Inverter vs charger

[NCbob]

My bus currently has (3) Grp 31 12V batteries and (1) old beater charger which I know from experience will eat up the batteries if I don't watch it like a hawk.

Our plans for the use of this coach is stricly 'post'.. no boondocking. Occasionally, while traveling we might avail ourselves of the hospitality offered by Walmart. Since we have a 12.5 KW diesel generator I can't envision the need for an inverter. The current 12/110 V refrigerator is going...will be replaced by a straight 110V unit.

DC lighting is at a minimum just sufficient to negotiate midnight trips to the B/R, etc.

Other than the need for power for a laptop, should I decide to use a GPS program, I find it impractical to invest in an invertor/charger as against a quality 12V charger.

The 24V system is just for engine starting and lights..I have a 24V portable charger to back up that system.

In searching for such a charger I'm unable to find one which won't eat up batteries as a hobby.

Any suggestions?

Thanks,

NCbob

[belfert]

I would install a converter to supply DC power when you have 110 volt.  A converter will also charge the 12 volt batteries.

I really like the Intelli-Power converters with the Charge Wizard.  It has a true 3 stage charger so your batteries won't get fried.

Brian elfert

[Ross]

Without an inverter, you'll have to run the genset when ever you are not plugged in to keep the fidge cold.  A good inverter/charger would keep the fridge cold on battery power and charge your batteries and charge your batteries when you are plugged in.  I use a Heart 3000.  It's been keeping my 3 house batteries charges for 3 years now.  I bought the inverter rebuilt from someone here.  I forget his name now, but it's been a great inverter.  It has the remote up in the main panel and all.

Mine is set up so the inverter has it's own panel.  Going down the road I can run everything in the bus except the AC units from propane or inverter.  If I start the genset or plug in at a pole, the inverter stops inverting and starts charging and switches to Pass-through mode.  When I shut down the genset or unplug from the pole, the inverter starts inverting again.

[Chuck Newman]

NCBob,

Brian and Ross are correct.  One prefers an inverter/charger, but there are many smart three stage converters only on the market.
Simply do a google search for "3 stage charger".  Converter and battery charger both mean the same thing.  They convert 120 vac to
12 vdc.  Or 24 vdc, depending on your needs.  Keep two things in mind:

1. Not all battery chargers/converters are smart three stage units that will not overcharge your batteries.  They still manufacture plenty of
brute force battery chargers, including ones designed for RV use.  There will probably always be a market for these.

2. The better (translation higher dollar) three stage converter/chargers for RV use have better filtering to run your DC appliances and
electronic devices.  Of course, if you only will charge batteries with the device, filtering is not an issue.

Chuck Newman

[El-Sonador]

Hi...

When you finally make your choice, you will probably want a system to monitor the state of your batteries, charging rates, battery temps and many other functions of your electrical systems including auto start of your gen set should your batteries get tooooo low....

Monitoring and maintaining a system is one of the most important things you can do after you have installed the system of your choice. So you may wish to consider a system that has the required options that can do this for you.

This information is just food for thought, if you or others have not yet thought about monitoring after the fact...

Steve




Here is one sample of many systems that can do this for you to give you an idea of what is possible...

• Windows®-based.

• Operates on commonly available PCs and laptops.

• Displays all readings on a single screen. Graphical images indicate power routing.

• You see the present condition of your system at a glance.

• Calculates watts, battery temperature, generator run time and Kilowatt-hours.

• You see information that is not readily obtained from the charger/inverter/converter itself.

• Keeps a running history of readings.

• You see minimum, maximum and average values for the past hour, day, week, etc.

• Compares readings against selectable high and low limits.

• You see and hear when a reading has gone beyond your threshold of comfort.

• Outputs to file the accumulated hourly readings every day.

• You can see and compare past system performance using a spread-sheet program.

• You can fully control your charger/inverter/converter from your PC, just like using the charger/inverter/converter's own control panel that will most likely be stuffed into one of your bays.

[DrivingMissLazy]

Steve, great post. This, in my opinion, would be one of the wisest purchase decisions any nut could make.
Richard

Hi...

When you finally make your choice, you will probably want a system to monitor the state of your batteries, charging rates, battery temps and many other functions of your electrical systems including auto start of your gen set should your batteries get tooooo low....

Monitoring and maintaining a system is one of the most important things you can do after you have installed the system of your choice. So you may wish to consider a system that has the required options that can do this for you.

This information is just food for thought, if you or others have not yet thought about monitoring after the fact...

Steve







Here is one sample of many systems that can do this for you to give you an idea of what is possible...

• Windows®-based.

• Operates on commonly available PCs and laptops.

• Displays all readings on a single screen. Graphical images indicate power routing.

• You see the present condition of your system at a glance.

• Calculates watts, battery temperature, generator run time and Kilowatt-hours.

• You see information that is not readily obtained from the charger/inverter/converter itself.

• Keeps a running history of readings.

• You see minimum, maximum and average values for the past hour, day, week, etc.

• Compares readings against selectable high and low limits.

• You see and hear when a reading has gone beyond your threshold of comfort.

• Outputs to file the accumulated hourly readings every day.

• You can see and compare past system performance using a spread-sheet program.

• You can fully control your charger/inverter/converter from your PC, just like using the charger/inverter/converter's own control panel that will most likely be stuffed into one of your bays.

[TomC]

I also second the notion of the inverter/charger.  I have an older style Trace inverter/charger that is a modified sine wave (the newer ones have closer regulation, or steps that can be considered true sine wave).  Mine automatically switches from power to inverter mode in a fraction of a second-almost undetected except for a quick flash of the 120v lights (the few that I have) and automatically switches back to non inverter mode when there is power, but has about a 5 second delay incase it is the generator spooling up.  The charger portion is up to 130 amps, I have mine set at 80amps for my two 8D AGM's and also can set the charge, bulk, float settings suggested by Lifeline (you can set it up to match any type of battery your using.  When I had wet batteries, I had the charger set at 50 amps so not to over charge the two batteries).  The thing with a converter is that it does only that.  Let me throw in a couple of sinarios.  Your at your favorite power pole using the computer and the power dies.  With your set up, you just lost all that you were doing on the computer.  With the inverter, the gap would be a fraction of a second, and most computers have small power packs to comensate for small gaps in power, so you'd be fine with the inverter.  Another is the 120v reefer.  Again at the power pole and the power goes out and the campsite has strict no generator rules.  Or your travelling down the road on a nice weather day where you don't need A/C.  With the converter, you need to run the generator all the time you are travelling (which is not good for the generator.  All Diesel generators should have at least a 25% load to keep it warm and not wet stacking {when the generator is running cold and can't burn all fuel and the unburned fuel starts to collect in the exhaust causing the liquid to drip from any small opening in the exhaust}).  With the inverter, the reefer will run on the inverter whether it be going down the road on a nice non A/C day or the few times you have to dry camp.  Another is running the microwave.  With the converter everytime you need the microwave, or coffee maker or any 120v power, you have to start the generator.  Again, short starts of a Diesel generator not letting it warm up is very hard on it.  With the inverter and several deep cycle batteries, you can use the coffee maker, inverter, computer, TV, without firing up the generator.  Also, the new generation of inverter/chargers have some nice features.  True sine wave form that makes for clean electrictiy (my modified sine wave makes the microwave hum and cook times are longer, some electric motors, like my stove hood, run slower).  They have load sharing, where the inverter will kick in to help the power pole in the event you have a brown out or you're plainly using more juice than the power pole can provide.  Also, it has generator automatic start when the batteries get down to a voltage you set it at.  So even with you not at the bus, you'd be guaranteed that you wouldn't come back to dead batteries. The cost is a bit more, but REALLY worth it in the long run-which I assume you're convertin the bus for is many years of use!  Good Luck, TomC

[NCbob]

All of the above is great advice and I thank you for it.  But, thinking about it, lets go one step farther.  Currently I have a generator start battery (Grp31)..sitting all by itself and not tied into the house bank (of 3 Grp 31's).  There is currently no system for charging the house bank while underway.  However there is a small alternator (I don't know the rating) driven my the main engine to charge the generator battery (the 12V headlights feed off that battery...but I don't do much night driving).

As I soon will be removing the bus AC, thus freeing up belt space and the cranckshaft drive pulley, would it be to my advantage to include the generator start battery into the house bank (making 4 grp 31's) and allow the alternator to charge the complete set (4-31's) while driving?

I can anticipate some the discussion against doing this...but I'm a nut about maintaining batteries and all 4 are new.  I know...how would I start the generator if the house bank went down or bad.  The answer is:  This is a bus ..not an ocean liner.  I'd somehow find a way to replace the batteries without the need of the generator.  My engine is 24V starting and I have (2) new 8D's for that.  As long as I can get the main engine started, get the air up and find a Wal-mart...I got batteries, right?

If need be I can increase the size of the 12V alternator to charge house batteries underway. I've got all the HP I need to drive one.

Now to the inverter Vs. Convertor.  Perhaps my situation is unique.  If we're going to want sandwiches, etc. while traveling...we'll make them ahead of time.  My wife has a handicap (my problem) and I don't allow here to wander about the bus when it's moving. The reefer will maintain cold all day unless it's opened a number of times.  Our traveling habits are to put what we're going to want, water, juices and sandwiches in a cooler.  We're in our 70's and NO kids on board ....EVER!

Didn't mean to prattle on like this but these are my thoughts.

Thank you for your patience.

NCbob

[jjrbus]

 I like your comment, "not an ocean liner"  I tied my genset into the house batts. I use genny very little.   If the house batts are down, I have a selector switch, I can start the genny off the bus batts, if that dosen't work I can pull the van up and start it with jumper cables. If the van battery is dead, I better hope that my cell phone is getting a signal.
  I am not one for the most expensive way to go is the best way. But an inverter makes a lot of sense, You are going to pay big bucks for a quality battery charger, Which is part of a good inverter, then the money you save not running the genset. It will not take long befor it pays for itself.
                                                                                 Work?/Play safely Jim

[gus]

As you know the gen requires a battery connected at all times for the small flywheel alternator. This is a waste of a Gp31.

Put a small lawnmower battery on the gen and use the Gp 31 for start or bus, whicever it is rated for. Then use a simple toggle switch and a solenoid to connect the starter batteries as a booster for gen starting if needed.

I use this system and it works fine.

[NCbob]

"As you know the gen requires a battery connected at all times for the small flywheel alternator. This is a waste of a Gp31"

Excuse me, Gus, but I believe you might be mistaken there.  I don't know what generator you're using but...being a retired Onan Generator Dealer I know that flywheel alternators have permanent magnets which when passed over a fixed stator produce AC loltage which is rectified by a voltage regulator to DC voltage to charge a battery.  They require no battery hookup...other than the starting battery needed for cranking and the ignition source.

In the case of diesel generators (and larger gasoline and LP fueled generators) there is usually a winding in the generator end which is enabled to furnish the battery with sufficient DC power to maintain the battery...but not necessarily enough to recharge a large battery bank.  Normally that job is relegated to a Convertor.

Diesel generators will run fine without a battery connected...no ignition power needed.  Gasoline or LP powered generators will die from lack of an ignition source...but might damage some windings in the generator end.

Now, where were we?

NCbob

[Ross]

I have a smaller separate battery on the genset.  My reasoning there is that if I space out and kill the house bank dead, I'll still be able to start the genset to recharge.  I also have a 24V charger on the start batteries that is only connected when it's needed.  With a separate battery on the genset, I can kill both the house and the start batteries and still have the genset to recharge both.  I tried to design the systems on the bus to be as self supporting as possible. 

I'd say that if you don't care about having 110V underway, then go with a good charger and a 12V alternator on the bus engine.  If you decide later on that you need inverter power underway, like for a microwave, you can always add a small inverter.  If you intend to always be on a power pole, you could even go without a genset.  Without a genset, you would have to be on a pole to run large loads like AC's, but if that's your plan anyway, it might work.

[El-Sonador]

Perhaps my situation is unique. 

If we're going to want sandwiches, etc. while traveling...we'll make them ahead of time.  My wife has a handicap (my problem) and I don't allow here to wander about the bus when it's moving.

The reefer will maintain cold all day unless it's opened a number of times. 

Our traveling habits are to put what we're going to want, water, juices and sandwiches
in a cooler. 

We're in our 70's and NO kids on board ....EVER!

Hi...

Your situation does seem to be unique to me also, at least on the surface, given the information posted here so far...

Maybe I have missed something here in our attempts to offer advice to your original question... You are a retired Onan Generator Dealer, with obviously lots of valuable knowledge in this area as GUSC has witnessed, yet it would appear that your thinking process is one that would prefer to utilize the very basics for power requirements while traveling down the hwy in your own converted private motor coach, using a cooler as your refrigeration source, during your retirement years.

This has compelled me to ask for your help in light of the information given here and your experiences as an Onan Dealer [retired].... Should generators and inverters be avoided to that extent...?

Steve

[Chuck Newman]

Steve,

Who distributes the WinVerter software?

Will it work with the newer Xantrex inverter/chargers or just Trace units?  Specifically the 4024?

Thanks

Chuck

[El-Sonador]

Steve,

Who distributes the WinVerter software?

Will it work with the newer Xantrex inverter/chargers or just Trace units? Specifically the 4024?

Thanks

Chuck

Hi Chuck...

I run this program with my 4024 and it is great.
There is also a free download version but you will need the RS-232 phone cable to connect to your computer.

GOTO... www.righthandeng.com/hm_sw.htm

* Supports control of multiple SWCAs and associated inverters (one at a time, up to 8 inverters) via a single RS-232 serial port.
* Supports two instances so that you can simultaneously control two inverters at the same time (requires the use of two RS-232 serial ports).

Steve