Question for the RV Electricians Out There - RV-Dreams Community Forum

Terry and Jo · RV-Dreams Family Member

Question for the RV Electricians Out There

53 Merc · RV-Dreams Family Member

Terry, I am electrically challenged, but there are a lot of things that run on 12V power. Such as landing gear, propane detector, all lights (at least in my rig) and the frig uses 12V power to run the control circuit. Such things as furnaces may or may not be needed, but the blower is 12 V.

Given large capacity batteries, you could easily do without the converter, just unplug it from 120V (same thing as being without shore power).

Understand, this is from someone that has to have help to change a light bulb.

bjoyce · RV-Dreams Family Member

If the inverter dies you can wire around it fairly easily until it is fixed, but you can't bypass it. If it is an inverter/charger they wire in a cheap converter to keep your batteries charged so the 12 volt works. When the inverter comes back they take the converter out ready for the next customer (they can charge rent on it) and wire the inverter back in. I wonder why they did not do that since that is what most techs do?

It sounds like you have a big inverter/charger which has an automatic transfer switch in it. That means that when on shore power the power to the inverted outlets will be from shore power. If the inverter switch is on then if the shore power goes out then the inverter will take over since the automatic transfer switch will engage. If the inverter switch is off then when the shore power goes out then there will be no power to the inverted circuits.

-- Edited by bjoyce on Saturday 9th of October 2010 08:11:09 AM

Terry and Jo · RV-Dreams Family Member

Hey, Ken. I'm 64 years old, so I KNOW how to change a lightbulb. Let me know when you need help and I'll trade my experience for some of your mechanical experience. A vehicle mechanic......I ain't.

Bill,

Yes, ours is a pretty heavy duty inverter. Xantrex SW3000 with something like 4 batteries. And, yes, I think it is an inverter/converter. As you can see by our "signature" below, we've got a pretty good sized fifth wheel. As for the "by-pass" we aren't living in our Mobile Suites yet, so they've kept it at the dealership.

I am primarily concerned about if and when the inverter should quit while we are living full time in it and lose electricity as to what we could do until the inverter was fixed or replaced. My understanding is that with an inoperative inverter, we would be without any electricity, even if on shore power or generator.

Not that I want to, but should one buy an inexpensive converter to carry around? Or, do they just not have that many problems with inverters? I seldom ever hear of problems on the forums with them. So, maybe I have concerns for no good reason.

Thanks for your reply.

Terry

bjoyce · RV-Dreams Family Member

I think you have concerns with no reasons since those big inverter/chargers do not die that often.

It is relatively easy for someone who is handy with electricity to wire around the 120 volt part of the inverter, you wire the appropriate wire from the input side of the inverter to the output, all three of them. It is good to double and triple check the work but I have replaced an inverter/charger and believe me I am not that good at working with electricity. A short piece of the right size Romex and lots of electrical tape would do since this is a temporary workaround so all of your outlets are now hooked directly to shore power. The 12volt wires need to be capped off or used with a temporary battery charger like a converter.

Now you have to supply 12 volt to the batteries to keep them up while the inverter/charger is repaired or replaced. If you have solar and sun you might be OK if you have enough solar charging to keep the batteries up from the small 12 volt load. If you will be traveling every day your truck will charge the batteries slowly as you travel. You can hook a car battery charger to the batteries each night and charge them, a hassle but doable. Many RV techs have a cheap converter that came out of someone else's RV when they upgraded to a better converter or inverter/charger that they keep around for just such situations. When I say "cheap" I am talking about those $150 Magnatek and such converters that can only charge the batteries with about 10 amps and they only do float charge. The good converters are over $200, have three stage chargers and can charge at 40 to 80 amps. A converter is a battery charger that also can supply 12 volts from shore power but is also made to be used all the time, unlike a normal battery charger.

Now for something interesting:
I know people who frequent places with flaky electricity like Mexico, Yukon, some parts of the Maritimes or a long extension cord from a friend's house. They wire in a good converter to the batteries in addition to their inverter/charger, or just keep the one that came with the RV when they add an inverter/charger. The converter has its own shore power connection, a 15 amp plug that hooks to a normal extension cord. They use the converter to keep the batteries up instead of their normal shore power cord in these flaky situations. The converter will charge using 5 to 9 amps of 120 volt and can handle wild voltage fluctuation and keep on going. They run what they can off the inverter. For this application a 40 to 45 amp converter works great, it doesn't need as many 120 volt amps but will still supply a couple thousand amp-hours of charging per day.

Bill and Linda · RV-Dreams Family Member

Terry:

I suggest you just need a spare 12 volt converter – but one large enough to take care of the 12 volt charging and operating 12 volt loads for the rig. If I am not mistaken, the SW3000 has no 110volt change-over switch that feeds the entire trailer as the other Bill was surmising. (Xantrex did have one of those types of units, the RS3000, but you don’t have one and they have been discontinued according to last report.)

I carry a spare 12 volt converter and had to use it once when the primary unit smoked. (Infant mortality – stuff happens.) As a reminder to some, you need 12 volts for a lot of things including running the control boards in the refer. No 12 volts, no cold food. So even if you are setup when the SW3000 inverter/charger fails, you’re still in trouble without 12 volts. (BTW, some AC thermostats, like mine, also run off 12 volts from the trailer 12 volt buss; so without 12 volts, no air-conditioning either.)

To the point at hand, a nice 45 amp converter, such as a DLS-45 45 Amp Power Converter w/IQ4, could be installed with a 12 volt switch feed to the batteries and 12 volt trailer power buss. This backup converter would only be connected and plugged in if the SW3000 failed. How you do this mechanically would “depend” and I won’t go all that as I don’t know how easy you want to make this. But you should have “a plan” on how to do this if you carry the converter as a “non-installed” spare so you have a clue should the SW3000 fail.

The unit I am suggesting should run the trailer fine, just don’t turn on every 12 volt light in the place, as well as charge the batteries with an intelligent charger built in. Yes, you can spend less money. My suggestion is just that, a suggestion based on experience and the fact I wanted something that could work for weeks if it had to. (Actually my spare is a 60 amp unit, but I tend to over-build things. J) See if you care too:

http://www.bestconverter.com/DLS-45-45-Amp-Power-Converter-wIQ4_p_336.html

A qualified RV electrician would have no trouble connecting this and making it safe, but it would cost more in labor to do the wiring than the converter costs. (Web price I noted on the converter was $165 for a unit that would should the rig and charge the batteries as an acceptable backup unit IMO.)

Don’t know how much this helps, but I thought I would give it a shot for your consideration.

Safe travels
Bill

Terry and Jo · RV-Dreams Family Member

Wow. Good information.

Now, another theoretical to throw in. Our Honda EU3000is generator also has a 12V battery charger built into it with a separate outlet for that purpose. While I don't have any of the technical information at hand, would that serve to charge the batteries?

This is assuming that I did like Bill Joyce suggested and wire "past" the inverter so that I had shore power 110V to the appropriate places. Then, would the batteries still be able to keep up with the refer control boards, thermostats, and other 12V applications?

Or, would I be better off with the DLS-45 because of the "smart" technology?

Yeesh. Almost wish I hadn't asked this, but if not for my benefit, it may really help out someone else.

Sorry for the extra questions, Guys, but I like to be prepared. Shoot, I still have the Boy Scout Handbook from when I was a kid. And, that was some time ago.

Terry

NorCal Dan · RV-Dreams Family Member

While I don't understand what you're trying to do with bypassing the inverter, I know for a fact that batteries, even if not being used, will lose their charge. And you will find that your rig requires 12VDC for many of the installed items. You can easily survive in a rig that only has 12VDC and no 120VAC. Whatever you decide to do make sure something is keeping your batteries charged up.

Racerguy · RV-Dreams Family Member

Terry, you remind me of a very good friend of mine by trying to think of everything and have a plan for it.Even though the rig will be your home I might suggest you take it easy, relax and leave some things to chance. wink

Jim01 · RV-Dreams Family Member

Terry, I have to agree with Racerguy, you can't plan for everything that might go wrong with an RV. We've been on the road for almost 10 years now, and have never been in a situation that couldn't be at least temporarily fixed until we could get to a place to get parts or to a shop where it could be repaired.

Take it easy, don't try to over plan. More than likely the things you plan for will not happen anyway.

Jim

Terry and Jo · RV-Dreams Family Member

But, Guys!!!

I have a reputation to uphold as the "King of Overkill."

Terry

(But, yeah. I get your point. I'll try to "temper" myself a little bit.)

Bill and Linda · RV-Dreams Family Member

Terry and Jo wrote:

But, Guys!!!

I have a reputation to uphold as the "King of Overkill."

Terry

(But, yeah. I get your point. I'll try to "temper" myself a little bit.)

Well, I can understand the “don’t worry about it,” but for those of us who would rather be prepared about things that we can actually deal with I'll continue to answer your questions because without 12 volts you don’t have a rig. But I’ll also be glad to forgetabout it if you like. J

First, concerning Bill Joyce’s suggestion of “a wire” to by-pass the inverter so as to get 110 volts on the outlets; just asking to get clarification: When the inverter was removed, did you verify outlets “fed” by the inverter (and there is likely other stuff in addition to the outlets fed by the inverter) actually had no power on them when shore power was connected? (I’m just gathering some clarification on this point of actually needing a by-pass as such, you might not. It just depends on how they wired the rig.

As to the Honda Generator charging the batteries; yes, it will charge the batteries. But the converter suggested is not only to charge the batteries but to “run” the 12 volt systems when you are plugged in to shore power. Without a source of 12 volts, independent of the batteries, you’re going to be running that generator most of the time. In many cases it won’t “charge” as fast as you will drain the batteries. As I am know for saying too often, it depends.

You would really be surprised at how many amps the lights and refer draw. My refer draws 1.5 amps just idling. Lights are about 1.5 amps each. (If you have the new LED’s they are a lot less. You might, don’t know.) Anyway, my suggestion was to allow you to have a full failure of the inverter, and with a standby converter, still be in business 24/7 when on shore power. I hope this makes sense. If not, ask and we will further confuse. (Isn’t this fun?)

Bill

Terry and Jo · RV-Dreams Family Member

Bill and Linda,

I'll address you in that manner since "just Bill" could also be applying to Bill Joyce. In spite of the reasurances to not worry about it, you can be assured that I will still have my concerns. With your suggestion, Jo and I will definitely be considering the backup converter. It is certainly cheaper than buying another backup inverter.

As for what may have still had "shore power" even with the inverter out, that was all done at the dealership. Thus, I have no idea what may be affected. However, your question prompts me to experiment by unhooking the inverter at home and seeing if anything is still live with 120V. Good thoughts there, by the way.

I suspected that the generator's 12V battery charger function would be limited, especially considering the 12V usage in a fifth wheel. However, I think the 2010 Mobile Suites do have all LED lights. (Many would never believe how MANY lights there are in that camper.) While many are "pot" lights in the ceiling, there are also a number of wall lamps as well, not to mention the "pendulum" lights over the kitchen counter.

Thanks for your answers, Bill. And, don't hesitate to chime in anytime. I value everyone's posts and points, and yours are almost always great insights and information.

Terry

Gary · RV-Dreams Family Member

This is all great information. Provides those who are in the process like Terry and Jo some valuable "check this out to see what happens" type of scenarios that they can apply with their rig to determine what does/doesn't work.

It also provides those of us who are still dreaming with the possible "add ons" for their future rigs. Without this thread, I would not have thought about it.

Although rare in occurrence, these things happen. I like the idea of redundant systems but cost becomes a factor in those decisions. How robust do you want your back up systems to be and how often will they be used?

Just more things to think of! Thanks!

53 Merc · RV-Dreams Family Member

Gary wrote:

It also provides those of us who are still dreaming with the possible "add ons" for their future rigs.
Although rare in occurrence, these things happen. I like the idea of redundant systems but cost becomes a factor in those decisions. How robust do you want your back up systems to be and how often will they be used?

I have seen Rvers that had a replacement part for just about the entire rig. (Makes one wonder if the significant other is not towing a replacement RV). Then, there are the ones that travel happily with no spare "parts", and just have a great time.

Personally, I fall somewhere in the middle. I carry a spare (longer) water hose, an add on dump valve just in case the other ones leak, a spare sewer hose and enough tools that I can make simple repairs. Of course, duct tape and wire are major components of the tool box. We also carry a few bulbs to fit various lights. But, that is just about it.

I seem to notice people that obsess about things going wrong, generally get their wish. Others just enjoy the experience. Kind of like, is the glass half empty or half full.

Luvglass · RV-Dreams Family Member

I agree with 53 Merc, A few simple spares and a basic tool box are all that are needed.

There's no practical way to anticipate what might go wrong and be prepared, and quite frankly, I don't think it's necessary.

There are very few places you are apt to be that are too far from a technician, dealer, or spare parts supplier.