clearly.

https://www.youtube.com/watch?v=rLDgQg6bq7o

LOL, nice one.
I have known about the retro for a decade but its always funny

OK, I just got back from the rig and did some more looking and testing.
1) My generator is an Onan Emerald (Liquid Vapor Type). It is a 6500 GenSet
I had turned off the LPG tank before I left last time and today I couldn't smell any rotten egg around the gennie.
Opened up the valve on tank and after about 15 seconds or so I could smell it.
Could not locate the solenoid switch. Must be in the back area somewhere.
I am assuming that this is not correct. I should not be able to smell the vapor at all since that means my LPG is venting to air somewhere correct?

2) I got the rear AC unit running as well as some other lights, microwave, etc.
As it turns out, the breakers on the front of the generator were flipped off so that one was pretty easy.
Front AC unit is not seeing 120vac. It is non-op and I tested the wiring at the unit. No AC present.
I guess I need to trace the wiring back to its source.
I found the breaker box, yes cleverly hidden behind a door and at the floor level. There is a note on one breaker that says "Rear Air" but no other AC unit is labeled meaning the front one but it has to be plumbed through there to have some sort of breaker in place right? There were only 4 breakers in the box but nothing specific to the front Air unit.

The manual states that I already have a transfer switch between the shore power and the GenSet.
Where it is located I have no idea as of yet.

I know I have a long way to go here but satisfied that every time I go to the rig, I find more new and interesting things.
The rear AC unit blows nice and cold so that's a plus!

Bernie

 

[Charlie 5320]

On my Magnatec the switch is behind the panel. To get to mine I'll either have to remove the panel or remove the oven to get to it.

If you smell propane when you turn on the tank you probably have a leak somewhere. Is the tank near the generator? If it is the tank valve could be leaking. Are you opening it all the way? If not use the bubbles on the valve itself.