12/24V selectable trolling motor

O

offonleave

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Joined
Feb 23, 2008
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I am trying to figure out the wiring for my bass boat and have some questions, keeping in mind that I am electric idiot.

I have three batteries, one main and two auxiliary. I think that I need to run the two auxiliary batteries in series to draw my 24V, hooking this to the Perko Switch in position 2 with my 12V main taking position 1.

Will this system cause any problems with charging in the All position? Any problems with other accesories that do not draw 24V? Can I start my boat with the 24V auxiliary battery?

Thanks
 
Silvertip

Silvertip

Supreme Mariner
Joined
Sep 22, 2003
Messages
28,765
Re: 12/24V selectable trolling motor

I first want to make sure you understand the difference between series and parallel wiring. The difference is shown below.

SeriesandParallel.jpg


Now its up to you to tell us whether you really have a 24V trolling motor or whether you have a 12V trolling motor that is running off of two PARALLEL wired batteries. Those two batteries still provide only 12V whereas the SERIES connection provides 24V.

So if you really have a 24V system, and unless you enjoy sparks, you cannot connect two series wired batteries (24V)into a battery switch shared by a single 12V battery. The output of the engine alternator is 12V. The engine starter runs on 12V not 24V so it won't like that either. What do you suppose would happen to all the 12V accessories and instruments the split second they had 24V applied rather than 12V? Does POP and smoke come to mind. Again, IF you have a 24V system, unless you break the series connection between the two troller batteries and then connect them in parallel you cannot charge them from the engine. Setting the switch to BOTH or 2 would surprise you and any 12V accessories on the boat. As I explained before, your best option is to dedicate two of the batteries to the trolling motor with those two connected in series. That configuration looks like shown below and totally separate from the engine battery and accessories. In that configuration you don't even need the switch. Leave the start battery dedicated to the engine and accessories. Install a two-bank on-board charger to charge the troller batteries with shore power. Unless you have an engine with a very high output alternator you would have to run wide open for hours to charge the batteries.

24VTrollerWiring.jpg
 
S

Seljablu

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Joined
Nov 8, 2009
Messages
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Re: 12/24V selectable trolling motor

This is some good information, this information will be very helpful when I decide to mount my trolling motor on to my boat. I recently received a motorguide 12/24 trolling motor, it is a Silence 725 and the model # is 725. I searched the web for some literature on it and I have not found anything at all. Can anyone help me with this. It will be greatly appreciated.

Thanks

Trolling with no Info

Seljablu
 
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