Shorted out battery

[NIMROD]

I use 3 group 29 deep cycle batteries in my boat. 2 run 24 volt trolling motor and other runs everything ( lights , electronics , pumps , ect ) and starts big motor . The reason I run all deep cycles is because running everything off starting battery could pull it down too low on a full day trip .
My question is did the starting battery short out ? It failed to start motor and arched when I tried to jump off one of my other batteries . I had to disconnect that battery and hook up leads to one of my other batteries . Went and bought a new replacement as soon as I got back home .

[Barnacle Bill]

Don't mean to insult your intelligence but are you sure you jumped the batteries correctly? Its easy to get turned around while at sea. Keep an eye on your motor's charging circuit. Arcing a battery like that is a very easy way to blow a diode(s) in the rectifier.

[nuttin but net]

I was wondering if you may have somehow developed a loose connection. Was the battery you changed dead or low. I run 4 batteries and 1 of them is only for cranking.

[Cray]

Not nesecarlly, if cranking battery was almost dead and your trolling battery was hot it is going to arc some. One thing to always remember when jumping is hook up positive first then the ground side. Really reduces the chance of arc or at least reduces the amount of arc. Also if jumping you might have acidently hit it with 24 verses 12 since you were usin trolling battery.

[NIMROD]

Battery was getting weak and yes hooked up correctly ( cables color coded ). It was an old battery and charger had shown it was bad when last charged . But it seemed to have shorted out and went completely dead , would not even run a depth finder . Thanks .