Thread: Batteries

In line is an uncommon terminology. Do you have 12v or 24v motor? There is a connection diagram in the help file on TM.

To do this, you will probably have to add another battery. You could be stranded if you try using your cranking battery in parallel with your TM battery. To do what you want is called running batteries in parallel, so they give more life and NOT more volts. Batteries in series add the voltages together and if you do this, you have a 24V system. The batteries in a flashlight are in "series".....a positive end touching a negative end touching another positive end and so on. A "parallel" set up remains at 12V for you. Connect the two positives together and connect the two negatives together.

I think this is what you mean by "inline" (actually called "in parallel"):



And "vic n" is correct .... you can very easily draw down your cranking battery, in this setup, to where it may not start your outboard.

What you really need is two NEW deep cycle trolling batteries, hooked in parallel, for longer trolling time with a 12V trolling motor. Hooking up a 2yo battery with a new battery is just going to decrease the lifespan of the new battery.

If your outboard isn't big enough to recharge the starting battery while running around on the lake, you may have to get a 3bank charger ... or another automatic charger to hook the starter battery to, as you'd probably want the two trolling batteries hooked up to the current 2bank charger. Though, you could hook up one bank to the two trolling batteries (pos post on one battery & neg post of the other) ... but, that would likely take twice as long to bring them up to full charge.

I'm in your situation ... I have a 12V 42lb thrust TM that runs off the trolling battery (group 29) and the 90HP outboard runs off the starter battery (group 27), and I have a 2bank 10amp/bank onboard charger. My batteries are 3yrs old, and I can usually only get about 4-5hrs of on/off moderate speed trolling out of the battery before it starts to weaken significantly. I know when it's weakening, because my bow mounted DF starts fading out or turns off due to the weak current flow (it's connected to the power line of the TM). Luckily, for me, I don't do a whole lot of constant trolling, as a rule.

But, don't take my word for it ... there are others on here that are more knowledgeable about this stuff, than I am. I defer to their expertise, and any corrections they care to make on my statements.

... cp

Thanks for replies. Yes I was talking about parallel. Pappy also answered another question, I was wondering if my two bank charger would charge all three batteries. I can pull start my little 25 hp but I would rather turn the key. This has answered all my questions guys, now out to the garage to tinker around!

Originally Posted by mccowan

Thanks for replies. Yes I was talking about parallel. Pappy also answered another question, I was wondering if my two bank charger would charge all three batteries. I can pull start my little 25 hp but I would rather turn the key. This has answered all my questions guys, now out to the garage to tinker around!

I just noticed your location .... do you actually "spider rig" on Herrington Lake ?? Or do you venture off to other lakes ??

... cp

Originally Posted by CrappiePappy

I think this is what you mean by "inline" (actually called "in parallel"):



And "vic n" is correct .... you can very easily draw down your cranking battery, in this setup, to where it may not start your outboard.

What you really need is two NEW deep cycle trolling batteries, hooked in parallel, for longer trolling time with a 12V trolling motor. Hooking up a 2yo battery with a new battery is just going to decrease the lifespan of the new battery.

If your outboard isn't big enough to recharge the starting battery while running around on the lake, you may have to get a 3bank charger ... or another automatic charger to hook the starter battery to, as you'd probably want the two trolling batteries hooked up to the current 2bank charger. Though, you could hook up one bank to the two trolling batteries (pos post on one battery & neg post of the other) ... but, that would likely take twice as long to bring them up to full charge.

I'm in your situation ... I have a 12V 42lb thrust TM that runs off the trolling battery (group 29) and the 90HP outboard runs off the starter battery (group 27), and I have a 2bank 10amp/bank onboard charger. My batteries are 3yrs old, and I can usually only get about 4-5hrs of on/off moderate speed trolling out of the battery before it starts to weaken significantly. I know when it's weakening, because my bow mounted DF starts fading out or turns off due to the weak current flow (it's connected to the power line of the TM). Luckily, for me, I don't do a whole lot of constant trolling, as a rule.

But, don't take my word for it ... there are others on here that are more knowledgeable about this stuff, than I am. I defer to their expertise, and any corrections they care to make on my statements.

... cp

Sonar screen is a pretty expensive battery monitor?