12v/36v switchable wiring diagram?

[KJR]

Hi All, new to the forum here and I am sure this topic has been presented before but I could not find an answer for my specific situation:

I currently have a 2 battery system with a perko switch(1, 2 or ALL), running a V8 I/O and I am adding a 36V MK Riptide 101 to the transom of the boat.

I have seen a few wiring diagrams on how to get 12v from the first battery(for the main V8 engine), and then 36v to the TM, but they have all been a little different, mainly with the ground wires.

My questions are:

Can anyone direct me to, or create for me a diagram that would yield me the proper routing to be able to use the perko switch on bank #1 for the main engine, and then be able to switch the perko to #2 or ALL when I want to run the TM?

Is there a better way to do this rather than using the Perko switch?

Should I just make it a 4 battery system?

Thanks in advance for your input!

[RickJ6956]

I would treat the trolling motor power as a completely independent system of three batteries and a 3-bank 12v charger.

You should also consider adding a fifth battery as a house battery to prevent your main starting battery from being drained while you're fishing (using electronics & stereo). Put the Perko switch on that set of batteries.

[Silvertip]

First, you can't use a single dual battery switch in a 36 volt system and I can but I won't provide a diagram for what is a mistake. Using one of the batteries in a 36 volt trolling motor system for a start battery will leave you stranded at some point in time. Put three batteries in series for the trolling motor and install a new starting battery. And no! -- you cannot keep four batteries charged from the engine alternator. You could wire the battery switch to the first battery in the string of the 36 volt system but the only purpose it would serve is an emergency start and charging of just that one trolling motor battery. My suggestion would be dump the switch and carry a set of jumper cables.

[KJR]

First, you can't use a single dual battery switch in a 36 volt system and I can but I won't provide a diagram for what is a mistake. Using one of the batteries in a 36 volt trolling motor system for a start battery will leave you stranded at some point in time. Put three batteries in series for the trolling motor and install a new starting battery. And no! -- you cannot keep four batteries charged from the engine alternator. You could wire the battery switch to the first battery in the string of the 36 volt system but the only purpose it would serve is an emergency start and charging of just that one trolling motor battery. My suggestion would be dump the switch and carry a set of jumper cables.

I know I can't keep the batteries charged. I understand, thanks.

I must add that the lake I am going to use and store the boat doe snot allow gas engines so only the trolling motor will be used. I don't need to preserve the main 12V engine battery as I am not allowed to start the inboard on the lake.

I don't really have room for 5 batteries on my boat. That is also why I would like to make the 3 battery system work for both applications.

The engine and TM will never be used on the same outing.

[Silvertip]

Alright then -- but all three of the batteries should be deep cycles and preferably the same capacity although that only matters if you need to get maximum run time out of the system Run time will be limited by the lesser capacity of the three. Here is a diagram of a 36 volt system. Eliminate the dual battery switch as it is not needed in either of your scenarios. The second diagram shows how to take 12 volts off a 24 volt system but it is identical to a 36 volt system. WARNING: Take 12 volts for the starter off the left-most battery. Taking it off either of the other two runs a great risk of ground and over voltage situations that can fry electronics. Also note that the battery cables going to the engine must be the original large cables and there is no circuit breaker on those cables. The engine will charge ONLY the battery it is connected to.

And one other WARNING: DO NOT attempt to jump the left-most battery from either of the other two unless you want arc welder-like sparks.



And this

[KJR]

Thanks Silvertip !

I got a similar diagram from another forum, but that person had the TM+ to battery #1, and TM- to battery #3.

Glad I sought more information.

[Silvertip]

It doesn't matter which battery has what number. If I numbered them 1,2,3 from the right reather than the left it is still 36 volts. Or you can start wiring with the ground on Battery 2 and work to the left. It is still 36 volts coming out the other end.

[KJR]

OK, got it.

I will use your diagram and exclude the perko since it is no longer needed.

I have now been researching for a 3 bank charger. Could you perhaps give an educated recommendation?

I see some that have been given high recommendations on various forums, actually have very poor reviews...

Thanks again and as well for your 'newb patience' !

Best,

Keith

[Silvertip]

I happen to be a "Guest" fan although I have a Pro-Mariner on one of my boats.

[KJR]

I see a lot of good reviews on the Promariner prosport 20 Plus, but I am also looking into the BassMaxxII. Looks like a neat system.

Anyways, thanks again for the tips. I got everything in last weekend and all works great. I even had time to make a custom transom mount for the riptide.
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