HD6E starter motor

It has been a year since I posted about my starter motor troubles. I rebuilt my   starter and starter solenoid. I replaced the wire connecting the batteries with #2 welding cable. I used #2 wire on my HD6G that has both batteries in the same battery box. I got back to the HD6E and hooked up the wires to start it. The left hand battery box smoked and the connecting wire came off the terminal end. I replaced the wire checking that all connecting cables were tight. I pressed the starter button again and the right battery box smoked melting the terminal connector. I replaced the #2 cable with the #0 cable with the keyed battery disconnect under the seat. I turned the key and the starter solenoid clicked without me pressing the starter button. I turned the disconnect off but it didn't go off. The battery cables got warm. I loosened the terminal ends. I could rotate them but I could not remove any of them. I had to spread them with a screw driver because the heat reduced the battery terminal diameter. I recharged the batteries and found the year old batteries could only hold 25% charge. My $25 replacement battery disconnect came today. Rating 200 Amp continuous 1000 Amp intermittent. Hope it goes well when I try to start it tomorrow.

Not sure of the age of a HD 6E, but probably old enough it left from the factory with 2, 6 volt batteries. So a 12 volt system by using batterers in series.  So if using 2, 12 volt batteries today you want them in parallel.