Inverter in RV Electrical System

[bajajoaquin]

I've put a 400w solar system on my Class C RV broadly following the Will's blueprint for that setup. I have a small inverter that powers "external" devices. I'm also helping a friend put solar on his Lance slide-in truck camper. In both cases, we want to be able to use the microwave off of batteries. I'm looking at 700w inverter microwaves in both cases. In both cases, the microwave plugs into an outlet in the cabinet and we would like to keep that.

Broadly speaking, what am I looking at doing to make this happen? Is there any advice for getting started here?

 

[sunshine_eggo]

1500W bare minimum inverter (700W microwave will consume 1200W), 2000W preferred.

Battery capacity depends on energy usage.

If the camper has a way to plug into shore power, you should be able to adapt a means of plugging into the inverter. If there's a converter in the circuit for 12V power/charging, you'll need to disconnect that.

My preferred method is to essentially leave the rig untouched and provide "on board shore power (OBSP)." So in addition to the 12V already present, you would have an additional 12 or 24V battery and inverter. If the "OBSP" battery goes dead, you still have the rig's 12V system as backup.

When plugged in to the OBSP, the on board converter is providing the 12V and charging the existing 12V. Yes, this is a little inefficient, but the actual wattage loss is very small and is greatly outweighed by the convenience, flexibility and backup aspect.

 

[bajajoaquin]

1500W bare minimum inverter (700W microwave will consume 1200W), 2000W preferred.

Battery capacity depends on energy usage.

If the camper has a way to plug into shore power, you should be able to adapt a means of plugging into the inverter. If there's a converter in the circuit for 12V power/charging, you'll need to disconnect that.

My preferred method is to essentially leave the rig untouched and provide "on board shore power (OBSP)." So in addition to the 12V already present, you would have an additional 12 or 24V battery and inverter. If the "OBSP" battery goes dead, you still have the rig's 12V system as backup.

When plugged in to the OBSP, the on board converter is providing the 12V and charging the existing 12V. Yes, this is a little inefficient, but the actual wattage loss is very small and is greatly outweighed by the convenience, flexibility and backup aspect.

Sorry, but could you explain that further?

 

[Zapper77]

I've put a 400w solar system on my Class C RV broadly following the Will's blueprint for that setup. I have a small inverter that powers "external" devices. I'm also helping a friend put solar on his Lance slide-in truck camper. In both cases, we want to be able to use the microwave off of batteries. I'm looking at 700w inverter microwaves in both cases. In both cases, the microwave plugs into an outlet in the cabinet and we would like to keep that.

Broadly speaking, what am I looking at doing to make this happen? Is there any advice for getting started here?

I'm not familiar with "inverter" microwaves but generally speaking microwaves have an efficiency of 60%'ish. So a 700W microwave will consume 1100 watts. My 1000 watt inverter will not run a 700 watt microwave.

 

[Pierre]

Install a 2000W inverter / solar / battery system as an alternative supply with an ATS ( auto transfer switch ) to select between inverter / grid. Few other mods are also required for optimal operation.

 

[Zapper77]

Appears inverter microwaves are around 90% efficient. https://ecocostsavings.com/microwave-wattage/

 

[Alice2021]

Sorry, but could you explain that further?

I guess he said 700W microwave actual starting power is not 700W ,but 2 times higher,so 1500W inverter is good for you, and 2000W inverter is better for you

 

[sunshine_eggo]

Appears inverter microwaves are around 90% efficient. https://ecocostsavings.com/microwave-wattage/

Tests with a kill-a-watt of the most common panasonic show the same inefficiency; however, they benefit from the ability to actually run at reduced power settings vs. toggling 100% and 0%.

I guess he said 700W microwave actual starting power is not 700W ,but 2 times higher,so 1500W inverter is good for you, and 2000W inverter is better for you

No. Not starting power. Run power. A 700W microwave will continuously consume 1200W while it's running.

The surge as the magnetron is energized is absurdly high, but it happens so quickly, most inverters don't even register it as happening, so it's not considered.