Inverter/charger/switch question

[daddyoften]

I'm looking at running all 12v led lights and radios. A house refrigerator. And the normal AC outlets and roof air conditioners. I'm thinking 6 to 8 golf cart batteries. For now I will use the included 4.5kw gen.
So what are people using for an inverter/charger?  I'm looking at like a magnum 3kw inverter with a 125a dc charger and a 60 a switch all in one unit.   I'm not looking at boondocking much but want the option. Do you think that is enough? Or should I go to dual 2kw's? I'm on a some what tight budget but I also want to do it right the first time.
Thank you,
Eric

[eagle19952]

you can pretty much forget air conditioning on batteries...

refrigeration maybe 20 hours....

it takes a very sophisticated inverter to run a microwave.

[akroyaleagle]

Running AC loads off a inverter is not difficult.

6 to 8 6v golf cart type batteries will do what you want if they have enough amperage.

A 3000w (not kilowatts) will run one AC and the refrigerator off the engine altenator through the batteries if the
engine is at road rpm and the altenator is large enough. You simply have to be able to put equal or more amps in than you are taking out of the batteries.

If you try to run an AC off the inverter while parked, it will kill the batteries in minutes.

I have a Vanner 3600w true sine wave inverter, It runs off of 6 6v Surette Rolls Royce batteries. These are very expensive high AH batteries. I also have a bench tested 300 amp altenator that I can couple to the batteries with the flick of a switch. That allows me to operate one roof air and all other AC loads (I also have a household refrigerator/freezer) while cruising.

I recommend if you have an auto defrost freezer as we do, install a switch so that when "boon docking" you can switch the auto defrost function off. Simply turn it on when you are charging the batteries, however you do that

(I consider boon docking to be at a rally with no external power. If I really wanted to do that, I'd sell the coach and go back to a tent)

My inverter runs the microwave/convection fine. If we are going to use them for some time, we run the generator. Heating things up is no problem. We do not make coffee often with only the inverter. It works but anything that creates heat sucks a lot of amps.

My block heater is not connected to the inverter bus. I need shore or generator power for it.

I have done it this way for over 18 years.

Others will differ, but I believe if you put all your eggs in one basket, one rotten one will ruin the lot. My inverter is a inverter only. I also have two 100 amp chargers with a sensor between them. If the demands are less than one charger will supply, it runs alone. If the demand exceeds the capabilities of one charger, the other will automatically join in.

My feelings are, if everything depends on the inverter and the inverter fails, you no longer can charge your batteries either.

I am not an electrician! I only know everything electrical is manufactured with a certain amount of smoke in it.
If it stops working, get it fixed.
If you try to fix it and let the smoke out, you need a new one.

There are a lot of smart guys. Some of them are on this board. If you are like me and are a bit dimwitted when it comes to electrical, let them educate you. Or do as I did and pay through the nose to hire an expert. The first step is to figure out what your power requirements will be and design to that specification.

It's late tonight so I hope I have helped.

Welcome to this madness.

[eagle19952]

Joe, how about a ball park $$ amount....

I was thinking from the point of view...
I'm thinking 6 to 8 golf cart batteries... and ... I'm on a some what tight budget ....

[akroyaleagle]

Don,

As the old saying goes...."If you want to dance, you have to pay the fiddler".

You'd have to price the inverter online. Mine is a Vanner, I've had it 18 years and I think they are out of business.

L-16 type 6volt golf cart batteries start a little over $100 at Sam's. The more AH you need, the more they will cost.
If you cheap out and get the low amp hour batteries you will not be happy. BTDT!

I have had two sets of 8 8D 12volt batteries = 1 year each.  
6 6volt L-16 auxillary power unit batteries = 6 years + and were still OK.
I now have 6 Surette 6volt batteries (same size as L-16s) = 10 + years and show no signs of weakening. They were guaranteed 8 years in RV application. I got a pretty good deal on them from a distrubuter in Phoenix. I had a Alaska Dealers license so avoided sales tax also. Seems they are 595AH each. So 3570AH for the set. You'd need a whole bay of batteries to equal that!

I would check the distrubuters in the larger towns for them. If they get a year or so old they may be discounted.
The off grid folks have never discounted them and they are more expensive.

I check the water every couple of years and seems I added a little once. Most folks would say I use them hard.

These longer replies this late at night seem to have a lot of mistakes in them I keep correcting.

Hope this helps. If you want, we'll discuss it on the phone sometime. I sometimes have a harder job explaining things on the computer.

[bevans6]

If you can run a 24 system to power the inverter, current loads and cable requirements fall in half.  but it depends on what voltage your bus is - many GM's are 12V.  The Magnum 3012 (and the newer 3012 Hybrid) is an excellent inverter and charger, it's the 12V version of my Magnum 4024.  You can't go wrong with it, but get the remote control.  Adds a lot to the control of the unit.  Call it $2k for that inverter, set up and installed, more for the H version.  I have four US Battery 232AH 6V batteries, $100 each-ish, and obviously the more the merrier.  I over-night with no power often, my microwave is just fine on the Magnum.  My actual prime use for the whole setup is running the roof-top AC while driving.

Brian

[Debo]

Hi Eric,

I feel qualified to comment on this because I've pretty much just been through all of this. What I'd recommend as a first step is arriving at your best guess of your electrical requirements, and how you're going to use your coach before getting too far down the road of figuring out equipment you need. Talking about components before you know these things is a little like leaving on a trip and not knowing your destination. Yeah, it can be done that way, but probably not as efficiently - or cheaply.

Sit down with your travel partners and figure out what a regular day would look like as far as energy consumption. How many hours a day will the fridge run? How much power does the average fridge use? How long does it have to run on batteries? Do that for every item, and you'll come up with a number of watts or amp/hours you need in a day. Use this number to plan your system. Cruising sailboats do the same thing, and there are websites that will help you calculate these things. If you're like me, you might find that your electrical requirements are less than you were thinking. It might also lead your thinking in directions you hadn't anticipated.

The other thing is figuring out alternative ways to run things. For example, to run your roof air units from batteries can be done, but to do it for long periods (8 hours for example) is going to get expensive. Perhaps you decide that if the A/C is needed, you'll just run the generator. These are all individual decisions, but there are a lot of ways to "skin a cat," so to speak. In your planning, you may find that you're trying to solve imaginary problems that don't (or won't) exist. I'm just suggesting that it might be worth sitting down and doing a little "best guess" planning before starting to chase your tail about what inverter to get. If I've done anything wrong in my conversion, it's that I've spent too much money solving problems that existed only in my head before I knew the actual situation.

Hope this helps.

EDIT: FYI, my setup is the same as Brian's (above).

[luvrbus]

Surette truly the Rolls Royce of batteries did you buy those from Copper State Battery in Phoenix Joe sometime they are affordable there when they want to move some stock around 

Fwiw mine lasted 15 years I gave them to guy that sent them back to factory for a rebuild and he is still using the Surette if I knew you could have those rebuilt I would have kept them 

[bevans6]

The Surrette factory is a few miles from me here in Nova Scotia.

Brian

[daddyoften]

Thank you all very much for all the great information.  I'm quite busy so please don't ever take my lack of response as rudeness.  I guess I need to sit down and figure things out.  I don't even have the bus in my possession yet but it is ours!    We will be traveling with 6 out of our 8 kids and of course my wife and I.  We plan on a full size house fridge along with only roof a/c's for cooling, and using one of those while we drive when it's hot enough for it.  Microwave might get used without shore power but I don't think much.  We are planning most of our time hooked up at a campground but want the option of boon docking from time to time.  I like to plan be able to do just about anything at anytime.  I will have a 4.5kw genset but I don't want to have to keep transporting gas for it.  I'm not sure if I'll convert it to propane or not to just reduce one fuel type on the bus.  The gen set doesn't have a tank yet either so I'll have to figure that out, hence another reason to consider going LPG.  I'm just trying to learn about the things I don't know about so when the time comes to work on it I can get after it!  We are looking at doing quite a quick build on this unit. 
Thanks again,
Eric

[Oonrahnjay]

Thank you all very much for all the great information.  I'm quite busy so please don't ever take my lack of response as rudeness.  I guess I need to sit down and figure things out.  I don't even have the bus in my possession yet but it is ours!    We will be traveling with 6 out of our 8 kids and of course my wife and I.  We plan on a full size house fridge along with only roof a/c's for cooling, and using one of those while we drive when it's hot enough for it.  Microwave might get used without shore power but I don't think much.  We are planning most of our time hooked up at a campground but want the option of boon docking from time to time.  I like to plan be able to do just about anything at anytime.  I will have a 4.5kw genset but I don't want to have to keep transporting gas for it.  I'm not sure if I'll convert it to propane or not to just reduce one fuel type on the bus.  The gen set doesn't have a tank yet either so I'll have to figure that out, hence another reason to consider going LPG.  I'm just trying to learn about the things I don't know about so when the time comes to work on it I can get after it!  We are looking at doing quite a quick build on this unit. 
Thanks again,   Eric 

      We were all starting at one time.  A couple of things - if you haven't already bought the genset, think of diesel.  It's practical to run on the same fuel as your engine, you can put in a separate tank or pull from the main tank, etc.  And diesel generators are usually quieter (a BIG consideration with gennies).  PS - some people have tried the "air cooled - construction type" genset sold on the shelf at Home Depot in RV's -- usually with very bad results.  It's very difficult to get enough cooling air, they don't stand up to over-the-road engine/road vibration well, and they're devilishly loud.  No matter what you pick, look at the Park noise rating - and you'll almost certainly have to have a water-cooled unit to get one quiet enough to not drive yourself, your family, and your parking neighbors totally nuts!
      Also, I don't have roof units but many people I've talked to say that one roof A/C isn't enough under most conditions from "warmish" to hotter.  I know a couple of people who say that for 3 people traveling down the road at temps mid-80's or above, you really need about three.  Considering they'd probably have a driver and passenger up front with the big heat transfer of the windshield, the other passenger more in the middle of the bus ("living room"), and the engine under the bedroom, even three is marginal.  Add "American Western desert temps" and you need even more.  Plus, you're looking at 8 people - that a lot more  heat and water vapor/humidity loading right there than most of us would experience.  Lowering the humidity is a very important part of air conditioning, too, so that should be factored in.   So, think hard about the number of A/C units you'll need - in practice.
      Finally, A/C units (and refrigerators) pull a lot more current when they're starting up than just running.  Some people say that if you think you'll need 4kw (4000 watts) to run your A/C's and fridge, then you should budget at least 30-35% more wattage (i.e. about 5200 - 5500 "peak watts") for your power supply.  With a 50 amp, two leg (240 - 120V) shore power supply that's no problem but it makes a lot of difference in generator size. 

[daddyoften]

An older Koehler 4.5kw twin cylinder gas gen set comes with the bus,  It's a regular rv gen hence why it doesn't have a fuel tank.  Great information. Our floor plan is going to be a bit different than most, I might run 3 a/c's. I keep hearing that 2 isn't enough so I need to think about that one. We are thinking about a side isle with a 5+ ft bedroom, a 6 ft bunk room, 5-6 ish ft bath and then the rest to kitchen and living room, so our living and seating area will be smaller than most and there will be a door at the beginning of the hallway. And yes I know a side isle in a 4107 will be a squeeze.

[Oonrahnjay]

An older Koehler 4.5kw twin cylinder gas gen set comes with the bus,  It's a regular rv gen hence why it doesn't have a fuel tank.  Great information. Our floor plan is going to be a bit different than most, I might run 3 a/c's. I keep hearing that 2 isn't enough so I need to think about that one. We are thinking about a side isle with a 5+ ft bedroom, a 6 ft bunk room, 5-6 ish ft bath and then the rest to kitchen and living room, so our living and seating area will be smaller than most and there will be a door at the beginning of the hallway. And yes I know a side isle in a 4107 will be a squeeze.  

     A center aisle is good because if you shut the door forward and aft of it, it's part of the room.  Not so a side aisle, but with 8 people in the bus, it might be the best solution for your needs (accessibility for some people while quiet/privacy for others).
     I'd suggest you think about the bathroom sink outside the bathroom.  If it's inside, is one person is shaving/ putting on makeup/ bruching teeth and another person wants to use the potty, you have a crowd.  If the sink is in a corner outside, it doesn't "control" the bathroom.  It is a tip I got from a long-time S&S owner and I like it (although I usually have 6-7 fewer people in my bus than you will).

[daddyoften]

Good idea on the outside sink, that's a thought. Another reason for the side isle is making enough headroom for the fridge and stackable w/d, which can only sit in the middle roof line

[Oonrahnjay]

Good idea on the outside sink, that's a thought. Another reason for the side isle is making enough headroom for the fridge and stackable w/d, which can only sit in the middle roof line 

     Have you thought about a roof raise?  It is a big investment in time (and in $$$ somewhat) but if you're trying to put 10 gallons in a 5 gallon bottle, it will go a long way towards giving you a lot more useful room.  I think that with your plans for so many people on board, you'd need it even if you found a place for the appliances elsewhere.  And yes, a w/d on board is a very good thing. 
     And be creative.  My bus has no "bays" for storage underneath so I've had to put things in in other places.  For instance, my fridge is sunk 8" below floor level; that gave me lots of issues with cutting out the floor area, framing it in, getting fridge air circulation right, etc. but it allows me to put it where I want it.
     Somebody once told me that one hour of planning, looking at things other people have done, working out your needs in detail etc. is worth 15 hours of building.  I think it's worth even more than that.  They laugh at me for going back and re-doing things and moving things around but I feel that the effort is worth it -- I only wish that I'd planned better in the first place.

Good luck,   BH    NC    USA