Voltage drop

I just bought a 1971 Cheoy Lee Clipper 36 in February. I have since instaled a DC refrigeration unit. Th refrigerator senses low voltage and reduces demand on the batteries. It also is not very effective when it does this. I have noticed a voltage drop of almost 1 volt from the battery to the back of the battery switch. This causes the refrigerator to slow down and sometimes stop.

The original owner ( I bought it from the original owner) has added a lot of radio gear and other miscelainious wiring I am still trying to track down. I have been told that the battery cables could be old and maybe cracked.

Is this a good place to start fixing the problem?

 

"I have noticed a voltage drop of almost 1 volt from the battery to the back of the battery switch"

That is a very serious voltage frop mate, the batteru cables are obviously either too small or have a mechanical failure in them.

I would expect on a 36 footer that the battery cables to the house battery would have to be capable of carrying up to 100 amps in operation. This would need a cable of #4 in your language, it will do about 150 amps over a 5 foot length (remember when measuring cables that the TOTAL length is the primary concern, that means from the battery to the unit and back again).

Use a #2 wire if it is 10 feet.

If you can tell me the wire length and the amperage of the whole house syatem, I can advise further.