| Author |
Message |
Jason (24.217.113.23)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, April 14, 2002 - 1:21 pm: | |
we are still in the converting stage of our bus and have gotten to the point of power. We don't want to spend $1,000 for an inverter, but don't know how to power our stuff? What is a good reasonable inverter that will be sufficient for an RV application. We don't know exactly what appliances and such will go into the bus. What specs do you think we need. Thanks |
jmaxwell (66.42.93.125)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, April 14, 2002 - 2:11 pm: | |
Jason: A fair amount of thought is necessary for sizing and applying an inverter to your conversion. Your first consideration will be to decide what u want to power with the inverter and then determine the wattage consumption of the most power hungry appliance that u want to power thru the inverter; that is the minimum capacity inverter that u will need. I personally would not consider anything less than 1500 watt continuous, which can be bought for $250-500 (depending on your shopping practices). These are the electronic models, non-auto switching, no built in chargers. Just simple (well, not quite simple) mod-sinewave that will adequately power just about anything they have the capacity for. They do display effeciency losses under high inductive loads (motors), but for most applications they will work just fine. So, u need to calculate your maximum wattage load that u intend to power at any one time, get an inverter with that capacity, and then install a battery bank that is capable of supplying the inverter for a reasonable period of time. U can find the type of inverters I refer to from a lot of sources, primarily mail order under various names; StatPower, Power to Go, Wagan, Wagner, Whistler, etc. The best source I have seen for them on the net is HeartlandAmerica.com (cheapest) They have a 2000 watt for under $600. Ideally, these types are dedicated to what u want to power up and not integrated into the coach 110v permanent wiring since even the slightest cross-feed voltage will blow them. For your convenience and peace of mind, I would seriously consider saving money somewhere else in the conversion and spend the money on a good integrated inverter, such as the Trace U series. I personally don't believe that u need a pure sinewave model unless u want to power up some big loads, in the 3kw range or higher. Just IMHO. |
Rodger Manecke (Rodger) (67.235.199.57)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, April 14, 2002 - 2:36 pm: | |
Someone on this board mentioned he bought a rebuilt Heart, at a rediculously low price from a guy, Heart plant employee, who rebuilds them. Check the archives and maybe you can find the source.
Rodger |
FAST FRED (209.26.87.92)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, April 14, 2002 - 2:53 pm: | |
The biggest advantage of a first class inverter is the battery charger that can be part of it.
If you hope to do extended boondocking the battery pack will be a very large expense.
The pack needs to be charged and maintained very well ,or it becomes a huge AND continuing expense.
The easiest way to keep the batts at there best is with a good monitoring system , and a good 3 stage charger , that also can equalize..
The choice between chop chop electric or pure sine wave is needed depends on your decision to use air cond from the engine alternator.
With out sine wave (SW) power the air cond will run , but the output of cold air can be reduded up to 40%.
There is also a reduction in the power , and higher ON time for a fridge used on none SW power .
So the first decisions are how costly will the battery bank be , how hard will it be used , how will you maintain it?
Then decide if tools, TV, sat dish , and the microwave will be the inverters prime job, or air cond on the road.
Finally you will need to decide if the battery charging will be time limited, as from a gen set.
Or unlimited,as overnite in a campsire with 120V.
In that case the quality of the system will make a huge difference in the output of the charger.
A few ( the $$$ ones) can stand gen set electric and make about 75% of there charge rating .
The poorer inverter / chargers will seldom get to 40% of their ratings on a medocre gen set , so charging times can doubble or tripple.
Only a concern , if its a concern to your life style.
Lots to decide early in the conversion .
FAST FRED |
Stan (216.95.238.84)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, April 14, 2002 - 6:34 pm: | |
I don't understand Fast Fred's comment that an A/C will put out less cold on a square wave inverter. I thought all inverters were 60 cycle and that AC motors phase locked to the 60 cycle power. If they are running the same speed, why do they make less cold? If they are not running the same speed they go up in smoke real fast. |
mspeer (216.60.141.135)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, April 14, 2002 - 7:31 pm: | |
try ebay
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=2016790254 |
Jason (24.217.113.23)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, April 14, 2002 - 9:10 pm: | |
I am still confused. I know that my microwave will take 800watts, my soundsystem 120 watts, and that isn't everything! I still have Tv, water heater, Backup cam, lights, coffe maker, fridge, ect. 920watts for two appliances seems high to me. Granted I am the most novice of the novice beginers, but is 2000 watts going to do it for me or should I get 2 2000 watt Galaxy inverters for my bus? |
Henry Draper (12.82.128.38)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, April 14, 2002 - 10:57 pm: | |
Hi Jason,
No, you don't need 2 2000-watt inverters! Plus, you haven't even asked the question yet of how many batteries do you need to provide power to the inverter. But you'll get there!!
The thing to remember about calculating your loads is time of use. For example, your microwave may draw 800watts, but that's 800 watts per hour! You'll probably only run the microwave for 5 to 10 minutes. I won't do the math, but you get the picture.
Here is a good site to get a sense of inverter sizing: http://www.xantrex.com/Mobile/rv.html. Once there, there is a printable file selection on sizing an inverter. It even provides you a worksheet.
Unless you're going to have a totally electric coach, you should be able to get buy nicely with a 2500 or 3000 watt inverter.
If you're looking for a real good deal, I can hook you up with one, CHEAP! (Totally refurbrished Heart Interface model.)
Henry Draper |
Lin (65.184.0.189)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, April 14, 2002 - 11:03 pm: | |
Jason- It depends on if and how you are willing to manage your power usage. The microwave and the coffee maker are not on that much and don't have to be run at the same time. I wouldn't plan on doing the hot water with the inverter, except maybe running down the road if your alternator is adequate and you are not using the other big draws. Some things are better done by the generator. |
Tom Caffrey (Pvcces) (12.146.33.50)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, April 14, 2002 - 11:32 pm: | |
Hi Jason, We bought our inverter from the same seller as the one mentioned in the thread above and we bought the same inverter.
If you look at the feedback, you will see our user name well down in the page and the feedback we posted for him.
We just installed the inverter last month and we are very happy with it.
Fast Fred's comments were valid for our old inverter because the micrwave took at least 50 % longer to make a cup of coffee, but the new one is as fast as being on shore power.
Your power system requires 3 elements to work well. One is an adequate inverter for your loads. The one above will run an air conditioner on the road or an electric heater, but it is wasteful to use your batteries that way when boondocked. That inverter is designed for RV use.
Another is a good metering system for your batteries, such as a Link 1000 or 2000. It may cost half as much as the inverter, but you will not know what is going on without it.
The last thing is batteries suited to your loads and charger. The charger in the inverter above is 100 amps and will easily produce that on your generator, while powering other equipment. At a minmum, you will want 4 golf cart batteries for good service.
The Galaxy inverters that you mention do not have any chargers and they have a fairly high idle current. You will not want to leave them on when boondocking unless you need them. The inverter on ebay should be available for around $700 and you can leave it on all the time without worrying about it, as long as the coach is in use.
If you use a 30 amp generator (4KW), you can integrate the whole works so that you will seldom have any trouble using what you want and understanding what your batteries can handle.
One thing I would avoid is using battery power to run heating or cooling loads of any size, such as a water heater, which run any length of time. These loads will require considerable cost to deal with.
Try doing keyword searches to see what has already been posted here on the board. There is a lot to learn in the beginning.
Tom Caffrey PD4106-2576 |
Jason (24.217.113.23)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, April 15, 2002 - 4:53 pm: | |
This coach is not going to be used for camping, so I don't need a charging function. It is basically going to be used as an over the road tour coach. Since I need something simple, I was going to build a circuit breaker panel sorta thing in one of the baggage bays, then put a power outlet on the wall, which will serve as the input to the panel. I would then mount dual galaxy 2000's on the wall, and then use a double headed cord to attach the power from the inverters to the circuit breaker panel. Then, if I have the bus parked at a relative's house I can just use a longer double headed extension cord and plug it into my bus? It is simple, but I couldn't get it into words, sorry. |
Jason (24.217.113.23)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, April 15, 2002 - 6:18 pm: | |
Nevermind, I can't connect two inverters together. I am loosing my mind. I think i'll use 1 3000 watt Galaxy inverter for my project. What is a high idle current? |
Lin (65.184.0.189)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, April 15, 2002 - 6:57 pm: | |
"Double headed extension cord" Does that mean you have a male plug at each end? If so, that is obviously extremely dangerous. You never know who might touch it. No one expects a plug to be live. That is the type of gross negligence that can get someone hurt, and someone else into deep civil and criminal legal problems. |
Jason (24.217.113.23)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, April 15, 2002 - 7:08 pm: | |
You are right Lin, I will correct this by having the bus end of the cord wired into the system instead of having it loose. This will only leave 1 end to mess with. Same with the inverter. I will have a plug plugged into the inverter, and wire the other end into the box. When I want to hook up to the house I will just flip the swith off on the inverter and plug into the house, I find a way. |
Peter Broadribb (Madbrit) (216.67.218.69)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, April 15, 2002 - 7:14 pm: | |
If you go to a good trailer supply house, they should have a weatherproof flush mount box for using a regular extension cord to bring in 120v power into the 120v circuit in the trailer. It has a male type socket behind a flip-up protective cover, for you to push the female end of the cord onto.
Peter. |
Wayne Buttress (Flyingb) (66.52.189.105)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, April 16, 2002 - 12:31 am: | |
Henry Draper,
I would be interested in a refurbished Heart Interface inverter/charger that you mentioned in your message.
Wayne Buttress |
Tom Caffrey (Pvcces) (12.146.33.174)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, April 16, 2002 - 10:15 pm: | |
One thing I don't think gets enough press here on the board is the fact that these big inverters can do power sharing.
When we visited a friend in the Portland area, he offered us the use of an extension cord on a 15 or 20 amp breaker. The cord looked like a 16 guage one.
I asked him how much power he was comfortable with being run through his cord and he said that he would like us to hold it to 10 amps.
We reset the Link to 10 amps, and we were able to top off our batteries while using the power for cooking and the fridge without worrying about it, because as soon as we turned on the microwave, the charger output dropped. As soon as we finished with the microwave, the charger went right back to high output. Slick!
I gather that some versions of the Trace can provide makeup power if the generator is overloaded, so that you can run more than the generator is rated for while boondocking.
I haven't actually checked that out, yet. I think these inverters go a long way to making power use in these coaches very easy.
Tom Caffrey PD4106-2576 |
Scott Whitney (24.205.239.4)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, April 17, 2002 - 12:24 am: | |
Yeah, I think it is one of the Trace true sine units that will actually sync up and kick in some AC to help an overloaded shore power or genset. The Hearts will reduce charger consumption as needed but I don't think they will help by adding any AC.
Well, I have been following this thread for awhile now and think it might be an appropriate time to ask my question. I have a Heart Marine 12-30 (thanks Henry!) and am considering various ways to wire it. It has two AC inputs and two AC outputs. My genset is a 6kw and also has two outputs 20 & 30 amp.
I am considering using a 4 conductor 50 amp shore cord and feeding both legs from the shore cord (via a main breaker panel) and both legs from the gennie to a transfer switch (or possibly just using a plug & receptacle in place of the transfer switch for the time being). Then from the transfer switch to both AC inputs on the inverter. Both outputs from the inverter (which has an auto-switching feature) go to my sub panel and on to all loads. I'd have two legs all the way thru, although I'd never use 220 for anything. But it would be there if I needed it later.
I know that by doing this, I have the possibility to overload the inverter (running 2 Air Conditioners is the only example I can think of) But I think I'd rather practice manual load balancing and have everything in the coach wired to the inverter. That way, I can run any device from any power source at will.
I use propane for all heating, cooking, and water heating so my biggest electric loads will be the ACs and battery charging. And 99 times out of 100 I would only run both ACs while on shore power or one of them while underway (using alternator power)
I know it is not idiot-proof because turning on both ACs while on inverter power will overload and trip the breakers. But the alternative is separating loads and trying to predict my needs. Does that make sense?
Scott |
FAST FRED (209.26.87.48)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, April 17, 2002 - 5:25 am: | |
Should work like charm.
AS the use of a plug system is the ONLY lightning proof method and is fast and easy , you might want to keep it.
But a small bit of planning will be required to manage the loads, how will the next owner do?
The simpler the systems are to understand and operate , the better.
FAST FRED |
Scott Whitney (24.205.239.4)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, April 17, 2002 - 12:05 pm: | |
Thanks for the feedback.
I am not really worried about the next owner. It is in old transit so will never fetch top dollar no matter what I do. I think a simple instruction to some future owner like, 'Don't run both ACs when you are on the inverter.' shouldn't be too difficult to remember. As long as it is safe and to code, I am happy.
Scott |
Don Peter (172.166.31.71)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, April 17, 2002 - 7:40 pm: | |
I still wonder why one would want to run the air off an inverter? Why not just run the generator? I would think that a 120VAC generator running an air conditioner would be much more energy efficient than a 12 or 24 alternator that gets its voltage converted to DC via diodes and then loses another 10% or so of that through an inverter. I can't imagine having enough battery capacity to be able to run the air very long without having to get charging from somewhere. -- Don |
Jojo Colina (Du1jec) (209.75.20.72)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, April 17, 2002 - 8:10 pm: | |
I have a trace 3624 and 10 100amp/hr 12volt AGM batteries wired series/parallel for a total of 500 amp/hr 24v. I use my 24volt bus alternator via an SAR v3 voltage regulator to charge the batteries while in route and it will keep up the batteries while running one of my Coleman 13500 BTU roof airs.
Saves run time/maintenance on my generator.
The inverter alone will power the one roof air for about 4 hours if needed. |
Tom Caffrey (Pvcces) (12.146.33.9)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, April 17, 2002 - 10:53 pm: | |
Scott, I think the things that you need to check include:
1) does the inverter input and output feed onto two isolated legs? This would require two inverters in one, I think.
2) is the transfer switch designed to switch isolated loads? This would be necessary if you connected the inverter to 220 shore power.
3) does the power sharing feature read the power going through only one side of the transfer switch?
We struggled with some of those same issues with out inverter because it had one input but two output breakers.
In the end, we tied the two output breakers together so the inverter would have full control of the power passing through it and used a relay to detect the prsence of 220 shore power. Our gennie outputs only 110.
When our cord is plugged into the gennie, we feed all the circuits because the 220 sensing relay ties them together.
If we plug our cord into a 220 source, the circuits are split, with the inverter and one air on one side and the other air and other circuits on the other side.
This way, we can run on any source and we can run anything anytime, and we can charge batteries; we just have to avoid the second air if on light duty shore power.
We put in the voltage sensing circuit before discovering that the various 110 adapters tie both the hot legs together. Just the same, I'm not sorry we went to the trouble.
The setup is simple and pretty much trouble-free.
FWIW |
Scott Whitney (24.205.239.4)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, April 18, 2002 - 2:19 pm: | |
Hi Tom,
I've been thinking about your response and questions since last night. I don't know the answers quite yet. I'll have to reread the inverter manual again.
Maybe to simplify, I should clarify. At this time, I only have on AC purchased, but plan on a second in the future. Also, the more I think about it, I will probably skip the automatic transfer switch for the time being, and just use the manual plug/receptacle system to switch btwn gennie & shore. The inverter still has an internal transfer switch though.
Maybe I can ask another question while I research more about the inverter's internal operation. . .
Would it be foolish to not use a 50A plug/receptacle and instead wire the shore cord and gennie using 30A & 20A plugs instead? I think that would solve question number two.
Since I never will need 220, maybe that is a better way to go? My thinking is a four conductor shore cord which has a male 30A & male 20A on the park side. The other end is hard wired to the main breaker box (which then feeds the inverter inputs). The gennie would have female 30A & 20A receptacles. So when I have hook-ups, I connect the 30A and the 20A plugs into the shore power. Otherwise, during travel etc, my shore cord is plugged into my gennie. I'd never have to worry about using an adapter from 50A to 30A + 20A either.
I guess the alternative is just passing the 20A circuit around the inverter and dedicate it to the second AC.
I also want all circuits live when visiting a private house on a 15A or 20A cord. . .(but of course, managing power usage manually)
I think I need to draw all this out. . .as I am rambling now. Sorry.
Scott |
Stephen Fessenden (Sffess) (67.226.254.52)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, April 18, 2002 - 11:01 pm: | |
Go with the 50 amp plug and buy or make adapters for 30 amp, 20 amp, combined 20 and 30 amp. It is more versatile and is the way all RVs hook up. You may not ever need 220 but you may enjoy the easy hookup in most RV parks. |
Tom Caffrey (Pvcces) (12.146.33.126)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, April 19, 2002 - 12:38 am: | |
Hi Scott,
I think you have seen the problem I was trying to point out. The solution is where do you tie L1 to L2 when on 110 power.
If the inverter is designed to switch 220, then you can run straight through it to your breaker panel containing the branch circuit breakers.
AFAIK there is no reason to run through any breaker before introducing the power on the cord to the inverter. It should have all the protection it needs built in. The cord will need to be 6 guage, however.
For your setup, if you feed power from your generator or shore power through the inverter and straight to your individual breakers, you shouldn't need to worry about getting anything you want to work on any kind of power.
When you plug your cord into an adapter for 110, L1 and L2 (the black and the red wires) are tied together and connected to L1 in the adapter plug.
This means that power to your loads will travel through the inverter and through both circuit breakers in its output. Power sharing will only work for the loads on L1.
Perhaps you can buy adapters that don't do this. I don't know. I'm sure they could be made up.
To get power sharing to work on both L1 and L2, it is necessary to connect all branch circuits to L1 while disconnecting L2. I would think you would want to do this anytime you were on 110 power.
I think one way to avoid turning on the second air conditioner when you were on 110 shore power or the inverter would be to use a 220 model.
It would have to be connnected across L1 and L2 in the branch circuit box and anytime there was no 220 power, it wouldn't run. You wouldn't have to remember anything, then.
I figure a relay is the easiest way to detect 110 or 220 power and automatically reroute loads to L1 in the inverter. But it has to be done at the right place in the circuit.
For those campgrounds that put two legs of 110 instead of 220 into their 50 amp outlets, I would expect the coach to act like it was a single leg of 110.
I hope this helps. There are certainly lots of possibilities!
Tom Caffrey PD4106-2576 |
Tom Caffrey (Pvcces) (12.146.33.126)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, April 19, 2002 - 12:51 am: | |
Scott, one other thing. If you used a 220 air for your second air, and had two plugs, a 20 and a 30, then if you turned on the air conditioner, the second 110 plug would be hot and someone could be shocked on it.
Tom Caffrey PD4106-2576 |
Jerry (205.188.193.46)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, April 19, 2002 - 6:05 am: | |
Jason - Hope we can make a book recomendation on this list. Regarding Inverters and all kind of other electrical info I highly recomend "Desinging Electrical Layouts" by George D Myers. Did a real good job of explaining a LOT about inverters -- like the difference between square wave, modified sine wave, "true" sine wave and each's impact on different systems, selecting battery banks,....just about every issue brought up here so far and a lot more. Good job of explaining in terms just about anyone can understand plus enough techinical stuff for those that want that too. I've an electronics background and this bood was a great help to me.
Jerry PD4106-1750
St Louis, MO |
Scott Whitney (24.205.239.4)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, April 19, 2002 - 2:57 pm: | |
Yes, I agree. Good book. After reading this thread over a few times last night, I opened Designing Electrical Layouts as my bedtime reading. It is a little bit outdated, but not too bad. I'd like to see George write a second edition to include some the more modern inverter features. But it is an excellent book, nonetheless.
Scott
P.S. Tom: I am also going over the inverter manuals again to see exactly how they handle the switching of L1 & L2. It appears that I could dedicate L1 to the inverter's charger and a second air cond. L2 would be switched/passed thru to run all other inverter circuits from a sub panel. When on 50Amp, the charger and 2nd AC share a leg and the other leg handles all other coach loads. If I use a 50-30A adapter, the two legs are tied and I am not sure what happens then. . . I am going to have to diagram this out with every single wire represented. |
Jason (24.217.113.23)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, April 19, 2002 - 7:34 pm: | |
Thanks Jerry, I live in STL also, nice place huh? |
Tom Caffrey (Pvcces) (12.146.33.80)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, April 19, 2002 - 11:34 pm: | |
Hi Scott, I think you've about got it figured out.
When we were installing our inverter, I tried working from my head, and found myself making mistakes.
I had drawn out a complete diagram and as soon as I started keeping the it in front of me, everything went fine.
With a little patience, you'll wind up with a nice setup.
Tom Caffrey PD4106-2576 |
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