Charger/Converter Setup Suggestions

[Brett G]

Hi All, we've owned our first bus less than a year.  It's a 1970 MC7 Challenger.  It's been a lot of fun so far.  So....I'm wanting to upgrade some of the electrical and looking for suggestions.  Here's my situation right now, as far as understand.  Some electrical has been upgraded from the previous owner. I do realize there is limited information here. 

-Bus has a Vanner 80 amp equalizer that will equalize the 24v starter batteries (2) and the House batteries (1)

-Charging only happens when the bus is running.

-Bus has some 12 volt lights and stereo

-Bus has a 10KW Onan diesel that I can start from inside bus. Powers 2 new roof mounted air, lights, receptacles, etc.

-50 Amp shore hookup - switch inside will switch to generator or shore

-Older Vaner inverter that only powers 1 outlet.  It's loud and seems unsafe

-Old battery chargers (24v / 12v) that don't work

I would like to go with a converter charger that can do many things all in one but.  Charge, auto-switch, convert, auto-start gen, etc.

24V or 12V converter/charger?

Some pics  https://plus.google.com/photos/110667739701584973079/albums/6096471556406280865?authkey=CLSjyrCQ5PGIaQ

Any questions or suggestions would be helpful.  Thanks in advance.

Brett

[bevans6]

I would suggest that you do pretty much exactly what I did - haven't found a major flaw yet!  MCI bus often/usually has the big 250 amp alternator at 24 volts.  That makes your choice of a 24 volt inverter and 24 volt house battery system a natural - you can bridge the house bank to the start bank for charging or to run the inverter from the alternator over the road - sufficient capacity to run air conditioners, etc.  I chose a Magnum 4024 pure sine inverter.  It should be wired through a breaker panel to supply any outlets that you want to be able to be powered by the inverter, and it is a top notch battery charger as well, fully programmable.  Next, you use the Vanner equalizer to stabilize the charging of the house bank while supplying all of your 12 volt load requirements.  It will ensure that charging is equal while charging, and will supply the 12 volt loads from the entire 24 volt house bank when boon-docking.  You can choose an automatic battery bridging switch, or use a manual Marine style A - B A+B switch like I do.

Next is the external supply and the generator.  I don't know if your generator and external 50 amp supply is set up for 120 or dual 120/240 volt service - they get done both ways.  Start with a stand-alone automatic transfer switch (ATS) that suits that will automatically switch between external (priority for me) and generator (set up as the secondary choice for this ATS).  The output of this ATS will supply a breaker panel with any loads that you want to be non-inverter powered.  I'd put things like the hot water heater, the second or third air conditioner, like that, on this panel, and this panel will feed the external/generator power to the inverter.  The inverter will have an internal ATS that will either pass through the external power to it's breaker panel, or will supply that panel from inverted battery power if there is no external power and the generator is off.  If there is any external source of power, the inverter will automatically switch to battery charging.

This is about as seamless and painless a system as I have been able to come up with.  

Brian

[Brett G]

Awesome info. Thank you

[bevans6]

Forgot to mention the other "killer" reason for going to a 24 volt house system and inverter is the current capacity requirement to the inverter is cut in half compared to a 12 volt system.  Makes everything related to DC wiring far easier and cheaper.  For example, I have to find a shop with the right hydraulic crimper to make up 4/0 cable ends, but I can make up 1/0 or 2/0 myself just fine.

Brian

[Brett G]

Man....that Magnum 4024 is expensive.  If I'm going to do it, I'm going to do it right.  Thanks

[TomC]

I have the advantage of the bus running on straight 12vdc. I have 2-31 batteries for start, 2-8D Lifeline AGM for house connected by a switched relay for charging by the bus, or by the inverter since my generator is hooked up to the starting batteries. Generator-10kw Powertech wired straight 120vac. I use just one side of the 50amp shore power, then don't have to worry about balancing the load, ever.
My electrical has one breaker box for either shore power, or generator power. That goes to the main breaker box for items that I want powered straight from the shore or generator-like the 3 roof airs, one of the water heaters, washer-dryer, refer & freezer (both also 12vdc). A 30 amp circuit going through the inverter to the third breaker box for inverter items-2nd water heater (to have hot water going down the road), bath heater, microwave, toaster oven, plugs. I have a Trace 2,500watt modified wave inverter that's 20 years old and still works perfectly. It also is a smart charger with 100amp charger.
Very simple system, all manual, very little to go wrong. Good Luck, TomC

[Brett G]

Cool, cool. I'll need the luck:)

[Oonrahnjay]

    My system is very much like Tom and Brian's (except I went with a 12V inverter and house bank -- if I had to do it again, I'd go 24V).  It's based on a 12V Outback inverter/charger.  Works very well; it's not cheap but it works well.   One thing I do differently is my Atwood water heater runs on propane, 120V, or a loop off the engine coolant (for hot water while going down the road), not much more $$$ than a basic RV water heater - although more expensive than Tom's two "household type" water heaters - and it works very well.  It also has a tempering mixer; the water in the heater tank is heated to about 190 degrees but as it's taken out, it's mixed with cool water to give an output into the hot water pipes of about 118 degrees (slightly adjustable).  That provides an output of about 16-18 gallons (depending on the temp of the cool water) from a 10 gallon heater.
    But that's just details.  The basic design of the system works well.

[flynbanjo]

My system is very similiar to the system that Brian described and it works great.  If you are looking for a Magnum 4024 inverter you might try talking to Southeast Power Systems in Orlando Florida. www.diesel-plus.com
 
I paid about $1600 for the inverter.  I think it was a pretty good deal

[Brett G]

Thanks for the replies.  It would be nice to run 1 air conditioner for short periods of time......going down the road and not run the generator.

[bevans6]

If your MCI is similar to mine, there is a 1/0 gauge wire running from the main disconnect switch ( and hence the batteries and the 4/0 starter motor run back to the alternator) across the bay to the AC electrical bay on the ceiling of the driver's side front luggage bay.  It also feeds the main 24 volt bus in the front wiring closet,  Anyway, having tossed the stock air conditioning I used that existing wire to connect my house batteries and the inverter to the bus charging system.  The 1/0 wire supports the load of an air conditioner perfectly well (but wouldn't support the full 4,000 watts of the inverter at full wack - I have an appropriate fuse to protect the wire).  Since my batteries and generator are in the old AC condenser bay, and my inverter is in the front luggage bay just behind, it made a very easy install.

Brian

[Dave5Cs]

Man....that Magnum 4024 is expensive.  If I'm going to do it, I'm going to do it right.  Thanks

Got mine from these guys for about 1,700.00 Normally they are 2,500.00 if they have anymore left. It was also the 4024 Hybred one.
www.thehousewaresstore.com
Look under Marine and then inverters.

[Brett G]

Thanks Dave

[bevans6]

I think I have some pictures of my set up.

The Magnum is mounted on some 1" stand-off's that I made, and there is a sheet aluminium heat shield between it and the plywood wall.  The little breaker box has a 30 amp input breaker for the feed from the Magnum (that I could dispense with, probably) and breakers for the air conditioner and the two branch circuits that I run from the inverter.  Other loads (AC feed to refrigerator, hot water, the bay outlets for things like the air compressor) are all fed from another breaker panel that is inside the bus.  You can see the first main input ATS on the front wall of the bay, and my manual battery bank bridging switch above the Magnum, along with the fuse.  

Refer to my earlier explanation (first reply to this thread) for the description of my layout.

Brian

[Brett G]

I think I have some pictures of my set up.

The Magnum is mounted on some 1" stand-off's that I made, and there is a sheet aluminium heat shield between it and the plywood wall.  The little breaker box has a 30 amp input breaker for the feed from the Magnum (that I could dispense with, probably) and breakers for the air conditioner and the two branch circuits that I run from the inverter.  Other loads (AC feed to refrigerator, hot water, the bay outlets for things like the air compressor) are all fed from another breaker panel that is inside the bus.  You can see the first main input ATS on the front wall of the bay, and my manual battery bank bridging switch above the Magnum, along with the fuse.  

Refer to my earlier explanation (first reply to this thread) for the description of my layout.

Brian

Nice and neat.