Battery when on shore power

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WILDinTHEwoods

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My camper will be setup permanent at the campground.  I was planning on NOT putting a battery on it.  Why should I?  I'm plugged in.  I've heard that there has to be a battery there to complete the circuit for the 12V system.  T/F?  Also, I have read a few threads here that say to have the battery for a filter for the 12V system.  With both recommendations for the battery the current is direct.  Power goes from the supply to the appliance.  If the current went from the inverter > to the battery > then to the appliance the battery would have to be there, and the battery would act as a filter to regulate the voltage... I think.  I don't know.
 

utmtman

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Most all the newer rvs have to have a battery in order to complete the circuit.  Not everything in your rv will run off of shore power.  Some items are 12v. 
 

WILDinTHEwoods

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utmtman said:
Most all the newer RVs have to have a battery in order to complete the circuit.  Not everything in your rv will run off of shore power.  Some items are 12v.   

So, the power comes from the power box > the inverter > the battery > the lights.  If I am correct here.  I do have to have a battery, and the battery does probably act as some kind of power regulator or filter.
 

jamesnaddie

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There are some 12 volt requirements that will exceed the capacity of the converter and that's when the battery comes into play as well.  It provides the peak demands so you not only need a battery but one that is in decent shape.
 

John From Detroit

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As for a battery... There are converters and there are battery chargers improperly labeled "Converter"  As it happens I have a converter, The output is so clean that not even my ham radios can detect any ripple when the  batteries are disconnected.

On the other hand,  There is at least one brand that outputs half-cycle AC at 120Hz (These numbers are NOT accurate but basically it is 14 VAC with a six volt offset)  This is the make that is noted for boiling batteries dry by the way so if you are set up with shore power 100% of the time,  DITCH that make. Get something good. 

Normally I'd suggest something like a Progressive Dynamics with a Charge Wizard but if you don't have a battery to charge, you don't need the wizard.

PD's are good.  Consider keeping the battery for power fail situtations though (in which case you need the wizard)

 

WILDinTHEwoods

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John In Detroit said:
There is at least one brand that outputs half-cycle AC at 120Hz (These numbers are NOT accurate but basically it is 14 VAC with a six volt offset)  This is the make that is noted for boiling batteries dry by the way ...

I think that is the one I had in my last camper.  Which is one of the reasons I don't want a battery on my new camper.  Two years ago we were setup perm for a month and the battery wound up 1/4 low on water.  And last year we were setup perm for the summer and I had to top off the battery a couple of times through the summer to keep from ruining the battery.
 

Gary RV_Wizard

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There's a fair chance you won't need to have a battery in the circuit - it depends on your particular RV and how it was designed. Try it and see - you can always buy a battery if needed.

Remember that shore power may sometimes fail in a campground. Your fridge and water heater won't run without any 12VDC at all, so with no battery and no shore power for the converter, the back-up LPG modes for fridge and water heater will not work either. A single 12V battery is not expensive and might be worth it just in case.
 

Karl

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I think that is the one I had in my last camper.  Which is one of the reasons I don't want a battery on my new camper.  Two years ago we were setup perm for a month and the battery wound up 1/4 low on water.  And last year we were setup perm for the summer and I had to top off the battery a couple of times through the summer to keep from ruining the battery.
Think of a battery (or multiple batteries) as a big water tank - the kind you see near cities. It's there to provide a constant supply of water to homes regardless of how much rain you've had in the last week. It gets filled up slowly with the rain water through a small pipe (converter), and is dispensed through a large pipe (battery) as the demand requires. If the rainfall is heavy and the tank can't hold any more, it runs out the top. If the rain is VERY heavy, the pressure of it can be too great for the tank and it splits at the seams (battery boiling). A charging regulator will prevent this from happening - it's like a valve that shuts off the flow when it becomes too great. That's what we call a 3-stage converter/charger. It will allow a heavy charge when the battery is low, tapers off to a lower charge when the battery reaches full charge, and goes into float mode to maintain a full charge level. Take, with a grain of salt, all you've heard about half-cycles and voltage offsets - they're not pertinent to your situation. What you want is a dependable source of power when 'shore power' (120VAC) fails. For that you need a battery for your 12V loads (lights, etc.) and maybe an inverter to change to 12VDC to 120VAC for things like tv sets, coffee makers, and other regular appliances. 
 

WILDinTHEwoods

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Karl said:
That's what we call a 3-stage converter/charger. It will allow a heavy charge when the battery is low, tapers off to a lower charge when the battery reaches full charge, and goes into float mode to maintain a full charge level.

I will find out what brand of converter I have when it gets delivered.  I'm sure it's not a 3-stage unit.  Are all converters also chargers?  Is there something I can put in between the converter and the battery that will keep the battery from getting over charged or should the converter be doing this for me already?
 

Ned

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A converter is just that, it converts 110VAC to 12VDC to run your 12V devices.  It may or may not have a charging function as well.  Until you get the RV and we know the make and model of the converter, we can't answer your question specifically.
 

WILDinTHEwoods

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Ned said:
A converter is just that, it converts 110VAC to 12VDC to run your 12V devices.  It may or may not have a charging function as well.  Until you get the RV and we know the make and model of the converter, we can't answer your question specifically.

Thank you for your help guys.  We'll reopen this when I know what I have.
 

WILDinTHEwoods

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The converter/charger is a 3-stage unit. 

manufacturer: World Friendship Company

model:  WF-8930/50N ULTRA

www.wfcoelectronics.com

I downloaded the .PDF spec. file.  Any input?... that's a good one, if it's not too late supply the camper manufacturer with a different one to instll, ect.
 

Karl

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model:  WF-8930/50N ULTRA
Couldn't find anything with that model number but did find the WF-8935AN which  replaces the entire 120VAC and 12VDC distribution center, and is probably what you meant. As far as the converter function is concerned, I like the idea of having LED's to indicate which fuse is blown. Otherwise it's pretty standard for a 30A breaker center. The battery charging function is a good, 3-stage unit, but the maximum charging current of 35 amps is a bit on the wimpy side. I'd go with the WF-8955AN which provides 55 amps for charging. If you were talking about the converter/charger only (not the distribution center) I'd still bump it up to the 55 amp model.
 

Karl

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The pdf file shows that the unit can be used for either 30A or 50A service, but the wiring diagram is for a 50A/4-wire hookup. You would need to bridge the two 30A 'hot' busses or c.b.'s in order to use all 10 c.b. slots with a 30A/3-wire supply, otherwise you would have 5 slots for c.b.'s with no power. Not a big deal, as each of the remaining 5 powered slots can utilize a double breaker. It doesn't address the maximum battery charging current, but if you say it's 65 amps, that's fine. 
 

WILDinTHEwoods

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1. Bulk Mode
a). When the converter detects that the output voltage of the battery has dropped to 13.2VDC, the converter will automatically boost the output voltage to 14.4 volts, this means the battery energy is less than 50%.

b). If converter detects that the output voltage is 14.4 volts, the converter will drop to 13.6 volts (Absorption Mode), this means battery energy is full.

c). The converter will supply the output voltage of 14.4 for a period of time, then the converter will automatically return to 13.6 volts. This is to avoid battery damaged under a prolong period of charging .

2. Absorption Mode:  During this period the converter will keep the voltage at 13.6 volts.

3. Float Mode:  After a prolong period of sensing no load or demand the microcontroller automatically places the converter in the ?Float Mode?.
 

WILDinTHEwoods

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I received an e-mail message back from the converter manufacturer today. 

"No, you don't. This is a switching power supply and it does not require the use of a battery to filter the circuits."

This was his response to my question.  In his e-mail he gave his phone numbers and I was still a little confused.  When I called he was very helpful and most important to me is his product knowledge. 

The converter that his company makes might not be the very best Forest River Inc. could have installed in my camper, but their employees are friendly, courteous, and knowledgeable.

 
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