Trailer charging fuse in TV

We had 2 6 volt batteries installed last spring and hadn't been able to get out to camp until this fall. We were told that the 6 volts would last about twice as long as the two 12 volt, which is important since we dry camp. We had disconnected the batteries over the summer as instructed by the people who put in the batteries and plugged in the trailer for several days before our trip.  The battery level dropped quickly on both of our short (3 and 4 night) trips. On the second one the meter showed empty when we got home, though the fridge was still running.  Apparently the trailer charging fuse in our Honda Pilot is a 20 amp fuse and it had blown, though no short circuit, so the car was not charging the trailer.  Honda says we can't put in a larger fuse. Has anyone else had this issue and if so, how have you dealt with it?

Thanks! We do use propane  for the refrig. while camping, but the battery while driving.  We understand that it is illegal to drive with the gas tank on.  We'll take a look at the wiring, though we are not DIYers.  It doesn't seem right that the fuse blew, when the Pilot is set up as a towing vehicle. 

Ditto!

Thank you for your input on the gas vs. electric.  Do you think that will take care of the problem of the fuse blowing, with the refrig. on gas instead of the battery?

A) the pod tried to pull more amps then 20. Fuse blew. It's what they do.

B) you say you plugged the pod in for a couple days to charge the batteries before going out.. Is the pod stored where it can be left plugged in? THAT is the best way to maintain your batteries. Leave the pod plugged in all the time.

C)Run the fridge on gas. Even in California it isn't illegal. This is one of the myths of RVing that just will not die. YES there are a couple restricted areas, mostly automotive ferries and tunnels in the east, but many of those even are restriction by AMOUNT of propane, and TT's toting a 20 pounder or two are NOT in violation.

D)adding a jumper or bypass wire, 10gauge or better, and fusing it appropriately, may or may not be a problem. MANY modern vehicles will see that as an unexpected draw on the alternator and set a CEL, SVC VCL, or other error response.

E)Letting your batteries sit, for months, disconnected or not, is not good for them. Anything longer then 90 days they should be charged, not trickled, charged.

F) Also, (if you didn't) you need to precool the fridge for a day or two, and precool anything you are going to put in it. It's a small space, with very little thermal mass. It needs as light a work load as possible.