Adding extra batteries

oyly wrote:

Gjac wrote:
I would create two separate battery banks especially if you are worried about running a furnace all night while dry camping. Charge each separately with your 45 amp converter. This way you can add batteries with more amp hrs and not worry about balancing the batteries. I don't know about prices in Japan but I have not been able to find true deep cycle 12v batteries for the price of two 6 v GC batteries with equivalent amp hrs.

How would I get through the night with the furnace on if I do this? Seems I would have to get up after 4 hours to switch to the other battery bank!? :(

I have been trying to respond to your post for the last 2 days but have been unsuccessful. My two batteries 230 ah GC type easily last through a cold night. In the summer they last 7 days and are at 50 percent SOC. What temps are you camping in? What are your other amp draws? Another option is a portable propane heater with no DC power reqs.