Need Help understanding Charging System on my RV.

The alternator should be large enough to fully charge both battery banks in a few hours of driving, so more than "some" depending upon battery discharge and driving time.

The 50A RV service is 120/240V 50A 4 wire. This is the same service as a house except houses are generally 100 to 200A. A house supplies both 240V and 120V appliances. And appliances can use both voltages like a oven with 120V control and lights. Very few RVs have 240V appliances because they will not work with a 20 or 30A plug or a 120V gen.

My charger/inverter has a 120V 30A input for the charger and a transfer switch that routes the 120V to 2 output circuits that power part of the coach. When the inverter is off the output power comes from shore power or the gen. When the inverter is on then it's input power comes from the 12V batteries and the transfer switch routes it's 120V output to the same 2 AC output circuits. Your charger and inverter may be different but the operation will be similar.

Very rare for a battery and inverter setup to supply power for high draw appliances like A/Cs, HW etc. A 15A A/C for example would require about a 165A draw from the batteries and that is massive. Hence the common gen for that purpose.

Another transfer switch chooses between the gen or shore power for the RV. Generally it defaults to shore power until the gen is running and then switches to the gen power.

I never run the gen when plugged into shore power and not because the transfer doesn't work but because should if fail for some reason with a short it will definitely let the smoke out as you suggest.

Transfer switches: Automatic Transfer Switch or ATS.

on our class A gasser, the inverter/converter charger is supplied with power either by the hookup post, genny or the engine alternator.

- the engine alternator charges the house batteries which, in turn, provided 12 VDC to the 12volt appliances, furnace, water pump, and lights as well as to the inverter which powered SOME 120VAC appliances (fridge, tv sets, microwave) and SOME 120VAC outlets. Coach Air Conditioning was NOT powered by the inverter.

- the hookup post and genny provide power to everything...all outlets, appliances, air cond, 12vdc items, etc.

Thank you both very much for the input. My microwave/convection oven appears to be plugged in to an outlet running on an inverter. The clock is on all the time even when I am not docked on shore power. I need to confirm as I do not like this oven running from an inverter.

My MW is the only unit on one of the 2 inverter outlets. However the inverter is turned off so it's only using power when on shore or gen. If we do use it on the batteries the inverter is turned off after use.

The inverter has a transfer switch as well. When you are not connected to shire power or running the generator, the MW is powered by the inverter. When you have 120V service available, the incoming power by-passes the inverter and powers all things in the coach directly from the incoming power source.

PaulRVer wrote:
Thank you both very much for the input. My microwave/convection oven appears to be plugged in to an outlet running on an inverter. The clock is on all the time even when I am not docked on shore power. I need to confirm as I do not like this oven running from an inverter.

Hi,

I got little to no charging from the alternator to the house batteries.

Last year I moved to a dc to DC charger powered from the alternator. I now get up to 20 amps of charging. For me, it was a huge improvement.

There may be a transfer switch in your inverter. What is the make and model?