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Old 01-09-2016, 11:30 AM   #1
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Invertor/Charger to Breaker...whats missing?


Sorry if this was posted before but here goes:

I would like my bus power system to be full-battery/invertor for now. I will invest in solar PV later)..

I'm trying to wrap my brain around how I would go about wiring an invertor/charger to a 100 amp circuit breaker. My understanding is that the hardwiring the invertor/charger will act as my "main" power, correct?.

How does shore power fit into this equation as far as charging my batteries?

Would I need a 30-amp outlet on the side of my bus (or could plugging shore power to an invertor with an extension cord do the trick?

What am I missing?

Sorry for being such a newbie.
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Old 01-09-2016, 12:20 PM   #2
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An inverter transforms battery power to AC mains power. Energy would go through heavy wire from batteries into inverter, and through lighter wires from inverter to ordinary household type wall sockets.

A charger takes energy, usually from AC mains, and puts it back into the batteries. The "shore power" term comes from the marine world; it means the cord you toss out of the bus (boat) and plug into some terrestrial power outlet (something on shore/dock). The charger would receive power through the "shore power" cord. In some arrangements the inverter is switched out when shore power is connected so that all the sockets inside are fed directly from the shore power.

It's probably a bit premature to be choosing amperage of circuit breakers or sizing of wires or other equipment until you have a better idea about how large a system you're building; in other words, what kinds of loads it needs to support, how much stuff at the same time, for how long, etc.
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Old 01-09-2016, 03:16 PM   #3
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mix up of terminology

a power invertor "inverts" power from 12 V to 120 V this is typical here in USA

a Converter will convert 120 V to 12 V which is typical in USA

so look at it this way:

You plug bus into a powered 120 V outlet, power goes into your buses panel and gets divided up by breakers etc and goes to each outlet giving 120 v to use (12 ga wire will handle 20 amps of 120 v and that is plenty like a typical house circuit)

If you want to run everything on 12V, then you would plug bus into a 120V outlet and power would go to the convertor/battery charger and be converted to 12v, which then can power everything with 12 V, if you use a 45 amp convertor this will give you say 35 amps to use while still charging batteries

Now keep this in mind!!!

using 12 V power to power 120 v appliances takes alot of amps/power to work and it is not very efficient and of course makes heat

900 watt microwave needs at least a 1500 watt power invertor to run (85% of invertor output) to power that load

900 watts/12.6 v= 72 amps of 12 V input at very min, actual use would be like 2000 watts/12.6=158 amps of 12 v

this would require very short cables from battery to invertor and they will be welding cable size (plenty of charts on line)

My setup uses a 175 amp fuse on 12 v side, big cables and dual deep cycle batteries to power fridge,microwave, crockpots etc while driving down the road

a basic 45 amp 12 v charger wouldn't be able to keep up with the load, which means if you are set on 12 v only, limit electrical amenities

just some stuff to think about
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Old 01-09-2016, 07:57 PM   #4
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Join Date: Oct 2011
Location: Snowflake, Arizona
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You will find that the largest RV plug you will find is a 50 amp plug so
a 100 amp breaker box is overkill for your needs. My bus has a 50 amp
RV breaker panel with a 40 amp breaker to the inverter for the battery
charger side of the inverter. I bought an inverter with a built in charger.
I then have a 40 amp sub panel to protect the output side of the inverter.
So I have outlets through out the bus which run off the inverter and others
that run off shore power out of the main panel. The inverter will also function
as a pass thru unit when attached to shore power automatically.
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