We came back to the boat from my hip replacement and the first thing that also needed replacing was our group 27 "Lifeline" Beta diesel engine starting battery. It was just over 5 years old, just out of warranty and did not turn over the engine. The top had bulges in it by the studs so it was shot.
We do not need such a large or expensive battery but do need an AGM battery. We have a PSS shaft seal that the battery sits on top of and so the battery needs to be sealed. We were a little overwhelmed at getting the boat ready to live on so hired "Rick" at "Marine Services Mazatlán" to do the job.
We had them purchase a battery and a new marine battery cable for the switch we installed [but never finished]. The switch needed a short cable to the battery.
They put the new battery in the old box and strapped it down. That made it so the cover did not fit on the battery box. The box is for a bigger battery. Also there was pressure on the posts as the cables were pressed against the top edges of the battery box.
The cable they brought they hooked to the switch so the switch would work. However they twisted the cable upside down to fit it on the positive battery terminal. That put stress on the terminal and added two cables to the positive terminal and it only should have one. If it was done correctly the second twisted cable would be the only cable to the battery and would not need to be twisted. There are four places on the switch for cables and they used only two, they should have used three.
Some people swear by "Marine Services. Mzatlán" but others not so much. We found on this job, the only one they did for us, that we would not have them do another.
and bottom so the cables would fit without any stress on them.
so we would not have a live cable hanging about.