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Help understanding my RV electrical components

SkippyJonJones

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Aug 17, 2021
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I'm working on updating my RV power system and adding solar. I have a basic understanding of my system but wanted to ask for some help on next level details. I can piece together my components, but I'm lacking the understanding of how some items work together.

I currently have a 12v 2 X 6v AGG 225Ah batteries (shown below with 2 12v 100Ah) system with a 3000w inverter. I'm considering new lithium batteries, solar and possibly going to 24v. Here's what I'm trying to pickup...

  1. Converter power - If a converter is sized at 50A, is that shore power that it can handle to charge the batteries along with anything else running in the camper at the time (lights, fan, fridge or other smaller pulls)? I know it is charging the battery that then feeds the DC fuse box, but will the converter have any other job with the fuse box?
  2. AC Panel - Is this separate from the DC fuse box or part of that? I know the difference between AC and DC, but I'm not sure how the camper outlets are wired for AC when the camper is plugged into shore. Why don't I need a switch between AC and DC? It must be automatic because I'm not doing anything other than plugging the camper into my garage.
In the diagram below I'm not sure how the wiring is connected to the converter, fuse panel and AC components. The previous owner connected the inverter directly to the battery with fuse.

1649456710591.png
 
Converter power - If a converter is sized at 50A, is that shore power that it can handle to charge the batteries along with anything else running in the camper at the time (lights, fan, fridge or other smaller pulls)?
An RV style converter makes 12 volt dc out of ac shore power
50 amps is the rated dc output of the converter.

I know it is charging the battery that then feeds the DC fuse box, but will the converter have any other job with the fuse box?
The converter charges the battery and services the dc loads.
  1. AC Panel - Is this separate from the DC fuse box or part of that?
Most RV have a combined ac/dc panel.
AC breakers on one side and dc fuses on the other.
  1. I know the difference between AC and DC, but I'm not sure how the camper outlets are wired for AC when the camper is plugged into shore.
|<-master_breaker<-inlet<-pedestal
|->branch_breaker->branch_circuit
|...
  1. Why don't I need a switch between AC and DC?
The converter is usually on a dedicated breaker.
Opening the breaker will disable the converter.
If you have a battery then your dc fuse block will still be energised by the battery.
In the diagram below I'm not sure how the wiring is connected to the converter, fuse panel and AC components. The previous owner connected the inverter directly to the battery with fuse.
Watch out for a power loop between the inverter and the converter.
Is it a standalone inverter or is it an inverter/charger?
I know how to do this properly but I can only guess at what the previous owner did.
 
Last edited:
The attached text file describes what the dc domain topology should be.
It also shows two different possibilities for the ac domain, 1: discrete inverter and auotmatic transfer switch, 2: inverter/charger

Updated: fixed thinko in topo
 

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An RV style converter makes 12 volt dc out of ac shore power
50 amps is the rated dc output of the converter.
So why not get a bigger converter (in amp rating)? Such as a PowerMax 75A or 100A vs 45A? Is it just a cost situation?

The converter charges the battery and services the dc loads.
Is the converter wired just to the DC fuse panel or to the positive and negative blocks? My camper is in storage right now, so I can't really dive in yet.

The converter is usually on a dedicated breaker.
Opening the breaker will disable the converter.
If you have a battery then your dc fuse block will still be energised by the battery.
So the AC power when plugged into shore will close the breaker? Or the power from the battery opens it?

Watch out for a power loop between the inverter and the converter.
Is it a standalone inverter or is it an inverter/charger?
I know how to do this properly but I can only guess at what the previous owner did.
It's a standalone converter. I'm concerned about the inverter being directly wired to the batteries. Should it instead go to the positive/negative bus bars? How is the loop prevented?

Thanks for your help. Your other threads have been very informative.
 
So why not get a bigger converter (in amp rating)? Such as a PowerMax 75A or 100A vs 45A? Is it just a cost situation?
Because someone decided your rv's dc loads and battery could be serviced adequately with a 50 amp converter.
Your question seems odd, perhaps I don't understand your real question.
Is the converter wired just to the DC fuse panel or to the positive and negative blocks?
Factory install is typically the former.
So the AC power when plugged into shore will close the breaker?
No the breaker is manual.

Or the power from the battery opens it?
Not usually.
The converter charges the battery and services the loads simultaneusly because the battery, converter and dc load center are all in parallel.
It's a standalone converter.
I meant to ask about the inverter but mis-typed.
I'm concerned about the inverter being directly wired to the batteries.
I don't like it either.
Should it instead go to the positive/negative bus bars?
Have a look at the topology I attached previously.
How is the loop prevented?
Have a look at the topology that I attached previously.
Pay particular attention to the ac_domain topos.

The dc domain may look confusing but there is a legend to explain all the elements.
If you have questions I'm glad to answer.
 
updated topo
 

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