Inverter usage

[mswingle2@verizon.net]

Can you run your inverter while driving to power your laptop? If yes, how many hours can you let it run?

[tbutler]

We have our inverter on all the time. When we pack up and leave a park, we bring in slides and then unplug. The inverter picks up from there. How long it lasts depends on what load you put on the inverter. A laptop is a small load. I monitor our usage during our travels and we run 6 to 9 amps base load and have a 440 amp hour (4 ea 6V batteries) to run the inverter. We also have a roof-mounted solar panel, but even on cloudy days we have no problem using the inverter all day long. It will run all day and run the TV for several hours at night before we have to use the generator or be plugged in. When we plug in, the inverter will recharge the batteries and we're back in business.

So the question comes down to what is your base load and what is your battery source to run the inverter? If you don't have an easy way to answer these questions, just try it on a day when you expect to be plugged in at night. Unless you have a small battery supply or a very large base load, I'm guessing it will work fine for you.

Base load is the stuff you can't turn off, the electronic controls on the refrigerator and the various safety devices (smoke detector(s), CO detector, LP detector), indicator lights on switches, other sensors, etc. Part of our base load (with the inverter on) is our alarm clocks, the microwave clock, probably a few other things I can't think of now.

I was recently at Camping World and mentioned something about an inverter to another motor home owner with a very nice motor home and they said they never used their inverter and I was amazed. I just wouldn't imagine not using such a useful device. We run battery chargers for our phones on the inverter if needed while traveling, stop and turn on the computer or the TV to check weather, catch up on the news on TV while eating lunch, our AC current is always on! We recently upgraded to a true sine wave inverter with automatic generator start (our old one had auto gen start but it quit working) so basically when the inverter runs the batteries down it kicks on the generator and we don't have to worry about the batteries getting run down even when we are boondocking.

[rooooger]

Tom very good info. We to run our inverter almost every day we roll. We are going to be adding 2 more batteries(4 total house), roof solar, larger pure sin inverter and a separate alternator for just the house side. I will be checking into the auto gen set start you refer to for it makes so much sense to have it too. Thanks, R(O)(O)(O)(O)ger from Sunny So Cal

[mswingle2@verizon.net]

Can you run your inverter while driving to power your laptop? If yes, how many hours can you let it run?

Thanks for your input. One more question, when you are done driving for the day, and plug into your campsite, does the inverter automatically turn off or do you turn it off manually? We have a Dimensions Inverter in a 2005 Winebago joruney. margy Swingle

[tbutler]

Margie,

I can't say how yours works, we have a Xantrax RS3000 inverter/charger. When we plug in, ours goes into battery charger mode. It then recharges the house batteries off the shore power (RV park electric). When we stay in a park, it continues to keep the house batteries in top charge. There are loads on the batteries even when you are plugged in. The lights in the coach run off the batteries, the controls for the refrigerator and hot water heater and of course the furnace controls and fan is driven by battery power. As these loads draw from the batteries, the inverter/charger restores the charge on the batteries.

This is why I say we never turn off our inverter/charger. Never even think of doing it unless we have service being done on the electrical system and turning it off is a safety issue for the workers. The inverter/charger is one of the real convenience items in our motor home. We never have a power outage. In fact, we have had occasions when we are sitting in our motor home at night watching some TV and the generator kicks on. Only then do we find out the whole park has been out of electric for hours!!!

[jimbrightly@worldnet.att.net]

Margie, Tom is entirely correct. I've hosted several inverter seminars at FMCA internation conventions over the years, and all the manufacturer reps agreed that the inverter never has to be turned off except during longtime storage. That is the only time I turn mine off because I store my coach on a storage lot where electric hookups are not available.

[wolfe10]

As Jim said, when storing the coach turn the inverter off.

In addition, when dry camping turn it off when you do not need 120 VAC. It takes a little power (amps) to keep it in "standby mode"-- both from inverter consumption itself and from parasitic load from things like the TV and other appliances.

Brett Wolfe

[lsauer1]

Well, don't laugh, as this is probably a stupid question - but when the inverter is turned on, do all the outlets work in the motorhome, or just some? How do I know where to plug in the laptop? We do not turn our inverter, as my husband says it runs down the batteries. I'm going to show him this forum, so he will change his mind and turn on the inverter. I have been running the laptop using an inverter powered through the dash.

[bobdinsmore@optonline.net]

I have a related question: My coach batteries do not charge when driving down the road. Is the engine alternator supposed to charge the house batteries? If the answer is YES, what do you suspect the problem is? A year ago I had the same problem, Monaco told me to replace the Battery Isolator, I did, I recall this fixed the problem but now the batteries are not being recharged by the alternator. Plugging in to shore power does recharge them. Thank you.

[ricklamb@mac.com]

Let me throw my 6 1/2 cents in.

Your inverters will be different, depending upon model and year produced. For later model year coaches, and Xantrex inverters, the following happens:

When no electric power (incoming 120v) is available (from either shore or generator), and the inverter is on, the inverter will provide 120v power by inverting 12v battery power to 120v. How long that event will last depends entirely upon the amount of 120v appliances demanding power, and especially upon the amount of Amps demanded.

When you connect to shore power or start the generator, the inverter recognizes incoming 120v and stops inverting. The inverter then becomes a charger and charges the inverter's batteries. Few inverters also charge the coach batteries. Most coaches charge the coach batteries via a converter, mounted elsewhere.

The chassis (engine) batteries are charged by the engine's alternator. If your coach sits for a long time, without some sort of disconnect switch thrown, the chassis batteries will drain.

The only downside to having your inverter on constantly, is when you are using shore power, or are running your generator, and either fail for one reason or the other, the inverter switches to provide power to your appliances. You may not realize that your coach is not receiving shore or generator power, and wind up draining your coach's inverter batteries. This is bad, especially when you are going out the door for a day long venture, and the problem is a simple flip of a breaker. You return to dead batteries, and a coach that hasn't had power for a while.

There are a lot of opinions on batteries, ie 6v vs 12v for the inverter, and coach. But when choosing a battery you need to know how much power is in the battery, and how fast (or slow) the battery will give up that power over time. There are formulas to calculate this event.

Just my few cents.

Rick

[tbutler]

Well, don't laugh, as this is probably a stupid question - but when the inverter is turned on, do all the outlets work in the motorhome, or just some? How do I know where to plug in the laptop? We do not turn our inverter, as my husband says it runs down the batteries. I'm going to show him this forum, so he will change his mind and turn on the inverter. I have been running the laptop using an inverter powered through the dash.

Try it and see! In our coach, all the outlets work. The inverter won't run some appliances. It runs the coffee maker but that puts a real load on the inverter and thus the batteries. In fact anything that generates heat from electricity like small electric heaters consume large amounts of electric. The inverter won't run the air conditioners, the washing machine or possibly the microwave. After a night of boondocking on a cold night with the furnace running our batteries will be pretty run down. I'll start the generator to recharge them and then make coffee while the generator is running and recharging the batteries. If Louise wants the microwave for making breakfast I'll leave the generator on for that. Our inverter has a battery charging sensor and it is set to shut off the generator when the batteries are fully charged. I'll usually let the generator run to automatic shut off meaning that the batteries are then fully charged for the coming day. If we are going to be plugging in early in the day, I'll leave the batteries partially charged and wait to plug in to finish the job.

Your husband is correct that the inverter will run the batteries down. How fast depends on how many things you have running and the number and condition of your batteries. The inverter should be connected to your house batteries. If it were connected to your engine batteries, then running batteries down would be really bad. If you are using the dash 12V outlet to run your computer, that is probably running off the engine batteries.

Running down the house batteries is what they are there for. You can recharge them by plugging in later in the day or by running the generator. In both cases the charger function of the inverter is changing 110V electric to 12V current to charge the batteries. If you are worried about running down the batteries, simply make sure that most electrical loads at the outlets are turned off. A laptop, a couple of alarm clocks, even an occasional TV program shouldn't drain the batteries in a day. Of course your house batteries run things like the controls on the refrigerator and hot water heater and also operate the furnace so you want to be sure you have enough charge to operate those essential services. As I said, try it out to see if it will meet your needs. We find using the inverter a real convenience that makes living in the motor home more comfortable.

[ricklamb@mac.com]

Bob:

I doubt that your coach batteries are charged by the engine alternator. Monaco uses a Converter, which is plugged into a 110 outlet somewhere in your coach. This outlet is usually not on the inverter, so it is powered only when you are plugged into shore power or running the generator. Find the Converter (mine is a Progressive 9000), and see if you have a charge Wizard plugged into it. If your batteries are the type that have water, that you have to check frequently, the charge Wizard will decrease the amount of "boil", and therefore the amount of white battery acids you have to clean out of your battery compartment.

Rick

[pnixon235]

Hi Folks

Been lurking for a while and find this topic interesting due to the changing world of electronics in our coaches. I have an older coach (99 Rexhall) and I am in the process of upgrading some of the electrical systems. I find one of the more useful things has been power cords for our laptops that plug directly into 12volt outlets eliminating the need for inverters. Very useful in the car also. The next change is to a Xantrex inverter/converter to provide 120v and to charge the new AGM house batteries. Old converter charges at less than 10amps and the new Xantrex is capable of 40-50amps. Should be huge increase in recharging depleted house batteries. Hope this might help.

Paul

[wolfe10]

Bob,

First, you already know that the alternator USED to charge both house and chassis battery banks, so indeed it should (as it does on 99% of coaches).

There are two basic types of battery isolators:

1. Solenoid-based isolators (look like large electrical relay with two large lugs and one or two small ones).

2. Diode-based isolators ( usually rectangular with 3 large lugs and large area of cooling fins)

I will answer for #2 as that is most likely-- if you have #1, let us know and we can talk you through troubleshooting it.

With engine off, one large lug should read the same as chassis battery voltage (use digital voltmeter-- at Sears, Radio Shack, etc for around $20). Another large lug should read the same as house battery voltage). The third lug should show zero, as it goes to the alternator.

With engine on, the "alternator lug" (usually center one) should show alternator voltage (likely around 14.0 VDC). Both of the other large lugs should show the same and about .6 VDC less than the alternator lug (due to loss across diodes).

If one of the diodes is burned out, it will not pass current to its battery, so that lug would continue to read battery voltage rather than the higher voltage provided by the alternator.

If that is not it, look for a fusible link between isolator and house battery bank.

Brett Wolfe

I have a related question: My coach batteries do not charge when driving down the road. Is the engine alternator supposed to charge the house batteries? If the answer is YES, what do you suspect the problem is? A year ago I had the same problem, Monaco told me to replace the Battery Isolator, I did, I recall this fixed the problem but now the batteries are not being recharged by the alternator. Plugging in to shore power does recharge them. Thank you.

[don0344]

I too have a related question. I have a 1998 Monaco Diplomat with four 6V house batteries and two coach batteries. My inverter is a Xantrex Freedom 458-20 2000 VA unit. The controller is also a Xantrex. Occasionally I can hear a clicking sound coming from the isolator (the round black component in the battery compartment with two large terminals and two small terminals). I clicks off and on for several minutes at at time, then goes silent for long periods. The time interval from on to off is about a second. Since this device apparently switches the charging from the inverter to either the house batteries or coach batteries, I wonder why it does this momentary pulsing. There is no indication on the control panel of any activity other than the usual readout when the frequent switching takes place. Since it would seem that the inverter would switch to one or the other battery systems for sustained charging, I'm wondering if this pulsation indicates a problem with charging system.

Thanks,

Don

[don0344]

Sorry, I somehow posted a duplicate and don't see any way to delete it.

Don

[ragdahl]

Paul,

I do not know anything about the Xantrex unit you are referring to BUT with a new purchase you should be sure that the battery charger control has a "temperature compensated" feature. This is a MUST have when purchasing a new battery charger, especially with AGM batteries. Temperature compensation measures the battery temperatures and allows for higher charging voltages without boiling the battery liquid - a must to achieve full battery charge

I suggest you go to http://www.amsolar.com web site and open up "Education" section and read it all. It is by far the best reading in a tenderfoot's (me) language.

Bret Wolfe mentioned the Isolator and I consider it maybe more important than the battery charger. Our 2003 Dynamax coach is on a Ford Econoline Cut-Away Chassis with a V-10 for power. This unit had Ford's upgraded alternator (130 amp) and Dynamax used Intellitec Specialty's Solenoid Type Coach/Chassis Isolator and this unit is very Multi-Functional. (1)The unit allows the Motor Alternator to charge the Coach batteries (and provides power for the small invertor I use for our TV; DVD; Sound System; and Computer) when driving down the road. Unfortunately the voltage of the alternator is controlled by the chassis battery requirements, therefore even though the alternator will put out a 14.2 volts it usually operates at a 13.4 volts. (2) When plugged into shore power, the unit permits the house converter (battery charger) to also charge the chassis battery. (3) You have a "coach storage" manual on/off switch to isolate the two battery systems (coach/chassis) so you will not discharge both at the same time during coach storage. (4) During dry camping, you use BOTH Chassis and Coach system until the voltage drops to 11.8 volts and then the Isolator seperates the two battery systems (the Isolator measures both battery system voltages). (5) If either battery system is below 11.8 volts at ANY TIME the Isolator keeps the two systems seperated - this means if driving down the road and the alternator cannot maintain both systems above 11.8 volts due to load (head lights; driving lights; running lights; and house inverter loads) the systems are seperated and if the house inverter is on you will run down the house batteries. Now the Isolator lets you manually close both relays momentarily to start your generator using the chassis battery as a power source. This momentary control can also be used to power the chassis battery should in not have power enough to start your engine.

I look forward to replacing our inverter/converter to a new temperature compensated model. I have changed out our two 12volt wet cell batteries for two larger 6 volt AGM that provide 75% more amp/hour storage capacity. But our battery charger only puts out 13.4 volts and therefore, we do not properly maintain the charge for the batteries.

Richard Dahl F180829

2003 Dynamax Isata 250SL

Ford V-10 Gas

Valley Springs, CA

[emulsified2000@yahoo.com]

Inverters have an off switch?

[bobdinsmore@optonline.net]

Brett, thank for your very clear reply, but I have configuration #1, a solenoid-based isolator. Here is the solenoid layout (two large lugs and two small terminals):

- One large lug goes to the chassis batteries and the other to the coach batteries.

- A small rectangular isolator with three small wires:

... The center blue wire connects to a blue wire entering (from ???) into the battery compartment

... The isolator red and black wires connect separately to the small terminals on the solenoid

... There is another wire pair entering the battery compartment (from ???0); the red one goes to

the "small-red" terminal on the solenoid, and the white one goes to the "small-black" terminal)

on the solenoid.

Thanks for your help!

Bob

[rkelbaugh@routesixsigma.com]

If you are driving with an inverter with house batteries, you should be flexible to use it to your hearts content while the engine is running. Check to see that you have an battery isolator. If so, the house batteries will be on charge from the engine alternator and the inverter is just drawing from the power that the alternator is replenishing. We have a 2000 watt inverter with 4 house batteries, and my wife even runs the crock pot while going down the road. While we can't use the microwave without generator, our fridge is always drawing. So, depending on the installation, that inverter provides a great deal of convenience when disconnected from shore power.

[tbutler]

I have been reading the ongoing discussion in this topic for some time. There were things that didn't ring true with me, from my own knowledge of my coach and from differences in statements from different posters. So I went to the owners manual for my coach and re-read everything related to the inverter, batteries and alternator. From the previous discussion, it is apparent that different coaches have different systems for interfacing with the alternator, inverter and batteries. From our users manual, the information for our coach is as follows.

The alternator charges the entire electrical system including the chassis (engine starting) batteries and the coach (house) batteries when the engine is running. There is a caution not to use the alternator to recharge discharged house batteries as it may overload and overheat the alternator causing damage to the alternator. rdlamb's statement is probably correct for his coach but his statement is not true for all Monaco coaches.

When we use the inverter while driving this puts a load on the house batteries and thus the entire electrical system and the alternator will attempt to make up for that. A continuous large load in our case could result in overheating the alternator.

When we plug in the shore power, or when we use the generator, the inverter switches over from inverting to charging the house batteries. There is a battery maintainer (different from a converter) in the system which will allow the battery charge from the inverter/charger to the house batteries to be diverted to the engine batteries once the house batteries are fully charged. Thus, when parked for any length of time the house batteries are fully charged and the battery maintainer automatically switches to charging the engine battery as needed. The battery maintainer has an automatic circuit breaker which will trip if it draws more than 15 amps and then automatically reset. If the engine batteries are discharged and the maintainer is drawing more than 15 amps, it will click off, then back on repeatedly until it pauses. Could this be the cause of the clicking noise don0344 reported? It will resume putting a charge on the engine battery if the engine is started and then shut down after the alternator has put a base charge on the battery.

Again, the above information is from the owners manual for our coach. It can not be applied to all makes and models of motor homes, maybe not even the same make and model from a different year.

Knowing what kind of coach someone has (year, make and model) can help find an answer to their questions. You can put basic coach information in your signature as I have done below. This helps everyone understand your problem and helps those who attempt to answer your question.

[don0344]

Thanks for your reply, Tom. I purchased my motorhome last November and spent the past 5 1/2 months living in it parked in an RV park near Tucson. I took my first road trip last Tuesday and drove the 150 miles from Tucson to McDowell Mountain Regional Park in Scottsdale, AZ so I have almost no experience with a motorhome. I have to say I was white-knuckling it on I-10 for about half the trip. It was windy and there were lots of semis on the road. After awhile I began to get the hang of it and was able to relax a bit. Previously I had been pulling a 26' Jayco travel trailer with a Toyota Tundra TRD pick up. This 27,000 motorhome is a whole 'nuther ball game both to drive and to live in.

As far as my inverter goes, it is a new one. The old one was not charging any of the batteries to full capacity so I had it replaced. My batteries all seem to be charged to full capacity both the house batteries and the chassis batteries. There are no indications on either the Xantrex control panel or on the Xantrex inverter itself of any problems. On the inverter the invert led flashes green which, according to the Xantrex manual, means the inverter is in standby mode, and the charge light is solid green which indicates that external AC power is applied. The relay seems to drop in and out even when I have turned the inverter off at the control panel. Although it stops clicking on and off for long periods of time I would say that it is active more than it is inactive. One problem is the inverter compartment is right below my bedroom and the clacking is loud enough to interfere with a good night's sleep. I have a pair of ear plugs on the night stand for that reason.

Don

[tbutler]

Thanks for your reply, Tom. I purchased my motorhome last November and spent the past 5 1/2 months living in it parked in an RV park near Tucson. I took my first road trip last Tuesday and drove the 150 miles from Tucson to McDowell Mountain Regional Park in Scottsdale, AZ so I have almost no experience with a motorhome. I have to say I was white-knuckling it on I-10 for about half the trip. It was windy and there were lots of semis on the road. After awhile I began to get the hang of it and was able to relax a bit. Previously I had been pulling a 26' Jayco travel trailer with a Toyota Tundra TRD pick up. This 27,000 motorhome is a whole 'nuther ball game both to drive and to live in.

As far as my inverter goes, it is a new one. The old one was not charging any of the batteries to full capacity so I had it replaced. My batteries all seem to be charged to full capacity both the house batteries and the chassis batteries. There are no indications on either the Xantrex control panel or on the Xantrex inverter itself of any problems. On the inverter the invert led flashes green which, according to the Xantrex manual, means the inverter is in standby mode, and the charge light is solid green which indicates that external AC power is applied. The relay seems to drop in and out even when I have turned the inverter off at the control panel. Although it stops clicking on and off for long periods of time I would say that it is active more than it is inactive. One problem is the inverter compartment is right below my bedroom and the clacking is loud enough to interfere with a good night's sleep. I have a pair of ear plugs on the night stand for that reason.

Don

Don,

Your coach is six years older than ours so your battery maintainer may look different than ours. You mention that the inverter compartment is below your bedroom, ours is under the bathroom near our bedroom. Is the clicking coming from the inverter also? Is it only coming from the relay you mention in your first post? You mention a function for that relay that is similar to the battery maintainer we have. Our battery maintainer is in a compartment adjacent to the battery compartment and below our bedroom.

The battery maintainer that I wrote of is a large bar arrangement with cooling fins. It has two terminals to the batteries, one marked chassis and the other marked add'l for house batteries. It has a third terminal in the center labeled negative. There is an adjacent battery maintainer lockout which looks to be a kind of relay, small square, with four blade terminals. Our manual doesn't mention the lockout but does say that the battery maintainer will automatically reset when it is over amperage. The manual does mention that the battery maintainer will click off and on repeatedly and then go silent if it can not achieve a constant charge (pulling too many amps trips the internal auto-reset circuit breaker). If your batteries are charging fully, then the battery maintainer wouldn't be cycling off and on unless the internal automatic reset function or circuit breaker was faulty.

Now, here is another possibility. We just installed a new Xantrex Inverter and I immediately encountered a condition that I hadn't encountered with our older inverter. The new inverter has a "load sense" function. When load sense is activated, the inverter will switch from standby to active at intervals you program into the inverter. When load sense switches on and detects a significant electrical load it will stay on and supply electric to that load. If there is no load or only a very light load, it will switch back to standby and then back on to check the load again after the programmed interval. All this is going on only when you have no AC source, shore power or generator supplying electric.

Here is the point of my mentioning load sense. After the installation of our new inverter, we were camped for a while. When we unplugged from the shore power, the inverter went into load sense function. Since we didn't have any major loads on the circuit it would constantly switch from standby to on, back to standby. I could tell this was going on because I was standing right next to the TV, VCR and other AV electronics. I could hear everything switching on, then off, then on and so on... It took a trip to Camping World where we had the inverter installed before I figured out what was going on. I took the inverter out of load sense (programming at the control panel) and everything was fine. Maybe, just maybe, this is the source of your clicking? Does the clicking happen when you are plugged in? If so, it wouldn't be the load sense function. If the clicking problem occurs when you are unplugged then I would suspect the load sense function. It would click off and on until there was a sufficient load on the circuit and then it would stay on (no clicking) until the load dropped off the line and the clicking would return. The clicking wouldn't come from the inverter, it would be other electronics being turned on and off as the inverter switches on and off over and over. Perhaps a malfunction in the inverter is doing something similar with the battery charging function?

I'll be interested in the solution to your problem. Be sure to post your findings to us when you finally resolve the problem.

[don0344]

I bought my coach second-hand and, unfortunately, much of the manufacturers' literature is missing. I may have mentioned, too, that this is my first motor home. I traded up from a travel trailer. The Monaco owners manual only gives a cursory explanation of the electrical system. I had no information on the inverter until I recently had the new one installed. I could find no reference on either the Monaco site or the Xantrex site to a "battery maintainer." I had searched the Xantrex site for an answer to the switching problem and found a reference to a relay that continuously switched back and forth however it was associated with a red LED on the inverter front panel and since I didn't have that condition I didn't pay much attention to the article although I saw a sentence that said that a charging threshold my have been set too low or too narrowly, causing the rapid relay switching. I just went back to the Xantrex site but am unable to find that message and I can't find any instructions on how to set those kinds of parameters in the inverter. The "problem" solenoid looks to me like the starter solenoid in a car. It's a black cylinder about three inches long with terminals on top. There are two large terminals. One goes to the 6V house battery bank and the other goes to the two 12V starter batteries. The smaller terminals apparently connect to control circuitry but I don't know where the signal comes from - from the inverter or some other source?. The inverter is installed in a compartment that is adjacent to the battery compartment both of which lie directly beneath the bedroom making it tough to sleep when the relay is doing its thing. Earplugs help.

[tbutler]

Don,

I would love to help but I'm 1000 miles away and headed the other direction! Anyway, I just don't know enough about your system to help you. I have two sources that may help. First, there is a Monaco group on Yahoo that has a pretty high level discussion on-going. There seem to be some experts with experience on technical aspects of all Monaco products. I suggest you contact them, their address is: http://autos.groups.yahoo.com/group/Monacoers/ From that web site I got a Monaco Tech number that one of the posts said was now active. That number is 800 450-6336. You might try that and report back to us if it is a working number and what kind of help you were able to get. I also saw an e-mail address for Monaco Tech Help but can't find it right now. When I come across it again I'll pass it along as well.