How to run fridge/freezer off extra battery

[mauisanna]

Aloha! I don’t have an RV but I do have a 1972 VW bus converted to be a coffee bus and have a question. My first thought was an RV forum because it is similar to how RVs operate!
I would like to be able to run my fridge and freezer off of an extra battery while in transit and parked (but not necessarily operating).
Right now I run the fridge and freezer off of a 2000w generator while operating (I park in one spot only, and the bus plugs directly into generator and everything is powered by an inverter ). I also power an electric kettle and coffee grinder with the generator. When I’m not operating (in transit) the fridge and freezer remain unpowered. When the bus is parked at my house it is plugged in (power from the house plugs directly into the exterior of the bus (1972 VW) and everything is powered through the inverter).
What I would like to be able to do is charge an extra battery while it is plugged in to the house so that it is possible to have the fridge and freezer running (off the extra battery) while I am parked/in transit for a little while. My husband could do it if I can get step by step instructions on what to do! Thank you so much for your help!

[Sam_Spade]

MEXICOWANDERER wrote:
Need a total and complete list of refrigerator and freezer brand names and model numbers.

If you do NOT start the discussion with this information it likely will just be a waste of time.....and maybe money too.

Why ? Because the way you THINK things work may not be how it works at all.

[2112]

If I understand your question correctly, you have three modes, parked, transit and operation.
Parked is at your house and you have house power available.
Transit is when you do not have power available.
Operation is when you are powered with the generator.

You require powering only the fridge and freezer with the battery during transit. You are not operating the kettle or blender with battery power. You can recharge the battery during Parked and Operation.

How many hours a day are you in Transit mode?
How many hours a day are you in Operation mode?

[MEXICOWANDERER]

Need a total and complete list of refrigerator and freezer brand names and model numbers. Total hours of operation daily. Number of hours driven. It is a complex formula that can only be done by the numbers