RivRunR
Well-known member
I've searched the forum, but haven't quite found the answer to my questions, or if I did I didn't know it...I'm not great at the electrical stuff...
I currently run 2 separate, identical Interstate series 29 marine deep-cycle batteries:
1 for a 12V MK Edge 40 bow-mounted TM
1 for the cranking battery on a 1980 Johnson 70 (has "alternator"), plus lights, bilge, livewell, and depth finder.
Typically I run the OB very little, usually no more than 10 minutes just to get to the spots I fish, then it's several hours on just the trolling motor, then another 10-15 minutes back to the ramp. So, the trolling motor battery gets a lot more use, sometimes to the point that it dies, and it has to be charged after every trip, but the cranking battery rarely needs charging. I have a good battery charger (but with no "deep-cycle" setting), problem is I have to park the boat outside, and can't always charge the batteries after every trip because I don't want to leave the charger out in bad weather.
So, what would be the best way to set up my batteries? What I'd like is a set up where I can maintain the most charge on the TM battery, but never lose the ability to crank the OB...pull start isn't really an option...I've tried it. If I run the 2 batteries in parallel I would lower the draw on the TM battery, but couldn't I also draw down the OB battery to the point where it won't crank? From what I've read here I think that I could cure that problem with a switch, and point it to "both" when the OB is running (and when it's on the charger), but again, I run the OB so little that I don't know if I would get much out of that set up, plus I'd probably forget to flip the switch every time I crank the OB anyway. And would there be a problem when charging them rigged in parallel if the OB battery has so much more charge than the TM battery?
I guess another option would be an on-board charger, but I'm completely ignorant about how those work, so I have to rely on you guys whether it would help in my situation. I also run another depth finder on the bow from a small, mower-sized battery, but I expect that with the size difference that it is kind of out of the on-board charger equation?
Anyway, sorry to be so wordy, but I wanted to give the full picture, and I would really appreciate your suggestions on the best set up.
Thanks!
I currently run 2 separate, identical Interstate series 29 marine deep-cycle batteries:
1 for a 12V MK Edge 40 bow-mounted TM
1 for the cranking battery on a 1980 Johnson 70 (has "alternator"), plus lights, bilge, livewell, and depth finder.
Typically I run the OB very little, usually no more than 10 minutes just to get to the spots I fish, then it's several hours on just the trolling motor, then another 10-15 minutes back to the ramp. So, the trolling motor battery gets a lot more use, sometimes to the point that it dies, and it has to be charged after every trip, but the cranking battery rarely needs charging. I have a good battery charger (but with no "deep-cycle" setting), problem is I have to park the boat outside, and can't always charge the batteries after every trip because I don't want to leave the charger out in bad weather.
So, what would be the best way to set up my batteries? What I'd like is a set up where I can maintain the most charge on the TM battery, but never lose the ability to crank the OB...pull start isn't really an option...I've tried it. If I run the 2 batteries in parallel I would lower the draw on the TM battery, but couldn't I also draw down the OB battery to the point where it won't crank? From what I've read here I think that I could cure that problem with a switch, and point it to "both" when the OB is running (and when it's on the charger), but again, I run the OB so little that I don't know if I would get much out of that set up, plus I'd probably forget to flip the switch every time I crank the OB anyway. And would there be a problem when charging them rigged in parallel if the OB battery has so much more charge than the TM battery?
I guess another option would be an on-board charger, but I'm completely ignorant about how those work, so I have to rely on you guys whether it would help in my situation. I also run another depth finder on the bow from a small, mower-sized battery, but I expect that with the size difference that it is kind of out of the on-board charger equation?
Anyway, sorry to be so wordy, but I wanted to give the full picture, and I would really appreciate your suggestions on the best set up.
Thanks!