Wiring batteries in 24 volt and 12 volt configurations

I had an idea and was wondering if it would be possible, currently I have a 24-volt system for my trolling motor. Can I wire the two batteries in parallel to get 12 volts while running 24 volts for the trolling motor so I get a longer run time for 12 volt accessories on my boat? I was planning on separating my Humminbird Electronics away from my other accessories using a separate fuse block. My plan is to run my electronics off of my cranking battery with its own fuse block and run my boat accessories off of my trolling motor batteries with a separate fuse block as long as I can get 12 volts between the two batteries.

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You you could but one should not hook or it’s not recommended to hook electronics to TM batteries dur to interference you would most likely encounter. I would hook them to your cranking battery or a separate lithium type battery which is what I do not that mine is the right way. Here is some reading.

Can I Connect Fish Finder To Trolling Motor Battery

My plan was to have a separate fuse block for my electronics that would be ran off of my cranking battery. The fuse block that I would run boat accessories off of would be connected to the trolling batteries. That would be things like my bilge pump, bow and Stern lights, and aerator timer. Just don't know about the radio being ran off the trolling motor due to the possible speaker noise when the motor was active.

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I use LED bow and stern lights to minimize pwoer draw, but I run the aerators, bilge pump and all the accessories off the cranking battery. If I feel it is getting a little low I crank the motor and let it charge it for a while. Are you running the cranking battery down with your accessories?

I did run the battery down in the past but it was due to a faulty regulator not charging the battery when I was running but since I have replaced the regulator everything has been fine. Even if I do not use the trolling batteries for my fuse block I am still going to use a separate fuse block just for the Humminbird Electronics. I'll be running 8 gauge wire from the battery through a 20 amp inline circuit breaker. I will be running All Electronics to that fuse block using 10 gauge wire. I'm only running 8 guage because that is the wire I pulled off of the old trolling motor before I upgraded to 6 gauge with the terrova.

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While it is possible to pull a 12v output out of a 24v battery Setup = it is very important which battery (of the 2 available batteries) is used as the 12v positive/negative circuit ... (only 1 of the 2 available 12v positive and negative posts of the 2 batteries is actually a 12v circuit) ...
Attachment 420744

Using the second battery (in the 24v system) as a 12v circuit does not certainly have a 12v negative leg of a 12v circuit (that specific negative battery post is used as a continuation of the 24v circuit - NOT A NEGATIVE) ...

Using the 2nd battery (in the 24v system) as a 12v circuit (where the 2nd battery negative is not really a 12v negative) creates a phenomenon wherein the 12v circuit (additionally connected) will look for a 12v ground path ...

This can end up as electrolysis corrosion on the big motor lower unit as the 12v circuit finds its return path thru the water to the lower unit ...

That is garbledebook ... the way it is explained to me is .... adding a 12v circuit to a 24v series battery Setup should always be connected to the 1st battery starting at the negative post of the entire 24v circuit ... because that negative battery post is the only TRUE negative path available ...

Rickie

:hesaid

I never thought of I that way. You took me to school on that one. One question though, why doesn't electrolysis occur when a charger is connected to positive and negative of both batteries?

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My head is spinning now! LOL

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Originally Posted by rnvinc

While it is possible to pull a 12v output out of a 24v battery Setup = it is very important which battery (of the 2 available batteries) is used as the 12v positive/negative circuit ... (only 1 of the 2 available 12v positive and negative posts of the 2 batteries is actually a 12v circuit) ...
Attachment 420744

Using the second battery (in the 24v system) as a 12v circuit does not certainly have a 12v negative leg of a 12v circuit (that specific negative battery post is used as a continuation of the 24v circuit - NOT A NEGATIVE) ...

Using the 2nd battery (in the 24v system) as a 12v circuit (where the 2nd battery negative is not really a 12v negative) creates a phenomenon wherein the 12v circuit (additionally connected) will look for a 12v ground path ...

This can end up as electrolysis corrosion on the big motor lower unit as the 12v circuit finds its return path thru the water to the lower unit ...

That is garbledebook ... the way it is explained to me is .... adding a 12v circuit to a 24v series battery Setup should always be connected to the 1st battery starting at the negative post of the entire 24v circuit ... because that negative battery post is the only TRUE negative path available ...

Rickie

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Do you know if you would still get graph interference with this setup?

I would think if your running Mega Live and/or Mega 360…or any Livescope or Live view, as sensitive as these are,,,you want to stay away from wiring to your trolling motor batteries. All you can do is try it and see if you pick up interference. Everybody I read about on bbc forum uses a dedicated electronics battery or a battery that has everything but the trolling motor attached including their big motor. There is a noise rejection setting on mega live and some have it set as high as possible to get rid of interference even on their dedicated electronics battery.

Quote:

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Originally Posted by huntersdad

I never thought of I that way. You took me to school on that one. One question though, why doesn't electrolysis occur when a charger is connected to positive and negative of both batteries?

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I do not know the answer to this one ...

Catfan may be able to answer this if he sees this thread ... and he can probably shed even more light on the point I noted ...

Rickie

Quote:

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Originally Posted by BuckeyeCrappie

Do you know if you would still get graph interference with this setup?

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Quote:

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Originally Posted by cevans

I would think if your running Mega Live and/or Mega 360…or any Livescope or Live view, as sensitive as these are,,,you want to stay away from wiring to your trolling motor batteries. All you can do is try it and see if you pick up interference. Everybody I read about on bbc forum uses a dedicated electronics battery or a battery that has everything but the trolling motor attached including their big motor. There is a noise rejection setting on mega live and some have it set as high as possible to get rid of interference even on their dedicated electronics battery.

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cevans explained your question better than I could have ...

Rickie

Quote:

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Originally Posted by rnvinc

I do not know the answer to this one ...

Catfan may be able to answer this if he sees this thread ... and he can probably shed even more light on the point I noted ...

Rickie

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Diodes placed properly in the chargers prevent any concerns!